A summary of 20 years of forest monitoring in Cinnamon Bay watershed, St. John, US Virgin Islands

Tags: Cinnamon Bay, St. John, Virgin Islands, stems, Virgin Islands National Park, volcanic rock, U.S. Virgin Islands, National Park Service, Hurricane Hugo, species composition, U.S. Department of Agriculture, Forest Service, Picturesque Cruz Bay Harbor, Cinnamon Bay Watershed, Cruz Bay, Peter L., Coral Bay, Virgin Islands Resource Management Cooperative, the Virgin Islands, Virgin Islands, Hawksnest Bay, Reef Bay, Fish Bay, Krum Bay, Caribbean Journal of Science
Content: United States Department of Agriculture Forest Service International Institute of Tropical Forestry General Technical Report IITF­34
A Summary of 20 Years of Forest Monitoring in Cinnamon Bay Watershed, St. John, U.S. Virgin Islands Peter L. Weaver
Author Peter L. Weaver, Research Forester, U.S. Department of Agriculture, Forest Service, International Institute of T ropical Forestry, Jardнn Botбnico Sur, 1201 Calle Ceiba, San Juan, PR 00926-1119. Cover photos Top right: The island's attractive scenery prompted President Eisenhower to authorize the establishment of the Virgin Islands National Park as a sanctuary of natural beauty in 1956. Left: A hiker looks up at large Ceiba trees (Ceiba pentandra) at an interpretative stop on one of the many hiking trails scattered throughout Virgin Islands National Park. Bottom right: Picturesque Cruz Bay Harbor with government house situated on a narrow peninsula. All photos in report by Peter L. Weaver. October 2006 International Institute of Tropical Forestry Jardнn Botбnico Sur 1201 Calle Ceiba San Juan, PR 00926-1119
A Summary of 20 Years of Forest Monitoring in Cinnamon Bay Watershed, St. John, U.S. Virgin Islands Peter L. Weaver Abstract St. John, and probably the Cinnamon Bay watershed, has a history of human use dating to 1700 B.C. The most notable impacts, however, occurred from 1730 to 1780 when sugar cane and cotton production peaked on the island. As agriculture was abandoned, the island regenerated in secondary forest, and in 1956, the Virgin Islands National Park was created. From 1983 to 2003, the staff of the International Institute of T ropical Forestry monitored 16 plots, stratified by elevation and topography, in the Cinnamon Bay watershed. The period included Hurricanes Hugo in 1989 and Marilyn in 1995 and a severe drought in 1994-95. In all years, plot tallies showed that from 55 to 60 percent of the stems were in height classes between 4 and 8 m, and 75 percent of the stems were in diameter at breast height (1.4 m above the ground; d.b.h.) classes between 4 and 10 cm. Stem density was greatest on the summit, followed by ridges, then slopes, and lowest in valleys. After 20 years, 65 percent of the original stems survived, with an average d.b.h. growth rate of 0.07 cm year-1. Tree species abundances varied by topography and elevation within the watershed. In 1983, total aboveground biomass on all plots combined averaged 138.7 t ha-1; by 2003, it had declined by nearly 7 percent. In 1983, biomass was greatest on the summit, intermediate on slopes and valleys, and least on ridges; by 2003, the quantities for all sites had converged except on the summit plot. In 1992, total aboveground productivity was estimated at 10.64 t ha-1 year-1. Standing herbivory for leaves was 4.5 percent, and the herbivory rate was 4.6 percent per year. The standing crop of litter was 9.33 t ha-1. Hurricanes had a major impact on forest structure and species composition. The trees impacted (snapped, uprooted, or standing dead) by Hurricane Hugo totaled 210 ha-1 after 10 months and 288 ha-1 after 19 months. The proportion of impacted stems differed by elevation, topography, aspect, and slope. Tree species with 20 individuals showed a difference in the proportion of impacted stems, ranging from as low as 0.6 percent for Pimenta racemosa (Mill.) J.W. Moore to as high as 22.8 percent for Nectandra coriaceae (Sw.) Griseb. In conclusion, the structure, species composition, and forest dynamics within the Cinnamon Bay watershed vary in time and space, and short-term observations characterize only a fragment of the watershed's continuously changing vegetational history. Monitoring of forest structure and dynamics should continue. Keywords: Biomass; dry forest; monitoring; St. John, U.S. Virgin Islands; tree species.
ii
Contents Page Abstract..................................................................................................................................... i List of Figures ....................................................................................................................... iv List of Tables ......................................................................................................................... v Introduction .......................................................................................................................... 1 Historical Perspective .......................................................................................................... 1 Setting: St. John and Cinnamon Bay ............................................................................... 5 Geology ................................................................................................................................. 5 Physiography and Soils ......................................................................................................... 5 Climate .................................................................................................................................. 5 Hydrology .............................................................................................................................. 6 Vegetation .............................................................................................................................. 7 Terrestrial Research Initiative ................................................................................................ 9 Methods at Cinnamon Bay .............................................................................................. 10 Results at Cinnamon Bay .................................................................................................. 11 Forest Structure .................................................................................................................. 11 Number of stems ............................................................................................................ 11 Height classes ................................................................................................................ 14 D.b.h. classes .................................................................................................................. 14 Crown classes ................................................................................................................ 14 Forest Dynamics ................................................................................................................. 14 D.b.h. increment ............................................................................................................. 14 Biomass increment ....................................................................................................... 14 Species composition ...................................................................................................... 16 Discussion ............................................................................................................................ 18 Climate ................................................................................................................................ 18 Forest Structure .................................................................................................................. 18 Forest Dynamics ................................................................................................................. 21 Species Composition .......................................................................................................... 21 Conclusions .......................................................................................................................... 24 Acknowledgments .............................................................................................................. 25 Endnotes ............................................................................................................................... 25 Literature Cited .................................................................................................................. 25 Appendix A--Chronology of major events (exploration, settlement, forest exploitation, forest recovery, terrestrial research, and tourism) in the history of St. John, U.S. Virgin Islands, with emphasis on the Cinnamon Bay watershed ..................... 29 Appendix B--Stem density by species and year on 16 plots totaling 0.8 ha in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands ........................................................ 32 iii
List of Figures Figure 1--Location of places mentioned in text.................................................................. 4 Figure 2--Climatic diagram for the Cinnamon Bay watershed based on 30-year normals for Catherinberg, 1971 to 2000 (N 18°20', W 64°45')............................................. 6 Figure 3--Vegetation types on St. John (Woodbury and Weaver 1987)............................. 7 Figure 4--Total number of stems on all plots combined in the Cinnamon Bay watershed: green bars = surviving stems from the initial tally in 1983; yellow bars = cumulative ingrowth; brown bars = cumulative mortality of ingrowth; blue bars = total stems in particular year. Surviving stems are equal to total stems at first measurement in 1983. Ingrowth begins in 1988, and mortality of ingrowth starts in 1993....................... 11 Figure 5--Total number of stems by crown classes on all plots combined from 1983 to 2003......................................................................................................................... 14 Figure 6--Abundance of stems by species on all plots combined in 1983 and 2003........ 24 iv
List of Tables Table 1--Forest monitoring plots on St. John .................................................................... 9 Table 2--Summary of stems by height class, topography, and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands ...................................................................... 12 Table 3--Summary of stems by d.b.h. class, topography, and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands ...................................................................... 13 Table 4--D.b.h. increment from 1983 to 2003 for all surviving stems in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands ...................................................................... 15 Table 5--Summary of total aboveground biomass by year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands .............................................................................. 17 Table 6--Summary of total aboveground biomass by topography and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands .................................................... 17 Table 7--Summary of structural and species composition data in 1983 for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands .................................................... 20
vi
Introduction The Virgin Islands are comprised of two political units: the American islands of St. Croix, St. Thomas, and St. John; and the British islands of Anegada, Tortola, and Virgin Gorda. From the standpoint of history and archeology, the islands are part of the Lesser Antilles; geographically and geologically, however, they are part of the Greater Antilles (Sleight 1962). The Virgin Islands, first occupied by Indian groups migrating from South America (Hatch 1972), were inhabited, at one time or another, by explorers, colonists, and opportunists from Britain, Denmark, France, Holland, Spain, and the United States (Varlack and Harrigan 1977). In addition to human activities-- mainly colonization, plantation agriculture, and later subsistence activities and grazing--the Island's forests have been periodically disturbed by hurricanes and severe droughts (Colуn-Dieppa and others 1991). The landscape today is largely cultural, having been shaped as much by human activity as by natural processes and events (Tyson 1987). Since the 1950s, scientists at the International Institute of Tropical Forestry (IITF) have been involved with forestry research in the U.S. Virgin Islands. The purpose of this report is to provide an overview of past and current knowledge of St. John's forests, particularly with regard to the Cinnamon Bay watershed, by: · Reviewing the impact of past human activity · Briefly summarizing the setting--geology, physiography, soils, climate, and hydrology · Reviewing past and present vegetation studies and forest monitoring on St. John · Synthesizing 20 years of research in the Cinnamon Bay watershed, including the most recent measurements in 2003. Historical Perspective The presence of Archaic Period pre-ceramic sites in the northern Virgin Islands (St. Thomas, St. John, and Tortola) suggests human activity as far back as 1700225 B.C. (appendix A). About 2000 years ago, Indians of the Saladoid culture from the Orinoco region of Venezuela arrived at Coral Bay and later migrated to other sites on St. John, including Cinnamon Bay (Bullen 1962, Tyson 1987). From then until the Caribs
arrived less than a century before Columbus, the Islands probably received sporadic use by the Indians. Destructive storms and droughts made permanent settlements on many Caribbean islands difficult and no doubt contributed to inter-island movements (Haas 1940). The Indians, with small populations confined largely to the coast, had little impact on the vegetation of St. John before European settlement (MacDonald and others 1997). The basic materials used by these groups were stone, shell, bone, and wood (Dookhan 1974). Subsistence activities involved mollusk collecting, fishing, and slash-and-burn agriculture to cultivate manioc, corn, potatoes, yams, beans, and peppers (Dookhan 1974, Hatch 1972, Sleight 1962). Columbus landed in St.C roix on November 14, 1493, on his second voyage to the New World. On departure, unfavorable winds drove his vessels Cinnamon Cay, Cinnamon Bay shoreline, and lower watershed from midway along the Cinnamon Bay trail. Virgin Islands National Park, noted for its panoramic views, was set aside in 1956 as a sanctuary of natural beauty (October 1982).

southeast of Virgin Gorda (Dookhan 1974). Columbus then sailed west toward Hispaniola through a cluster of islands he named after St. Ursula and the 11,000 virgins (Varlack and Harrigan 1977), passing St. John on November 17 (Lawaetz 1991, map on page 32). The island was probably uninhabited at that time. In 1595, Sir Francis Drake visited the Virgin Islands. Later, the channel between St. John and Tortola was named to commemorate his ventures. In 1671, Denmark and Norway established a trading post on St. Thomas; soon after, the first consignment of African slaves arrived, and permanent settlements and agriculture were developed (Dookhan 1974). In 1675, two men were sent to St. John with munitions and provisions, an action viewed by Denmark as official possession and the basis for subsequent territorial claims (Larsen 1986). In 1684, the Danes took possession of St. John, and between 1718 and 1725 they established a settlement and several sugar cane and cotton plantations (Cosner and Bogart 1972, Larsen 1986). Soon after, the Danes built a small fort in Coral Bay (the Fortsbjerg) to show that the island was occupied (Larsen 1986). In 1727, Peter Durloo acquired a small "cotton piece" with 11 enslaved laborers along the shore of Cinnamon Bay (Knight 1999, page 4). Subsequently, roads and large estate houses were built, and much of St. John was terraced (Cosner and Bogart 1972). In 1727, a Town Bailiff was appointed (Larsen 1986). By 1728, much of the natural vegetation had been disturbed by the island's 800 inhabitants in the development of nearly 90 plantations (Hatch 1972, Tyson 1987), and no large timber remained (Larsen 1986). By 1739, the island had 110 plantations, many operated by absentee owners working through local managers. In 1733, "a long drought, a hurricane, a plague of insects, and finally an autumn storm, all the same year" (Harman 1961, page 47) accompanied by harsh measures against the slaves led to a revolt that killed one-third of the white inhabitants and destroyed one-half of the island's plantations (Cochran 1937, Harman 1961, Hatch 1972) (appendix A). The dwelling house, storage building, and boiling house at Cinnamon Bay were looted and burned and the cane fields set ablaze (Knight 1999). The uprising was crushed by the French 6 months later (Raphael 1967). By the late 1730s, the areal extent of agricultural activities on the Cinnamon Bay plantation was most likely at its peak.
