EDMOND PASHO1*, ARBEN Q. ALLA1, VASIL MARKU1
1Departamenti i Pyjeve, Fakulteti i Shkencave Pyjore, Universiteti Bujqësor i Tiranës, Kodër-Kamëz, 1029 Tirana, Albania.
*Corresponding author e-mail: epasho@ubt.edu.al
Abstract:
Trees in the Mediterranean region are facing high growth variability and increased drought stress. Investigation of these issues is critical to understand species-level responses to altered climatic conditions. In this study it was explored the growth variability of Quercus macrolepis trees from southwest of Albania. Growth variables such as height, diameter at breast height, crown area, age, sapwood and inter annual radial growth (earlywood, latewood and tree-ring widths (TRW)) were measured. Basal area increment (BAI) and growth change using a 5 and 10-year window were calculated based on tree-ring width data. Regression analysis was performed between growth variables to figure out the relationship among them. Correlation analysis was employed to assess the drought impact (standardized precipitation index) calculated at cumulative time scales (1-24 months) on radial growth (TRW and indexed BAI (iBAI) of the studied species. The growth variables showed high variability among trees and strong significant positive relationship with each other. Several periods of growth change were identified considering the 5 and 10-year window, principally due to human disturbances. Significant positive response to drought index were observed for both TRW and iBAI, mostly during summer months at cumulative time scales >4 months. TRW showed higher and longer response to drought index as compared to iBAI. These results are crucial to understand the vulnerability of Quercus macrolepis radial growth to increased drought stress in the region and to apply adequate management strategies to mitigate future effects of changing climate conditions on tree growth.
Keywords: Quercus macrolepis; tree growth variability; disturbances; drought impact.
