Robust evaluations of the covariance of leaf and root traits among trees and their influence on soil processes have been limited by the lack of data on many species from constrained environmental conditions.  In order to address this knowledge gap, we analyzed a database of plant traits, soil biogeochemical properties, and soil biotic community parameters from a temperate forest common garden experiment in Poland, which contains replicated, monoculture plots of 14 different tree species.  A combination of multivariate and traditional statistics were used to evaluate the data. 

Results/Conclusions

Correlation analyses showed that some leaf and root traits were well coupled (e.g. calcium content, specific leaf area and specific root length) while others were not, including traits often linked to biogeochemical cycling (lignin and nitrogen content, C:N ratios).  Specific leaf area (SLA) was significantly correlated to many leaf and root traits, indicating its potential to describe a substantial amount of variability in above- and belowground plant traits.  Our analyses of relationships between plant litter traits and soil properties revealed that many soil properties were highly correlated with an ordination of leaf litter and root traits (i.e. were correlated with the collective variance of leaf litter and root traits), including leaf litter decomposition, pH, nutrient availability, microbial biomass, earthworm abundance, and fungal diversity and abundance.  Specific leaf area was also significantly correlated to many soil properties, but did not explain as much variation as the collective covariance of leaf and root traits.  Our results also demonstrated that leaf and root traits which are uncoupled (e.g. root and leaf N content) may have unique influences on soil properties.  Notably, litter traits were not related to total C or N storage in mineral soils.  Thus litter traits may have less influence on long-term biogeochemical processes, despite clear impacts on decomposition and soil biota.  Finally, differences between angiosperms and gymnosperms were shown for leaf and root traits as well as soil properties.  These two phylogenies, in their limited representation at our field site, appear to have distinct traits and influences on their environment.