In 1741, Moravian missionaries arrived from Germany to work with the island's inhabitants (Kemp 1990, Low and Valls 1985). They began using the sturdy hoop vine (Trichostigma octandrum) and more delicate wist reed (Serjania polyphylla) to make market baskets, placemats, and hats. These items were marketed through the 20th century in the United States and Germany. During the second half of the 18th century, the demand for sugar continued to rise (Raphael 1967). By 1760, plantations occupied 98 percent of the land surface (Tyson 1987), and by the 1780s, Cinnamon Bay was a well-developed estate (Hatch 1972). A land use map produced at that time showed that about 35 to 40 percent of the island was cleared. Relatively flat areas in the interior and along the coast were favored for cultivation (MacDonald and others 1997). Denmark was the first state to outlaw the slave trade in 1792 (Hatch 1972), and by 1803 its transatlantic slave trade had ceased. In 1805, tax records for the sugar estates showed that only 15 percent of St. John was in cane and 5 percent in other crops; also, "a great deal of good land [on the Cinnamon Bay plantation is] in woods or uncultivated" (Knight 1999, page 39). From 1807 to 1818, "outbreaks of yellow fever and smallpox, a period of British occupation during the Napoleonic Wars (1807-1815), the failure of the estates to sustain their enslaved populations after the abolition of the transatlantic slave trade, and, in Europe, the perfecting of the process to extract sugar from the sugar beet, all conspired to drive down the Danish West Indian economy" (Knight 1999, page 43). By 1823, nearly three-quarters of the Cinnamon Bay property served little purpose other than to provide fuelwood and the occasional harvest of wild fruits and fowl (Knight 1999). In 1848, after riots on St. Croix, Governor General Peter von Scholten ordered the emancipation of all slaves in the Virgin Islands (Dookhan 1974). The anchoring of Confederate ships at Charlotte Amalie harbor during the Civil War first prompted an American interest in purchasing the Virgin Islands. At that time, the combined effects of emancipation and increased competition from sugar beets grown in temperate latitudes led to the decline of both sugar estates and population on St. John (Haas 1940). In 1868, the new owner of Cinnamon Bay introduced livestock and dairy cattle, ending the production of

sugar cane. Offshore fishing, cultivation of swidden fields, charcoal production, and grazing became the major occupations (Haas 1940, Near 2003, Olwig 1985). In the 1880s, when Cinnamon Bay was reported all in bush, residents began harvesting the leaves and berries of the bay rum tree (Pimenta racemosa) for perfumes and cosmetics. Bay rum production, peaking around 1920, remained the island's most important industry through the 1940s. Bay rum trees regenerated naturally, and owners cleared competing vegetation as desired (Hatch 1972). Subsistence cultivation at the time included tanias,
okra, cassavas, yams, pigeon peas, sweet potatoes, and beans, along with bananas, papayas, and other drought-tolerant fruits (Haas 1940). The recurrent negotiations to purchase the Virgin Islands, rekindled and then suspended during the Spanish-American War, were reinitiated during World War I (Dookhan 1974, Haas 1940). In 1917, two centuries after Danish colonization, one-half century after the Civil War, and one week before entering World War I, the United States bought the Virgin Islands for $25 million (Hatch 1972, Zabriskie 1917). Between 1900 and 1950, the population of scattered settlements on St. John, linked by donkey trails, was around 800 inhabitants. As of 1950, with boats as the primary means of transportation, the island had one truck, two jeeps, and one bulldozer (Low and Valls 1985; MacDonald and others 1997), and St. John was still "the quiet place" (Hatch 1972). The quiet place began to change in 1952 when the Virgin Islands government created a Tourist Development Board to promote tourism (Dookhan 1974) and Laurence Rockefeller started to purchase 55 percent of St. John. In 1956, President Eisenhower authorized the establishment of the Virgin Islands National Park as a sanctuary of natural beauty (Robinson and Henle 1978, fig. 1). Agriculture, grazing, hunting, and wood cutting within Park boundaries were gradually eliminated (Olwig 1980, O'Neill 1972). In 1962, marine waters and submerged lands totaling nearly 2300 ha were added to the Park. In the same year, a bill "to acquire lands, waters, and interests therein by purchase, exchange, condemnation, or donation or with donated funds" was being considered to lessen impacts caused by in-holdings (O'Neill 1972, page 143). The bill was ultimately modified to prevent unfair land condemnation. Since then, the Park has generated considerable economic activity centered around its spectacular scenery. In 1976, the Virgin Islands National Park became a Biosphere Reserve.
Stand with bay rum trees (Pimenta racemosa) in dry evergreen woodland at Cinnamon Bay. The harvest of bay rum leaves and berries for the production of cosmetics and perfumes peaked in the 1920s and remained an important island activity through the 1940s (October 1982).
Atlantic Ocean
12
Whistling Cay 9
St. John U.S. Virgin Islands
Du
rloe Cays 7 11 2 B 5 A
B 44 3 10
A 1 8 13
Leduck Island
6 Flanagan Island
Legend Roads Watershed boundaries Park Service boundary
Caribbean Sea
0 0.45 0.9
1.8 Kilometers
14
0
0.45 0.9
1.8 Miles
Place names cited in text 1. Bordeau Mountain 2. Caneel Hill 3. Catherinberg 4. Cinnamon Bay watershed (two major guts)
5. Cruz Bay 6. East End 7. Hawksnest 8. Lameshur 9.Threadneedle Point
10. L'Esperance
A. Centerline Rd
11. Lind Point (research center) B. North Shore Rd
12. Mary Point
13. Minna Hill (Cob's Hill)
14.Ram Head
Figure 1--Location of places mentioned in text.
Today, much of St. John is covered by late secondary forest which began to regenerate in the mid- to late 1800s. Although negative comments have been recorded during interviews--such as "the park is just preserving brush, mongooses and jackasses" or "the island was beautiful when it was filled with cows and grass" (Olwig 1980, page 28)--tourism has been responsible for the dynamic growth of the island, leading to the conclusion that "Today St. John's economy is based squarely on tourism" (Low and Valls 1985, page 91). The trickle of visitors to the Virgin Islands in the 1930s increased to 55,000 in 1962 and to > 2.3 million by 2002 (appendix A). At the same time, the Park protects critical dry forest and provides winter habitat for neotropical migratory birds (Askins and Ewert 1992).
Despite protection from most developmental activities, the Park still experiences impacts caused by tourism, home construction, and introduced animals. The Park already has excellent facilities: a paved road along the north shore, numerous well-maintained trails, and at Cinnamon Bay, a camping complex with dining facilities and a commissary (Olwig 1985). The clearing of unpaved roads, parking areas, and sites for house construction, however, is causing sedimentation rates greater than during the plantation era (Anderson and MacDonald 1998, MacDonald and others 1997, Reid and Dunne 1984). The potential impact of sedimentation on coral reefs and their organisms remains a serious concern (Rogers 1990). Feral pigs, goats, and donkeys frequently roam onto private properties and public recreation areas and continue to pose problems for the survival and growth of certain plant species.

Setting: St. John and Cinnamon Bay St. John occupies 52 km2 and is located about 100 km east of Puerto Rico. The island is 15 km long from Cruz Bay to East End and 8 km wide from Threadneedle Point to Ram Head (fig. 1). Cinnamon Bay watershed is 1.32 km2 or about 2.5 percent of St. John. It is in the north central part of the island, north of Centerline Road. The road which runs along the southern edge of the watershed approximates the island divide. Geology St. John is geographically and geologically part of the Greater Antilles, being part of the Puerto Rican platform and Antillean Geanticline (Hatch 1972). Its geologic history appears to date back to the upper Jurassic or Lower Cretaceous when volcanic magmas erupted on the ocean floor (Donnelly 1966). Eruption was mainly by flows because overlying sea water prevented explosive emissions. Toward the end of this period, either volcanic accumulations or structural uplift made the sea shallower, and pyroclastic material increased. Subsequently, major uplift occurred, and deposition altered from marine on gentle slopes to both subaerial and marine on relatively steep slopes adjacent to an emergent island. Volcanism and erosion continued on the exposed island until the Eocene time when quartz-diorite plutons were emplaced. About 85 percent of the Cinnamon Bay watershed is classified as the Louisenhoj formation. This formation contains augite-andesite volcanic breccia (clastic sedimentary rock made up of angular fragments) and tuff (rock consolidated from volcanic ash) with minor conglomerate, all of Cretaceous (possibly Albian) age (Donnelly 1966). The Water Island Formation, comprised of quartz keratophyre flows (volcanic rock, mainly albite and quartz, with chlorite, micaceous minerals, and iron oxides) and flow breccias of the Lower Cretaceous age, occupies about 7 percent of the watershed at the highest elevations in a narrow strip along Centerline Road. Another 8 percent of the watershed along the shoreline is overlain by Quaternary alluvium. Physiography and Soils St. John is comprised of an east-west ridge with steep north-facing slopes; the southern part of the island has several spur ridges extending southward
from the island divide. Bordeaux Mountain is the highest point at 390 m. Slopes in excess of 30 degrees occur on > 80 percent of the island (CH2M Hill 1979, see endnotes). The island's coastline is irregular and has numerous bays and small coastal plains associated with major drainages. Cinnamon Bay watershed ranges from sea level to about 300 m in elevation and is drained by two major guts (fig. 1). Steep slopes covered with loose rock and numerous narrow valleys filled with boulders characterize the landscape. Part of the Cinnamon Bay coastal plain has been developed for tourism. In 1966, Soil Scientists completed a survey of St. John (Rivera and others 1966) and in 1980 revised the island's soil taxonomy (Lugo-Lуpez and Rivera 1980). All of St. John and 41 percent of the entire U.S. Virgin Islands are classified in the Cramer-Isaac soil association (Rivera and others 1970). This association is characteristic of very steep mountainsides, steep lower slopes, and narrow alluvial fans and flood plains. The soils range from shallow to moderately deep, are well-drained, and lie over volcanic rock. Boulders and rock outcrops are common. Most of the Cinnamon Bay watershed is in capability classes above III, indicating that the preferred land use is permanent tree cover (Rivera and others 1966). Climate St. John has a tropical maritime climate. The island lies in the path of the northeast trade winds, but east and southeast winds are also common (Cosner and Bogart 1972). Relative humidity averages about 75 percent. In general, the continuous trade winds accompanied by low rainfalls, high evapotranspiration, long hours of sunshine, and high ambient temperatures accentuate drought conditions on the island. The rainfall-producing mechanisms on St. John are similar to those of nearby Puerto Rico, varying mainly due to the island's smaller size and lower elevation (Calvesbert 1970, Colуn-Dieppa and others 1991). Much of St. John's rainfall is orographic and is deposited as the moisture-laden trades pass over the island's interior. Easterly waves also produce rainfall, mainly from May through November. Tropical storms and hurricanes occasionally develop in the easterly waves and may cause high winds and heavy downpours. These phenomena occur mainly from

July through October, with the greatest number of events during August and September. Cold fronts descend from North America from November to April. The degree to which they influence rainfall depends on their intensity and rate of progression into the Caribbean. Rainfall varies on St. John by location. The mountainous interior stretching from Cinnamon Bay to the lower southeastern slopes of Bordeaux averages > 1200 mm year-1; areas to the east and west receive less, to as little as 900 mm year-1 (Bowden and others 1970, Ewel and Whitmore 1973). Extended periods of heavier annual precipitation or prolonged drought occur occasionally (Bowden and others 1970, ColуnDieppa and others 1991). The 30-year rainfall normal (1971-2000) for Catherinberg, about 1 km west of the Cinnamon Bay watershed, is 1240 mm year-1 (Southeast Regional Climate Center 2003) (fig. 2). The wettest 4-month period, August through November, receives 600 mm, or 46 percent of the total; the driest 4-month period, January through April, receives 285 mm, or 22 percent of the total. The wettest and driest months are November with 160 mm and February with 60 mm. The corresponding annual temperature normal is 24.8 °C. August is the warmest month, averaging 26.3 °C, and January the coolest month, averaging 23.1 °C. Records collected from 1921 to 1967 at Cruz Bay show that the lowest and highest temperatures were 15 and 35 °C (Cosner and Bogart 1972, fig. 1). Figure 2--Climatic diagram for the Cinnamon Bay watershed based on 30-year normals for Catherinberg, 1971 to 2000 (N 18°20', W 64°45').
Hurricanes are a regular phenomenon in the Caribbean, as indicated in an old Creole proverb: "June, too soon; July, stand by; August, come it must; September, remember; October, it's over" (Cochran 1937, page 101). Twenty hurricanes passed over or near St. John before 1900 (in 1695, 1707, 1714, 1729, 1733, 1742, 1748, 1772, 1785, 1793, 1819, 1825, 1830, 1837, 1866, 1867, 1871 (two events), 1876, and 1899), the most destructive of which appear to have occurred in 1695, 1772, 1785, 1819, 1837, 1867, and 1899 (Dookhan 1974, Lawaetz 1991). Ten hurricanes passed over or nearly over St. John during the 20th century, including unnamed hurricanes in 1916, 1924, and 1928 and hurricanes Connie in 1955, David in 1979, Hugo in 1989, Marilyn in 1995, Hortense in 1996, Georges in 1998, and Lenny in 1999 (ColуnDieppa and others 1991, Forthun 2005). In addition, seven moderate or severe regional droughts were experienced during the 20th century alone: moderate, from 1938 to 1942, 1945-48, and in 1959; and severe, in 1957, 1964, 1967-68, and 1994-95 (Colуn-Dieppa and others 1991, Rogers and Reilly 1998). Hydrology Water resources are scarce on St. John. During the 18th and 19th centuries, colonists obtained water from a few natural springs, large-diameter wells, and small surface reservoirs (Cosner and Bogart 1972). Archeological, historical, and geological evidence, however, indicates that water resources were greater in the past (Jordan 1972). The most recent decline is attributed to changes in land use from agriculture to secondary forest. Because most rainfall is light, runoff on St. John is limited to 5 or 10 percent of the rainfall, with the remainder being lost through evapotranspiration (Cosner and Bogart 1972). Annual groundwater recharge is low, and groundwater aquifers are confined to narrow alluvial valleys with limited storage capacity, scattered beach sand deposits, and fractured volcanic rock (Cosner and Bogart 1972, MacDonald and others 1997). St. John has several springs, including one at Cinnamon Bay, and spring-fed pools, but no permanent streams (Cosner and Bogart 1972). Storm runoff is considerable, and small pools of water may be observed in guts a few days after heavy downpours. The yield from springs is low, becoming intermittent during droughts. Cinnamon Bay has six

wells. One is used for water supply and another, called the old Danish well, for recording water data (Cosner and Bogart 1972, Torres-Sierra and Rodrнguez-Alonso 1987). Vegetation Taxonomists made the earliest studies of the vegetation in the Virgin Islands, mainly on St. Croix and St. Thomas (Eggers 1879, Britton 1918, Britton and Wilson 1923 to 1930). The first surveys on St. John were made when there was less forest cover and much of the island was inaccessible. During the 1940s, a British researcher assigned to work the West Indies proposed a general classification for Caribbean forests (Beard 1944, 1949, 1955). A few years later, moist and dry forest types were recognized on St. John based on Beard's system; in Figure 3--Vegetation types on St. John (Woodbury and Weaver 1987).
