The developmental dynamics and structure of old-growth forests often serve as
important baselines for forest management. Nonetheless, long-term information on
natural patterns of development and mortality is rare for many commercially and
ecologically important forest types. This study uses a long-term dataset from a large (2
hectare), stem-mapped plot within an old-growth Pinus resinosa (red pine) forest in
Itasca State Park to quantify patterns of forest structural development and mortality
events over an 87-year period. These patterns were compared with those found in other
old-growth red pine -dominated forests in northern Minnesota, as well as with
unmanaged second-growth and extended rotation red pine forests to quantify the range of
variation in structural conditions and to evaluate the effectiveness of extended rotation
forestry at promoting the development of late-successional structural conditions.
Old-growth forests were more structurally complex than unmanaged secondgrowth
and extended rotation red pine systems, due in large part to the significantly higher volumes of coarse woody debris, higher snag densities, and spatially random
patterns of mortality found in old growth. Nonetheless, extended rotation thinning
treatments, by accelerating advancement to larger tree diameter classes, generated
diameter distributions closely approximating those found in old growth. These results
suggest that extended rotation treatments may accelerate the development of old-growth
structural characteristics, provided that random patterns of mortality are emulated and
coarse woody debris and snags are deliberately retained and created on site. These and
other developmental characteristics of old-growth systems can inform red pine management when management objectives include the restoration of late-successional forest conditions.
University of Minnesota M.S. thesis. July 2012. Major: Natural Resources science & management. Advisors: Anthony W. D’Amato, Shawn Fraver. 1 computer file (PDF); viii, 86 pages, appendices A-B.
Silver, Emily Jane.
Structure, development, and spatial patterns in Pinus resinosa forests of northern Minnesota, U.S.A..
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