Association Analysis Between the Site Index Model and the Site Factors of Cunninghamia lanceolata Timber Forest in Western Zhejiang Province

摘要

Forest site conditions affect the tree growth. In this study, a site index model based on Richard’s theoretical equation was established using the dynamic monitoring data of forest resources in Lin’an District in Zhejiang Province, Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.] as the study object, and a difference equation to determine the internal relationship between site factors and forest stand growth. The FP-growth algorithm was used to explore the association rules between site and forest stand growth factors. A total of 175 factor association rules were obtained with the confidence coefficient and support degree of more than 80% and 10%, respectively. The main factors that influence the site quality of Chinese fir timber forest in Lin’an District are altitude, slope position, slope direction, slope gradient, soil type, soil texture, soil layer thickness, humus layer thickness, undergrowth vegetation species, and undergrowth vegetation coverage. The rules revealed the hidden associations between site factors and site quality and between site and forest stand growth factors in the Chinese fir forest. The results can provide a theoretical foundation for follow-up site evaluation work and are of great practical significance to scientific afforestation and forest management.