addition, special, or modified vegetation types were also recognized (Robertson 1957, see endnotes; Robertson 1962). In 1973, the life zone model (Holdridge 1967) was used to classify St. John into subtropical moist and subtropical dry forests (Ewel and Whitmore 1973). Because St. John receives about 900 to 1200 mm year-1 of rainfall, the entire island could be considered as transition between these two life zones. In 1982, St. John's flora was again surveyed using a modification of Beard's system to account for secondary and riparian vegetation (Woodbury and Weaver 1987) (fig. 3). This was the first study to focus on Park Service properties on both St. John and Hassle Islands. Ten vegetation types were recognized and mapped: mangroves, salt flats, and lagoons covered 2.3 percent of St. John; three types of moist forest 16.5 percent; four types of dry forest
Atlantic
Ocean
Whistling Cay
loe Cays
Hawksnest Bay
Trunk Bay
Cinnamon Bay
Moho Bay
Leinster Bay
St. John U.S. Virgin Islands Brown Bay Mannebeck Bay
Dur Great LLiattlmeeLsahmuresBhaury Bay Haulover Newfound Bay
Cruz Bay
Coral Bay
Round Bay
East End Bay
Great Cruz Bay Chocolate Hole
Fish Bay
Rendezvous Bay
Reef Bay
Caribbean Sea
Legend: Cover type (percent of island)
Mangroves, Salt Flats and Lagoons (2.3) Upland Moist Forest (8.9) Gallery Moist Forest (4.0)
Basin Moist Forest (3.6) Dry Evergreen Woodland (33.4) Dry Evergreen Thicket or Scrub (21.4)
Flanagan Island
Leduck Island
Saltpond Bay
Ram Head
0 0.5 1
0
0.5
2 Kilometers
1
2 Miles
Thorn and Cactus (6.3) Rock Pavement and Coastal Hedge (2.1) Secondary Vegetation (13.4)
Pasture (2.0) Urban (2.6) National Park Boundary

63.2 percent; secondary vegetation 13.4 percent; pasture 2.0 percent; and urban areas 2.6 percent. A checklist was used to rank nearly 800 plant species by life form and relative abundance in each vegetation type. Reputed medicinal uses were also noted. In 1987, the Park Service established a vascular plant herbarium with at least 600 species in 99 families at Lind Point (Knausenberger and others 1987). Specimens collected during the above survey were included in the collection. From the mid-1960s through the mid-1970s, researchers at the IITF described tree species in the U.S. Virgin Islands, including rare, endemic, and exotic species (Little and Wadsworth 1964, Little and Woodbury 1980, Little and others 1974). Later, taxonomists revised the flora of the West Indies,
including St. John, in comprehensive works (Howard 1979, 1988-89; Liogier 1985 to 1997, Liogier and Martorell 1982). Taxonomic work continued in the 1990s, when a new tree species and two previously described endemics were listed. Today, the island's flora contains 747 species of vascular plants, with 86 percent of the species being native. This includes 117 families (12 introduced) containing 489 genera (55 introduced) (Acevedo-Rodrнguez 1993, AcevedoRodrнguez and Strong 2005, Acevedo-Rodrнguez and others 1996). The three most common families are Fabaceae, Poaceae, and Euphorbiaceae, which account for 22 percent of the species. Orchids are represented by 9 genera and 14 species (Ackerman 1992) and pteridophytes (ferns and fern allies) by 5 families and 16 genera (Proctor 1989).
Thorn and cactus vegetation along St. John's south coast (October 1982).
Roy O. Woodbury as his colleagues and students knew him, collecting plant specimens in secondary dry evergreen thicket on the south slopes of St. John above Lameshur (October 1982).
Table 1--Forest monitoring plots on St. John a
Forest type
Location
Age (years)
Plot Number of Dateb Size No. species b (ha)
Number of Basal
stems b
area
(ha-1) (m2 ha-1)
Source
Dry evergreen
to gallery moist Cinnamon Bay 125 1983 0.05 16
69
3,378
30.4 Weaver and Chinea (1987)
Upland moist Bordeaux
110 1984 1.00 1
62
Gallery moist L'Esperance
90 1985 0.50 1
56
Dry evergreen
woodland
Hawksnest
>70 1986? 0.50 1
52
2,241 2,521 2,598
31.2 Earhart and others (1988) 31.6 Reilly and others (1990) 26.5
Secondary Secondary Secondary Secondary Dry evergreen woodland
Mary Point Lameshur Caneel Hill Caneel Hill Cinnamon
35 1988 0.05 2
8
50 1988 0.05 2
23
100 1988 0.05 2
27
100 1988 0.05 2
29
125 1988 0.05 2
30
1,660 4,900 4,110 3,080 4,320
4.9 Brown and Ray (1993) 17.9 Ray and Brown (1995a) 22.9 25.8 25.3
Dry evergreen
woodland
Caneel Hill 80­100 1991 1.00 1
49
4,288
23.7 Dallmeier and others (1993); Ray and others (1998)
Dry evergreen
woodland
Minna Hill c 100­120 1994 1.00 1
45
8,574
21.8
a Adapted from Rogers and Reilly (1998). The minimum d.b.h. varied by site: Set 1­Cinnamon Bay, 4.1 cm; Set 2­Bordeaux, L'Esperance and Hawksnest, 5.0 cm; Set 3­Mary Point, Lameshur, Caneel Hill, and Cinnamon, 4.0 cm; Set 4­Caneel Hill, 4 cm and Minna Hill, 2.5 cm. b Initial survey data. c Also called Cob's Hill.
Terrestrial Research Initiative In 1982, 14 groups formed the Virgin Islands Resource Management Cooperative to initiate baseline research in the National Park; by 1989, the cooperative had completed 29 reports (Anonymous 1988, Rogers and Teytaud 1988). In 1992, the status of the integrated approach to marine and terrestrial research was reviewed and summarized (Rogers 1992). As part of the research initiative, the IITF began forest monitoring in the Cinnamon Bay watershed in 1983 (table 1, fig. 1). Subsequently, forest structure and composition, diameter growth rates, species-site relationships, forest productivity, and the impacts of Hurricane Hugo were reported (Weaver 1990, 1992, 1994, 1996, 1998; Weaver and Chinea-Rivera 1987). Between 1984 and 1986, collaborators with the New York Botanical Garden set up permanent plots on Bordeaux Mountain, L'Esperance, and Hawknest
(Earhart and others 1988, Reilly and others 1990). After Hugo, these plots were assessed for damage (Reilly 1991, 1992, 1994, 1998; Rogers and Reilly 1998). In 1988, the University of Wisconsin began studies on plots at Mary Point, Lameshur, Cinnamon Bay, and Caneel Hill to determine species diversity and forest structure (Brown and Ray 1993, Ray and Brown 1995a). Finally, between 1991 and 1994, collaborators in the Smithsonian Institution's Man and the Biosphere Program set up permanent plots at Caneel Hill and Minna Hill (also called Cob's Hill) to determine species composition, stand structure, and forest dynamics (Dallmeier and Ray 1992, Dallmeier and others 1993, Ray and others 1998). The monitoring plots on St. John represent differences in vegetation age (i.e., the time elapsed since agriculture was abandoned), plot sizes, sampling design, and measurement procedures (table 1). The Cinnamon Bay plots (table 1, top) totaled 0.8 ha

and were established in forest at least 125 years old. Initially, the plots contained 69 species, averaged 3,378 trees per hectare and had an average basal area of 30.4 m2 ha-1. The other monitoring sites on St. John were on plots between 0.05 and 1.0 ha and located in forest between 35 and 125 years old. They varied in species numbers from 8 to 62, in stem numbers from 1,660 to 8,574 ha-1, and in basal areas from 4.9 to 31.6 m2 ha-1. As part of a systematic approach to dry forest restoration, some researchers tried to determine factors that limit natural regeneration on different sites (Brown and Ray 1993). Seed ecology and the use of propagules (seeds, seedlings, and rooted cuttings) were tested for restoration on degraded lands (Brown and others 1992, Ray 1993, Ray and Brown 1995b). Fruiting and flowering events for 66 woody species were observed in several areas during a 4-year period (Ray and Brown 1994). A survey of fruit dispersal by 148 native woody species showed that 74 percent was by animals, 18 percent by wind, 4 percent by sea currents, and 4 percent by selfdispersion. Nearly 60 percent of the 29 woody species tested in shade house conditions showed > 80 percent germination. The use of seedlings proved to be the most efficient method for establishing propagules on abandoned pasturelands. Methods at Cinnamon Bay Sampling in the Cinnamon Bay watershed used 16 plots, each 50 by 10 m, to determine forest structure and dynamics by elevation and topography (Weaver and Chinea-Rivera 1987). Five groups of three plots (situated on ridge, slope, and valley topography) were established at elevations of 60, 120, 180, 210, and 240 m. Ridge plots were entirely on convex topography and valley plots on concave topography; slope plots were on relatively uniform slopes. The final plot was at 290 m on level terrain near the summit of the watershed. All plots were georeferenced in June 1995. All trees 4 cm in diameter at breast height (d.b.h.), 1.4 m above the ground, were identified to species, measured, and tagged. Crown classes indicating the position of the tree in the canopy were also recorded (Baker 1950). A lower limit of 4 cm was used because it would provide data on the early survival and growth of tallied trees, many of which were small.
Carlos Rodrнguez in gallery moist forest near valley plot #1, Cinnamon Bay watershed, beginning the task of geo-referencing all 16 plots (April 1995). A rangefinder was used to estimate tree heights or lengths if leaning (to the nearest 0.5 m), and a diameter tape measured d.b.h. (to the nearest 0.1 cm). Trees were tagged using aluminum nails placed 15 cm below breast height to avert possible swelling at the point of measurement. During the initial survey d.b.h. was marked with paint. Measurements were made during June or July in 1983, 1988, 1993, 1998, and 2003. Biomass was determined using the relationship: Ln Y = -1.59 + 0.77 ln X, r2 = 0.94, Sy.X = 0.0345, n = 20 (Weaver 1994) where Y = total aboveground biomass in kg, and X = (D2 x h) where D = tree d.b.h. (cm) and h = tree height (m). Mean d.b.h. growth rates were determined by species for trees that survived the 20-year measurement period.
10
Upland moist forest stand marked with paint, second survey on ridge plot #10, Cinnamon Bay watershed (June 1988).
Certain qualifications regarding the methods are appropriate. Monitoring was carried out by a three-person field crew limited to visits of 12 working days once every 5 years. Some tree species, notably in the Lauraceae and Myrtaceae, are difficult to identify from the ground. Moreover, a detailed examination of tree health was not carried out before and after Hurricane Hugo; consequently, pre- and posthurricane species comparisons were kept simple and speculation regarding differences kept to a minimum. Results at Cinnamon Bay Forest Structure Number of stems--In 1983, the stand density for all plots combined was 3,378 trees per hectare (fig. 4, appendix B). Subsequently, it increased to 3,479 stems in 1988, then declined to 3,399 stems in 1993 and to 3,112 stems in 1998, before increasing
Figure 4--Total number of stems on all plots combined in the Cinnamon Bay watershed: green bars = surviving stems from the initial tally in 1983; yellow bars = cumulative ingrowth; brown bars = cumulative mortality of ingrowth; blue bars = total stems in particular year. Surviving stems are equal to total stems at first measurement in 1983. Ingrowth begins in 1988, and mortality of ingrowth starts in 1993.
11
to 3,171 stems per hectare in 2003. By 2003, nearly 65 percent of the stems tallied in 1983 still survived. The same pattern is evident for stems on ridge, slope, and valley topography (tables 2 and 3, totals). Stems on the summit plot, however, consistently declined in numbers from 1983 through 2003.
Cumulative ingrowth gradually increased from 262 stems per hectare in 1988 to 1,165 stems per hectare by 2003, when it amounted to 35 percent of the stems on all plots. Cumulative mortality of ingrowth climbed from 22 stems per hectare in 1993 to 166 stems per hectare by 2003 (fig. 4).
Table 2--Summary of stems by height class, topography, and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Topography and year Ridge 1983 1988 1993 1998 2003
Height class
<4 4­8
8­12 12­16 >16 stems ha -1
- - - - - - - - Mean over 5 plots - - - - - - - -
36 3,056 1,188
68
0
20 2,572 1,648 204
8
56 2,608 1,440 196
8
124 2,912 860
96
0
80 2,820 1,068 116
8
Total 4,348 452 4,308 3,992 4,092
Slope 1983 1988 1993 1998 2003
20 1,440 848 272 4 1,388 1,016 268 36 1,432 940 256 84 1,500 716 172 64 1,560 756 156
36 2,616 76 2,752 68 2,732 24 2,496 36 2,572
Valley 1983 1988 1993 1998 2003
80 1,364 44 1,444 96 1,420 172 1,480 36 1,620
740 152 148 2,484
720 188 180 2,576
680 144 156 2,496
484
88 124 2,348
592 100 116 2,464
Summit 1983 1988 1993 1998 2003
- - - - - - - - - Value for 1 plot - - - - - - - - -
40 4,460 2,100 200
0
20 3,820 2,660 260
0
60 3,860 2,560 220
0
160 3,580 1,500 360
0
80 3,180 1,500 340
0
6,800 6,760 6,700 5,600 5,100
All 1983 1988 1993 1998 2003
- - - - - - - - - - Weighted mean - - - - - - - - -
45 2,110
999 166
58
22 1,928 1,224 222
83
62 1,947 1,116 200
73
129 2,065
738 134
46
61 2,074
849 137
50
3,378 3,479 3,399 3,112 3,171
12
Table 3--Summary of stems by d.b.h. class, topography, and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Topography and year Ridge 1983 1988 1993 1998 2003
D.b.h. class (cm)
4­10 10­15 15­20 20­30 > 30 stems ha -1
- - - - - - - - Mean over 5 plots - - - - - - - -
3,492 592 176 3,468 680 196 3,344 696 168 3,068 672 152 3,140 672 184
76 12
96 12
88 12
84 16
88
8
Total 4,348 4,452 4,308 3,992 4,092
Slope 1983 1988 1993 1998 2003
1,716 504 196 140 60 2,616 1,804 544 176 168 60 2,752 1,796 540 176 164 56 2,732 1,656 472 164 160 44 2,496 1,732 480 172 148 40 2,572
Valley 1983 1988 1993 1998 2003
1,928 268 104 100 84 2,484
2,004 276 100 116 80 2,576
1,948 284
88
96 80 2,496
1,912 224
72
76 64 2,348
1,972 280
60
84 68 2,464
Summit 1983 1988 1993 1998 2003
- - - - - - - - - Value for 1 plot - - - - - - - - - 5,620 780 220 120 60 5,520 800 240 140 60 5,300 980 200 160 60 4,300 920 140 180 60 3,860 860 160 160 60
6,800 6,760 6,700 5,600 5,100
All 1983 1988 1993 1998 2003
- - - - - - - - - - Weighted mean - - - - - - - - - 2,581 475 163 106 53 2,619 519 162 128 51 2,546 536 148 119 50 2,342 485 130 111 43 2,380 501 140 110 40
3,378 3,479 3,399 3,112 3,171
13
Height classes--In all years of measurement, from 55 to 66 percent of the stems for all plots combined was between 4 and 8 m in height, and from 90 to 92 percent was between 4 and 12 m in height (table 2). Comparable values by topography were ridge, 58 to 73 percent and 94 to 97 percent; slope, 50 to 61 percent and 87 to 90 percent; valley, 55 to 66 percent and 84 to 90 percent; and summit, 57 to 66 percent and 91 to 96 percent. In all years, only about 2 percent of the total stems tallied on all plots were > 16 m tall. Valleys had the greatest proportion by topography, ranging from 5 to 7 percent. The height class > 16 m for total stems and for slope trees showed an increase in numbers from 1983 to 1988, a decline through 1998, and then a slight increase in 2003 (table 2). On valley topography, trees > 16 m increased from 1983 to 1988 and then declined through 2003. Stems > 16 m in height were absent from the summit and very uncommon on ridges. D.b.h. classes--In all years of measurement, 75 percent or more of the total stems was between 4 and 10 cm in d.b.h., and 90 percent was between 4 and 15 cm in d.b.h. (table 3). Comparable values by topography were ridge 77 and 93 percent, slope 66 and 85 percent, valley 78 and 88 percent, and summit 76 and 92 percent. In all years, < 2 percent of the total stems tallied on all plots were > 30 cm in d.b.h.. The greatest concentration of large trees was in valleys, where about 3 percent of the trees were > 30 cm in d.b.h. in all years. The d.b.h. class > 30 cm for total stems showed a consistent decline in numbers from 1983 to 2003 (table 3). In general, there was a decline in the d.b.h. class > 30 cm on all topographic positions. Crown classes--In 1983 and 1988, the percentage of stems by crown class averaged approximately 7.5 for both dominants and co-dominants, 20.0 for intermediates, and 65.0 for suppressed stems (fig. 5). In 1993, the percentage of stems was 8.5 for dominants, 12.0 for codominants, about 36.0 for intermediates, and about 43.5 for suppressed stems. In 1998 and 2003, the percentage of stems by crown class averaged about 3.6 for dominants, 9.3 for codominants, and 42.9 to 44.5 for both intermediate and suppressed stems.
