GROWTH GRADIENTS OF MULTI-AGED PURE ORIENTAL BEECH STANDS ALONG THE ALTITUDINAL GRADIENTS WITHIN A MESOSCALE WATERSHED LANDSCAPE

Abstract

Leaf Area Index (LAI) is one of the rare parameters that intend to represent the level of growth and productivity to some extent. Particularly from the ecophysiological and habitat frames, Fagus orientalis Lipsky is relatively less discovered species compared to European beech.The most suitable altitudinal ranges within Bartin watershed where multi-aged oriental beech (Fagus orientalis Lipsky) stands (mapobs) exist, were aimed to be determined based on the LAI measurements. Investigating the trends of the temperature and precipitation were also purposed in order to account the climate dynamics in the region. Bartin watershed is located at the northwestern of Black Sea Region in Turkey. Three sample altitudinal transects covered with mapobs were divided into 50 m imaginary gradients from where three hemispherical photographs were taken. LAI was derived from these photographs using the image analysis technique. The increase in the annual average temperature and decrease in the summer precipitation together with the rising winter precipitation indicate summer droughts and silent climate change. More than 60% of all mapobs concentrated at the hillsides with moderate slope degrees (15°-30°) on the gradients between 400 and 800 m asl. where annual total precipitation and mean temperature were 1370 mm and 9.6°C respectively. The sample mapobs with mean LAI higher than 2.00 occur within a broad range of altitudes between 450 and 1150 m asl. The mean LAI was its minimum levels below 400 m asl. whereas it reached up to 2.71 at the 700-750 m asl. where could be defined as optimum growth gradient for mapobs of this watershed landscape. South facing hillsides were relatively less favored aspects for all mapobs. The significant vegetation parameter; LAI can readily be used as a precise indicator of forest growth and productivity. Possible consequences of climate change on the forest ecosystems should be evaluated at the landscape scale which allow comprehensive forest landscape planning.