DRAFT

November 15, 2001

Compiled by Jay Watson, REO (FWS)



Definitions - Old-growth Forest

1. Old-growth forest - "An ecosystem distinguished by old trees and related structural attributes. Old growth encompasses the later stages of stand development that typically differ from earlier stages in a variety of characteristics which may include tree size, accumulations of large dead woody material, number of canopy layers, species, composition, and ecosystem function. More specific parameters applicable to various species are available in the USFS, Region 6, 1993 Interim Old Growth Definitions (USDA Forest Service Region 6, 1993). The Northwest Forest Plan SEIS and FEMAT describe old-growth forest as a forest stand usually at least 180 to 220 years old with moderate-to-high canopy closure; a multi-layered, multi-species canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground (USDA, USDI 1994a)." Record of Decision and Standards and Guidelines for Amendments to Survey and Manage, Protection Buffer, and other Mitigation Measures Standards and Guidelines [2001] Pg. 79 [2001 S&M ROD/S&Gs]

2. Old-growth forest - "Old-growth forests are forests that have accumulated specific characteristics related to tree size, canopy structure, snags and woody debris and plant associations. Ecological characteristics of old-growth forests emerge through the processes of succession. Certain features - presence of large, old trees, multilayered canopies, forest gaps, snags, woody debris, and a particular set of species that occur primarily in old-growth forests - do not appear simultaneously, nor at a fixed time in stand development. Old-growth forests support assemblages of plants and animals, environmental conditions, and ecological processes that are not found in younger forests (younger than 150-250 years) or in small partches of large, old trees. Specific attributes of old-growth forests develop through forest succession until the collective properties of an older forest are evident." [pg. 45] Committee on Environmental Issues in Pacific Northwest Forest Management, Board on Biology, National Research Council. 2000. Environmental Issues in Pacific Northwest Forest Management, National Academy Press, Washington, D.C. 280 pp. [2000 National Research Council] Read online at http://www.nap.edu/catalog/4983.html

3. Old-growth forest - A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground. Record of Decision [1994] for Amendments to Forest Service and Bureau of Land Management Planning Documents Within the Range of the Northern Spotted Owl Standards and Guidelines for Management of Habitat for Late-Successional and Old-Growth Forest Related Species Within the Range of the Northern Spotted Owl. F-4 [1994 NFP ROD/S&Gs]

4. Old-Growth Forest - A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground. FEMAT Final Supplemental Environmental Impact Statement on Managment of Habitat for Late-Successional and Old-Growth Forest Related Species Within the Range of the Northern Spotted Owl. Vol. 1, Glossary 11 [1994 FSEIS NFP]

5. Old-Growth Forest - A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; high incidence of large trees, some with broken tops and other indications of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground. FEMAT Thomas, T.W., et al. 1993. Forest Ecosystem Management: An Ecological, Economic, and Social Assessment Report of the Forest Ecosystem Management Assessment Team. US Government Printing Office 793-071. IX-24 [1993 FEMAT]

6. Old-growth conifer stand - Older forests occurring on western hemlock, mixed conifer, or mixed evergreen sites that differ significantly from younger forests in structure, ecological function, and species composition. Old growth characteristics begin to appear in unmanaged forests at 175-250 years of age. These characteristics include (1) a patchy multilayered canopy with trees of several age classes, (2) the presence of large living trees, (3) the presence of larger standing dead trees (snags) and down woody debris, and (4) the presence of species and functional processes that are representative of the potential natural community. Definitions are from the Forest Service's Pacific Northwest Experiment Station Research Note 447 and General Technical Report 285, and the 1986 interim definitions of the Old-Growth Definitions Task Group. Thomas, T.W., et al. 1993. Forest Ecosystem Management: An Ecological, Economic, and Social Assessment Report of the Forest Ecosystem Management Assessment Team. US Government Printing Office 793-071. IX-24 [1993 FEMAT]

7. Old-growth Forest - "Old-growth forests in our study area vary widely in their age and ecological state (for example, in composition and structure) which reflects a similar wide variability in their history and physical environments. Old-growth Douglas-fir forest are from about 200 to over 1000 years old; they undergo gradual but significant autogenic change during those centauries of existence and may also be subjected to varying number and intensities of disturbance events, such as windstorms. As a consequence, old-growth Douglas - fir forest can differ substantially in their degree of "old-growthness" --that is, in the degree to which they express the various structural and functional features associated with these forests; this variability must be considered in efforts to define and manage old growth." Franklin, J.F. and T.A. Spies. 1991. Ecological Definitions of Old-Growth Douglas Fir Forests. Pp, 61-69 in: Wildlife and Vegetation of Unmanaged Douglas -Fir Forests. Gen. Tech. Rep. PNW-GTR-285. Portland, OR: USDA, Forest Service, Pacific Northwest Forest and Range Experiment Station. [1991 PNW-GTR-285]