Investigation on snow damage on plantations in Sourdar- Vatashan region (Chamestan, Mazandran)

This research has been carried out in twenty-years-old plantations with species of Cupressus sempervirens, Acer velutinum, Populus deltoides and Alnus glutinosa, located in Sourdar- Vatashan forestry plan which have been damaged due to the heavy snowfall in February 2008. The study aimed at evaluating and comparing of the damage intensity in studied species and determining the correlation between effective factors with damage rate. Damage rate was evaluated using 30 circle sample plots with an area of 314m² in a systematic-random grid (125m×125m) in 48 ha area. Results showed that damagerate was 84% in Cypress stand, 6/18% in Poplar and 18.28% in Alder, while Maple stand remained intact. There is significant relationship between damage percentage and diameter at breast height (P<0.05), also between percentage of damage with pruning height, crown length and H/D ratio (P<0.01). Trees with diameter less than 20cm (d1.3<20cm), crown length more than 6m, pruning height less than 6m and H/Dratio more than 70 had a damage rate of 52.46%, 50.93%, 57.71% and 39.80%, respectively. Trees with diameter more than 20cm (d1.3>20 cm), crown length less than 6m, pruning height more than 6m and H/D ratio less than 70, had a damage rate of 18.75%, 13.18%, 7.04% and 18.36%, respectively. Therefore, theprobability of injury will increase due to increasing of H/D ratio and crown length and decreasing of pruning height and diameter at breast height. Considering the above mentioned criteria and ever green characteristic of cypress, the snow damage rate in this species is high. Hence, one can conclude that planting of native broad-leaved species such as maple could be more effective and promising in the region.