The Effect of Thinning on Atlas Cedar (Cedrus atlantic.Manetti)in North of Iran .

Effect of thinning on Atlas cedar (Cedrus atlantica Manetti) was investigated in a man-grown forest in Kelar-Dasht region, north ofIran. In this forest, a silvicultural practice, namely thinning was carried out in five replications, each of 200m area for removing 25% of tree basal area; besides that, five replications, each of 200m were considered as control. The results in a 5-year investigation period revealed that mean diameter growth in C. atlantica was twice as much in thinned stand than in control (p< 0.01) but statistical difference in mean height growth in the two stands was not significant. Vitality quality in most of trees was satisfactory but no significant difference of this term could be observed in the two treatments. Fruit bearing was significantly more abundant in the thinned stand. Plant diversity, presented by broadleaves ingrowth as well as herbaceous species, was more conspicuous in the thinned stand.