A comparison of productivity and related traits for European larch (Larix decidua Miller) and red pine (Pinus resinosa Ait.) across a site quality gradient in the Great Lakes region.

摘要

Productivity and related traits were compared for European larch ( Larix decidua Miller) and red pine (Pinus resinosa Ait.) in 27 forest stands, per species, that collectively represented a site quality gradient. There were two objectives: (1) determine site factor vs. productivity relationships for each species, and (2) examine the interrelationships of soil, leaf/canopy, and productivity characteristics over a range of resource availabilities for species that differ in leaf life span and related traits.; Productivity (site index and overstory annual net primary production) were most strongly related to the single variables of soil moisture (sign of the coefficient +) and nitrogen availability (+). Using stepwise multiple regression models, the combination of growing season temperature (July T +, growing degree days -) and site water balance (+) accounted for 71% of the variation in site index for European larch while growing degree days (-) and foliar %N (+) explained 32% of the variation in red pine site index.; Larch had greater leaf N, specific leaf area, leaf area index, and productivity than red pine and leaf N was the single species trait most strongly related to productivity for both species. Over a gradient of increasing soil moisture holding capacity, productivity and leaf N increased for both European larch and red pine and the rate of increase was modestly greater for European larch. Despite these interactions, there was no trade-off in productivity since European larch maintained higher productivity over the entire gradient.