The study on site quality evaluation for dahurian larch (Larix gmelinii Rupr.)

Site quality of larch (Larix gmelinii Rupr.) in Da Xingan Mountain in Inner Mongolia was studied systematically with about 1000 temporary plots and computer software. The nature of site class and site index curve was discussed in view of general mathematical model of height growth. The height growth of dominant tree of four divisions of forest stands were studied and site index tables were constructed respectively. In order to unify the comparing standard and convenience for management in this region, site index table was constucted too. Based on discussing the action and accuracy of forest type, a series of site quality evaluation (forest type-site index class-site index) was suggested. This subject of study is supported by the National Natural Scientific Fund (No. 39270549).     

黄土高原人工灌草系统不同立地条件土壤种子库特征

本研究通过野外调查取样与室内试验相结合，连续两年对黄土高原人工灌草系统不同坡向、坡位进行取样，以期对该区土壤种子库的物种组成、密度特征及其物种多样性进行初步了解。研究结果表明：该人工灌草生态系统土壤种子库共有9科，15种，其组成因坡位、坡向以及年份而异；坡向、坡位均显著影响土壤种子库物种多样性指数、丰富度指数与土壤种子库密度（P<0.05），土壤种子库密度为3 218～5 492粒·m^-2，总体呈现为阴坡显著高于阳坡（P<0.05），下坡位显著高于上坡位（P<0.05）；坡位和坡向均对物种均匀性系数无显著影响；年份对土壤种子库无显著影响。上述研究可为黄土高原人工灌草系统的可持续利用与恢复提供参考依据。     

Feasibility analysis of NIR for detecting sweet corn seeds vigor

This paper explores the feasibility of particle-based detection and grading of seed vigor based on a self-built seed single-granulation device using near infrared spectroscopy (NIRS). Sweet corn with uniform kernel size was used for this study. The seed samples were divided into three types, they were normal seeds, artificially aged seeds and heat-damaged seeds. A 2-part spectral acquisition of each seed were performed, one for the collection of seeds that fall into the detection zone within the separation pipe, another was on the static platform, whose collection was performed on 5 faces of each seed. Partial least squares discriminant analysis (PLS-DA) was used to classify the original data of the seeds. In the 2 parts, the discriminant results of the unprocessed normal seeds and the artificial accelerated aging seeds, the untreated normal seeds and the heat-damaged seeds showed that classification accuracy was higher than 98%. The research indicates that the spectral data of different positions of seeds can reflect their activity information, and it is feasible to detect and classify seeds in real time in the detection area of the separation pipeline.     

立地条件和林分结构对有林地生产力的影响

通过分析有林地生产力与立地条件和林分结构中各因子的关系,探索制约有林地生产力的主要因素.结果表明:不同立地质量中Ⅰ类地单位蓄积量最高(268.86±20.24 m3/hm2),不同坡向中东坡单位蓄积量最高(269.78±38.54 m3/hm2),不同树种组成中10杉类型单位蓄积量最高(259.33±14.62 m3/hm2);有林地生产力与林分年龄、林分密度正相关,相关系数R分别为0.590、0.460;有林地生产力与海拔、坡度相关性不显著.以上结果说明立地质量、坡向和树种组成对有林地生产力影响显著;有林地生产力与林分年龄、林分密度相关,与海拔、坡度无关.     

天然杨桦用材林高效经营技术研究

选择不同林分类型和立地条件,按不同经营密度分别设立固定标准地,开展立地类型划分和最适密度选择。同时,在固定标准地内,对林分生长性状、形质指标、干物质积累量、枯枝落叶分解量及养分归还量进行连续定位观测。结果表明:经营密度对林分生长、干物质积累和枯枝落叶分解影响较大,且以中等经营密度(0.7)效果最理想。在立地类型划分、最适经营密度选择、密度效应分析、径级-株数分布规律研究的基础上,针对不同培育目标,分别提出不同立地条件下天然杨桦(胶合板材、普通建筑材、纸浆材)用材林高效经营技术,为科学经营存量种质资源,最大限度提高森林生产力奠定理论基础。     

金融时间序列指标判别框架：以特质波动率为例

基于拐点集合判别的TBUD方法主要思路是分析拐点集合间的关系，并在高维空间进行划分，从而搭建判别模型，并将分析框架应用在特质波动率等若干指标上，利用实证数据得到结论。应用TBUD判别框架可以发现，特质波动率等指标无法对拐点集合进行清晰划分，因而并不具有预测能力。     

