Impact of climate and environmental changes on forest ecosystem's productivity (case study: Galugah)

According to the results of the current research, a new approach in application of dendrochronology, using broadleaved tree rings, as main element of productivity, to evaluate forest ecosystem productivity, has been introduced. In this investigation, tree ring widths of sample cores which have been taken by borer from various species at different elevations, have been analyzed to evaluate their productivity and possible competitions between species. Ecological application of dendrochronology is main aspect of this study. Results provided in this research, are part of a wide range of dendrochronology study which have been taken during more than six years (started in 2006) to consider climate change impacts on Hyrcanian forest ecosystems. Target species in this study are beech tree (Fagus orientalis Lipsky), oak (Quercus castanaefolia C. A. Mey.), hornbeam (Carpinus betulus L.), alder (Alnus subcordata), and maple (Acer velutinum), which have been selected in Galugah forest district in Mazandaran province. After visiting the forest site and considering the adapting maps, sample cores were collected along a transect line (profile) at three elevation levels, namely 350, 800, and 1380 meters above sea level. Target trees were more or less at same ages. In the study region, during the last 54 years, precipitation trend shows a decrease by 372 mm and temperature trend shows an increase by 0.59 oC. Variability in different species responses to inner (competition between species) and outer elements (environmental and climatic changes), at various elevations are highly dependent on species’ nature. Tree ring widths of Fagus orientalis Lipsky in low elevation during last 55 years has decreased, but tree ring widths of this species in medium elevation in the same period has increased. Tree ring widths of beech tree in high elevation have not changed significantly.