Number of stems
2,000
Dominant Intermediate
Codominant Suppressed
1,500
1,000
500
0 1983
1988
1993 Year
1998
2003
Figure 5--Total number of stems by crown classes on all plots combined from 1983 to 2003.
Forest Dynamics D.b.h. increment--The d.b.h. growth after 20 years of monitoring for all 1,742 surviving stems of 60 species averaged 0.07 ± 0.00 cm year-1 (table 4). Maytenus elliptica had the greatest number of survivors with 322 stems. Ten tree species were represented by a single individual. Growth rates for dicots varied from 0.01 ± 0.01 cm year-1 for Guettarda parviflora with five survivors to 0.22 ± 0.13 cm year-1 for Bucida buceras L. with three survivors. Coccothrinax alta, a palm, showed virtually no change, as expected. D.b.h. growth among crown classes was significantly different: dominant stems 0.10 ± 0.01 cm year-1 (n = 149), codominants 0.09 ± 0.01 (n = 119), intermediates 0.07 ± 0.00 (n = 360), and suppressed stems 0.06 ± 0.00 (n = 1,114). Biomass increment--The standing total biomass of 138.7 t ha-1 in 1983 increased to a high by 1988 and then declined to a low by 1998 before making a partial recovery in 2003 (table 5). Biomass accumulation was positive, averaging 2.42 t ha-1 year-1 from 1983 to 1988, then negative from 1988 through 1998, averaging -2.82 t ha-1 year-1, and then positive again from 1998 to 2003, averaging 0.92 t ha-1 year-1 (tables 5 and 6). The net change over 20 years was -11.5 t ha1, for an average decrease of 0.58 t ha-1 year-1.
14
Table 4--D.b.h. increment from 1983 to 2003 for all surviving stems in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Species
D.b.h. growth mean (SE) (cm/year)
D.b.h. range (cm)
Number of stems (no.)
Acacia macracantha Humb. and Bonpl. ex Willd. Andira inermis (W. Wright) Kunth ex DC. Ardisia obovata Desv. ex Hamilton Bourreria succulenta Jacq. Bucida buceras L. Bursera simaruba (L.) Sarg. Byrsonima coriacea (Sw.) DC. Capparis frondosa Jacq. Capparis cynophallophora L. Casearia decandra Jacq. Capparis flexuosa (L.) L. Casearia guianensis (Aubl.) Urban Capparis indica (L.) Druce Celtis trinervia Lam. Linociera caribaea (Jacq.) Knobl. Chrysophyllum pauciflorum Lam. Citharexylum fruticosum L. Coccothrinax alta (O. F. Cook) Becc. Cordia alliodora (Rulz and Pavуn) Oken Cordia collococca L. Cordia rickseckeri Millsp. Cordia sulcata DC. Coccoloba swartzii Meisn. Coccoloba venosa L. Crescentia cujete L. Daphnopsis americana (Mill.) J.R. Johnston Erythroxylum rotundifolium Lunan Eugenia monticola (Sw.) DC. Eugenia procera (Sw.) Poir. Eugenia pseudopsidium Jacq. Faramea occidentalis (L.) A. Rich. Ficus laevigata Vahl Garcinia magostana L. Guettarda elliptica Sw. Torrubia fragrans (Dum.-Cours.) Standl. Guettarda parviflora Vahl Guettarda scabra (L.) Vent Guazuma ulmifolia Lam. Inga fagifolia (L.) Wild ex Benth.
0.07 (0.02) 0.07 (0.02) 0.05 (0.01) 0.12 (0.03) 0.22 (0.13) 0.07 (0.01) 0.12 (0.06) 0.11 (0.03) 0.03 (0.01) 0.05 (0.01) -0.020 0.07 (0.02) 0.11 0.05 (0.03) 0.07 (0.01) 0.07 (0.01) 0.06 (0.01) 0.00 (0.01) 0.10 (0.02) 0.11 (0.03) 0.06 (0.02) 0.08 (0.03) 0.120 0.12 (0.04) 0.02 0.06 (0.01) 0.06 (0.01) 0.03 (0.01) 0.07 (0.01) 0 0.07 (0.01) 0.15 (0.10) 0.11 (0.03) 0.04 (0.01) 0.09 (0.01) 0.01 (0.01) 0.05 (0.01) 0.04 (0.01) 0.16 (0.02)
6.1­12.3 5.5­48.1 4.6­11.1 8.3­23.3 38.5­56.9 9.1­53.5 9.9­24.0 8.8­37.4 4.3­14.7 5.5­ 9.2 6.5 4.7­16.3 9.3 6.3­16.5 5.3­13.5 5.2­19.8 5.8­18.4 6.7­12.5 9.7­26.5 7.0­32.2 5.0­27.0 8.1­37.5 7.0 6.0­13.9 10.3 4.9­ 9.7 5.2­10.8 9.6­10.4 4.5­16.8 8.5 4.3­13.5 10.3­12.5 6.7­ 8.7 4.6­14.0 4.6­79.7 6.8­ 8.9 4.5­21.2 18.4­22.9 5.1­47.0
2 9 85 7 3 32 5 8 30 6 1 26 1 4 9 34 17 10 7 5 26 11 1 9 1 8 15 2 50 1 113 3 2 58 173 5 50 2 30 continued
15
Table 4--D.b.h. increment from 1983 to 2003 for all surviving stems in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands continued
Species
D.b.h. growth mean (SE) (cm/year)
D.b.h. range (cm)
Number of stems
Ixora ferrea (Jacq.) Benth. Krugiodendron ferreum (Vahl) Urban Lonchocarpus pentapyllus (Poir) DC. Manilkara bidentata (A. DC.) Chev. Maytenus elliptica (Lam.) Krug and Urban ex Duss. Meliococcus bijugatus Jacq. Morisonia americana L. Myrcia citrifolia (Aubl.) Urban Myrciaria floribunda (West ex Willd.) Berg Nectandra coriaceae (Sw.) Griseb. Phyllanthus nobilis (L. f.) Muell.-Arg. Pimenta racemosa (Mill.) J.W. Moore Pisonia subcordata Sw. Quararibea turbinata (Sw.) Poir. Randia aculeata L. Sabinea florida (Vahl) DC. Sapium caribaeum Urban Schoepfia schreberi J.F. Gmel. Sideroxylon foetidissum Jacq. Spondias mombin L. Tabebuia heterophylla (DC.) Britt. Tetrazygia angustifolia (Sw.) DC. Tetrazygia elaeagnoides (Sw.) DC. Zanthoxylum martinicense (Lam.) DC.
0.07 (0.05) 0.05 (0.01) 0.16 0.18 (0.02) 0.07 (0.00) 0.12 (0.03) 0.06 (0.02) 0.06 (0.00) 0.07 (0.00) 0.10 (0.02) -0.01 (0.02) 0.05 (0.01) 0.10 (0.02) 0.06 (0.01) 0.02 (0.01) 0.09 (0.01) 0.34 0.11 0.14 (0.01) 0.11 (0.03) 0.02 (0.01) 0.05 0.06 0.11 ± 0.04
6.9­10.1 6.3­11.8 13.2 11.4­37.2 4.4­34.5 6.2­50.4 5.7­ 9.4 4.3­12.9 4.5­26.3 5.9­14.1 8.2­18.0 4.2­21.4 6.7­30.2 4.7­12.2 5.0­17.3 5.3­33.7 21.5 6.6 8.7­12.0 28.8­69.0 4.7­32.2 6.5 7.8 19.3­38.7
Mean/Range/Total
0.069 ± 0.002 4.2­79.7
2 15 1 2 322 13 4 98 99 17 2 147 17 31 8 65 1 1 2 4 24 1 1 4 1,742
Cumulative biomass ingrowth increased from 2.0 t ha-1 in 1988 to 17.6 t ha-1 by 2003. By 2003, the residual stems initially tallied in 1983 still accounted for most of the biomass (table 5). In 1983, standing biomass varied by topography, ranging from an average of 120.3 t ha-1 on the ridges to 197.7 t ha-1 at the summit (table 6). Biomass increased on all topographies through 1988 and then decreased on all but the summit by 1993. Losses continued on all plots through 1998, with biomass declining most in valleys and least on ridges. By 2003, only ridge topography showed an average increase in biomass since the initial measurements made 20 years earlier.
Species composition--Eighty species were tallied on the plots throughout the 20 years of measurement: 69 in 1983 and 1988, 68 in 1993, and 74 in 1998 and 2003 (appendix B). Five species were originally recorded and later lost: one in 1988, three in 1993, and one in 1998. Eleven species not previously recorded were first noted as ingrowth: one in 1988, two in 1993, six in 1998, and two in 2003. Eighteen deciduous species with 365 stems and 51 evergreen species with 2,337 stems were present on the plots in 1983 (appendix B). By 2003, deciduous species numbered 21 with 357 stems, and evergreen species numbered 55 with 2,178 stems.
16
Table 5--Summary of total aboveground biomass by year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Factor
1983
Year 1988 1993 t ha -1
1998
2003
Survivors a
138.7
Ingrowth by year b
0
Cumulative ingrowth c 0
Total biomass d
138.7
148.8 2.0 2.0 150.8
137.1 4.3 6.5 143.6
109.8 6.5 12.8 122.6
109.6 3.0 17.6 127.2
Percent survivors e Percent ingrowth f
100.0 98.7 95.5 89.6 86.2
0
1.3 4.5 10.4 13.8
a Biomass of the survivors of the original stems (tallied in 1983) to the indicated year. b Biomass of the ingrowth for the particular year. c Sum of all ingrowth to the year indicated. d Total biomass = biomass of survivors + biomass of cumulative ingrowth. e Percent biomass of the 3,378 stems tallied in 1983 to the indicated year. f Percent of the total biomass attributable to ingrowth since 1988.
Table 6--Summary of total aboveground biomass by topography and year for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Topography a
1983
1988
Year 1993 1998 t ha -1
2003
Ridge
120.3 135.5 131.2 117.8 124.6
Percent change b -- 12.7 9.1 -2.0 3.6
Slope
135.2 146.8 143.9 123.0 123.3
Percent change -- 8.2 6.4 -9.0 -8.8
Valley
148.8 159.2 142.4 113.2 122.5
Percent change -- 7.0 -4.3 -24.0 -17.7
Summit
197.7 206.3 210.3 190.2 182.9
Percent change -- 9.0 6.4 -3.8 -7.5
Total
138.7 150.8 143.6 122.5 127.2
Percent change -- 10.3 5.0 -10.4 -6.9
a Means for ridge, slope, and valley are based on 5 plots; data on the summit is based on 1 plot; mean for the total is based on all 16 plots. b Percent change from 1983 to date indicated.
In 1983, the five most common species accounted for 1,126 stems or 41.7 percent of all stems tallied; in 2003, they totaled 1,247 stems or 49.1 percent of all stems (appendix B). In 1983, the 10 most common species accounted for 1,775 stems or 65.7 percent of all stems tallied; in 2003, they totaled 1,711 stems or 67.4 percent. Also in 1983, 23 species were tallied no more than five times and 11 species but once. By 2003, 32 species were tallied no more than five times and 10 species but once. Maytenus elliptica, ranging from 343 individuals in 1983 to 443 in 2003, was the most common species throughout the study. Moreover, the latter species along with Faramea occidentalis showed considerable flux in ingrowth and mortality, notably after Hurricane Hugo. The survival of 1983 stems varied by species and ranged from 0 to 100 percent (appendix B). Among species tallied at least 100 times in 1983, those with the best 20-year survival rates were M. elliptica (95 percent survival), P. racemosa (94 percent), and Myrciaria floribunda (89 percent). These species also increased in numbers from 1983 to 2003 by 29, 10, and 22 percent, respectively. The greatest increase in stems during the 20 years, despite a survival rate of only 56 percent, was by F. occidentalis, which had 31 percent more stems in 2003. The aforementioned four species increased from 822 stems, or 30 percent of the 1983 total, to 1,014 stems, or 40 percent of the 2003 total (appendix B). The 10 percent survival rate of Nectandra coriaceae was the poorest for species with at least 100 stems. Three species tallied in the watershed are endemic to Puerto Rico and the U.S. Virgin Islands: Chrysophyllum pauciflorum, Coccothrinax alta, and Cordia rickseckeri (appendix B). Two exotics accounted for 15 stems in 1983 and four exotics for 46 stems in 2003. Garcinia mangostana and Melicoccus bijugatus were present in 1983 and persisted through 2003; Carica papaya entered in 1998 and disappeared by 2003. Ficus elastica and Leucaena leucocephala entered in 1993 and persisted through 2003.
