Sichuan Native Poplars Seedling And Afforestation Tentative In Southwest Mountainous Region Of Sichuan

The poplar that a native tree species in Sichuan, was used as the experimental material in the seedling stage and mountain afforestation test in Liangshan state. According to the conditions of their seeding phenology, growth, photosynthetic physiologyand the survival rate and growth of afforestation, this thesis made comprehensive estimation for the polar secological adaptability and feasibilityof afforestation in Liangshan, which provided reference to extend "Chuan Xiang No.l" in the mountainous area of southwest Sichuan.The main conclusions are as follows:(1) Seedling tests showed:clones in the experimentcan adapt to the climate and soil conditions well in Xichang, in which the clones of "Chuan Xiang No.l", "P.yunnane-nsis Dode" and "P. gong gaensis" performed best. For example, the 1 year old cutting seedings’ height were as high as 4.42m(Chuan Xiang No.1) andas low as 2.6m(P.,sc-hneideri vear. tibetica).(2) Afforestation tests in many places showed "Chuan Xiang No.1" had good adaptability to the ecological condition in the mountainous area of southwestern Sichuan. So it was suitable for further promotion test in southwest Sichuan. In a short six months growth period, the seedings’ height of afforestation land were up to 2m inZhaojue county, while they were respectively 1.5 m and 1.6 m or 2 m in Ningnanand Huidong county. And the survival rates in the two places were separately about 50% and 60%.(3) Cutting afforestation technology by mechanical drillingwas worth promoting.B-ecause it was high efficient and cost low."Chuan Xiang No.1" poplar by punch and conventional digging afforestation had no significant differences in height and diameter growth and afforestation rate. However, the time of per hole(3min)required for the conventional afforestation was 9 times of the drilling machine (20s). Meanwhile, punch reforestation costs (0.206yuan/point) decreased by 60% compared to the conventional afforestation(0.5 yuan/point).(4) The afforestation techniques of "Chuan Xiang No.1" poplar in mountainous southwestern Sichuan are:① Suitable for spring plantingThe winter afforestation seedling height of "Chuan Xiang No.1 "is 1.48m and its di-ameter is 1.23cm; Spring planting height is 1.34m and its diameter is 1.16cm. So winter planting height was significantly higher than in spring (p<0.05) and no significant difference in diameter (p>0.05). However,64% survival rate of afforestation in spring and only 50% survival rate of afforestation in winter. To ensure the survival rate of afforestation the planting inLiangshan should be in spring.② Suitable for planting cutting specification is 35cm length and the small head diameter isbigger than 1.5cmThe afforestation cuttings of "Chuan Xiang No.l" are smaller and have lower survival rate while "Chuan Xiang No.1" are longer, thicker andhave higher survival rate but their afforestation cuttings are waste. Experimental studies showed that:the planting cuttings for the most appropriate specification is35cm length and above 1.5cm diameter.This specification is not only ensure high survival rate of afforestation and diameter growth, but also reduce the waste of cuttings.③ Suitable for growing at an altitude of 2200m below and not suitable for growing above an altitude of 3000m...