Variability in leaf area and stemwood increment along a 300-year lodgepole pine chronosequence

• Published in: Ecosystems (New York) Vol. 8; no. 1; pp. 48 - 61
• Main Authors: Kashian, D.M, Turner, M.G, Romme, W.H
• Format: Journal Article
• Language: English
• Published: New York, NY Springer-Verlag 01.02.2005; Springer; Springer Nature B.V
• Subjects: Age structure; Animal and plant ecology; Animal, plant and microbial ecology; basal area; Biological and medical sciences; Chronosequences; Coefficient of variation; Coniferous forests; Ecosystems; Fires; Forest ecology; Forest ecosystems; forest fires; Forest stands; forest succession; forest trees; Forests; Fundamental and applied biological sciences. Psychology; General aspects; Heterogeneity; Landscape ecology; Landscapes; Leaf area; leaf area index; Leaves; national parks; Pine trees; Pinus contorta var. latifolia; spatial variation; Stand age; Stand density; stand structure; stemwood; Synecology; Terrestrial ecosystems; timber production; tree growth; Wyoming; Rocky Mountains; United States; North America; America; Rocky Mountains; disturbance; Forests; stand structure; stand production; Wyoming; convergence; Pinus contorta; basal area increment; Leaf area; forest production; Basal area; Ecosystem; Gymnospermae; Development; fire ecology; Yellowstone National Park; succession; stand development; leaf-area index; Ecology; Perturbation; Fire; Coniferales; Spermatophyta; Leaf area index
• ISSN: 1432-9840; 1435-0629
• DOI: 10.1007/s10021-004-0067-1

Large disturbances such as the 1988 Yellowstone fires produce considerable spatial heterogeneity in ecosystem processes across landscapes, in part by affecting vegetation structure. However, the persistence of this heterogeneity with time since disturbance, and thus the role of large disturbances in shaping the heterogeneity of ecosystem processes over large spatial and temporal scales, remains unclear. Such an inquiry requires that variability as well as mean conditions of forest structure and growth be examined if changes are to be projected for heterogeneous postdisturbance landscapes. We studied a chronosequence of unburned, mature lodgepole pine stands (stand ages ranging from 50 to 300 or more years) to examine the variability in stand density, leaf-area index (LAI), and stem growth [basal area increment (BAI), a surrogate for aboveground net primary productivity (ANPP)] with stand age, the relationships between these factors, and how these factors were related to stand and site characteristics. Variation in LAI and BAI was explained primarily by differences in stand density and age ($r^{2}=0.51$for both LAI and BAI), and both LAI and BAI were most variable in the youngest age class [coefficient of variation (CV), 38% and 41% for LAI and BAI]. The relationship between LAI or BAI and stand density was significantly weaker$(r^{2}<0.20)$at stand ages characterized by canopy closure (50-175 years), suggesting that stand structure and production are closely linked. Thus, the spatial variability of stand production, which is initially very high following large fires in this landscape, is detectable for over a century before successional changes in forest structure greatly affect the initial postdisturbance landscape pattern of stand production. Given the recent focus on spatial heterogeneity of ecosystem processes across large landscapes, projecting changes in postdisturbance patterns of stand production has very strong significance for ecosystem science.