Foliar Nitrogen and Phosphorus Resorption in an Undisturbed and Pinus Pinaster Ait. Planted Forests in Northern Turkey

Abstract

Foliar resorption is closely associated with leaf senescence and conservation of nutrients, and protects the plant dependence on soil supply. In this study, leaf nitrogen (N) and phosphorus (P) dynamics, leaf resorption efficiency (RE) and resorption proficiency (RP) in some deciduous plants occurring in an undisturbed forest and a Pinus pinaster Ait. planted forest were investigated in northeastern Turkey. There were no significant differences among species with respect to foliar resorption efficiency and proficiency in undisturbed forest, whilst statistically significant differences were found among species regarding NRE, NRP and CRE in P. pinaster planted forest. CRE was found to be higher than for evergreen woody angiospcrms and graminoids present in the study area. NRE was higher in undisturbed forest than in P. pinaster planted forest. In both forests foliar nitrogen and phosphorus resorption were biochemically complete. It was found that phosphorus limitation occurred in deciduous plants in both forests with respect to N/P ratios during leaf senescence. Similarly, C/N ratio was found to be high during senescence. In P. pinaster planted forest N/P ratio and NRE (both mass- and area-based) were found to be low as compared to undisturbed forest.