Nutrient resorption estimation compromised by leaf mass loss and area shrinkage: Variations and solutions

Abstract

Leaf nutrient resorption helps plants minimize nutrient loss via litterfall. The commonly-used parameter to express the resorption, nutrient resorption efficiency (NuRE, the percentage of the leaf nutrient pool withdrawn before abscission), can be compromised by leaf mass loss (LML) and leaf area shrinkage (LAS) when they are not correctly accounted. However, the variations in LML and LAS and their consequences on real NuRE are still poorly understood. To explore the drivers of LML and LAS and their impact on NuRE, we conducted a comprehensive measurement on LML and LAS concomitant with NuRE for 46 deciduous woody species in a temperate forest. The LML and LAS ranged from –3.13% to 32.21% and 0.65% to 18.07%, respectively. On average, ignoring LML (LAS) underestimated the nitrogen and phosphorus resorption efficiencies by 6.93% and 7.39% (4.66% and 4.57%), respectively. The differences in LML and LAS among species and regions should be considered in NuRE studies. The LAS was significantly influenced by plant functional groups and leaf structural traits, while the LML was only weakly related to leaf-fall date. Green leaf area and thickness shrinkages could be used to model LAS. We finally provided suggestions for recovering the historical data and improving future measurements of NuRE.