Basic Theory And Technique Systems On Fast-growing And High-yield Poplar (P.tomentosa Carr.) Plantation Forest

By applying the principles of forest ecology, forest genetics, tree physiology and modern silviculture, and with directed cultivation, fast-growing, high-yield, good quality and high economic efficiency as guiding lines, white poplar (Populus tomentosa Carr.) is selected to solve the current problems existed in afforesttion and cultivation. In the main distribution area of Shandong Province, permanent and temporary sampling sites are sampled and modern biological statistic methods are applied to analyze the dominant factors influencing the growth of white poplar plantation forest. The study is expected to provide theoretic basis and corresponding techniques for the cultivation of white poplar plantation forest in Shandong Province as well as the North China. The main study contents include: 1) growth differentiation of white poplar (P. tomentosa) varieties. 2) Physiological basis for high-yield white poplar plantation forest, 3) White poplar plantation forestland classification and its evaluation, 4) Afforestation techniques of white poplar for high-yield production, 5) Technique system for high-yield polar plantation forest and its economic evaluation. The main results are as follows:1, Site factors influencing the growth of white poplar plantation forest include topography, soil type, soil texture and underwater level. In West Shandong alluvial plains of the Yellow River, importance of the factors are ranked in order as follows: topography > soil texture > underwater level > soil type, while in Central & South Shandong and Jiaodong area, soil texture > topography > soil type > underwater level.2, White poplar (P. tomentosa) plantation forestland is classified into 32 groups and site indices range from 9 to 19. Land with an index of 6 or above and mean annual increment of stock volume 9.0 m3 with a density of 495 tree per hm2 is believed the best for white poplar growth while land with site index of 14– 15, and mean annual increment of stock volume of 5.0 m3~7.5 m3 with a density of 495 tree per hm2 the second best. Land with site index below 13 is proved not suitable for the cultivation of white poplar (P. tomentosa) plantation forest.