عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This research investigated the accuracy and precision of prevalent methods of annual allowable cuts estimation for uneven-aged high forests based on real growth rate in different forest types in district 1 of Dr. Bahramnia forestry plan, shast kalateh of Gorgan. In order to determine volume increment using Mayer method, sampling of increment cores was done in 140 circle plots with an area of 0.1 hectare in a Systematic- Randomize pattern with (300×400 meters) dimention network an intensity of 3.33 %. Based on parcel level forest typing and site classification in similar compartment, study area has been divided to 4 forest types including Fageto-carpinetum, Carpino-parrotiom, Parrotio-carpinetum and mixed type in order to calculate volume growth rate and allowable cut in forest types and whole district. Estimation of allowable cut was carried out using eleven scientific current methods. The statistical comparisons were conducted using paired samples T-Test between the ibserved allowable cut rate (growth) and the estimated allowable cut rate based on eleven methods. Analysis of Variance (ANOVA) and Duncan test were used for determination of differences among suitable allowable cut methods in the various forest types. Results showed that among 11 methods for estimating allowable cut compared to observed growth, 4 formula have significant differences (P0.05), and results shown that one method (Van mantel) was unsuitable because of less or more than real growth in four forest types. Results showed that only Zahiraldin and Kohmian methods were suitable due to estimation of slightly lower than real growth.