Forests of Iran

Abstract

1 This resource update provides a short overview of the status of forest resources in the U.S. Virgin Islands (St. Croix, St. John, and St. Thomas) based on the third forest inventory funded and conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program of the Southern Research Station and by the International Institute of Tropical Forestry. Data estimates are based on field data collected using the FIA annualized sample design for the measurement year 2014 with comparisons made to data collected in 2009 and 2004. The sample plot population presented here for the U.S. Virgin Islands (USVI) consists of 106 plots (54 plots for St. Croix, 23 plots for St. John, and 29 plots for St. Thomas), collected across a period of 1 year. The data used in this publication were accessed from the FIA Database at http://fia.fs.fed.us/tools-data/ on May 2017. For methods used for forest area estimation and field data collection see Brandeis and Oswalt 2007. Overview Forest cover on the USVI remained relatively stable from 2009 to 2014 because the small change of 1.8 thousand acres (4 percent) is within the estimated sampling error (table 1). The number of estimated live trees with diameter at breast height (d.b.h.) ≥ 1.0 inch on forest land increased from 85.1 billion trees in 2009 to 92.2 billion trees in 2014, but this change (8 percent) is also within the error estimate. Nevertheless, net volume and aboveground biomass of live trees (d.b.h. ≥ 5.0 inches) increased 6.7 million cubic feet (46.6 percent) and 246.6 thousand tons (32.2 percent) respectively. Changes in annual net growth, annual removals, and annual mortality on forest land are within sampling errors and it is better to state that they held relatively steady at 0.76 million cubic feet, 0.03 million cubic feet, and 0.11 million cubic feet respectively. These estimates reveal a positive growth-to-removals ratio and a net total gain of 3.66 million cubic feet of volume over the entire 5-year period. Area (thousand acres) 45.16 9.36 46.97 8.66 1.80 Number of live trees >1 inch d.b.h. (million trees) 85.13 11.48 92.20 11.12 7.07 Net volume live trees >5 inches d.b.h. (million cubic feet) 14.29 18.80 20.95 17.84 6.66 Live trees aboveground biomass (thousand oven-dry tons) 766.96 12.18 1,013.58 12.17 246.62 Net growth live trees >5 inches d.b.h. (million cubic feet per year) 0.94 24.03 0.76 20.15-0.17 Annual removals of live trees >5 inches d.b.h. (million cubic feet per year) 0.04 68.18 0.03 55.18-0.01 Annual mortality of live trees >5 inches d.b.h. (million cubic feet per year) 0.16 35.60 0.11 26.79-0.04 Timberland Area (thousand acres) 12.02 24.77 9.98 27.09-2.05 Number of live trees >1 inch d.b.h (million trees) 24.72 24.84 16.95 27.90-7.77 Net volume live trees >5 inches d.b.h. (million cubic feet) 4.41 41.19 4.28 41.10-0.12 Live trees aboveground biomass (thousand oven-dry tons) 236.65 27.98 201.95 31.57-34.70 Net growth live trees >5 inches d.b.h. (million cubic feet per year) 0.22 61.60 0.19 30.47-0.02 Annual removals of live trees >5 inches d.b.h. (million cubic feet per year) 0.02 100.00 0.02 70.77 0.00 Annual mortality of live trees >5 inches d.b.h. (million cubic feet per year) 0.09 59.05 0.05 44.21-0.05