U.S. Virgin Islands’ forests, 2014.
| Authors: | Humfredo Marcano-Vega |
| Year: | 2020 |
| Type: | Resource Bulletin (RB) |
| Station: | Southern Research Station |
| DOI: | https://doi.org/10.2737/SRS-RB-227 |
| Source: | Resour. Bull. SRS–227. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. |
Abstract
The overall forest area in the U.S. Virgin Islands (USVI) experienced a period of relative stability from 2004 to 2014, considering that forest cover changes have been within sampling errors ever since 2004. A total of 46,967 acres of forest area (57.2 percent forest cover) was estimated in 2014 for the USVI. There were 29,610 acres of forest on St. Croix (56.1 percent forest cover), 9,830 acres on St. John (81.3 percent forest cover) and 7,528 acres of forest on St. Thomas (43.6 percent forest cover). A total of 121 tree species were encountered within a total sampled area of 8.1 acres in 2014. Typical species of USVI’s forest life zones such as Black mampoo (Guapira fragrans) and gumbo limbo (Bursera simaruba) figure as the ones with the highest importance values among trees with diameter at breast height (d.b.h., 4.5 feet) ≥ 5.0 inches. Alternatively, species characteristic of abandoned pastures or open forests and clearings such as white leadtree or tan-tan (Leucaena leucocephala) and Jamaican nettletree (Trema micrantha) have the highest importance values among smaller trees. The changes observed in volume, biomass, and carbon between 2004 and 2014 suggest a tendency towards more mature stages of development within the USVI’s forest stands. Estimates show an increase from 84.1 to 92.2 million trees from 2004 to 2014. This increase in number of live trees is parallel to the development from 14.5 to 20.9 million cubic feet of merchantable wood and an increase in stored carbon. There were 446,000 tons of aboveground carbon stored in the forests in 2004 and 798,000 tons in 2014. This amount of carbon in 2014 is equivalent to the CO2 emissions from the total number of barrels of oil that are consumed in the USVI in 13.5 years. The forest trees grew by 762,848 cubic feet each year but lost 113,254 cubic feet per year to natural mortality and another 31,939 cubic feet to removals, for a net annual gain of 617,655 cubic feet on average. This represents a net total gain of 3.1 million cubic feet of wood volume over the entire 5-year period between the last inventories (2009–14). A total of 159,695 cubic feet of wood were removed from the forests by cutting or land clearance over that same 5-year time period. Forest health indicators revealed that there were no widespread threats or diseases and only 0.5 percent of the live trees showed any signs of crown dieback or recent mortality. This bulletin intends to serve as a baseline for the interpretation of the effects of the hurricanes of September 2017 to the unique USVI’s forests, which are to be evaluated after an ongoing fourth forest inventory is completed.