Nutrient utilization strategies and age-related changes in larix principis-rupprechtii forests of different origins

Abstract

Abstract Aims: Investigations into the nutrient content and changes in the stoichiometry and nutrient resorption strategies of different original forests during their development are of great significance toward the establishment of healthy, high-quality forest ecosystems. Methods: 24 sample plots with age gradients were established in natural Larix principis-rupprechtii forests and plantations, from which mature and senescent leaves, new branches, fine roots, and soil were collected for analysis. The carbon (C), nitrogen (N), and phosphorus (P) contents were determined, and the stoichiometric ratios and resorption efficiencies were calculated. Results and Conclusions: The soil organic carbon and total nitrogen of the forests accumulated with advancing age, while the total phosphorus decreased due to higher consumption. Plantation trees tended to store scarce nutrients within inactive plant structures to prevent nutrient loss, whereas natural forest trees maintained a stable nutrient concentration within their active organs. Plantation and natural forest trees adopted highly conservative N and P utilization strategies through improved resorption efficiencies. However, natural forest change was weaker than in plantations. The mature leaves, litter, branches, and fine roots of natural forestswere more susceptible to soil P concentrations, whereas those of their plantation counterparts were more affected by soil N. Nutrient concentrations within the active organs of plantation trees were more strongly dependent on soil than natural forests. We considered that natural forests likely possessed a more extensive range of strategies to deal with the variable compositions and concentrations of soil nutrients, which might strengthen their resilience against the effects of aging.