Forest-Type Group Composition Forest Disturbance Loblolly-shortleaf and longleaf-slash pine groups comprise almost all of the 11 million acres of softwood forest types. Hardwood types and oak-pine forest type account for 54% of the timberland area totaling 13 million acres. The oak-gum-cypress and elm-ash-cottonwood groups make up the bottomland hardwood area. Almost 6.5 million acres are planted pine and represents 60% of softwood forest types or 27% of all timberland. On the average each year, about 6% of the timberland area experiences some form of disturbance or silvicultural treatment. Harvesting occurs on about 3% of the timberland area and accounts for 56% of the disturbance area. About 44% is caused by all the other disturbances. Fire, weather, insects, and disease account for about 28% of total disturbance each year. Area of Timberland by Forest-Type Group Loblolly-shortleaf and longleaf-slash pine 45% Planted 27% N atural 18% Oak-pine 12% Nonstocked 1% Bottomland hardwood 14% Oakhickory 28% Area (thousand acres) Final Partial harvest harvest Thinning Insects Disease Average Annual Timberland Disturbance Types 500 430 400 300 199 200 161 100 61 0 178 96 Treatment Disturbance 103 122 64 Fire AniOmtahlesr/Wghreuaatzimhnaenrg Growing-Stock Tree Volume ( 5.0 inches d.b.h.) -- 1972 to 2004 Growing-stock trees--since 1972, volume has increased by 7.9 billion cubic feet or 31%. Softwood--has increased 2.6 billion cubic feet or 18%. Hardwood--has increased 5.2 billion cubic feet or 50%. Softwood 4 3 2 1 0 6 Hardwood 4 3 2 1 0 6 Billion cubic feet Billion cubic feet Growing-Stock Tree Volume on Timberland by Diameter Class 1972 1982 1989 1997 2004 8 1972 10 12 14 16 Diameter class (inches) 1982 1989 18 1997 20 22+ 2004 8 10 12 14 16 18 20 22+ Diameter class (inches) Million cubic feet Average Annual Mortality, Net Growth, and Removals Average Annual Change for Live Trees by Survey 2,400 Gross Growth Removals Mortality Net Growth1 Net Change2 1,900 1,400 900 400 0 -100 1982-1988 1989-1996 Survey period 1 Net Growth = Gross Growth - Mortality. 2 Net Change = Net Growth - Removals. 1997-2004 Net Change--This is an indicator of whether the forest tree-volume is increasing or decreasing, on average, each year during the survey period. For survey period 1989-1996 the average net change was +53 million cubic feet each year. Softwood inventory was -59 million cubic feet per year and hardwood was +112 million cubic feet. For survey period 1997-2004 the total average net change was +420 million cubic feet each year. Softwood was +248 million cubic feet per year and hardwood was +171 million cubic feet per year. This +420 million cubic feet per year is almost a seven fold increase of growth exceeding removals since the last survey period one of the key indicators of a sustainable timber resource and represents 1.1% of the total timberland volume. Mortality--Annual mortality of all live trees. 0.33 billion cubic feet per year, decrease of 9% since the last survey. Softwood 0.16 billion cubic feet per year a decrease of 5%. Hardwood 0.17 billion cubic feet per year a decrease of 12%. Net Growth--Annual Gross Growth minus Mortality. 2.0 billion cubic feet per year and increased 29%. Softwood 1.4 billion cubic feet per year. Hardwood 0.62 billion cubic feet per year. Net growth of live trees increased 36% for softwood and 14% for hardwood. Removals--Total annual removals of all live trees by harvesting or land clearing (conversion to nonforest). 1.6 billion cubic feet increased < 6%. Softwood 1.2 billion cubic feet. Hardwood 0.45 billion cubic feet. Annual removals increased 6% for softwood and 4% for hardwood. Percent Average Annual Net Change 50% Net Growth exceeds Removals 0% Removals exceed Growth -50% 26% -17% 1982-1988 38% 26% 21% -6% 1989-1996 Survey period Softwood Hardwood 1997-2004 Average Annual Net Growth/Removals for Live Trees Compared to Total Volume* Billion cubic feet 50 Net growth Removals 40 32.6 33.7 30 20 10 1.291.34 0 1982-1988 1.58 1.53 1989-1996 Survey period Volume 36.7 2.03 1.61 1997-2004 * Net growth and removals are shown on the same scale as total volume. Historically, net change represents about 1% of the total volume or less. Total inventory volume has increased almost 13% since 1988.