A comparison between understory phytodiversity of a natural forest and forest plantations (Case study: Langerud - Guilan)

Overexploitations of forests and degradation can be considered as a rational reason behind any reforestation project aiming at development and rehabilitation. For their specific characteristics, the forest plantations can affect the diversity of understory vegetation and cause ecological present or absent of herbs, forbs and bushes. The aim of the current study was to evaluate the floral diversity and understory vegetation cover in two reforestation projects (maple-ash and alder) planted in 1970s and a nearby natural stand located in the East of Guilan province, Iran. Twenty five plots (1000 m2) were random-systematically selected in each area. All measurements for forest trees as well as topographical features of the plots were considered. The diversity of the understory plants were also estimated using two micro-plots. One-way analysis of variance by means of the aspect and slope as covariances was run to evaluate the differences. Compared to forest plantations, the results showed higher diversity indices for natural forest. Alder plantation was also more diverse than maple-ash in case of micro-flora. Shannon diversity index and Simpson evenness index were characterized as favorite indicators to evaluate the plant diversity and distribution, respectively.