乔木的

The change of landuse patterns in 1977-1998 shows indirectly the desertified land had been restored and is being restored. The relationship between landuse patterns and soil types was also analysed in this paper, from 1977 to 1998, the areas of rangeland and mobile sand dunes decreased in most soil types and the areas of woodland, shrubland and farmland increased, which means that the modification of landuse patterns due to limitation of soil types will be helpful to desertification control.

同时土地利用格局的时空变化与土壤类型间关系的分析表明，1977-1998的20余年间，在四种主要土壤类型上各种土地利用类型的变化具有一定的规律性，草牧场和流动沙地的面积基本上呈减小的趋势（分布在风沙土上的草牧场面积除外），而乔木林地，灌木林地和农地面积均为增加的趋势，这说明在土壤类型这一土地自然属性的严重制约下，人们被迫调整其土地利用格局，从而有效地遏制了荒漠化的发生和发展。

The analyses of social and economic development indicate that, up to 1998, the total population in Yijinholo County is 143, 949 persons, the population density is 24 persons per square kilometer, large population number results in land exploitation for food and overgrazing in rangeland. The change in temporal and spatial pattern of landuse from 1977 to 1998 demonstrates that mobile sand dunes was replaced by rangeland and woodland and partial shrubland in the middle of study area changed into rangeland and farmland from 1977 to 1987, while mobile sand dunes and rangeland transformed into shrubland and farmland in a small parts from 1987 to 1998, the above-mentioned change is proved by the change of fractal dimension index and fragmentation index at landscape and its element levels.

对近50年来伊旗社会经济发展的分析结果表明，虽然人口增长率基本上呈下降趋势，但由于人口基数较大，截至1998年底，伊金霍洛旗的人口总数达143949人，人口密度为24人／平方公里，较高的人口密度带来了更多的生存需求，使得大量的草牧场被开垦，而剩余的则严重超载。1977-1998年间伊土地利用结构总体格局变化的分析结果表明，1977-1987时段内主要是流动沙地为草牧场和乔木林地所取代，伴随着中部的部分灌木林地转换为草牧场和农地：而1987-1998时段内主要是草牧场和流沙地为灌木林地和农地特别是灌木林地所取代，而景观及各景观要素的分维度指数和破碎度指数的变化也充分证实了这一结论，虽然在前10年（1977-1987年）中大面积的灌木林被砍伐，但土地利用格局的整体变化间接地反映出该时段内荒漠化的状况正在发生逆转。

Firstly, according to study dynamic changes of the elements structures in succession about natural and artificial forest, then summarized regular patterns;at the same time.based on the study of Coupling Relationship between structure and function of water conservation forest established the ideal structures from the stand level and the watershed level. The ideal structures from the stand level: uneven-aged, double layer and mixed structure, and trend to natural forest. The watershed level followed the same principle, that is double layer patches, uneven-aged forest well-distributed and to build up different forest patches in watershed.

首先，经过对北京山区水源林天然林和人工林结构要素的演替动态研究，提出其发展规律，同时依据水源林结构与功能耦合关系研究，从林分层次和流域层次上分别构建了水源林的理想结构，其中，林分层次上水源林的理想结构为：异龄、复层、混交的结构状态，林分结构趋于天然林结构的特征；在流域层次上水源林的理想结构为也应形成&复层&、&异龄&、&混交&的结构，即：在流域各水源林斑块间形成林冠层复层、斑块内部乔木、灌木、草本层的复层；不同水源林年龄面积上的均匀分布；形成不同水源林斑块间的镶嵌分布。

The results showed that the species richness,the speciesdiversity and its biomass of understorey vegetation decreased with the stand age in-creasing.There was the most significant negative-linear relationship between thiskind of changes and age.It is possible that the certain shading condition may benefit to understorey growing better.The richness,diversity index and biomass of thevegetation in eucalypt plantation decreased with CPR increasing,however,after ro-tating by watermelon one rotation,the richness,the diversity index and biomass ofunderstorey in CP stand increased,this result will provide the possibility of therestoration and reestablishment of vegetation in eucalypt plantations.The nutrientstorage of understorey decreased in accord with the productivity decreased withCPR increasing,this is the result which the stand enviroment became worse and thestand stratum competed with the vegetation for the water and fertility of soil.

结果表明，随着年龄的增长，桉树林下植被物种丰富度降低，多样性减少，生物量下降，这种变化趋势与年龄存在极显著的负线性关系；随着造林密度的增加物种丰富度降低，多样性也下降，但林下植被生物量尚有增加，可能是一定程度的庇荫有利于桉树林下植被的生长；随连栽代次的增加，桉树林下植被丰富度降低，多样性指数下降，生物量减少；但在轮作一茬西瓜后的林地，物种丰富度提高，多样性指数升高，生物量增加，为桉树林下植被的恢复与重建提供了可能性；随连栽代次增加，林下植被养分总量逐代下降，与生产力下降一致，这是林分环境恶化后上层乔木和林下植被对水肥竞争的结果。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。