Response of wild pistachio (Pistacia atlantica Desf.) to resin exploitation

Background and objectives: wild pistachio (Pistacia atlantica Desf.) trees have social and economic importance due to resin exploitation and its great role to supply livelihoods for forest dwellers of Zagros regions. The purpose of this study was to investigate the response of wild pistachio (Pistacia atlantica Desf.) to resin exploitation. In this research, biometrical indices of wild pistachio trees (collar diameter, total height, trunk height, trunk height to total height ratio, crown height and crown area) were used to assess the impact of resin exploitation on wild pistachio trees.
Materials and methods: Two stands including an abandoned stand (resin had been exploited in the past, but resin exploitation had ceased for the last 22 years (1991-2013) with an area of 4.8 ha and an utilized stand (undergoing resin exploitation) with an area of 9.6 ha, with similar physiographic conditions were selected in the villages Bivandbala and Bivandpaeen, Javanroud, Kermanshah province. In the two selected stands, a full callipering was performed. We recorded the tree species and collar diameter for all trees with collar diameter larger than or equal to five cm. Moreoverو total height, trunk height and crown diameter were measured in wild pistachio trees as well.
Results:The results showed that the mean of biometrical indices of wild pistachio such as collar diameter, total height and crown height in diameter classes were significantly different between the two studied stands. The value of studied quantitative variables was higher in abandoned stand expect collar diameter. Trunk height, trunk height to total height ratio and crown area did not show any statistically significant difference between the two studied stands.
Conclusion: Resin exploitation is an important source of income for forest dwellers in the northern Zagros. The traditional resin exploitation method is ecologically and economically inefficient. To improve the livelihood of forest dwellers, it is necessary to replace the traditional method with a scientific method which is economically and ecologically sustainable. In addition to the traditional resin exploitation, the absence of regeneration of wild pistachio is a threatening factor for existence of these stands. The main objective for a policy maker should be ensuring the sustainability of wild pistachio stands and the continuity of resin exploitation income for the next generations. Therefore, it is necessary for conservation authorities to make the prerequisite of seed regeneration, maintenance and warranty of regeneration establishment in wild pistachio stands instead of attaining interest and toll for issuing resin exploitation contracts.