U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Modeling dead wood in Fennoscandian old-growth forests dominated by Norway spruce

Ranius, T., Jonsson, B.G., Kruys, N.
Canadian journal of forest research = 2004 v.34 no.5 pp. 1025-1034
simulation models, forest trees, old-growth forests, quantitative analysis, equations, stochastic processes, decayed wood, Picea abies, forest management, biodegradation, coarse woody debris, computer software, tree mortality, Sweden, Finland
If equilibrium is assumed in unmanaged forests, the volume of coarse woody debris (CWD), V(CWD), may be calculated from (i) the volume of living trees, V(living), (ii) average volume of a dead stem in relation to when it was alive, k, (iii) tree mortality rate, m, and (iv) residence time of CWD, t, by the equation V(CWD) = V(living)kmt. We parameterized this equation with data from Norway spruce (Picea abies (L.) Karst.) dominated forests in Fennoscandia. The V(living) was assumed to be directly proportional to forest productivity. Tree mortality data were from the National Forest Inventory, while it was difficult to find quantitative data on k and t. The predicted amounts (74-138 m3/ha, with larger amounts in the south) and size distribution (a negative exponential distribution of the number of stems) of CWD corresponded fairly well to averages from field inventories. By using a computer simulation program, the variability in tree mortality, density of living trees, and residence time of CWD were considered. In the simulations, the amount of CWD varied widely between 1-ha plots, especially for individual decay classes. Therefore, this model could be used to predict averages from larger landscapes unaffected by large disturbances, while no model can predict the amount of CWD at individual plots.