依兰松花江大桥桥址方案的选择

从依兰松花江江段的江道、堤防、城镇规划等方面出发,选择三个桥址进行比较,最后确定A桥址为依兰松花江大桥推荐桥址。     

天然次生林立地质量评价的研究

本文以天然次生林为试验材料 ,采用方差分析 ,用偶数同阶打分法 ,对天然次生林的各小班 ,进行立地质量评价并绘制林场的立地质量评价图和立地质量等级 ,使以后的林场经营更加可靠、科学。     

Frost heaving of forest tree seedlings: a review

Soil frost heaving is the result of the formation of ice lenses in the soil caused by a segregation of the soil water. Ice lenses are growing from below and pushed upward. Seedlings heave when they are pushed out of the ground by the ice sheet formed at the surface of the soil. Frost heaving may greatly reduce growth and survival of forest tree seedlings particularly in regions where freezing and thawing are accompanied by high soil moisture. Resistance to frost heaving increases with size of seedling as the ability of a seedling to anchor itself increases. A few methods, such as fertilizing, choice of planting spots, sowing or planting at the proper time, shading, and use of mulches, appear to be effective in controlling frost heaving. Shade from natural plant cover can greatly reduce frost heaving.     

不同立地条件5年生马尾松幼林的生产力及其分配

在福建邵武不同立地条件的林地上,对5年生马尾松林分的生产力及其分配进行研究,结果表明,立地质量越好,马尾松的生物量越大,生产力越高,干材分配率也越高。     

广西红锥天然林原生境自然因子调查分析

通过调查统计广西15个红锥(Castanopsis hystrix)天然林县市的气候和土壤因子,结果表明广西红锥天然林分布的地区属南亚热带季风气候区,以红锥天然林为主的森林是我国南亚热带季雨林化常绿阔叶林的代表类型;红锥天然林分布以赤红壤、红壤林地出现较多,土壤酸碱度为微酸性(pH 4.36~6.23)。根据对广西红锥天然林原生境生长发育的主要气象因子的分析结果,初步确定广西红锥的现实生态位宽度。     

Critical RGC-Expected Survival models for predicting Survival of planted white fir (Abies concolor Lindl.) seedlings

Heretofore, only regression models using average RGC as the independent variable were available to predict the survival of planted seedlings. Now, however, Critical RGC-Expected Survival models are available. Each model predicts the survival of a population on sites with the same Critical RGC as specified by the model. Survival is predicted to equal the percent of the seedlings in the population that have RGCs that Critical RGC. These models are validated by a chi-square goodness of fit test which determines the probability that the survival predictions made by a model agree with the survivals observed on a planting site. In validating a model, the harshness of the planting site is also quantified in terms of its Critical RGC. In this paper, three Critical RGC-Expected Survival models are validated, demonstrating that RGC controls survival on both harsh and gentle sites. On the harsher sites, the Critical RGC for survival was 40 cm; whereas on the gentler sites, it was 20 cm.     

基于对偶回归的杉木与马尾松地位指数互导模型

应用对偶回归分析法,结合相关系数分析,对雪峰山地区324块同时具有杉木和马尾松地位指数值数据的样地进行对偶回归分析,建立了不同地地貌类型的雪峰山杉木与马尾松地位指数互导模型,模拟效果较好。预测误差值分布稳定,建模的平均相对误差为1.95%,模型适用性检验的平均相对误差为3.18%。不仅解决了地位指数代换偏差较大,精度不够高的问题,而且简化了建模的过程,提高了模型的实用性。     

Mounding site preparation: A review of European and North American experience

Mounding site preparation in the northern boreal and temperate regions is reviewed under the following headings: Terminology, History, Kinds of mounds, Effects of mounding, and Mound making.     

金沙滩林场立地类型划分和树种选择

通过对金沙滩林场土壤、植被的详细调查和定点试验，认为土壤水分是影响树木成活及生长的主要因子，并以土壤水分为标准，把该林场划分为７个立地类型，针对各种立地类型的特点，提出了不同区域适宜栽植的树种和林种     

雪峰山杉木、马尾松地位指数互导模型的研究

在同一立地条件下，实现不同树种地位指数之间的转换，建立地位指数互导模型具有重要的现实意义和理论研究价值。本文采用SPSS12．0对雪峰山地区324块同时具有杉木和马尾松地位指数值数据的样地进行11种方程的模拟分析，并进行误差分析，最终得出最优的杉木、马尾松地位指数互导模型。