The influence of competition and dimensionalspatial characteristics of trees on their radial growth in Old-Growth Sl tioara forest, Romania

The paper tries to identify how the radial growths of trees from old-growth forests areinfluenced by some forest structural elements, but also how the radial growths depend on the biometriccharacteristics of trees. The analysis was made for mixed natural stands of coniferous and beech fromSl tioara Natural Reserve. All selected natural stands have an uneven-aged structure. The main resultshave showed that tree diameter influences the radial growth especially in the case of shadow intolerantspecies (Norway spruce); when the preferences for light are decreasing, the correlation level betweenthe two mentioned characteristics is also decreasing (beech, silver fir). The influence of neighbouringcompetitors on the radial growths of trees from the three main species was determined. The first tencompetitor trees were identified and their competition on the reference trees was calculated according tothe Hegyi pattern. It was found that, in natural uneven-aged stands, radial growths are mostly influencedby the competition exerted by the first nine competitor neighbours for Norway spruce, the first twocompetitor neighbours for silver fir and the first seven in case of beech. The competing neighbours thatmostly influence the radial growth were analysed with respect to their azimuth against the referencetrees. It was observed that the radial growths of Norway spruce are mostly influenced by the competitorslocated in S and SE. For silver fir and beech the highest influence over the radial growths comes from thecompetitors located in NE and E.