17
Discussion Climate Bordeaux Mountain at 390 m does not reach the 600 to 750 m base of trade wind cumulus clouds in the Caribbean (Baynton 1968). Consequently, it does not present as formidable an obstacle as encountered on the more mountainous Caribbean islands where rainfalls are greater. St. John's climate is dry and is characterized by rain-laden tropical depressions, tropical storms, and hurricanes, as well as prolonged droughts. The 119-year record at Cruz Bay shows that annual precipitation ranged between 600 and 1900 mm and that total monthly rainfall was unpredictable and extremely variable by year (Brown and Ray 1993). Moreover, high monthly rainfalls did not necessarily mean that the entire month was wet; rather, that heavy downpours had occurred at least once or twice. At the beginning of measurements in 1983, the watershed was recovering from previous events, including a severe drought in 1967-68, a low-pressure system accompanied by strong winds in 1969, and the glancing impact from the massive and powerful Hurricane David in 1979 (Colуn-Dieppa and others 1991). Earlier, Hurricane Connie of 1955, a lowpressure system of 1960, and severe droughts in 1957 and 1964 probably caused some tree mortality. Earlier still, human settlement and associated land use dramatically influenced the watershed's forest resources (Knight 1999, Tyson 1987), causing changes in the relative abundances of species that will persist for centuries. The 20 years of measurement in the Cinnamon Bay watershed span an eventful period from 1989 to 1995, with two hurricanes and a pronounced drought, and two uneventful periods from 1983-88 and from 1996 to 2003 when these climatic phenomena did not occur. Hurricane Hugo of 1989 passed over the northeastern tip of Puerto Rico, about 100 km west of St. John (Brennan 1991). Meteorologists estimated sustained winds of 160 km hour-1 with gusts to 190 km hour-1 for nearby St. Thomas, based on radar observations and local damage (Reilly 1991, Weaver 1994). Moreover, in September of 1995, Hurricane Marilyn traversed the northern Virgin Islands with winds estimated at 155 km hour-1, destroying about 30 percent of the homes on St. John (Rappaport 1996).
Droughts have also had significant effects on the island's forests. The drought in 1994-95 was the driest 18-month period on St. John during the 20th century (Gibney 2004). Total rainfall at nearby Caneel Bay was only 54 percent of the 40-year average (Rogers and Reilly 1998). Near the end of the drought, the island's forests had very dry soils even within drainages, the landscape had a brownish cast, leaves dried and fell to the ground, and noticeably more light reached the forest understory. The accumulation of dry leaves in a loose arrangement on the soil surface, analogous to unnailed shingles on a roof, made walking up steep slopes difficult. Preliminary data for plots at Caneel Bay showed that mortality after the drought was greater than that reported for some sites after Hurricane Hugo (Rogers and Reilly 1998). It is noteworthy that the century's severest drought was followed by a hurricane, highlighting the extremes that characterize the climate of St. John. Forest Structure The 20-year fluctuation in total stem numbers-- an increase from 1983 to 1988, a decline from 1988 to 1998, then another increase through 2003 (fig. 4) --reflects distinct periods of forest development, as noted after the 1932 Hurricane San Cipriano in the Luquillo Mountain forests [Luquillo Experimental Forest (LEF)] in northeastern Puerto Rico (Crow 1980, Weaver 1989). The first period appears to be the maturing of the forest after disturbances that occurred before the initiation of measurements. The second period reflects stem losses due to hurricane impacts, and the last period shows the initiation of post-Hurricane Hugo recovery. The notable exception to the general pattern is the extremely high stem density on the summit plot in 1983 (tables 2 and 3). The continual decline of stems on the summit probably reflects a natural thinning, along with losses associated with the 1994-95 drought and Hurricane Marilyn. Biomass fluctuations, both by topographic position and total, parallel the trends in stem numbers (tables 5 and 6). The impacts of Hurricane Hugo in Cinnamon Bay watershed included defoliation, broken branches, split trunks, uprooted trees, immediate mortality, and delayed mortality up to 19 months after the storm (i.e., aboveground woody biomass decreased by 210 t ha-1 after 10 months and by 288 t ha-1 after 19 months) (Brown and Ray 1993; Weaver 1994, 1998).
18
Cruz Bay harbor. (Top) During dry conditions, June 1995; the 1995 drought was the driest on record during the 20th century. (Bottom) During humid conditions, June 1998. 19
The tallest trees on 44 percent of all plots were lost, including four of the five valley plots, where the greatest proportion of large trees occurred (Weaver 1994, 1998) (tables 2 and 3). Greater hurricane impacts on larger trees and those at low elevations in valleys were noted at other sites (Reilly 1991, 1994). The net impact was the creation of openings within the forest that allowed more light to reach the soil surface. The continual rise in cumulative ingrowth after1993 (fig. 4) indicates that sufficient light was available at the forest floor to stimulate regeneration and early growth of many species. After Hugo, increases in the density and diversity of seedlings were observed on the Hawksnest and L'Esperance plots, whereas decreases were evident on Bordeaux (Rogers and Reilly 1998). L'Esperance suffered the most damage whereas Bordeaux maintained a fairly dense understory after the storm. Direct and indirect light at all three sites, estimated from canopy photographs, decreased by about 50 percent 2 years later as the canopy recovered (Rogers and Reilly 1998). Proportions of stems in different crown classes changed considerably during the 20 years of measurement (fig. 5). Before Hurricane Hugo, the mature forest contained a moderate proportion of canopy trees that shaded a large number of suppressed stems. Hurricane damage either reduced or eliminated
the influence of many dominant and codominant stems (Weaver 1998), allowing more light to penetrate the forest. Consequently, the proportion of intermediate stems increased, and the proportion of suppressed stems decreased. Mean heights and mean diameters for all stems in 1983 varied little by topography, whereas the mean heights and mean diameters for dominant and codominant stems alone were greatest in valleys and smallest on ridges (Weaver and Chinea 1987) (table 7). Mean values by plot are heavily influenced by the inclusion of numerous small stems, whereas mean values for canopy trees alone better indicate topographic effects on height growth. Average basal areas were similar on all topographic positions except the summit, where the high stem density inflated the value (table 7). Structural components of the forest related to net primary production were previously determined for Cinnamon Bay (Weaver 1994, 1996): · Specific leaf areas--from 58 to 192 cm2 g-1 by species, averaging 99 for the forest · Average standing crop of loose litter--933 g m-2, partitioned among leaves (36 percent), woody (55 percent), fruits and flowers (4.5 percent), and miscellaneous material (4.5 percent)
Table 7--Summary of structural and species composition data in 1983 for the Cinnamon Bay watershed, St. John, U.S. Virgin Islands a
Factor (units) Mean height for all stems (m) Mean height, tallest trees (m) Mean d.b.h. for all stems (cm) Mean d.b.h., largest trees (cm) Mean basal area (m2 ha-1) Number by topography (total) b Number per plot (range) b
Topography
Valley
Slope
Ridge Summit
Mean (SE)
Total
Structure
8.4 (0.5) 29.7 (2.1) 9.3 (0.6) 18.7 (0.8) 29.6 (6.5)
8.4 (0.4) 19.1 (0.9) 10.2 (0.5) 12.2 (0.3) 31.3 (2.1)
7.2 (0.2) 13.5 (0.5) 8.0 (0.1) 9.7 (0.1) 27.6 (2.1)
7.5 (0.1) 14.6 (1.1) 7.9 (0.2) 10.6 (0.2) 43.6
8.0 (0.2) NA 9.1 (0.6) NA 30.4 (2.3)
Species composition
37 14­20
49 17­21
43 19­25
16
69
16
14­25
NA = Not applicable. a Source: Weaver and Chinea-Rivera (1987). b Plots: valley, slope, and ridge = 5 each; summit = 1.
20
· Standing herbivory--between 0.2 and 12.1 percent by species, with a weighted mean for all species of 4.5 percent The nearest comparable values geographically for island forests come from three different subtropical life zones along an elevational gradient in the LEF of Puerto Rico. Ascending this gradient through subtropical wet forest, lower montane wet forest, and lower montane rain forest in the LEF, the mean specific leaf area declines from 127 to 47 cm2 g-1, loose litter from 600 to 430 g m-2, and standing herbivory from 7 to 5 percent (Weaver and Murphy 1990). Mean aboveground woody biomass decreases from 190 to 80 t ha-1 along the same gradient. The Cinnamon Bay watershed values are within the range of those in the LEF except for loose litter, which decomposes more slowly in the drier environment. Forest Dynamics The 20-year mean annual d.b.h. growth for the 1,752 survivors in Cinnamon Bay was the same as the 5-year annual d.b.h. growth for 2,537 survivors between 1983 and 1988 (Weaver 1990). Moreover, the 20-year d.b.h. growth by crown classes was similar to and paralleled the 5-year d.b.h. growth by crown classes. D.b.h. growth generally slows as a forest matures. The Cinnamon Bay watershed, however, is currently recovering from numerous recent disturbances. A short-term decline in d.b.h. growth was noted for most tree species on plots at Bordeaux, Hawksnest, and L'Esperance after Hurricane Hugo (Reilly 1998). This phenomenon may be attributable to crown damage and to costs associated with crown recovery, including refoliation and the regrowth of branches and twigs. Similar comparisons were not run for the Cinnamon Bay dataset because the posthurricane measurements were confounded by 1.3 years of prehurricane growth (i.e., 5-year measurements were made in June 1988 and June 1993 with the hurricane in September 1989). In 1992, the total aboveground net primary productivity rate in the Cinnamon Bay watershed was estimated at 10.64 t ha-1 year-1 (Weaver 1996). The relatively high value had the following components: · A total litterfall rate of nearly 8.97 t ha-1 year-1 · A leaf litterfall rate of 5.1 t ha-1 year-1
· April and September peaks in leaf litterfall · April and October peaks in flower and fruit fall · An April peak in the fall of miscellaneous material · A herbivory rate of 4.6 percent per year (or 0.25 t ha-1 year-1) · A 5-year biomass change of 1.42 t ha-1 year-1 · A litterfall turnover rate of 0.96 times per year The nearest comparable values geographically for total aboveground net primary productivity rates (in t ha-1 year-1) again come from the elevational gradient in the LEF of Puerto Rico. Values there were subtropical wet forest 10.5, lower montane wet forest 7.6, and lower montane rain forest 3.7 (Weaver and Murphy 1990). The relatively high Cinnamon Bay watershed productivity was determined during the post-Hurricane Hugo recovery period (tables 2, 3, and 6). In contrast, the LEF values were from closed forests 30 to 50 years after major hurricane impact. Elsewhere on St. John, flowering peaks were noted in April and June, continuing at a moderate rate until September (Ray 1993, Ray and Brown 1994). Fruiting diminished between October and February, reaching a maximum during the dry season. The frequent hurricanes and pronounced droughts maintain the forests on St. John in a state of flux that influences d.b.h. growth rates, biomass accumulation, litterfall rates, and net primary productivity. Species Composition With 75 percent of the species and 86 percent of the stems evergreen, the Cinnamon Bay watershed classifies as dry evergreen woodland (Beard 1955, Woodbury and Weaver 1987). Species numbers varied in space, being greatest on slopes, intermediate on ridges and in valleys, and least on the single summit plot (Weaver and Chinea-Rivera 1987) (table 7). In the lower montane wet forest of the LEF, the cumulative number of species tallied in a similarly designed study was greatest on ridge topography, intermediate on slopes, and least in valleys (Weaver 2000). In the LEF, greater species numbers on ridges than on other topographies was attributed to two factors: the occurrence of rare species and higher stem densities on ridges. The net effect of stem density is to increase the sample size and the likelihood of encountering a new species. The histories of the Luquillo and Cinnamon Bay forests, however, are different. The
21
Litterfall baskets used during the productivity study in dry evergreen woodland on ridge plot #13, Cinnamon Bay watershed (February 1992).
Extension ladder used during canopy herbivory sampling in dry evergreen woodland on ridge plot #13, Cinnamon Bay watershed (February 1992).
upper areas of the LEF remain largely undisturbed by humans. In contrast, the natural vegetation of the Cinnamon Bay watershed, and virtually all of St. John, was formerly devastated by plantation agriculture. The 20 species most frequently tallied in the Cinnamon Bay watershed showed site preferences along elevational and topographic gradients (Weaver and Chinea-Rivera 1987): · Torrubia fragrans, Ardisia obovata, Myrcia citrifolia, and Eugenia procera are very common on the summit, followed by ridge topography at high elevation; Guettarda scabra and Cordia rickseckeri have a similar distribution but are less common. · Maytenus elliptica, Sabinea florida, and P. racemosa are most common on ridges, the
first and second at mid-elevations and the third at high elevation. · Daphnopsis americana is found mainly on ridges at all elevations, particularly at mid-to-high elevations. · Myrciaria floribunda and N. coriaceae have relatively even distributions with regard to topography, the first being most common at low elevations and the second with a dip in number of stems at mid-elevations. · Bursera simaruba is most common on slopes and Capparis cynophylophora on slopes and ridges, both at low to mid-elevations. · Guettarda parviflora and Chrysophyllum pauciflorum are most common in valleys and on slopes at low elevation.
