Some wood anatomical, physiological, and silvicultural aspects of silver fir dieback in Slovenia (NW Yugoslavia)

Abstract

Silver fir dieback in Slovenia (NW Yugoslavia) was evaluated, and growth suppression and some physiological and anatomical aspects of growth ring formation were studied. The drastic growth suppression after 1950 was reflected in poor basal area increment, and by discontinuous as weil as missing rings. Only in the most diseased trees the height increment was affected. Generally latewood percentage and tracheid dimensions remained unchanged. The physiological mechanism of wetwood formation in sapwood of fir is discussed and compared with red heart formation in beech. On the basis of preliminary experiments, osmotic transport is suggcsted from sapwood to heartwood through the intermediate dry zone. Dieback is significantly correlated with microsite factors such as rockiness and stoniness (r = 0.47*), soil cover continuity (r = 0.55**), and proximity of forest roads (r = 0.43*).