福建省国有林场采伐调查设计

福建省国有林场采伐调查设计分伐区规划与伐区采伐调查设计两步完成,伐区采代调查设计主要有伐区调查设计、伐区工艺设计、准备作业工程设计和采伐调查设计说明书编制等内容。     

浅谈Excel软件在伐区调查设计中的应用

随着科学技术的飞速发展，计算机应用越来越广泛。就我区国有林场而言，计算机在资源管理、财务管理、文字处理等方面已有初步应用，但在林业专业性、技术性较强的伐区调查设计工作上，尚未得到真正实际意义的应用和推广。迄今为止，在伐区调查设计工作中，从林分蓄积量、伐区采伐量、出材量的计算；伐区生产工艺设计；生产费用预算等数据处理，到设计表生成和输出，一直沿用传统的手工操作或借助计算器，浪费大量的人力物力财力，工作效率较低，容易出错，不易校对，成果内容不统一、设计不规范。因此，采用计算机技术开发伐区调查设计计算…     

云南省"天保"工程区人工商品林采伐实施要点及问题探讨

在云南省天保工程区进行人工商品林合理采伐是实现森林三大效益和合理经营的需要，是解决还贷和缓解木材供需矛盾的需要，其实施要点包括伐区调查、伐区作业设计、伐区施工。通过2003年的采伐试点，分析了人工商品林采伐实施中存在的问题，提出了今后的实施对策。     

实现黑龙江省森工林区伐区调查设计信息化的条件分析

通过对黑龙江森工伐区调查设计方法与传统的工作流程、伐区调查存在的特殊性、伐区调查数据情况等进行具体分析,阐述了黑龙江省森工林区伐区调查数据采集和信息管理的要求。     

伐区调查设计存在的问题及对策

分析了目前伐区调查设计工作在监督管理、队伍建设、调查经查、调查技术与方法等方面存在的普通性问题，提出了相应的对策，为改进伐区调查设计工作，提高伐区调查设计成果质量提供参考。     

评价伐区蓄积调查质量的探讨

利用有关评价伐区蓄积量调查质量的资料，对各种不同规定进行比较分析，统一了蓄积调查误差概念、计算公式和计算方法，使伐区蓄积调查检查验收和森林调查设计步入科学化、规范化进程。     

伐区蓄积量调查方法的比较分析

伐区资源调查是项繁重的基础工作，为了寻求简单、快速、精度高的伐区蓄积量调查方法，采用福建省建瓯市地区不同林分的10片伐区的调查资料，对全林实测法、圆形标准地法、角规绕测法3种方法调查结果进行了对比分析。结果表明采用角规进行伐区蓄积量调查能获得高效精确的结果。     

直干桉人工商品林采伐作业设计探讨

以弥勒市2013年天保工程区直干桉人工商品林采伐作业设计为例,探讨了伐区外业调查的内容、方法、计算结果、采伐量报批、伐前公示、伐区工艺设计、采伐作业、注意事项、伐区管理等各个环节的实施情况,作为科学、准确编制采伐作业设计说明书的基础。     

集体林区伐区调查设计中亟待解决的问题与对策

自1989年省林业厅制定了（福建省伐区调查设计管理规定》以来，森林采伐的源头消耗得到了一定的控制。但通过几年来伐区调查设计成果质量的大检查，发现在伐区调查设计工作中还存在不少问题：一是在一些地区伐区调查设计率和设计质量合格率仍很低，伐区界线调绘、面积量算、蓄积量测定、出材量设计等达不到精度要求的现象较为普遍；二是违反政策规定和技术规程，串用采伐类型和方式，超期限间伐，超强度择伐，甚至有的调查人员未进行现场勾绘和实测照抄资源档案材料的现象也时有发生；三是借定向培育小径材和公路沿线改种果树等名义随意降低…     

伐区调查设计中存在的问题及对策

森林采伐调查设计是林木采伐生产管理的源头和基础,伐区调查设计精度的高低是确保伐区作业质量的关键。国有森工企业的伐区调查设计主要存在采伐方式、应伐木、采伐间隔期设计不合理等问题。提出了解决上述问题的对策与建议。     

GPS在二类调查外业中的应用

介绍了GPS在森林资源二类调查中的应用方法及注意事项。     

Estimation of GPS positional accuracy under different forest conditions using signal interruption probability

We proposed a signal interruption probability (SIP) value indicating the frequency of global positioning system (GPS) signal interruption or the fragmentation of GPS data, and used it to estimate the success probability of ambiguity resolution in carrier-phase differential GPS (DGPS) as well as the horizontal precision of code-phase DGPS under different forest conditions. In field tests, a rover was set up at four observation points, each representing a different condition within a forest. At each observation point, static surveying was conducted for four periods of 30 min, and data from the first 1, 5, 15, and 30 min from each observation point were extracted for analysis. The position of each point was calculated by baseline analysis using three types of GPS data, i.e., dual-frequency (L1 and L2), single-frequency (L1), and code-phase DGPS data. The results showed that ambiguity resolution was a key factor in determining the horizontal accuracy of carrier-phase DGPS, and that the success probability of ambiguity resolution differed greatly according to forest conditions, which were well explained not by the index of the canopy opening but by the SIP. Furthermore, estimation of the success probability of ambiguity resolution was made based on the SIP and the observation period using a logistic regression model. The horizontal precision of code-phase DGPS was also estimated based on the SIP and the observation period. In conclusion, the SIP was found to be an effective indicator of GPS positional accuracy under different forest conditions.     

