FOREST SITE INFLUENCE ON BIRCH GROWTH AND HEALTH: LITHUANIAN CASE STUDY

Abstract

The study aims to determine the growth and health response of Betula pendula and Betula pubescens growing in the forest sites of different soil fertility and humidity in Lithuania. The analysed data was collected under the Forest Monitoring Level I of ICP-Forests program. Lithuanian forest sites classification described by Vaičys et al. (2006) was used for the data analyses. The obtained results show that better condition of B.pendula was recorded for the birch trees growing in more humid sites and for B. pubescens – growing in the dryer sites. Also it was found that the lowest defoliation was typical for dominant and codominant trees and it did not depend on site humidity. The highest data variation of B. pendula stem diameter between forest sites of different humidity were found in the birch stands up to 50 years old. For younger B. pendula trees, higher diameter was recorded in more humid sites compared to the less humid sites. The stem diameter of B.pubescens trees was higher in the sites with normal moisture and temporary overmoistured soils compared to those growing in the permanently overmoistured and peatland soils.