森林开拓

They carved out great areas of land from the virgin forest .

他们在原始森林中开拓出大片大片的土地。

Pioneer species A species that colonizes a new physical environment,for example land exposed by retreating glaciers,felling of forest,or bare mud on coasts or estuaries.

先锋种：可以开拓新的自然环境的生物种类，如冰河消退露出的陆地，砍伐后的森林，海岸或河口处裸露的泥沙滩。

Some particular measures to be taken are as the followings:(1) to establish a uniform harmony mechanism in the river basin in order to have a general plan for wetland protection and utilization;(2) to combine the existing protection districts according to lake drainage area and species distribution, and to construct new wetland protection region in order to solve problems in management districts;(3) to develop wetland restoration and reconstruction;(4) to carry out reforesting in formerly cultivated land and to construct shelter forest of the Yangtze River in order to control soil erosion and to preserve the water resource;(5) to protect and utilize reasonably the wetland resources in the middle and lower reaches of the Yangtze River;(6) to strengthen the research of wetland science.

具体可采取以下措施：在流域内建立统一协调机制，对流域湿地进行保护与合理利用，合理布局，统一规划；按湖泊流域和物种分布整合现有保护区，建立新的湿地保护区，解决目前管理上的制约问题；大力开展湿地修复重建；推进退耕还林、长江防护林等工程建设，发挥森林治理水土流失、涵养水源的作用；在保护的前提下科学合理地利用长江中下游湿地资源，开拓新的生产力；同时加强湿地科学研究。

In about a century' s time, their livelihood of swidden agriculture has been changing greatly along with the natural and social environment change. Before 1950s, as a minor group frequently move in the subtropical mountainous area characterized by scarce arable land, high forest coverage rate and sparse population, Kemu people has long been engaged in swidden agriculture which was simple, called for no sophisticated production tools and was suitable for frequent movement. At that time, they adapted to the environment change mainly by moving frequently from one place to another, and their livelihood was featured by complete dependence on environment, frequent movement and swiddening without continuous cultivation. From 1950s to early 1970s, their way of adaptation changed into migration within defined territory and shortterm fallow featured by complete dependence on environment, migration within limited area and short fallow. In early 1970s, they leaned from outside to cultivate irrigated fields and plant cash forest and their livelihood was featured by complete dependence on environment and agro-forestry.

近一个世纪以来，随着其所处自然环境和社会环境的变迁，其刀耕火种的生计方式在不断地变化：20世纪50年代以前，作为频繁迁徙于山多地少、森林覆盖率高、人烟稀少的热带、亚热带山区的弱小族群，以开发容易，便于流动作业不需要复杂生产设施的刀耕火种为其传统的生计方式，主要以迁徙的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为完全依赖型、随意迁徙型、无轮作型；20世纪50年代至70年代，其主要以固定区域内迁徙和短期轮作的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为完全依赖型、在固定区域迁徙型、短期轮作型刀耕火种；20世纪70年代初，其主要以外文化——开拓水田及人工造林的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为部分依赖型、粮林轮作型刀耕火种；20世纪80年代以后，其主要以发展橡胶种植业对环境变迁进行调适，其刀耕火种生计方式的特征表现为暂时依赖型刀耕火种。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。