Algorithm for improving the co-registration of LiDAR-derived digital canopy height models and field data

Improving trees location under LiDAR-derived digital canopy height models (DCMs) is of great interest as discrepancies between both dataset influence the accuracy of the estimations of forest attributes. A method is proposed for the co-registration of LiDAR-derived DCMs with local field positional measurements under a dense tree canopy. This approach consists of two main stages: (1) the assessment of the match between the LiDAR-derived digital terrain model and topographic surveying measurements when shifting the coordinates around a measured position; and (2) a comparison between the field height of selected trees and the LiDAR-derived DCM. Satisfactory results were obtained from geo-referencing field data and LiDAR models for characterizing the forest structure in heterogeneous Pinus sylvestris stands. Closure error of topographic surveying was 17.7 cm, and GPS accuracy to 95 % probability was below 10 cm, thus considerably lower than the resolution of the LiDAR models (1 m-pixel). The best co-location for field trees and LiDAR models provided a coefficient of determination of 0.56 between field-measured tree heights and LiDAR-derived DCM values.     

Comparing the precision and accuracy of GPS positioning in forested areas

The objective of this study is to clarify the performance of the Global Positioning System (GPS) in forested areas after selective availability (SA) was turned off. In this study, we conducted a field test on horizontal and vertical positional errors of GPS positioning at different points in forested areas. The precision and accuracy of GPS positioning at different points were then calculated and compared. Furthermore, the effect of differential GPS (DGPS) on precision and accuracy was analyzed using analysis of variance (ANOVA), and the necessity for DGPS after SA was turned off was discussed. As a result, the largest horizontal precision errors were found to be in the plantation forest, followed by the natural forest and forest road. On the other hand, precision errors were smallest at the landing, around which there were no obstacles. Horizontal accuracy errors were greatly improved by using the DGPS. Large vertical precision errors were produced in the plantation forest, on the forest road, and in the natural forest, while those at the landing were much smaller. Vertical accuracy errors were also relatively small at the landing. In conclusion, tree canopies greatly affected precision errors, and the DGPS improved not horizontal precision but horizontal accuracy. The autonomous GPS is sufficiently useful for purposes in which horizontal positional errors of a maximum of 10m are allowable. However, the DGPS should be used for surveying and mapping, for which higher accuracy is necessary.     

GPS技术在林业工作中的应用

GPS在林业系统中的应用广泛，具有定位、导航、求积三大功能。GPS求积功能的开发，为三类作业设计调查带来了一种技术上的突破。相对于以往的森林罗盘仪测量有了质的飞跃。     

广东林区GPS GIS TM遥感图象的几种叠合方法之精度研究

通过对ＧＰＳ、ＧＩＳ、ＴＭ遥感图象叠合的三种方法进行比较、分析,认为在广东林区,采用以ＧＰＳ坐标数据为主,综合ＧＩＳ,辅以目视判读的叠合方法,进行ＧＰＳ、ＧＩＳ、ＴＭ遥感图象叠合效果最好。在ＧＰＳ、ＧＩＳ、ＴＭ遥感图象叠合前,必须对ＴＭ遥感图象作局部几何纠正,特别是在植被组成复杂,林下植被多且高,中等郁闭度,坡位中部,坡度陡的地方。     

GPS在沿海地区基层林业调查中的应用

通过分析沿海地区地形的特点,利用GPS接收仪定位、测距、导向、划定边界及测量面积等功能,阐述了GPS技术在沿海地区林地征占用、林业案件技术鉴定、基干林带划界、野生动物常规调查等方面应用实践,总结GPS技术的优缺点,探讨未来GPS技术在林业调查中的应用方向。     

GPS和GIS技术在额敏县护林防火中的应用

简要论述了GPS和GIS的功能及在额敏县森林防火中的应用情况,并通过一个案例对具体的应用方法和步骤进行了说明。认为在Mapgis地理信息系统中,将卫星林火监测热点数据进行坐标转换、定位以确定具体的地理位置,为扑火指挥提供辅助决策,较以往采用传统方法准确、快捷。     

基于六株木法的杉木蓄积量估测研究

蓄积量是森林资源调查和监测的重要指标。本研究以湖南省攸县黄丰桥林场杉木树种为研究对象,采用随机抽样方法布点,共布设样地110块,其中杉木有效观测样地97块。样地内调查以距离样地中心位置最近的6株木为对象,观测每株杉木的胸径、树高及最远杉木到样地中心的距离,并计算这6株杉木样圆的覆盖面积,来估测样地蓄积量。结果表明：在95%的可靠性下,平均胸径估测精度为90%,平均树高估测精度为88%,蓄积量估测精度达89%,说明利用六株木法估测杉木蓄积量具有较好的效果。     

全球定位系统（GPS）在林业上应用的介绍

全球定位系统是全球性的卫星定位和导航的三维测量系统，能提供连续实时的位置，速度和时间信息，具有观察方便，定位精度高和费用低等优点而被许多行业广泛地应用。ＧＰＳ在林业中主要是应用于林区测量控制网的建立，林区道路勘测设计，与航空遥感技术相结合进行森林资源清查，病虫害监测，与地理信息系统相结合建立森林资源的管理系统等方面。