Study On The Growth Process On Main Conifers In Jingouling Forest Farm

There are large areas of over-cutting forests in Changbai Mountains. It is very significant for forest management to study on growth process of over-cutting forests. The author took analysis data of coniferous trees which were major in Jingouling Forest Farm, Wangqing Forest Bureau, Jilin province, including Pinus koraiensis, Picea rubens and Abies alba as research objects, and then analyzed the growth process of main coniferous trees in over-cutting forests in Changbai Mountains. The author used a lot of study methods, for example comparing annual increment and average increment of individual growth factors, dividing growing stages, and giving appropriate growth curves, and then compared the corresponding results with those of primary forests.The results were as follows:(1) The annual increment's maximum value of diameter at breast height (DBH) and height (H) of Pinus koraiensis, Picea rubens and Abies alba appeared in about 80 years. The annual increment's maximum value of DBH of Pinus koraiensis appeared later than that of H, while for Picea rubens and Abies alba, the two factors appeared nearly at the same time.(2) The annual volume (V) increment of Pinus koraiensis kept growing in the first 110 years, while for Picea rubens and Abies alba the factor reached the top at 100 years or so.(3) The rather appropriate growth process equations of DBH, H and V were quadratic equations excepting that of Pinus koraiensis. In addition, power function also had certain advantages.(4) At the same site quality class the DBH growth of Pinus koraiensis, Picea rubens and Abies alba was better than the average value of the same coniferous tree species in northeastern primary forests obviously. The difference became more clearly after the middle period of tree growth.(5) At early time Pinus koraiensis in the over-cutting forests grew better than in the primary forests. Over-cutting had more influence on the smaller diameter grade of Pinus koraiensis.(6) The basal diameter growth in the first 10 years of Pinus koraiensis and Abies alba increased during recent 100 years, especially during recent 70 years. But for Abies alba seedlings, there was no this trend.