22
· Faramea occidentalis and Quararibea turbinata are most common in valleys at mid-elevations, Inga fagifolia at mid-to-high elevations, and Casearia guianensis in valleys at low to high-elevations. · Torrubia fragrans, tallied on 15 of the 16 plots in the watershed, has the highest plot frequency. Climatic events affect tree species differently. Hugo damaged a total of 8.4 percent of all stems but damage varied among 24 species with 20 stems (Weaver 1998). Damage ranged from 0.6 percent of all P. racemosa to 22.8 percent of all N. coriaceae. Damage also varied along gradients or in accordance with certain factors: · By elevation: 9.5 percent of the trees above 180 m in elevation were damaged versus 7.0 percent of the trees below 180 m · By topography: 11.3 percent of the trees in the valleys were damaged, 5.3 percent on slopes, 7.9 percent on ridges, and 10.6 percent on the summit · By aspect: 12.4 percent of the trees facing a northerly direction (N10°W to N) were damaged as opposed to 6 percent facing west (N30°W to W) and 7.5 percent facing east (N30°E to E) · By slope: 14 percent of the stems on relatively level terrain (i.e., slopes 5 percent) were damaged as opposed to 5.6 percent of the stems on intermediate slopes (i.e., slopes between 20 and 25 percent) and 7.5 percent of the stems on steep terrain (i.e., slopes 40 percent) The secondary forest in the Cinnamon Bay watershed is among the oldest on the island (table 1). Species distributions and abundances in other watersheds with different rainfall and land use history most likely will show other trends. Moreover, the total sampling area in this study of Cinnamon Bay is relatively small, with each plot representing a single topographic position along an elevational gradient. Earlier research on a 4-ha plot in moist semi-evergreen forest (apparently, basin moist forest) of Reef Bay showed a preponderance of clumped tree distributions with short distances between trees (Forman and Hahn 1980). Microhabitats within the forest were suggested as a possible factor to account for tree distributions on that plot. Species numbers also varied in time, being lower in years before and immediately following Hurricane
Hugo than in 1998 and 2003 (appendix B). Similar trends were noted about 14 years after Hurricane San Cipriano in both the subtropical wet and lower montane wet forests of Puerto Rico's Luquillo Mountains (Crow 1980, Weaver 1989). A few years after the storms, numerous stems regenerated in openings, including many secondary species (Crow 1980). Species diversity may be determined several ways, including equitable representation, and requires interpretation (Peet 1974). Although the total number of species in the Cinnamon Bay watershed increased between 1983 and 2003, the total number of stems declined by about 6 percent; moreover, four of the most common species, Maytenus elliptica, Myciaria floribunda, P. racemosa, and F. occidentalis, also increased their representation among all species from 30 to 40 percent (fig. 6, appendix B). The first three of these species were observed to be among the most resistant to hurricane impact within the watershed (Weaver 1998). In contrast, N. coriaceae was among the species most heavily damaged during Hugo (Weaver 1998). In 1956, after Hurricane Betsy in Puerto Rico, N. coriaceae showed a similar loss of stems (Wadsworth and Englerth 1959). Both F. occidentalis and Maytenus elliptica demonstrated considerable dynamics with regard to ingrowth and mortality, particularly after the hurricanes (appendix B). Exotics were not common on the plots, accounting for only 0.6 percent of the total stems in 1983 and 1.9 percent in 2003. The openings created by the hurricanes allowed the number of exotic species to double and the number of exotic stems to triple from 1983 to 2003 (appendix B). Most notable were increases of Meliococcus bijugatus near mature trees and the arrival of L. leucocephala, which was previously absent on the plots. In southwestern Puerto Rico, only one-third of the 23 exotic species introduced into late secondary subtropical dry forest at Guбnica were judged as successful (Chinea 1990). The remaining species were either scarce or had disappeared. Of the exotics currently tallied on the Cinnamon Bay plots, M. bijugatus, unsuccessful at Guanica, is likely to persist for a considerable period. The species is capable of regenerating and competing in forest stands and is likely to increase during the next century (Francis
23
Number of stems
500
450
1983
2003
400
350
300
250
200
150
100
50
0 1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 Number of species
Figure 6--Abundance of stems by number of species for the individual plots in 1983 and 2003.
and Liogier 1991). It is already very abundant at L'Esperance and Hawksnest (Earhart and others 1988). Leucaena leucocephala is abundant in young secondary forests elsewhere on St. John but will probably decline at Cinnamon Bay in the absence of major disturbance. Garcinia mangostana and Ficus elastica are not regenerating in Cinnamon Bay and will likely disappear over time. In general, exotics appear to be less successful within intact late secondary forests than in recently abandoned pastures or storm-created forest gaps. Conclusions Caribbean islands like St. John that do not reach the cumulus cloud base at 600 to 750 m are too low to induce much local precipitation. Therefore, their forest ecosystems are exposed not only to an annual procession of rain-bearing tropical depressions along with occasional tropical storms and hurricanes but also to recurrent droughts of varying intensity and length. To date, 20 years' monitoring in the Cinnamon Bay watershed has provided a wealth of information on forest structure, stand dynamics, and species composition during a brief period with two major hurricanes and a severe drought. Indeed, major disturbances are as much a part of the island's climatic regime as are relatively quiet periods.
Monitoring the 16 Cinnamon Bay plots, stratified by environmental gradients in elevation and topography, should continue as long as possible. Dry forests similar to those found on St. John have experienced so much human intervention throughout the world that some consider them to be threatened (Janzen 1988, Ray and others 1998). The only examples of permanent plot monitoring in Caribbean dry forests with > 15 years of data are on St. John (table 1) and in Puerto Rico's Guanica Forest (Murphy and Lugo 1986a, 1986b). The extent to which the complex patterns observed in the Cinnamon Bay watershed may be extrapolated to other sites or future climatic events on St. John remains as conjecture. First, the study design, although replicated by topography, is confined to the northern slopes of the island. Moreover, since the plots are located along an elevational gradient, each plot provides observations that reflect a single combination of factors. Other watersheds vary in morphology, rainfall, previous agricultural practices, time since agriculture was abandoned, and consequently, in forest structure and species composition. Storms or droughts may vary in intensity, duration, or recurrence. In the case of hurricanes, a difference in prestorm conditions, trajectory, wind velocity, associated tornados, and rainfall could yield varying impacts, even within the same watershed (Weaver 1998). Moreover, as
24
observed already, Hurricane Hugo showed differential impacts by aspect with greater damage on the south (exposed) side of St. John than the north side (Rogers and Reilly 1998). Continued human intervention (e.g., clearing for road construction or home building) on private properties within the Park (inholdings) or near its border is another factor that varies by site and worsens with time. Localized clearing breaks up the integrity of the forest, probably lessens its resistance to storms, and certainly facilitates the invasion of secondary species and exotics. Acknowledgments The project began through the enthusiasm of Robert Brander and continued with the generous support of Caroline Rogers. In 1982, Roy O. Woodbury, now deceased, surveyed St. John's flora. Working with him in the field was a memorable experience. In addition, several groups assisted during the 20 years of work on St. John, including the U.S. Department of the Interior Biological Resources Division with small grants and field support, the U.S. Department of the Interior National Park Service staff with their reference library, and Friends of the Virgin Islands National Park with other assistance. Individual field help was received from Giglia Beretta, Elizabeth Ford, Juan Ramirez, Nelson Repollet, Carlos Rivera, Alberto Rodrнguez, Carlos Rodrнguez, Myriam Salgado, and Ivan Vicens. Frank H. Wadsworth, past director of the International Institute of Tropical Forestry (IITF); Thomas Brandeis, a researcher with the Forest Inventory Program; and Ernesto Medina, a researcher with the Instituto Venezolano de Investigaciones Cientнfcas, offered valuable comments on the manuscript. Maya Quiсones of the Geographic Information System and Remote Sensing Laboratory of the IITF helped develop the maps. This work was made possible through grant IAA# F211703-0009 from the U.S. Department of the Interior National Park Service, Atlanta, GA, and was done in cooperation with the University of Puerto Rico at Rнo Piedras. Endnotes CH2M Hill. 1979. A sediment reduction report to the Department of Conservation and Cultural Affairs, Government of the U.S. Virgin Islands, St. Thomas,
U.S. Virgin Islands. Unpublished report available at CH2M Building, 3011 SW Williston Road, Gainesville, FL. 32608. Robertson, William B., Jr. 1957. Biology report: initial study and development survey, Virgin Islands National Park. Homestead, FL: 54 p. Unpublished report on file at Library, U.S. Department of the Interior Geological Survey, Natural Resources Conservation Service, Virgin Islands National Park, Biosphere Reserve Center, Lind Point, 1300 Cruz Bay Creek, St. John, VI, 00830. Literature Cited Anonymous. 1988. Abstracts of Virgin Islands Biosphere Reserve Res. Rep. 2-28. Report 1. St. Thomas, VI: U.S. Department of the Interior National Park Service; Virgin Islands Resource Management Cooperative, Virgin Islands National Park. 36 p. Acevedo-Rodrнguez, Pedro. 1993. Additions to the flora of St. John, United States Virgin Islands. Brittonia. 45(2): 130-137. Acevedo-Rodrнguez, Pedro; Strong, Mark T. 2005. Monocots and gymnosperms of Puerto Rico and the Virgin Islands. Contributions from the United States National Herbarium. 52:1-415. (65 figures). Acevedo-Rodrнguez, Pedro [and others]. 1996. Flora of St. John, U.S. Virgin Islands. Memoirs of the New York Botanical Garden. 78: 1-581. Ackerman, James D. 1992. The orchids of Puerto Rico and the Virgin Islands. Rнo Piedras, PR: University of Puerto Rico Press. 168 p. Anderson, Donald M.; MacDonald, Lee H. 1998. Modeling road surface sediment production using a vector geographic information system. Earth Science and Landforms. 23: 95-107. Askins, Robert A.; Ewert, David N. 1992. Population studies of migratory birds in Virgin Islands National Park. Park Science. 12: 12-13. Baker, F.S. 1950. Principles of silviculture. New York: McGraw-Hill. 414 p. Baynton, Harold W. 1968. The ecology of an elfin forest in Puerto Rico: 2. The microclimate of Pico del Oeste. Journal of the Arnold Arboretum. 49(4): 419-430. Beard, J.S. 1944. Climax vegetation in tropical America. Ecology. 25: 127-158. Beard, J.S. 1949. Natural vegetation of the Windward and Leeward Islands. Oxford Forestry Memoirs. 21: 1-192. Beard, J.S. 1955. The classification of tropical American vegetationtypes. Ecology. 36(1): 89-100. Bowden, Martyn J.; Fischman, Nancy; Cook, Patricia [and others]. 1970. Climate, water balance, and climatic change in the northwest Virgin Islands. St. Thomas, VI: College of the Virgin Islands, Caribbean Research Institute. 127 p. Brennan, J.W. 1991. Meteorological summary of Hurricane Hugo. Journal of Coastal Research. Special Issue 8: 1-12. Britton, N.L. 1918. The flora of the American Virgin Islands. Memoirs. Brooklyn Botanic Garden. Brooklyn, NY: 19-118.
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Britton, N.L.; Wilson, P. 1923-1926. Descriptive flora-- spermatophyta. Botany of Porto Rico and the Virgin Islands. Vols. 5, 6. In: Scientific Survey of Porto Rico and the Virgin Islands. New York: New York Academy of Sciences. 1,289 p. Brown, Becky J.; Ray, Gary J. 1993. Restoring Caribbean dry forest: a systems framework for site analysis and restoration research. In: Leith, H.; Lohmann, M., eds., Restoration of tropical forest ecosystems. Amsterdam, Netherlands: Kluwer Academic Publishers: 53-61. Brown, Becky J.; Ray, Gary J.; Mendelson, Tamra C. 1992. Restoring the degraded dry forests of Virgin Islands NP. Park Science. 12(2): 6-7. Bullen, Ripley P. 1962. Ceramic periods of St. Thomas and St. John Islands, Virgin Islands. Report 4. Maitland, FL: Central Florida Museum, William L. Bryant Foundation.: 1-49. Calvesbert, Robert J. 1970. Climate of Puerto Rico and the U.S. Virgin Islands. Climatography of the United States 60-52. Silver Spring, MD: U.S. Department of Commerce, Environmental Science Services Administration, Environmental Data Service. 29 p. Chinea, J.D. 1990. Бrboles introducidos a la Reserva de Guбnica, Puerto Rico. Acta Cientнfica. 4(1-3): 51-59. Cochran, Hamilton. 1937. These are the Virgin Islands. New York: Prentice Hall. 236 p. Colуn-Dieppa, E.; Torres-Sierra, H. Ortiz, J. 1991. U.S. Virgin Islands: floods and droughts. U.S. Department of the Interior Water Supply Paper 2375. San Juan, PR: U.S. Department of the Interior, Geological Survey: 521-526. Cosner, Oliver J.; Bogart, Dean B. 1972. Water in St. John, U.S. Virgin Islands. San Juan, PR: U.S. Department of the Interior, Geological Survey; National Park Service; Government of the Virgin Islands. 46 p. + map. Crow, Thomas R. 1980. A rainforest chronicle: a 30-year record of change in structure and composition at El Verde, Puerto Rico. Biotropica. 12(1): 42-55. Dallmeier, F.J.; Comiskey, J.A.; Ray, G. 1993. User's guide to the Virgin Islands Biosphere biodiversity plot 01, U.S. Virgin Islands. Washington, DC: Smithsonian Institution/Man and the Biosphere Biological Diversity Program; National Park Service. 210 p. Dallmeier, Francisco; Ray, Gary. 1992. Smithsonian Institution's permanent monitoring plot: research opportunities in a rare semievergreen dry woodland. Park Science. 12(2): 5. Donnelly, Thomas W. 1966. Geology of St. Thomas and St. John, U.S. Virgin Islands. In Hess, H.H., ed. Caribbean geological investigations. Geological Society of America Memoir. 98: 85-176. Dookhan, Isaac. 1974. A history of the Virgin Islands of the United States. St. Thomas, VI: Caribbean Universities Press and Bowker Publishing Company for the College of the Virgin Islands. 321 p. Earhart, John E.; Reilly, Anne E.; Davis, Matt. 1988. Initial inventory of three permanent forest plots in the Virgin Islands National Park. Biosphere Reserve Res. Rep. 27. St. Thomas, VI: Virgin Islands Resource Management Cooperative, Virgin Islands National Park. 128 p. Eggers, Baron H.F.A. 1879. Flora of St. Croix and the Virgin Islands. Bulletin 13. Washington, DC: U.S. Department of the Interior, U.S. National Museum; Government Printing Office. 118 p.
