Preliminary Study On Planting Techniques Of Pulp Forest For No.3 Chenglü Bamboo Clone In Mountainous Region Of North Guizhou

Using Bambusa pervariabilis McClure as female and Dendrocalamopiss daii Keng as male parent,Chenglübamboo is a hybrid breaded by Guangxi Institute of Forestry Science in 1980,and it was introduced to mountainous region of north Guizhou for the purpose of pulping. The study based on the theory of plantation cultivation,clone population ecology,plant tissues and so on,combined with surface investigation and fixed samples determination,and the bamboo shooting,young bamboo's height growth,water content,biomass,leaf area,selection of plant site,planting density,and structures of bamboo clumps adjusting of Chenglübamboo No.3 were studied.Through the research of rule of bamboo shoot and degraded shoot about Chenglübamboo No.3,it show that,during the bamboo shoot,especially the bamboo forest which grow in more slope area than the others must pay attention to loose plough and hilling timely.When leave living bamboo shoots,it should preserve the excellent bamboo shoot which emerge before the peak of shoot.It should strength bamboo shoot thinning properly,reduce consumption of nutrition of stand,and beneficial to the growth of bamboo shoot.Through the observation of young bamboo of Chenglübamboo No.3 in 104 days,it could divide its height growth process into initial stage,dominant growing period,and end stage. Dominant growing period is the bamboo main growth stage and it account for the most part of the height growth.The height growth of Chenglübamboo No.3 was different between the daytime and the nighttime.The total trend was that young bamboo growth at nighttime was greater than that at daytime.Though the relative humidity between height growth of young bamboo and meteorological factors,it shows that relative humidity larger,maximum temperature higher and sunny hours higher had a significant effect on the height growth,but the rainfall,mean daily temperature and minimum temperature had indistinctive effect on it.Through the analysis of biomass it shows(1)The factors of diameter,culms height,culms weight,branch weight,leave weight,and the total above ground weight have closely relationship,and reach significant level.(2)The fitting equation between biomass and the diameters is W=0.0849D^2.0036.(3)The biomass distribution of different components above-ground shows that culms＞branch＞leaf.(4)According to the cluster analysis,the plantations could be divided into the lowest yield plantation,low yield plantation,mean yield plantation,high yield plantation and the super high yield plantation.The water contents of bamboo culms was varied in the different ages,la(71.5%)＞2a (56.3%)＞3a(47.9%).It also was different in different parts,base(62.4%)＞middle (59.0%)＞upper(54.4%).The optimum model between the diameter and the leaf areas is M=91974.8-50277D+ 10460.2D²-56.144D³,R²=0.9012.The leaf areas index of the plantations is mostly below 6 at present,and it do not reach the high yield structure.Through the field survey of 31 plots Chenglübamboo No.3,and from the analysis of effects of 6 factors on the growth,it shows that altitude,slope position,soil thickness and sloppiness were the leading factors which had significant effects on the growth of Chenglübamboo No.3.Combined with the result of t-test,it obtained that the best suitable site types wereâ… zb5,â… zb6,â… Sb5 andâ… Sb6,The suitable site types wereâ… zb3,â… zb4,â… Sb3,andâ… Sb4.The unsuitable were allâ…¡(≥800m) and all a(upper slope) or 1 and 2(thin soil).Through the investigation of vegetation spaces of Chenglübamboo No.3 showed that soil thickness,altitude,slope position and slope degrees of the 6 site factors affected the space extension and they exist significant differences or very significant differences.Because differentiation of site conditions,even the site suitable to cultivate,its choice of planting density should not in a unified standard.The density of 833 trees/ha which is 3m×4m could be used in well site,but in the poor site such as mid soil thickness,the planting density would be increased to 952trees/ha which is 3mx3.5m or 1111trees/ha which is 3m×3m or more,it could as soon as possible to crown closure,and make pulp forest have lots of yield and well economic benefit.The experiment of plantation structure regulation shows that some old bamboos should be remained in the plantation.The traditional harvest customs "all cut each four year" is not rationale.The felling intensity should not be more than 60%.