The slenderness of the softwood Riparian forest species Salix alba L. and Salix fragilis L. in the protected area of Nestos Delta, Greece

Abstract

The slenderness (height/diameter or h/d ratio) is an important factor, which describes the type of stem that each forest species develops. It depends on the species, the tree age and the site conditions. It is a basic factor that characterizes the structure and stability of the stand and a means for the assessment of the dynamics of height course. The objective of the present study was to compare the slenderness (h/d ratio) of the riparian forest species Salix alba L. and Salix fragilis L., which are found in mixed and pure stands in a protected area of international importance. 25 sampling plots (5 replicates in five different types of forest structure) were established in the riparian forest of Nestos. The structure and the dynamics of the stands were studied according to the IUFRO classification using slenderness as the overarching instrument. While the stands of both willow species have a high forest structure, slenderness values of S. fragilis stands were lower (degree of slenderness 40), which in turn indicates a more stable stand structure, in younger stages compared to S. alba, which attains similar values at nearly twice as large the stem diameters. Key words: Slenderness, height/diameter ratio, Salix alba, Salix fragilis, riparian forest, Nestos Delta.