Tree species is more effective than season dynamics on topsoil function and CO2 emissions in the temperate forests

Abstract

AbstractSoil respiration is one of the most important operations controlling carbon (C) erosion from territorial ecosystems and a useful index of whole underground allocation of C and stand efficiency. However, how tree species effects root (i.e., autotrophic respiration) and soil microbial respiration (i.e., heterotrophic respiration), based on precise experiential schemes, are still restricted, even though crucial to guide the selection of species for reforestation and C management purposes. This research was done to study how tree species effect soil characteristics and function at stand level and which are the main drivers of soil CO2 emission in mixed temperate forests in northern Iran (Mazandaran province). Four most common tree species at the experimental site (Parrotia persica, Ulmus minor, Quercus castaneifolia, and Populus caspica) that surrounded by same species, were selected. Around each selected tree, four replicates of soil and litter samples were taken from (30 × 30 × 15 cm) and mixed to characterize soil physicochemical characteristics (i.e., bulk density, texture, water content, pH, electrical conductivity, N, organic carbon, and available P, K, Mg, and Ca), basal respiration and substrate (i.e., D‐manitol, D‐glucose, L‐asparagine, L‐arginine, gluconic acid, quinic acid, succinic acid, malonic acid, D‐glucosamine, L‐glutamine) induced respiration. In the litter characteristics, total N, C (OC), and C/N ratio were measured. Our results confirmed that soil chemical properties are more sensitive to species composition than soil physical ones. Moreover, individual tree species in mixed deciduous forests strongly influence induced microbial respiration, independently of the used substrates. On the contrary, season was the major factor explaining variations of basal respiration.