© 2005 Heron Publishing—Victoria, Canada
Seasonal variation in biomass and carbohydrate partitioning of understory sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis) seedlings
Catherine Gaucher (1, 2), Sébastien Gougeon (1), Yves Mauffette (1) and Christian Messier (1)
1. Groupe de recherche en écologie forestière interuniversitaire (GREFi) and Département des Sciences Biologiques, Université
du Québec à Montréal, C.P. 8888, Succ centre-ville, Montréal, QC, Canada, H3C 3P8 / 2. Corresponding author (gaucherc@sympatico.ca) / Received December 19, 2003; accepted June 30, 2004; published online November 1, 2004
Summary
We investigated seasonal patterns of biomass and carbohydrate partitioning in relation to shoot growth phenology in two age
classes of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.) seedlings growing in the understory of a partially harvested forest. The high root:shoot biomass ratio and carbohydrate
concentration of sugar maple are characteristic of species with truncated growth patterns (i.e., cessation of aboveground
shoot growth early in the growing season), a conservative growth strategy and high shade tolerance. The low root:shoot biomass
ratio and carbohydrate concentration of yellow birch are characteristic of species with continuous growth patterns, an opportunistic
growth strategy and low shade tolerance. In both species, starch represented up to 95% of total nonstructural carbohydrates
and was mainly found in the roots. Contrary to our hypothesis, interspecific differences in shoot growth phenology (i.e.,
continuous versus truncated) did not result in differences in seasonal patterns of carbohydrate partitioning. Our results
help explain the niche differentiation between sugar maple and yellow birch in temperate, deciduous understory forests.
Keywords:
photosynthetic:non-photosynthetic tissue ratio, root:shoot ratio, starch, total nonstructural carbohydrates.
