人造板甲醛释放量的对比测试

分别采用穿孔萃取法和干燥器法测试了刨花板、高密度纤维板、浸渍胶膜纸饰面刨花板和浸渍纸层压木地板的甲醛释放量。在测试中发现,用穿孔萃取法和干燥器法测甲醛释放量,两者所测得数据之间存在着一定的换算关系。     

胶合板用改性脲醛树脂的调制与应用

分别就改性脲醛(UF)树脂的调胶pH值以及面粉加量对胶液胶合性能的影响进行讨论.结果表明,随着pH值降低,胶合强度和预压强度增大,固化时间和适用期缩短,甲醛释放量降低;面粉用量增大对胶液粘度影响显著,对胶合强度、甲醛释放量有不利影响,但可改善预压性能.综合考虑生产实际,以pH值4.5和面粉加量20%为宜.     

Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations

The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation of Cryptomeria japonica from stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37–0.46) of the variation in dbh growth during a 5–11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8 m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09–0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50–0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.     

利用遥感技术对江边林业局进行森林资源调查

选取美国陆地卫星Land-sat-stm1999年3月成像比例尺为1：5万的TM453卫生数据，于2000年1－3月，对江边林业局森林资源进行了外业建标、室内判读和现地验证。结果判读一致率达92．3％，正判率达97．5％。     

总结经验 再接再厉 努力提升森林资源连续清查水平

森林资源连续清查是依法监测全国森林资源消长和生态状况变化的林业基础性工作,其成果是制定和调整经济社会发展规划和林业生态建设方针政策的重要依据。我国已经完成六次全国森林资源连续清查,积累的许多经验值得总结,更要适应生态建设的需要,进一步加以保持和发扬,并提升到新的水平。     

"3S"技术在森林资源二类调查中的应用前景

通过“3S”技术和传统方法在森林资源二类调查中的应用的比较,“3S”技术在工作量、费用、精度等方面均优于传统技术,在实践中值得推广。     

黑龙江省1980-1999年森林火灾释放碳量的估算

根据黑龙江省1980—1999年的森林火灾统计数据和对黑龙江省各森林类型地上生物量的估算,计算出黑龙江省森林年平均森林火灾损失地上生物量391758·65~522344·95t,占全国的6·4%~8·4%。年均释放碳176291·39~235055·23t,约占全国年均森林火灾排放碳的8%。用排放比法得出黑龙江省年平均森林火灾释放的CO2、CO、CH4、NMHC量分别为581761·6~775682·25t、34892·275~46523·04t、14091·11~18788·15t和6500~9000t。     

An inventory of Guadua (Guadua angustifolia) bamboo in the Coffee Region of Colombia

Management of renewable natural resources and the corresponding policy formulation should be founded on reliable data and information. This refers both to information on the resource itself and to information on the market situation. In this paper, we present methodology and major results of an inventory of the Guadua resources, in a study area of about 1 million ha within the Coffee Region of Colombia. This inventory produced for the first time sample-based statistical estimations of the Guadua area and growing stock. In the study area, land cover of Guadua patches was estimated to be 3.9% or about 40,000 ha (minimum patch area 0.3 ha). This is higher than figures published earlier. Estimation for mean number of standing culms (including shoots and dry culms) per hectare was 6,940 with a mean diameter at breast height of 10.8 cm, apparent commercial volume of 654 m3/ha, commercial wood volume of 304 m3/ha, oven-dry biomass of 311 ton/ha, and total carbon stock of 156 ton/ha. While the low-intensity sampling approach worked well and may serve as an example for similar studies, we identified a number of issues for further research, particularly in what refers to as the basic mensurational models for Guadua volume and biomass estimation from inventories.     

Energy and carbon dioxide (CO2) balance of logging residues as alternative energy resources: system analysis based on the method of a life cycle inventory (LCI) analysis

Using the method of a life cycle inventory (LCI) analysis, the energy balance and the carbon dioxide (CO₂) emission of logging residues from Japanese conventional forestry as alternative energy resources were analyzed over the entire life cycle of the residues. The fuel consumption for forestry machines was measured in field experiments for harvesting and transporting logging residues at forestry operating sites in Japan. In addition, a total audit of energy consumption was undertaken. It involved an assessment of materials, construction, and the repair and maintenance of forestry machines as well as the costs associated with an energy-conversion plant. As a result, the ratio of energy output to input was calculated to be 5.69, indicating that the system examined in this study could be feasible as an energy production system. The CO₂ emission per MWh_e (e: electricity) of the biomass-fired power generation plant was calculated to be 61.8kgCO₂/MWh_e, while that of coal-fired power generation plants in Japan is 960kgCO₂/MWh_e. Therefore, the reduction in the amount of CO₂ emission that would result from replacing coal with biomass for power generation by as much as 3.0 million dry-t/year of logging residues in Japan was estimated to be 1.66 million tCO₂/year, corresponding to 0.142% of the national CO₂ emission. This study provides evidence that Japan could reduce its domestic CO₂ emission by using logging residues as alternative energy resources.     

基于SPOT5遥感影像的样地判读

利用SPOT5卫星遥感资料在沾益县大坡乡进行了森林资源二类调查试点。共布设目视判读样地7711个、野外实测样地290个,其总体抽样精度为87 29%。介绍了工作方法,分析了判读结果和存在问题,提出了今后工作的思路。