Evaluation of application of the 15d method in Loveh forest, Golestan province

This study was carried out to evaluate the application of the 15d method and monitoring the alteration within the improvement area in district one from Loveh forest management plan after 28 years. A systematic sampling have been designed in a network of 150×200m with circle plots of each 0.1 ha for forest stand inventory and circle micro plots of each 0.01 ha for regeneration inventory. Based on available data from the previous inventory in the forests management plan and the current data that is collected from our inventory, some parameters including basal area, volume, forest composition and distribution in diameter classes were compared between 1982 and 2010 using analysis of t-test and chi-square test. The result showed that under this method, distribution in diameter classes in both 1982 and 2010 years have significance differences with normal distribution. The differences of basal area for Cappadocian maple (Acer cappadocicum), field maple (Acer campestre), elm (Ulmus glabra) and hornbeam (Carpinus betulus) were statistically significant. Volume of chestnut-leaved oak (Quercus castaneifolia), Cappadocian maple, elm, hornbeam and total volume per ha were also significantly different. Comparing of stem number and height of the stand showed that the density and height of the studied stand have increased after application of this method. Study of regeneration showed that the interventions cause the stand composition altering to hornbeam-oak. Our result indicates that the application of the method 15d has affected the mixture, species diversity and the structure of the stand. Therefore, in order to improve the structure and favoring of oak and noble species, we suggest thinning operations for 20 to 30 years with a positive selection from above.