genetic variation of functional traits related to drought tolerance in yellow birch seedlings
abstract
understanding patterns of variation in drought-related traits of hardwood trees is crucial
for conserving and managing north american temperate forests under climate change.
in this study, i examined provenance variation of yellow birch (betula alleghaniensis
britton) in traits related to drought resistance. yellow birch is a widespread and
economically important eastern north american hardwood species. a common garden
approach was used to compare height, diameter, biomass, leaf morphology, and stable
carbon isotopes among ten seed sources originating from across canada and northern
us states. analysis of variance (anova) of seedling height and diameter did not reveal
significant variation in either trait, while anova of a subsample (n=40) revealed
significant variation in height and leaf characters (average horizontal width, horizontal
width, maximum perpendicular width, perpendicular width 1, and perpendicular width
2). simple linear regressions revealed significant correlations between variation in leaf
morphological traits and climate at seed origin. temperature-related climate variables
were more strongly correlated with leaf traits than precipitation-related climate
variables. [...]