Ewel, John J.; Whitmore, Jacob L. 1973. The ecological life zones of Puerto Rico and the U.S. Virgin Islands. Forest Res. Pap. ITF-18. Rнo Piedras, PR: Institute of Tropical Forestry. 72 p. Forman, Richard T.T.; Hahn, D. Caldwell. 1980. Spatial patterns of trees in a Caribbean semi-evergreen forest. Ecology. 61: 1267-1274. Forthun, Gloria. 2005. Tropical systems affecting the U.S. Virgin Islands 1989-1999 as compared to Hurricane Hugo. SERCC Research Series Report. Columbia, SC: South Carolina Department of Natural Resources, Southeast Regional Climate Center. 29 p. Francis, J.K.; Liogier, H.A. 1991. Naturalized exotic tree species in Puerto Rico. Gen. Tech.Rep. SO-82. New Orleans: U.S. Department of Agriculture Forest Service, Southern Forest Experiment Station. 12 p. Gibney, Eleanor. 2004. Cinnamon Bay loop trail forestry conference field tour. In: Zimmerman, T.W.; Weaver, P.L.; Miller, J.M.; Combie, V., eds. Proceedings of the 7th annual Caribbean urban forestry conference 11th Caribbean foresters meeting, The future of trees in the Caribbean: biology, planning and management. St. Thomas, VI: University of the Virgin Islands Cooperative Extension Service: 79-86. Haas, William H., ed. 1940. The American empire: a study of the outlying territories of the United States. Chicago: University of Chicago Press. 408 p. Harman, Jeanne Perkins. 1961. The Virgins: magic islands. New York: Appleton-Crofts. 269 p. Hatch, Charles E., Jr. 1972. Virgin Islands National Park--St. John Island ("the quiet place") with special reference to Annaberg Estate, Cinnamon Bay Estate. Washington, DC: Office of Archeology and Historic Preservation. 220 p. Holdridge, L.R. 1967. Life zone ecology. Rev. ed. San Josй, Costa Rica: Tropical Science Center. 206 p. Howard, Richard A. 1979. Flora of the Lesser Antilles, Leeward and Windward Islands. Monocotyledonaceae. Jamaica Plain, MA: Arnold Arboretum, Harvard University. Vol. 3. 586 p. Howard, Richard A. 1988-89. Flora of the Lesser Antilles, Leeward and Windward Islands. Dicotyledonaceae. Jamaica Plain, MA: Arnold Arboretum, Harvard University. Vols. 4-6. Janzen, D.H. 1988. Guanacaste National Park: tropical ecological and biocultural restoration. In: Cairns, John, Jr. Rehabilitating damaged ecosystems. Boca Raton, FL: CRC Press: 143-192. Jordan, Donald G. 1972. Land-use effect on the water regimen of the U.S. Virgin Islands. U.S. Department of the Interior, Geological Survey, Professional Pap. 800-D. In: Geological Survey Research 1972: D 211-216. Kemp, Bernard A. 1990. Basketmaking on the island of St. John. The Clarion. 15(3): 52-59. Knausenberger, Walter I.; Matuszak, John M.; Ackerman Thomas, Tammy. 1987. Herbarium of the Virgin Islands National Park: consolidation and curation of a reference collection. Biosphere Reserve Res. Rep. 18A. St. Thomas, VI: Virgin Islands Resource Management Cooperative, Virgin Islands National Park. 51 p. Knight, David W. 1999. A brief history of the Cinnamon Bay Estate on St. John in the Danish West Indies 1718-1917. St. Thomas, VI: Little Norside Press. 88 p.
26
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Ray, Gary Joseph. 1993. The ecological restoration of a Caribbean dry forest on the island of St. John, U.S. Virgin Islands. Madison, WI: University of Wisconsin. 119 p. Ph.D. dissertation. Ray, Gary J.; Brown, Becky J. 1994. Seed ecology of woody species in a Caribbean dry forest. Restoration Ecology. 2(3): 156-163. Ray, Gary J.; Brown, Becky. 1995a. The structure of five successional stands in a subtropical dry forest, St. John, U.S. Virgin Islands. Caribbean Journal of Science. 31(3-4): 212-222. Ray, Gary J.; Brown, Becky J. 1995b. Restoring Caribbean dry forests: evaluation of tree propagation techniques. Restoration Ecology. 3(2): 86-94. Ray, Gary J.; Dallmeier, Francisco; Comiskey, James A. 1998. The structure of two subtropical dry forest communities on the island of St. John, U.S. Virgin Islands. In: Dallmeier, F.; Comiskey, J.A. (eds.). Forest biodiversity in North, Central and South America, and the Caribbean: research and monitoring. Washington, DC: Smithsonian Institution: 367-284. Reid, L.M.; Dunne, T. 1984. Sediment production from forest road surfaces. Water Resources Research. 20(11): 1753-1761. Reilly, Anne E. 1991. The effects of Hurricane Hugo in three tropical forests in the U.S. Virgin Islands. Biotropica. 23(4a): 414-419. Reilly, A.E. 1992. Impacts of natural and human disturbance on forests of St. John, U.S. Virgin Islands. Park Science. 12(2): 3-4. Reilly, Anne Elizabeth. 1994. Natural disturbance and short-term dynamics in three Caribbean forests on St. John, U.S. Virgin Islands. Athens, GA: University of Georgia. 131 p. Ph.D. dissertation. Reilly, Anne E. 1998. Hurricane Hugo: winds of change ... or not? Forest dynamics on St. John, U.S. Virgin Islands. In: Dallmeier, F.; Comiskey, J.A. (eds.) Forest biodiversity in North, Central and South America, and the Caribbean: research and monitoring. Washington, DC: Smithsonian Institution: 349-366. Reilly, Anne E.; Earhart, John E.; Prance, Ghillean T. 1990. Three sub-tropical secondary forests in the U.S. Virgin Islands: a comparative quantitative ecological inventory. Advances in Economic Botany. 8: 189-198. Rivera, Luis H.; McKenzie, William E.; Williamson, Henry H. 1966. Soils and their interpretation for various uses: St. Thomas and St. John, American Virgin Islands. San Juan, PR: U.S. Department of Agriculture, Soil Conservation Service, Caribbean Area. 52 p. Rivera, Luis H; Frederick, Wayne D.; Farris, Cornelius [and others]. 1970. Soil survey of the Virgin Islands of the United States. Washington, DC: U.S. Department of Agriculture, Soil Conservation Service. 78 p. + maps. Robertson, William B., Jr. 1962. Observations of the birds of St. John, Virgin Islands. Auk 79: 44-76. Robinson, Alan H.; Henle, Fritz. 1978. Virgin Islands National Park: the story behind the scenery. Las Vegas, NV: KC Publications. 48 p. Rogers, Caroline S. 1990. Responses of coral reefs and reef organisms to sedimentation. Marine Ecology Progress Series. 62: 185-202. Rogers, Caroline S. 1992. An integrated approach to marine and terrestrial research in Virgin Islands National Park and Biosphere Reserve. Park Science 12(2): 1, 27.
27
Rogers, Caroline S.; Reilly, Anne E. 1998. Insights into forest dynamics from long-term monitoring on St. John, U.S. Virgin Islands. In: Dallmeier, F.; Comiskey, J.A. (eds.) Forest biodiversity in North, Central and South America, and the Caribbean: research and monitoring. Washington, DC: Smithsonian Institution: 323-332. Rogers, Caroline S; Teytaud, Robert. 1988. Marine and terrestrial ecosystems of the Virgin Islands National Park and Biosphere Reserve. Biosphere Reserve Res. Rep. 29. St. Thomas, VI: U.S. Department of the Interior, National Park Service; Virgin Islands Resource Management Cooperative; Island Resources Foundation. 112 p. Sleight, Frederick W. 1962. Archaeological reconnaissance of the island of St. John, United States Virgin Islands. Report 3. Maitland, FL: Central Florida Museum, William L. Bryant Foundation,: 1-49. Southeast Regional Climate Center. 2003. Catherinburg, Virgin Islands NCDC 1971-2000 monthly normals. [email protected] (access date: November 11, 2003) Torres-Sierra, Heriberto; Rodrнguez-Alonso, Teresita. 1987. U.S. Virgin Islands water supply and use. U.S. Geological Survey Water Supply Paper 2,350. In: National water supply summary--water supply and use: U.S. Virgin Islands. San Juan, PR: U.S. Department of the Interior, Geological Survey: 485-490. Tyson, Jr., George F. 1987. Historic land use in the Reef Bay, Fish Bay and Hawksnest Bay watersheds, St. John, U.S. Virgin Islands, 1718-1950. Biosphere Reserve Res. Rep. 19. St. Thomas, VI: Virgin Islands Resource Management Cooperative, Virgin Islands National Park. 54 p. Varlack, Pearl; Harrigan, Norwell. 1977. The Virgins: a descriptive and historical profile. St. Thomas, U.S. Virgin Islands College of the Virgin Islands, Caribbean Research Institute. 72 p. Wadsworth, F.H.; Englerth, G.H. 1959. Effects of the 1956 hurricane on forests in Puerto Rico. Caribbean Forester. 20(1-2): 38-51. Weaver, Peter L. 1989. Forest changes after hurricanes in Puerto Rico's Luquillo Mountains. Interciencia. 14(4): 181-192.
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28
Appendix A Chronology of major events (exploration, settlement, forest exploitation, forest recovery, terrestrial research, and tourism) in the history of St. John, U.S. Virgin Islands, with emphasis on the Cinnamon Bay watershed
Year
Event
B.C. 1700450 450225
Archaic period pre-ceramic sites on northern Virgin Islands suggest possible activity in Cinnamon Bay. A pre-ceramic group (Ciboney) migrate through the Lesser Antilles from Venezuela and establish at Krum Bay in nearby St. Thomas.
A.D. 100400
Arawaks arrive in the Virgin Islands; occupation of St. John is indicated by materials collected from Cinnamon Bay, Coral Bay, and Cruz Bay.
1400s Caribs raid the Virgin Islands, attacking the more sedentary Arawaks. 1493 On November 14, Columbus lands at Salt River, St. Croix; on November 17, he sails past St. John and names the Virgin Islands.
1595 Sir Francis Drake anchors in the Virgin Islands, lending his name to the channel between St. John and Tortola.
1671 1672 1675 1684
Denmark and Norway establish a trading post on St. Thomas to exploit the Caribbean by means of the Danish West India and Guinea Company. First consignment of African slaves arrives in St. Thomas. Danes take possession of St. John, leaving two men, but make no attempt to colonize the island. Denmark formally takes possession of St. John.
1717 1725 1727 1729
Governor Erik Bredal begins the first settlement on St. John, followed by other migrations
in 1721 and 1724-25; subsequently, the total number of inhabitants varies as follows: 43
in 1717; 800 in 1728; 1,295 in 1733; 1,622 in 1739; 2,434 in 1773; 2,500 in 1841; 925
in 1901; 959 in 1917; 720 in 1930 and 1940; 749 in 1950; 925 in 1960; 3,500 in 1990;
and 4,300 in 2001.
St. John is a sugar-producing center; large trees are absent from the landscape.
Peter Durloe from Holland is the first to settle at Cinnamon Bay; Cinnamon Bay
estate has 11 documented enslaved laborers; subsequent estimates vary as
follows: 54 from 1738 to 1741, 53 in 1767, 69 in 1776, 99 in 1780, 82 in 1783, 75
in 1791-92, 79 in 1799, 113 in 1805, 81 in 1823 and 1835, 93 in 1842, and 91 in 1845.
Plantations in St. John total 87; subsequently they vary as follows: 109 in 1733, 110
in 1739, 83 in 1760, 69 in 1773, and 65 in 1800.
continued
29
Appendix A (continued) Chronology of major events (exploration, settlement, forest exploitation, forest recovery, terrestrial research, and tourism) in the history of St. John, U.S. Virgin Islands, with emphasis on the Cinnamon Bay watershed
Year
Event
1733 Drought destroys crops and causes food shortages; harsh treatment of slaves leads to a revolt in November, during which one-third of the white inhabitants are killed and one-half of the plantations are destroyed; slaves hold the island for 6 months. 1734 Slave insurrection is crushed by French soldiers from Martinique. 1730s The occupation of Cinnamon Bay watershed by the Jansen family peaks. 1741 Moravian missionaries arrive from Germany and introduce basket-making. 1780s Cinnamon Bay is a well-developed sugar estate; a topographic and land use map shows that 40 percent of St. John is completely cleared. 1792 Denmark is first European nation with colonies in the West Indies to abolish the slave trade. 1796 Area in sugar cane on St. John was 750 ha (15 percent), perhaps near the maximum; in 1805, it was about 15 percent and in 1847 about 6.5 percent.
1803 Danish transatlantic slave trade ceases. 1805 Considerable land in Cinnamon Bay watershed remains wooded or uncultivated. 1820 Epidemics in the Virgin Islands: in 1820 and 1843, small-pox spreads; in 1854, cholera; in 1867, both cholera and small-pox; in 1932, malaria. 1823 Nearly three-quarters of Cinnamon Bay provides fuel and the occasional harvest of fruits and fowl. 1848 Governor General Peter von Scholten orders the emancipation of slaves. 1865 The United States first expresses an interest in purchasing the Virgin Islands from Denmark to develop a naval station. 1868 Last attempt to produce sugar cane in Cinnamon Bay ends; new owner introduces livestock and dairy production. 1870s Sugar production declines on St. John. 1879 Eggers catalogs the flora of the Virgin Islands with some specimens collected from St. John and notes that the island has considerable forest cover. 1880s Cinnamon Bay residents harvest bay rum tree (Pimenta racemosa) leaves and berries to produce bay rum oil, the island's most important industry through the 1940s. 1884 Cinnamon Bay estate is reported to be all in bush (secondary forest). 1898 During the Spanish-American War, U.S. negotiations with Denmark to purchase the Virgin Islands are suspended.
1900s Early in century, cattle graze in the Cinnamon Bay watershed.
1917 The United States buys the Virgin Islands from Denmark; livestock, mainly cattle, graze on
some estates; only 3 percent of the island is under cultivation.
1920 Bay rum harvest reaches its peak.
1930s A few tourists arrive in the Virgin Islands; subsequently, they increase as follows: 55,000 in
1962; 281,000 in 1972; 970,000 in 1982; 1.9 million in 1992; and 2.3 million in 2002.
