Phenotypic Variation And Growth Characteristics Of Artificial Pinus Tabulaeformis Var

Pinus tabuleaformis is a main tree species widely used for afforestation in Loess Plateau, with a series of functions such as wind sheltering and sand fixation, soil and water conservation. Almost 80,000 hectares artificial forest of P. tabuleaformis were distributed in Ziwuling Mount in which the oldest P. tabuleaformis reached 30 years old. Not only growth characteristic of P. tabuleaformis, but also planting habitat affact the growth of artificial P. tabuleaformis. For the P. tabuleaformis planted in grassland, in shrub, under the Betula platyphylla stand, under the Quercus wutaishanica stand, firstly, seven phenotypic characters including length of needles, width of needles, thickness of needles, length-width ratio of needles, length and diameter of the current-year twigs, number of needles in the current-year twigs were measured to analysis phenotypic variation feature of P. tabuleaformis. Then height of annual growth and the end diameter of each section representing 6-year-growth of P. tabuleaformis after planting were measured to analysis the height growth character, diameter growth character and the relationship of each other. At last, with the help of hemispherical photography, growth of artificial P. tabuleaformis respond to under-forest habitats were revealed to discuss the suitable habitat for P. tabuleaformis saplings. Though these studies, theoretical basis can be provived for plantaion and nurture of P. tabuleaformis, transforming broad-leaved forest and vegetation recovery in Ziwuling mountain. Main research results in this paper were:(1) The seven measured phenotypic traits showed significant difference between or within populations. The mean phenotypic differentiation coefficient (VST) between populations(72.88%) was larger than that within populations(27.12%), which declared phenotypic variation of P. tabuleaformis mainly caused by environment.(2) Phenotypic variation coefficient (CV) of P. tabuleaformis planted in shurb was largest and that in grassland was smallest, which indicated growth of P. tabuleaformis in shurb was unstable while growth of P. tabuleaformis in grassland was more stable.The CV of P. tabuleaformis planted under the Betula platyphylla stand, under the Quercus wutaishanica stand were 21.19%,18.88%, respectively, which showed the discrete degree of phenotypic traits were placed in the middle.(3) Though cluster analysis, the 4 populations can be devided into 3 kinds. Populations under Betula platyphylla stand, Quercus wutaishanica stand belonged to a group, populations in grassland, in shrub belonged to the other two groups, respectively. The results showed that phenotypic traits of P. tabuleaformis planted under Betula platyphylla stand, Quercus wutaishanica stand were similar, while that in grassland and in shurb were different.(4) Height and diameter growth of P. tabuleaformis saplings in grassland was greatest, followed by the shurb habitat, under Quercus wutaishanica stand, the lowest was under Betula platyphylla stand. P. tabuleaformis saplings showed growth pattern that growth of early stage promote the later stage's growth. Annual height growth and section diameter demonstrated positive linear relationship. The planting years longer, the relationship more closely.(5) The current-year height, needle length, needle width, needle thickness, lengh and diameter of current-year twigs of P. tabuleaformis planted under Quercus wutaishanica, Betula platyphylla stand were influenced by Vissky, DSF, ISF, total direct radiation below canopy and canopy coverage. In these factors, Vissky and ISF occupied larger effect.