Impacts of Alder (Alnus subcordata) plantation on nutrient and plant diversity in site of Parrotia-Carpinetum natural forest

In this study, impacts of Alnus subcordata plantation on nutrient and plant diversity in site of Parrottia Carpinetum natural forest of kolloude region, Amol, Mazandaran were investigated. First, 6 releves 20 m × 20 m were selected in each stand. Nutrition, nutrient return and nutrient retranslocation properties followed by soil properties of each stand were studied. Then, impacts of stand parameters (diameter, height, litter thickness and crown cover percentage) together with soil properties on plant biodiversity were investigated. For purpose, leaf samples of green trees and fallen leaves have been collected inside wooden trap-based sampling to evaluate the nutrition, nutrient return and nutrient retranslocation in each stand. Soil samples were taken from 0-10 cm depth in each releves. So frequencies of herbaceous and woody plant were record. Results of nutrition, nutrient return, nutrient retranslocation and soil properties in the Alnus and natural stands showed that Alnus in consequence of higher N return, lower N retranslocation in fallen leaves of Alnus led to increase the soil N% and decrease the C/N ratio. Findings of impacts of stand parameters and soil properties on plant biodiversity showed in consequence of lower litter thickness, lower crown cover percentage and soil with higher N% and lower C/N ratio in Alnus in comparison with Natural forest led to increase in the richness of herbaceous plants. By attention to results of this study by Alnus subcordata plantation in degridated plain sites with poor drainage soil, can revive the soil N and Herbaceous richness in same sites.