1952 The Virgin Islands Tourist Development Board comes into existence; Laurence Rockefeller
buys and donates about 2,850 ha, or 55 percent of St. John, to the U.S. Department of
Interior Park Service.
1956 President Eisenhower signs Public Law 85-925 authorizing the establishment of the Virgin
Islands National Park.
continued
30
Appendix A (continued) Chronology of major events (exploration, settlement, forest exploitation, forest recovery, terrestrial research, and tourism) in the history of St. John, U.S. Virgin Islands, with emphasis on the Cinnamon Bay watershed
Year
Event
1962 1966 1976 1982 1983 1995
Marine waters totaling 2,287 ha are added to the National Park. A soil survey of the Virgin Islands is completed; in 1980, soil taxonomy for the island is revised. The Virgin Islands National Park is designated as a Biosphere Reserve. The Virgin Islands Resource Management Cooperative is formed among 14 entities to initiate baseline research in the Park. Forest monitoring: the U.S. Department of Agriculture Forest Service initiates permanent forest monitoring in the Cinnamon Bay watershed; subsequently, monitoring begins at Bordeaux, Hawksnest, and L'Esperance in 1984 by the New York Botanical Garden; at Caneel Hill, Cinnamon Bay, Lameshur, and Mary Point in 1988 by the University of Wisconsin; and at Caneel Hill and Minna Hill in 1991 by the Smithsonian Institution. Flora of St. John is completed.
2006
The U.S. Park Service hosts a 3-day conference entitled "Science in the Park" to celebrate the 50th anniversary of the Virgin Islands (VI) National Park, the 40th anniversary of the VI Environmental Resource Station (VIERS), and the 30th anniversary of the VI International Biosphere Reserve.
Sources: Acevedo-Rodrнguez and others 1996; Britton 1918; Colуn-Dieppa and others 1991; Dookhan 1974; Earhart and others 1988; Eggers 1879; Haas 1940; Hatch 1972; Harman 1961; Knight 1999; Larsen 1986; Low and Valls 1985; Lugo-Lуpez and Rivera 1980; MacDonald and others 1997; Near 2003. Raphael 1967; Ray and Brown 1995a; Ray and others 1998; Reilly 1991; Rivera and others 1966; Rivera and others 1970; Robertson 1957 (see endnotes); Tyson 1987; Varlack and Harrigan 1977; Weaver 1994, 1998; Zabriskie 1918.
31
32
Appendix B Stem density by species and year on 16 plots totaling 0.8 ha in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Species Acacia macracantha Humb. & Bonpl. ex Willd. a Amyris elemifera L. Andira inermis (W. Wright) Kunth ex DC. a Ardisia obovata Desv. ex Hamilton Bourreria succulenta Jacq. Byrsonima coriacea (Sw.) DC. Bucida buceras L. Bursera simaruba (L.) Sarg. a Capparis cynophallophora L. Capparis flexuosa (L.) L. Capparis frondosa Jacq. Capparis indica (L.) Druce Casearia decandra Jacq. a Casearia guianensis (Aubl.) Urban Celtis trinervia Lam. a Chrysophyllum pauciflorum Lam. b Citharexylum fruticosum L. Clusia rosea Jacq. Coccoloba swartzii Meisn. Coccoloba venosa L. a Coccothrinax alta (O.F. Cook) Becc. b Cordia alliodora (Ruiz & Pavуn) Oken Cordia rickseckeri Millsp. a, b
1983 Total
Ingrowth
1988 Mortality
Total
Ingrowth
1993 Mortality
Total
Ingrowth
1998 Mortality
Total
Ingrowth
2003 Mortality
Survival Total 1983­2003 percent
5
5
2
3
1
2
2
40
1
1
1
0
0
13
171
14
7
6
3
38
41
1
1
10
1
6
22
3
51
8
40
30
1
11
1
15
1
1
12
13
172
29
7
6
3
38
41
2
2
10
5
7
1
3
22
3
48
2
8
2
38
2
1
30
1
10
1
16
3
12
22
179
8
7
1
6
3
38
2
3
40
2
15
8
4
2
20
7
9
41
8
1
2
38
3
1
29
7
3
1
1
1
18
9
3
9
36
151
9
8
6
3
1
39
1
7
33
2
3
12
2
10
3
11
16
1
13
28
2
4
5
1
40
2
8
21
4
2
2
1
1
2
25
13
9
69
30
130
50
8
100
1
5
83
3
100
5
35
84
1
32
73
2
100
1
11
80
13
100
3
14
27
30
51
5
50
2
40
85
3
22
57
1
2
0
1
100
5
33
60
13
3
16
6
1
21
2
19
4
23
77
10
1
33
11
1
32
1
1
10
1
32
4
3
7
3
33
2
7
70
2
33
79
countinued
33
Appendix B (continued)
Stem density by species and year on 16 plots totaling 0.8 ha in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Species
1983
1988
1993
1998
Total Ingrowth Mortality Total Ingrowth Mortality Total Ingrowth Mortality Total
Cordia sulcata DC. a
14
Cordia collococca L. a
6
Crescentia cujete L. a
1
Daphnopsis americana (Mill.)
J.R. Johnston
43
2
Erythroxylum rotundifolium Lunan a 32
Eugenia monticola (Sw.) DC.
20
1
Eugenia procera (Sw.) Poir.
123
12
Eugenia pseudopsidium Jacq.
2
Faramea occidentalis (L.) A. Rich. 203
42
Ficus laevigata Vahl
8
Garcinia magostana L. c
2
Guazuma ulmifolia Lam.
5
Guettarda elliptica Sw.
80
Guettarda parviflora Vahl
6
8
Guettarda scabra (L.) Vent
81
5
Inga fagifolia (L.) Willd ex Benth.
56
2
Ixora ferrea (Jacq.) Benth.
2
Krugiodendron ferreum
(Vahl) Urban
17
1
Linociera caribaea (Jacq.) Knobl.
14
2
Lonchocarpus pentaphyllus
(Poir) DC.
1
Mammea americana L.
1
Manilkara bidentata (A. DC.) Chev.
2
Maytenus elliptica (Lam.)
Krug & Urban ex Duss.
343
23
14 6 1
8
37
5
27
1
8
13
3
17
118
4
2
2
243
53
1
7
2
2
5
80
5
1
13
8
78
5
7
51
3
2
18
1
1
15
2
1 1 2
1
365
26
2
12
6
1
10
27
1
7
21
3
6
10
1
12
110
8
1
1
26
270
52
1
8
1
2
2
3
6
79
1
13
13
70
3
5
49
3
2
1
18
2
15
12
1 1 2
2
389
33
1
11
6
1
15
13
5
19
2
9
40
78
1
52
270
3
6
2
1
2
8
72
1
12
9
64
14
38
2
1
17
3
24
1 1 2
13
409
2003 Ingrowth Mortality
1
3
3
1
7
2
13
37
41
1
3
8
2
1
2
2
1
1 11
40
6
Survival Total 1983­2003
percent
11
78
5
83
1
100
10
19
21
48
14
10
65
41
1
50
266
56
5
38
2
100
2
100
67
72
10
83
63
62
39
54
2
100
18
88
35
64
1
100
0
0
2
100
443
94
countinued
34
Appendix B (continued)
Stem density by species and year on 16 plots totaling 0.8 ha in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Species
1983
1988
1993
1998
Total Ingrowth Mortality Total Ingrowth Mortality Total Ingrowth Mortality Total
Melicoccus bijugatus Jacq. c
13
Morisonia americana L.
4
Myrcia citrifolia (Aubl.) Urban
155
27
Myrciaria floribunda
(West ex Willd.) Berg
111
9
Nectandra coriacea (Sw.) Griseb.
170
15
Phyllanthus nobilis (L.f.)
Muell.-Arg a
2
Pimenta racemosa (Mill.)
J.W. Moore
155
5
Pisonia subcordata Sw. a
20
Quararibea turbinata (Sw.) Poir.
58
7
Randia aculeata L. a
12
Rauvolfia nitida Jacq.
1
Rauvolfia viridis Roemer &
J.A. Schultes
2
Sabinea florida (Vahl) DC. a
105
3
Sapium caribaeum Urban
1
Schoepfia schreberi J.F. Gmel.
1
Sideroxylon foetidissum Jacq.
2
Spondias mombin L. a
8
Tabebuia heterophylla (DC.) Britt. a
30
Tetrazygia angustifolia (Sw.) DC.
1
Tetrazygia eleaegnoides (Sw.) DC.
10
2
Torrubia fragrans (Dum.-Cours.)
Standl.
239
12
13
1
4
1
3
179
9
1
119
7
21
164
8
2
160
6
20
1
65
5
12
1
2
6
102
1
1
2
8
1
30
1
3
9
9
242
15
14
3
5
11
177
7
3
123
12
77
95
8
2
2
164
4
21
70
4
1
11
1
2
11
91
3
1
1
1
2
2
7
2
28
1
1
2
7
1
20
237 17
17
5
36
148
8
127
60
43
2
6
162
2
19
25
49
2
10
18
76
1
2
2
2
5
4
25
1
4
4
30
224
2003 Ingrowth Mortality
5
10
15
11
3
21
9
1
1
8
5
1
2
9
2
14
13
Survival Total 1983­2003
percent
22
100
5
100
143
63
135
89
22
10
2
100
170
95
18
85
52
93
9
67
0
0
0
0
69
62
1
100
2
100
2
100
5
50
25
80
1
100
2
10
225
72
countinued
Appendix B (continued)
Stem density by species and year on 16 plots totaling 0.8 ha in the Cinnamon Bay watershed, St. John, U.S. Virgin Islands
Species
1983
1988
1993
1998
Total Ingrowth Mortality Total Ingrowth Mortality Total Ingrowth Mortality Total
Zanthoxylum martinicense (Lam.) DC. Zanthoxylum monophyllum (Lam.) P. Wilson a
8 208 1
8
2
6
2
4
1
1
2003 Ingrowth Mortality
Survival Total 1983­2003 percent
4
50
0
Subtotal
2,702 208
Cinnamomum elongatum
(Vahl ex Nees) Kosterm
1
Eugenia fragrans (Sw.) McVaugh Ficus elastica Roxb. ex Hornem. c
Capparis portoricensis Urban
Carica papaya L. c Cinnamomum cassia Nees c
Eugenia biflora (L.) DC.
Eugenia sintenisii Kiaersk.
Leucaena leucocephala (Lam.)
de Wit1, a c
Securinega acidoton (L.)
Fawcett & Rendle a Ceiba pentandra (L.) Gaertn. a
128 2,782 210 1 10 1
285 2,707 220
1
10
1
1
1
2
2
7
2
3
3
470 2,,457 206
1
31
11
1
1
2
2
7
2
3
18
3 1
206 2,457
64
32
1
10
1
1
2
0
2
7
2
21
3 1
Total stems
2,702 209
128 2,783 221
285 2,719 241
470 2,490 256
209 2,537
a Deciduous species. b Species endemic to Puerto Rico and the Virgin Islands. c Exotic species.
35
36
Weaver, Peter L. 2006. A summary of 20 years of forest monitoring in Cinnamon Bay watershed, St. John, U.S. Virgin Islands. Gen. Tech. Rep. IITF-34. San Juan, PR: U.S. Department of Agriculture Forest Service, International Institute of Tropical Forestry. 35 p. St. John, and probably the Cinnamon Bay watershed, has a history of human use dating to 1700 B.C. The most notable impacts, however, occurred from 1730 to 1780 when sugar cane and cotton production peaked on the island. As agriculture was abandoned, the island regenerated in secondary forest, and in 1956, the Virgin Islands National Park was created. From 1983 to 2003, the staff of the International Institute of T ropical Forestry monitored 16 plots, stratified by elevation and topography, in the Cinnamon Bay watershed. The period included Hurricanes Hugo in 1989 and Marilyn in 1995 and a severe drought in 1994-95. In all years, plot tallies showed that from 55 to 60 percent of the stems were in height classes between 4 and 8 m, and 75 percent of the stems were in diameter at breast height (1.4 m above the ground; d.b.h.) classes between 4 and 10 cm. Stem density was greatest on the summit, followed by ridges, then slopes, and lowest in valleys. After 20 years, 65 percent of the original stems survived, with an average d.b.h. growth rate of 0.07 cm year-1. Tree species abundances varied by topography and elevation within the watershed. In 1983, total aboveground biomass on all plots combined averaged 138.7 t ha-1; by 2003, it had declined by nearly 7 percent. In 1983, biomass was greatest on the summit, intermediate on slopes and valleys, and least on ridges; by 2003, the quantities for all sites had converged except on the summit plot. In 1992, total aboveground productivity was estimated at 10.64 t ha-1 year-1. Standing herbivory for leaves was 4.5 percent, and the herbivory rate was 4.6 percent per year. The standing crop of litter was 9.33 t ha-1. Hurricanes had a major impact on forest structure and species composition. The trees impacted (snapped, uprooted, or standing dead) by Hurricane Hugo totaled 210 ha-1 after 10 months and 288 ha-1 after 19 months. The proportion of impacted stems differed by elevation, topography, aspect, and slope. Tree species with 20 individuals showed a difference in the proportion of impacted stems, ranging from as low as 0.6 percent for Pimenta racemosa (Mill.) J.W. Moore to as high as 22.8 percent for Nectandra coriaceae (Sw.) Griseb. In conclusion, the structure, species composition, and forest dynamics within the Cinnamon Bay watershed vary in time and space, and short-term observations characterize only a fragment of the watershed's continuously changing vegetational history. Monitoring of forest structure and dynamics should continue. Keywords: Biomass; dry forest; monitoring; St. John, U.S. Virgin Islands; tree species.
The Forest Service, United States Department of Agriculture (USDA), is dedicated to the principle of multiple use management of the Nation's forest resources for sustained yields of wood, water, forage, wildlife, and recreation. Through forestry research, cooperation with the States and private forest owners, and management of the National Forests and National Grasslands, it strives--as directed by Congress-- to provide increasingly greater service to a growing Nation. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 ( TDD). USDA is an equal opportunity provider and employer.
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A Summary of 20 Years of Forest Monitoring in Cinnamon Bay Watershed, St. John, U.S. Virgin Islands

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