Tree mortality and deadwood dynamics in late-successional boreal forests
Aakala T. (2010). Tree mortality and deadwood dynamics in late-successional boreal forests. https://doi.org/10.14214/df.100
Abstract
Here I aimed at quantifying the main components of deadwood dynamics, i.e. tree mortality, deadwood pools, and their decomposition, in late-successional boreal forests. I focused on standing dead trees in three stand types dominated by Picea mariana and Abies balsamea in eastern Canada, and on standing and down dead trees in Picea abies-dominated stands in three areas in Northern Europe. Dead and living trees were measured on five sample plots of 1.6-ha size in each study area and stand type. Stem disks from dead trees were sampled to determine wood density and year of death, using dendrochronological methods. The results were applied to reconstruct past tree mortality and to model deadwood decay class dynamics. Site productivity, stand developmental stage, and the occurrence of episodic tree mortality influenced deadwood volume and quality. In all study areas tree mortality was continuous, leading to continuity in deadwood decay stage distribution. Episodic tree mortality due to either autogenic or allogenic causes influenced deadwood volume and quality in all but one study area. However, regardless of productivity and disturbance history deadwood was abundant, accounting for 20–53% of total wood volume in European study areas, and 15–27% of total standing volume in eastern Canada. Deadwood was a persistent structural component, since its expected residence time in early- and midstages of decay was 18 yr even in the area with the most rapid decomposition. The results indicated that in the absence of episodic tree mortality, stands may eventually develop to a steady state, in which deadwood volume fluctuates around an equilibrium state. However, in many forests deadwood is naturally variable, due to recurrent moderate-severity disturbances. This variability, the continuous tree mortality, and variation in rates of wood decomposition determine the dynamics and availability of deadwood as a habitat and carbon storage medium in boreal coniferous forest ecosystems.
Keywords
dendrochronology;
coarse woody debris;
old-growth;
stage-based model;
forest dynamics;
forest structure
Published 15 February 2010
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Available at https://doi.org/10.14214/df.100 | Download PDF
Original articles
Aakala, T., Kuuluvainen, T., De Grandpré, L., and Gauthier, S. 2007. Trees dying standing in the northeastern boreal old-growth forests in Quebec: spatial patterns, rates and temporal variability. Canadian Journal of Forest Research 36(1): 50-61.
https://doi.org/10.1139/X06-201
Aakala, T., Kuuluvainen, T., Wallenius, T., and Kauhanen, H. 2009. Contrasting patterns of tree mortality in Picea abies-dominated late-successional forests in two regions in northern boreal Fennoscandia. Journal of Vegetation Science 20: 1016-1026.
https://doi.org/10.1111/j.1654-1103.2009.01100.x
Aakala, T., Kuuluvainen, T., Wallenius, T., and Kauhanen, H. Episodic tree mortality in the pristine Picea abies-dominated taiga in the Arkhangelsk region, Northern Europe: drought as a primary disturbance agent in a mesic boreal forest. Manuscript.
Aakala, T., Kuuluvainen, T., Gauthier, S., and De Grandpré, L. 2008. Standing dead trees and their decay class dynamics in northeastern boreal old-growth forests of Quebec. Forest Ecology and Management 255: 410-420.
https://doi.org/10.1016/j.foreco.2007.09.008
Aakala, T. Coarse woody debris in three late-successional Picea abies forests in Northern Europe: variability in volume and models of decay class dynamics. Manuscript