نوع مقاله : علمی - پژوهشی
نویسندگان
1 مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی مازندران، سازمان تحقیقات، آموزش و ترویج کشاورزی، ساری، ایران
2 استاد دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The current study was conducted in the Kheiroud forest using the cluster sample plots implemented along the altitude (100- 1800 m). Within the circular sample plots in each cluster along the radius with length of 7.3 m (considered as line transect) and constant azimuth of 150 degrees, three diameter classes including 1-2.5, 2.5-4.5 and 4.5-7.5 cm were measured based on the line-intersected fallen woods. Using ordinal logistic analysis and based on the FWDS frequency on each diameter class, the FWDs observations (volume stock) were in turn categorized for the first diameter class (0.8- 1.5, 1.5-3, 3- 5 m3/ha), the second diameter class (3-4.5, 4.5-6, 6-8, > 8 m3/ha), and the third diameter class (10- 14, 14-18, > 18 m3/ha). The results of logistic analyses based on the log-likelihood test (X2= 0.06; P > 0.05) and pseudo-R2 (Pesudo-R2 = 0.001) showed that the altitude gradient has no significant effect on the volume accumulations of the FWDs in different diameter classes. According to the Cramer's V and Spearman correlation tests, the results demonstrated that altitude gradient significantly correlated with the stand types, aspect, species and decay of the FWDs in the study forest. T, the final results of modeling showed that the FWDs species and decay have only significant effects on variations of the first diameter class of FWDs volume stock (Pesudo-R2= 0.24; P < 0.05; X2= 22.61).
کلیدواژه‌ها [English]
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