Ten-year assessment of forest growth using permanent sample plots (Case study: Gorazbon District in Kheyroud Forest, Mazandaran province)

Determination of forest growth is one of the most important goals and tasks in forest management, which has always been accompanied by challenges in the implementation section due to the complexity of volume and growth process determination. Knowing the volume of standing trees and growth is mandatory in an accurate planning. The volumetric growth of forest stands is a basis for determining the annual cutting in planning and management of forest exploitation. Harvest of this amount of wood leads to forest sustainable development and, to some extent, can provide the wood needed in the country without raising a problem for these valuable resources. This study was done in Gorazbon district of Kheyroud forest in Mazandaran province. 258 permanent sample plots were measured in the circle area of 10 R. Then, volumetric growth and number of trees in forest stands were directly calculated. Results showed that the average tree numbers were 298.15 and 290.4 stems per ha in 2003 and 2012 respectively. The growing stocks were 335.8 and 367.7 sylve per ha sustainable forest management. Although beech constitutes 31% of the total number of trees in Gorazbon district, it accounts for 57% of the whole trees in terms of standing volume. Annual volumetric growth is 4 sylve per hectare and growth of tree number is -5.8 per hectare annually. Finally, it can be concluded that preparing an inventory by permanent sample plots provides the necessary information and detailed statistics to determine the volumetric growth and number of trees to contribute to proper management and decision making. Moreover, harvesting this volumetric growth can help the economy and lead to sustainable development of the forest at the same time.