The patterns of wood density and shrinkage in different directions in 22-year-old Populus euramericana trees from one clone were studied in an experimental plantation in Iran. | Research Article Turk J Agric For 34 (2010) 121-126 © TÜBİTAK doi: The within-tree variation in wood density and shrinkage, and their relationship in Populus euramericana Behzad KORD1,*, Ali KIALASHAKI2, Behrouz KORD3 1Department of Wood and Paper Science and Technology, Islamic Azad University, Chalous Branch, IRAN 2Islamic Azad University, Nowshahr Branch, IRAN 3Islamic Azad University, Malayer Branch, IRAN Received: Abstract: The patterns of wood density and shrinkage in different directions in 22-year-old Populus euramericana trees from one clone were studied in an experimental plantation in Iran. Sample disks were taken from each tree to examine wood density and shrinkage variation from pith to bark at 5%, 25%, 50%, and 75% of total tree height. The results indicate that radial position and height significantly affected all wood physical properties. Within-tree wood density and shrinkage varied at each height level, decreasing along the stem from the base upwards. Moreover, within the samples, at the same height level wood density and shrinkage in the radial direction increased from the pith outwards. Regression analysis showed that longitudinal, radial, tangential, and volumetric shrinkage each had a significantly positive correlation with wood density. Key words: Populus euramericana, wood density, wood shrinkage, variation, correlation Introduction Poplars are fast growing, early maturing species in temperate regions. They represent a potentially large source for timber production. All poplar species and hybrids are easily propagated by cutting and planting, and subsequent treatments are generally not very difficult (Spanos et al. 2001). Poplar tree improvement programs have emphasized improvements in growth, form, adaptability, and disease resistance (Hernandez et al. 1998). Poplar wood, which is light white in color, has no smell or taste, is easy to process, and has been widely used for many years. Some of its .