Understorey vegetation as an indicator of water content in till soils in Finnish Lapland

Artificial regeneration of Scots pine (Pinus sylvestris L.) has been applied to a variety of forest site in Lapland. Occasional failures in regeneration have been observed on sites with high soil moisture contents and originally dominated by Norway spruce (Picea abies (L.) Karst). Understorey vegetation was studied on four naturally pine-dominated and eight spruce-dominated sites to determine suitable indicator plants for assessing soil moisture regimes. Soil moisture contents were estimated using the in situ dielectric measurements with radar surface arrival detection targeted to a depth of 0-50 cm. The abundance and frequence of plant species were analysed using logistic regression. The most reliable indicators were found to be Stereocaulon and Cladonia lichens for the dry regime (θv<25%), and Polytrichum commune Hedw. and Carex globularis L. for the wet regime (θv>25%). It was concluded that the indicator plants found in this study provide an alternative to the traditional Finnish forest site type approach in recognizing high soil moisture regimes.     

The optimal nutrition of maize in the hungarian national long‐term field experimental network

In Hungary, maize is grown on 1 million ha and occupies more than 20% of the arable land. The rich assortment of maize cultivars of different vegetation periods and different responses to nutritional effects, water supply etc. gives the growers the possibility to choose the cultivars suiting best the site characteristics (Jolânkai et al. 1999). Among the cereals maize has the highest genetical potential. To utilize its yield and quality potential, soil types of high nutrient content and regular nutrient supply are required (Gyõrffy, 1979). Both over‐ and under‐fertilization have an unfavourable effect on the yield and quality of maize (Debreczeni, 1985). Crops can be supplied with the appropriate nutrient amounts only with the knowledge of soil characteristics in the different agro‐ecological regions (nutrient content, water supply, soil compactness, pH, nutrient supplying capacity etc.). In Hungary, a network of long‐term field fertilization trials with uniform fertilizer treatments has been maintained at nine experimental sites representing different agro‐ecological regions of the country. This experimental network gives a basis to test the nutrient responses of our main crops and calibrate their optimal nutrient supply (Kismányoky, 1991).     

Landscape Zonation, benefit functions and target-based planning: Unifying reserve selection strategies

The most widespread reserve selection strategy is target-based planning, as specified under the framework of systematic conservation planning. Targets are given for the representation levels of biodiversity features, and site selection algorithms are employed to either meet the targets with least cost (the minimum set formulation) or to maximize the number of targets met with a given resource (maximum coverage). Benefit functions are another recent approach to reserve selection. In the benefit function framework the objective is to maximize the value of the reserve network, however value is defined. In one benefit function formulation value is a sum over species-specific values, and species-specific value is an increasing function of representation. This benefit function approach is computationally convenient, but because it allows free tradeoffs between species, it essentially makes the assumption that species are acting as surrogates, or samples from a larger regional species pool. The Zonation algorithm is a recent computational method that produces a hierarchy of conservation priority through the landscape. This hierarchy is produced via iterative removal of selection units (cells) using the criterion of least marginal loss of conservation value to decide which cell to remove next. The first variant of Zonation, here called core-area Zonation, has a characteristic of emphasizing core-areas of all species. Here I separate the Zonation meta-algorithm from the cell removal rule, the definition of marginal loss of conservation value utilized inside the algorithm. I show how additive benefit functions and target-based planning can be implemented into the Zonation framework via the use of particular kinds of cell removal rules. The core-area, additive benefit function and targeting benefit function variants of Zonation have interesting conceptual differences in how they treat and trade off between species in the planning process.     

交通事故现场三维数字化信息的获取及再现

道路交通事故已成为全球共同面临的最为严重的社会公害之一,我国正处于道路交通事故高发期。交通事故现场的勘测对交通事故处理质量和深入分析事故产生的原因有着重要的影响。我们分析了现有的事故现场勘测方法的特点,介绍了利用激光扫描对交通事故现场进行三维数字化信息获取的新技术,论述了激光扫描原理、交通事故现场三维数字化信息获取和处理的过程及数据处理的常用方法,以及该技术的应用与发展趋势。