图像分割技术在木材表面缺陷识别中的应用   总被引：3，自引：3，他引：3  

邹丽晖  白雪冰 《森林工程》2007,23(1):27-29

阐述了图像分割技术在图像处理及分析中重要意义,以及主要的图像分割技术。以木材表面缺陷为主要研究对象,利用微分算子边缘检测、最优迭代阈值分割及形态学方法针对具有代表性缺陷死节和虫眼进行分割处理。  相似文献   

闽南山地桉树纤维材优良无性系的选择研究   总被引：17，自引：0，他引：17  

姚庆端  何水东  张金文  洪长福  李宝福 《林业科学》2003,(Z1)

对福建漳州岩溪、天马 2个试验点 1 3个桉树纤维材无性系的生长性状、木材纤维形态和化学组分等性能进行测定与分析 ,并经多性状综合评判 ,选择出具有较高的生长量、生物量和纤维产量 ,适合闽南山地发展的C9、C1 0、EC1、EC3、C6共 5个纤维材优良无性系 ,其中尤以C9、C1 0、EC1三个无性系的各性状为最优。这 5个无性系 ,3a生年平均树高和胸径生长量、每株干材重量和纤维产量分别可达 3 93～ 6 60m、3 83～ 4 97cm ,9 71～ 2 0 48kg·a- 1 和 4 3 6～ 9 5 2kg·a- 1 ,而且木材纤维形态和化学组成等特性良好 ,可进一步扩大繁殖、推广应用。  相似文献   

木材市场价格变化对森林资源资产经营的影响分析   总被引：5，自引：0，他引：5  

胡国登 《中南林业调查规划》2007,26(2):18-22

在对福建埔上国有林场自1995年以来的杉木价格变动趋势分析的基础上,以具有代表性的一般杉木中径材经营类型生长指标并结合有关技术经济指标,计算市场销售木材保本价格,据以分析木材价格变动对森林资源资产经营的影响,为森林经营者经营决策提供借鉴。  相似文献   

广东省马尾松经济成熟龄的初探     

龚益广  钱志能 《林业调查规划》2005,30(5):15-17

为探讨在市场经济条件下，使森林利用达到最大经济效益，搜集了广东省东部、西部、北部马尾松用材林的有关资料和数据，采用土地纯收益法、内部收益率模型、净现值一般模型3种方法，计算马尾松用材林的经济成熟年龄为17～20年，  相似文献   

甘肃省天然林区森林资源蓄积量及用材林消长变化     

熊奎山 《甘肃林业科技》2005,30(1):5-7

通过对甘肃省天然林区5次森林资源连续清查蓄积量及用材林蓄积量变化的分析，初步得出结论：1979-1988年甘肃省天然林区蓄积量为增长阶段，1988-1996年蓄积量属减少阶段，1996-2001年为增长阶段。通过对3个阶段的分析，说明甘肃省20多年来，天然林区蓄积量呈波浪式的增长、减少、再增长趋势，也充分说明了国家实施天保工程的正确性。  相似文献   

明溪县杉木马尾松商品材立木材积表编制的研究     

陈清平  邹秀华  李伟华  兰金奖 《福建林业科技》2002,29(1):17-22

应用树干分段的二元形数函数的削度方程、商品材材积方程和树干总材积方程的一致性方程系统编制明溪县杉木、马尾松的商品材立木材积表。既能充分利用公开发表的有效的测树信息和数表 ,又能结合区域的资源调查信息估测一致性系统中的参数 ,且编表的误差分布均匀 ,绝对误差和相对误差小  相似文献   

European forest accounting: general concepts and Austrian experiences     

Walter Sekot 《European Journal of Forest Research》2007,126(4):481-494

Within the European Union there exist three different frameworks for forest accounting at the national level. For purposes of the national accounts, the regulations of the European System of Integrated Economic Accounts (ESA) have to be observed. They require a distinction between forestry and logging and provide specific guidelines for the valuation of standing timber. In recognition of the special character of forests and forestry production, two satellite accounts are devoted to forestry: the Economic Accounts for Forestry (EAF) and the European Framework for Integrated Environmental and Economic Accounting for Forests (IEEAF). Although they were designed as complementary to the national accounts and refer to the same basic methodologies, the guidelines for forest accounting provided by the three manuals are not fully compatible. Just recently, a further integration and harmonization of the concepts for forest accounting has been proposed. Austria has implemented the valuation of the increment as an output of forestry as requested by ESA and produces the EAF tables on a regular basis. The possibilities for extending forest accounting to natural resource accounts for standing timber and the IEEAF have been investigated in terms of pilot studies. The Austrian experiences and results exemplify the problems and possible solutions associated with the adoption of the different European schemes. Data deficits and valuation issues restrict the significance of respective results to some degree, especially as regards forestry-specific extensions of the accounting schemes.  相似文献   

Tropical Timber Trade Flows in P.R. China     

HU Yanjie LIN Fengming SHI Kunshan Research Institute of Forestry Policy  Information  Chinese Academy of Forestry  Beijing  P.R.China 《中国林业科技(英文版)》2007,6(2):62-73

The historical transition of timber distribution pattern in China was presented firstly with main parts of timber flows in China, which included timber markets, timber transport system and regulations of timber transport. Based on the overview on tropical timber flows in China, the trade flows of tropical timber from production and imports of tropical timber to export of tropical timber products were analyzed by vivid illustrations. At the same time, problems in timber trade flows in China were analysed in the end.  相似文献   

Marketing constraints for Eucalyptus from farm lands in India     

N. C. Saxena 《Agroforestry Systems》1991,13(1):73-85

During the early eighties farmers in north-west India planted Eucalyptus on a massive scale for sale as poles and pulpwood. However, after 1986 farmers in this region have almost stopped growing Eucalyptus, as their experience with its marketing was not a happy one. The pole market got saturated, paper mills did not pay a remunerative price, and fuelwood prices were low and uneconomical. More important, because of legal restrictions on the transport and sale of wood, and other institutional factors, the gap in the farmgate price and the consumer price remained very wide. Wood markets have, on the whole, exploited the farmers, rather than helped them. Due to this, the short period of flirtation with tree crops seems to be over for at least resident farmers in those very areas in north-west India where they had so enthusiastically planted Eucalyptus in the early 1980s.Abbreviations BDO Block Development Officer - Headloaders poor people who collect firewood on their heads from forest lands for consumption and sale - m ha million hectares - Rs Indian Rupee 16 Rs = 1 US Dollar in 1989 - panchayat elected village organisation - pradhan village chief On study leave from the Government of India to the Oxford Forestry Institute, South Parks Road, Oxford, OX1 3RB, U.K. Present address: 17 Ponnappa Road, Allahabad 211001, India  相似文献   

浅谈锯材干燥产生干裂问题     

刘国军 《林业科技情报》2004,36(3):83-84

本文阐述了锯材在干燥过程中出现的干裂问题及产生的原因和防止办法。  相似文献