Patterns in root trait variation among 25 co-existing North American forest species
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- • Ephemeral roots have essential roles in plant and ecosystem functioning. In forests, roots account for a major component of carbon cycling, yet few studies have examined ranges of root trait variation and how different species vary in root form and function in these communities.
- • Root branching intensity, specific root length (SRL; root length per unit dry mass), root diameter, tissue density, phenolic concentration and nitrogen concentration were determined for the finest two root orders of 25 co-existing North American woody species sampled from mature plants in a single forest community. Trait correlations and multivariate patterns were examined to evaluate the most important trait differences among species.
- • Branching intensity, SRL, and phenolic concentration varied most widely among species (coefficient of variation (CV) = 0.42, 0.57 and 0.58, respectively). Species predominately forming ectomycorrhiza (EM) had a higher branching intensity than those forming arbuscular mycorrhiza (AM) with mycorrhizal types correctly predicted in c. 70% of individual observations by branching intensity alone. There was notably no correlation between SRL and nitrogen. Variation in SRL among species mapped partially along phylogenetic lines (consistency index (CI) = 0.44), with remaining variation attributable to differences in species’ ecological specialization.
- • Variation found in root traits suggests different nutrient acquisition strategies within this community, which could have potential species-level effects on carbon and mineral nutrient cycling.