阳性树种

阳性树种在群落中的地位较弱；

The intolerant trees have a rather weak status in the community .

耐荫树种优势度趋于降低，阳性树种优势度逐年增加。

Abundance of shade-tolerant trees tends to decrease and that of intolerant trees increases year by year .

本文以川西南山地阳性树种云南松为例，调查其林窗边界木的主要特征。

The Characteristics of gap border trees ( GBT ) of Pinus yunnanensis in the mountain area of Southwest Sichuan were investigated in this paper .

育苗中幼苗除强阳性树种不需遮荫外，大多数热带雨林树种幼苗和幼树期都需要一定的荫蔽条件才能生长良好。

Most of the seedlings and young trees of tropical rainforest species need some shady conditions in raising period to grow well except the pioneer species .

一些阳性树种如槲栎等，三十年前曾经在林中居优势地位，现在因为更新不良，优势在不断减弱。

And other species were the dominant elements in the stand thirty years ago , but now have become less prominent because of their poor regeneration .

杨桦次生林中白桦等阳性树种的株数所占比例较大，云冷杉针阔混交林的红松、云杉和冷杉在树种组成中表现较大成数。

In polar-birch secondary forest , Betula platyphylla had larger abundance than other species ', while Pinus koraiensis , Picea koraiensis , Abies nephrolepis were showed great number in species composition of broadleaved mixed forests .

落叶阔叶林和人工针叶林已成为该地带的主要植被类型，它将由强阳性树种占优势的群落向耐阴性树种占优热的群落演替，演替中土壤和人类有着积极的作用。

Deciduous broadleaf forest and artificial coniferous forest occupy most of the area , and will evolute from the communities of tree species with no shade tolerance to the communities of tree species with dominant shade tolerance .

但由于旅游干扰，乔木层马尾松在中度干扰群落中的生态位宽度降低了55%左右，灌木层马尾松、老鼠矢、油茶的主要优势地位已被阳性树种盐肤木所取代。

Because of the tourism disturbance , the niche breadth of Pinus massoniana of the tree layer has decreased by 55 % in the intermediate disturbance community . The dominant position of the Pinus massoniana , Symplocos stellaris and Camellia oleifera of shrub layer was replaced by Rhus chinensis .

中龄林阳性先锋树种优势度明显，演替层树种组成最丰富。

The dominance of the pioneer species is obvious in the middle-year forest . And the species in the succession layer is most abundant .