Controls on carbon and nutrient solubility in live and dead Betula
pubescens leaves across a boreal retrogressive chronosequence.
Abstract
1. Leaching – the release of elements from organic matter through
dissolution in water – plays an important role in biogeochemical
cycling and ecosystem processes. However, understanding the patterns in
and underlying drivers of element solubility in leaves lags far behind
that of other related plant traits. 2. In this study, we quantify the
solubility of carbon (C), nitrogen (N), and phosphorus (P) from leaves
of Betula pubescens - a widespread boreal tree species - across a 5182
year postfire retrogressive chronosequence. 3. We find that P is much
more soluble than C and N, and is released in solution mainly in readily
accessible mineral form. Solubility patterns are strongly related to
foliar chemical and structural traits, particularly for green leaves,
whereas metrics related to stand structure exert a stronger influence
over solubility from senesced leaf litter. 4. Overall, our results
indicate that leaching could constitute an important flux of nutrients
to the soil, particularly of P, and that the rate and spatio-temporal
pattern of this flux appear readily predictable from foliar and
ecosystem properties. Further application of the method across more
species and environmental contexts should allow for rapid integration of
leaching-related foliar traits into broader plant trait frameworks.