查询词典 forest tree

Random forests are a combination of tree predictors such that each tree depends on the values of random vector sampled independently and with the same distribution for all trees in the forest.

随机森林模型是决策树的集成，并且由一随机向量决定决策树的构造。

By comparing the similarity of grasshoppers' community in different habitat regions and clustering and PCA analyzing, the different habitat regions could be divided into 3 types: far off lake region including cutting blank and farmland region; near Lake Region including artificial larch tree and lakefront wetland; mountain site including crude redeposit broad-leaf weed-tree forest.

通过比较不同生境蝗虫群落的相似性，并经聚类和PCA分析，可将松花湖库区5种生境划分为三大类型，分别为远湖区生境，包括采伐迹地和农田；近湖区生境，包括湖边湿地和人工落叶松林；山地森林生境，主要是天然次生阔叶杂木林。

According to the character of vegetations and geography, Songhua lake Nature Reserve was divided into five kinds of habitats, artificial larch tree, cutting blank, lakefront wetland, farmland region, crude redeposit broad leaf weed tree forest.

根据植被和地形地貌特点，作者将松花湖库区划分为五种生境，即人工落叶松林、采伐迹地、湖边湿地、农田和天然次生阔叶杂木林。

Using a variety of diversity indexes to study the diversity of grasshopper in different habitat region, the results showed that diversity indexof 5 kinds of habitats has the order: crude redeposit broad-leaf weed-tree forest＞farmland region＞artificial larch tree＞lakefront wetland＞cutting blank.

采用各种多样性指数对不同生境蝗虫多样性进行了研究，结果显示，Shannon-wiener多样性指数的排序情况为天然次生阔叶杂木林＞农田＞人工林＞湖边湿地＞采伐迹地，Pielou均匀度指数变化和H′变化较为一致，相关系数为0.918，达到了显著性水平。

The traditional query tree optimization methods,parallel database optimization methods based on left linear trees and right linear trees,bushy trees,and operation of the forest,have their own pros and cons,they have been more in-depth and maturity of the study.The query optimization method based on multiple weighted tree has studied its model of parallel query plan,its complexity model of parallel query plan and query optimization algorithms.The semantic query method transforms an inquiry into one or several semantic equivalence inquiries then has to find and implement a strategy to achieve a better query.Agent-based parallel database query optimization using Multi-Agent technology to automatically search the integrity constraint conditions which are related to the determined query,there for,the efficiency between several relations' joins has been greatly improved.The parallel optimization algorithm,based on genetic algorithm which is suitable for multi-joins of cluster environment,has deeply studied the relations storage options,multi-joins query optimization and query processing and other key technologies based on cluster parallel database.

传统的查询树优化方法，即基于左线性树、右线性树、浓密树、操作森林的并行数据库查询优化方法，各有优劣，对其的研究比较深入、成熟；基于多重加权树的查询优化方法，研究了其并行查询计划模型、并行查询计划的复杂性模型和查询优化算法；语义查询优化方法将一个查询变换成一个或数个语义等价的查询，进而寻找并执行这些等价查询中具有较好实现策略的一个；基于Agent的并行数据库查询优化采用Multi-Agent技术自动查找与给定查询有关的完整性约束条件，使得多个关系间连接操作的效率得到很大的提高；基于遗传算法的并行优化算法，深入研究了基于机群并行数据库中关系存储的选择、多连接查询优化和查询处理等关键技术。

There are more than 2,000 plant species, with 178 branches of higher plants, 611 genera and 1158 kinds, of which 73 tree species are 473 kinds of Section 181, accounting for 80% of tree species in Guangdong, mainland China, 25 kinds of state protection, accounting for 67 to 37% of the , there is a protected plant yew trees horses, Fujian cypress, Tsuga-bin, sightseeing wood, etc., and Guangdong-Song 207 kinds of medicinal plant resources; county's forest coverage reached 73.1% and the stumpage volume of 5.34 million cubic meters m.

植物种类有 2000多种，具有高等植物178科，611属，1158种，其中乔木树种73科181属473种，占广东大陆树种的80%，国家保护的25种，占全国67种的37%，有一级保护植物红豆杉、伯乐树、福建柏、长苞铁彬、观光木、广东松等以及药用植物资源207种；全县森林覆盖率达73.1%，活立木蓄积量达534万立方米。

Based on the status of suburban forest of Harbin, 49 well-grown afforesting tree species including 32 species arbor, 16 species shrub and only 1 species vine which are mainly Pinus sylvestris var. mongolica, Betula platyphylla, Syringa oblata and Acer negundo et al, were selected in this study. An information system concerning tree species was established by sorting qualitative index, testing quantitative index as well as referring to other study results.

本论文从哈尔滨市城郊林种现状出发，选择了在哈尔滨地区生长良好的樟子松、白桦、紫丁香、糖槭等49种绿化树种，其中乔木树种32种，灌木16种，藤本1种，通过对树种定性指标资料的收集、整理以及定量指标的实验获得了树种全面、系统的信息。

According to the life form of species and their roles in communities, 6 species groups are used to do ordination analysis and environmental interpretation. The result suggests that:①Despite the strong man-made disturbance at lower altitude sites, the number and character of evergreen species show an change along the altitude gradient.②The rare and endangered species concentrated at two sectors along altitude gradient, corresponding to the upper and lower borders of the mountain mixed forest belt of evergreen and deciduous broad-leaved species.③The pioneer tree species concentrated on the middle and upper positions at lower elevation.④The deciduous accompany tree species show a great diversity on middle and lower position at middle and higher elevation.⑤Coniferous species differentiate along elevation and local topographical gradient.⑥Deciduous species in Quercus, Castanea, Fagus, Carpinus genus as well as coniferous species play primary community-constructing roles at different topographical position at Dalaoling region.

根据物种生活型及其在植物群落中的地位，分6个种组进行排序和环境解释，表明：①尽管低海拔地段受到强烈人为干扰，常绿种类仍显示了数量和性质沿海拔梯度的变化；②珍稀物种在海拔梯度上形成两个相对集中的区段，大致对应于山地常绿落叶阔叶混交林带的上下边缘；③先锋树种在中低海拔的中上坡位富集；④在中、高海拔的中低坡位，落叶的乔木伴生种显示了极大的多样性；⑤为数不多的针叶树种在海拔和局部地形梯度上也有明确分异；⑥它们和落叶的栎、栗、水青冈、鹅耳枥属物种在大老岭地区不同地形部位的植被中起着主要的建群作用。

In habitats of the broad-leaved forest, the dominant tree are the species of Fagaceae in tree layer, Theaceae, Saxifragaceae and Lauraceae in shrub layer, Cyperaceae, Dryopteris spp. and Liliaceae in herb layer.

在阔叶林型栖息地中，乔木层主要树种为壳斗科植物，灌木层植物以山茶科、虎耳草科和樟科等科的种类为主，草本层植物以莎草科、蕨类和百合科为主。

The diversity index and evenness index of tree species in medium-aged stands averaged 1.79 and 0.53. The dominant family for the forest was Fagaceae in terms of importance value, and the dominant tree species were Castanopsis eyrei, C. sclerophlla, Lithocarpus harlandii, and Cyclobalanopsis glauca.

肖坑亚热带常绿阔叶林的树种多样性较低，中龄林林分平均多样性指数和均匀度指数分别为1.79和0.53；依据优势度划分，该地区常绿阔叶林的优势科为壳斗科，优势种为甜槠、苦槠、青冈和东南石栎。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。