Growth responses of scots pine seedlings grown in peat-based media amended with natural zeolite.

Zeolite has many good features that makes it very attractive for nursery use as a growing media over others. This study was designed to investigate influence of different growing media and their mixtures (with zeolite and without zeolite) on morphological characters of scots pine seedlings. Twenty-one treatments of varying amounts of peat, fine pumice, coarse pumice, river sand, perlite and river sand were established and were sown with scots pine seeds. At the end of first growing period, 30 seedlings from each treatment were harvested and measured for height (SH), root collar diameter (RCD), root dry weight (RDW), stem dry weight (SDW) and total dry weight (TSDW). These parameters varied significantly among treatments and were lower in zeolite added media. SH negatively correlated with Na and K content and C/N ratio of growing media but positively correlated with Mn content of media. SDW and TSDW had positive correlation with N, Fe, Mn, total porosity and loss of ignition, and had negative correlation with pH, Ca, Na and K content.

Thinning effects on production, root biomass and some soil properties in a young oriental beech stand in Artvin, Turkey.

In this study, three thinning treatments were applied on a 0.54 ha young oriental beech (Fagus orientalis Lipsky) stand (25-30 years old) in Karadag, Artvin in the fall of 1999. The treatments were: (1) no thinning, (2) light thinning, and (3) heavy thinning. Prior to thinning, the stand averaged 15000 trees ha(-1) and 40.0 m2 ha(-1) of basal area, with an average mean diameter of 5 cm. Thinning reduced stand basal areas to about 31.1 and 24.9 m2 ha(-1) for the light and heavy thinning treatments, respectively. After 3-years, diameter increment was the highest in heavily thinned stand and the lowest in unthinned stand. The increment in stand basal area was about 10, 18 and 27% in the unthinned, lightly thinned, and heavily thinned stands, respectively. Fine root biomass significantly decreased with thinning and thinning had no significant effects on soil pH and soil organic matter content.