The entire continent and the majority of species are now affected: between 30% and 50% of the tree population.
整个大陆和大部分的物种（占树木的数量的30%至50%）目前都受到了影响。
The forest area of classic garden and ancient tree population should focus on the rejuvenation and pest control.
古树名木和古典园林中的森林区域要重点考虑古树的复壮措施及病虫害的防治等。
Since the isozyme techniques were used in genetic studies of forest tree population, great progress has been made.
本文评述了用同工酶技术研究林木群体遗传变异的情况，并对研究中应注意的几个问题进行了讨论。
Tree populations in the wild usually satisfy those criteria, but research centers would simply not have enough capacity to keep a large and diverse population of Torreya trees.
在野外生长的树木一般可以满足这些要求，但是研究中心没有能力保护数量足够多，基因足够多样化的香榧树。
Exploring tree population distribution patterns and interspecific spatial associations are helpful in elucidating the mechanisms underlying species coexistence in forest communities.
种群分布格局和种间空间关联性研究有助于深入理解物种共存机制。
In Hawaii, for example, a new pest-resistant species of papaya tree has been developed in response to ring-spot virus infections that have repeatedly damaged the native papaya-tree population.
比如，在夏威夷有一种新的抗虫害的番木瓜树。这种树可以抵抗环斑病毒的感染，而正是这种环斑病毒常常会降低当地番木瓜树的数量。
Kohler argues that pinon was disappearing from the locale of settlements and that this put an additional nutritional strain on the population, which used nuts from the tree as well as its wood.
"科勒认为，矮松正在从居住地消失，这让当地居民面临更严重的营养问题，因为他们食用矮松的坚果，并以矮松作为木料。
The result shows that the Tree class structure replacing the age structure is suitable for studying the structure and dynamics of Castanopsis fargesii population.
结果表明，应用立木级结构代替年龄结构研究栲树种群的结构和动态特征是适用的。
Molecular phylogenetic tree constructed by UPGMA and NJ method suggested that there were some genetic variation among different geographic population.
UPGMA和NJ法构建的种群间分子系统树基本一致，结果表明不同地理种群之间存在一定程度的遗传差异。
The method of dynamic comparable tree classification was introduced to study the population structure of natural Japanese red pine forest in Northeast China.
本文采用动态可比性林木分级法，研究了东北东部天然赤松林的种群结构。
This paper describes a method which has been used for stand population selection and classification based on the plus trees selection principle of a single tree.
本文将林木树种单株选优原则和方法运用到林木群体选择和划分上。
When you get — this is Rituparna, counting the leaves on a tree — you can estimate, from a sample, the population expected values.
如果你…像数叶子的睿都巴若那一样，只有部分样本的话，你可以来估计总体均值。
Breeding groups are being used to control inbreeding in a breeding population and to effectively achieve maximum genetic gains in some tree improvement programs of the United States.
在美国的一些林木育种项目中，育种群已用来控制种子园的近交、捕获最大的遗传增益的有效措施。
There are significant differences in growth in the young tree stage among different provenances of Sea Buckthorn and the differences are obvious with different geographic population variation.
试验表明，沙棘不同种源的营养生长和生殖生长以及果实生化成分都存在明显的差异。
There are significant differences in growth in the young tree stage among different provenances of Sea Buckthorn and the differences are obvious with different geographic population variation.
试验表明，沙棘不同种源的营养生长和生殖生长以及果实生化成分都存在明显的差异。
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