E0级胶合板用UMF树脂胶固化体系的研究

采用1%NH_4Cl和0.5%的H_3PO_4、草酸、酒石酸、甲酸构成的双组分固化体系加入F/(U M)摩尔比1.01～1.03的UMF树脂,可以降低树脂的pH值,提高固化速度,改善预压性能;用该双组分固化剂体系,加入F/(U M)摩尔比1.01的UMF树脂胶,实验室压制的杨木三合板、杂木三合板和工厂生产规模压制的椴木-杨木-椴木三合板、杂木三合板均符合E_0级胶合板国家标准的要求。     

大理市森林火险等级区划研究

森林火险等级区划是森林防火宏观决策和分类指导的科学依据．1996年国家公布的大理市森林火险等级已经与实际不相符．在调查研究的基础上,参照LY1063—92《全国森林火险区划等级》标准,将树种（组）燃烧类型、农业人口密度、路网密度、气温、风速、降水量6个火险因子的最新统计数据作为区划参数,按评定标准重新对大理市的森林火险等级进行修订,确认大理市森林火险等级为“Ⅰ级”,森林火灾危险性“大”,属国家一类火险区．     

湖南旅游资源及其开发利用研究

介绍了湖南旅游业历史沿革。湖南现有3036处景观,旅游资源分为7种类型,采用专家评价法与心理物理学派评价法相结合的方法,评出旅游资源质量等级为:一级131处,二级1015处,三级1369处。指出了湖南旅游资源的四大优势,提出了湖南旅游资源开发利用的指导思想、开发原则和可持续发展策略。     

Effect of shoot size and phenological variation of host plants on the spatial patterns of cynipid galls

The effects of shoot size and differences in budburst phenology ofQuercus serrata trees on the spatial patterns of galls were investigated for two cynipid species: the sexual generation ofAndricus moriokae and the agamic generation ofAphelonyx glanduliferae. There were marked differences in budburst phenology, but these did not affect the gall density on the tree. The galls of both cynipids showed a contagious distribution in their respective trees, but different abundance patterns under high gall density. The mean number of galls ofA. glanduliferae over a shoot size range was positively correlated with shoot size. More galls ofA. moriokae appeared on larger shoots on trees on which many buds had started growing before oviposition by the agamic adults. In the case of a tree on which a few buds had burst by the time of oviposition, the mean numbers ofA. moriokae galls on shoots of particular size ranges depended on the frequency of shoots in the size class. These results suggest that, although these cynipids prefer to attack larger shoots within a host tree, they may exhibit plasticity in their preference in response to changes in budburst phenology of the host plant relative to the time of oviposition.     

滇中地区森林火险等级预报方法的研究

经引起滇中地区森林火灾的主要细小可燃物的含水率及初始蔓延速度的大量试验数据为基础，结合大量林火历史资料，气象历史资料统计分析，找出规律，在对森林火险等级进行实测的基础上，建立数学模型和预报方法。经验证及对预报效果分析证明，本预报方法符合客观实际，是一种符合科学规律、简易、实用的预报方法，同时对引起滇中地区特大森林火灾的大气环流形势及物理量的变化作了分析，掌握了有关规律，为该地区的特大森林火险预报提     

Tree/wood quality in slash pine following long-term cattle grazing

Tree height, diameter, and grade were measured on 14 cattle grazing trial plots located on the Palustris Experimental Forest in Louisiana's Kisatchie National Forest. These plots had been established in the early 1960s. Mensurational data was gathered on 28 trees from grazed sites and another 28 from ungrazed plots. Increment cores were also taken from these trees. Statistical analyses showed no effect attributable to grazing on any of the variables measured: tree height, tree diameter at breast height, tree grade, growth rate, amount of latewood, unextracted specific gravity, or tracheid length. This revised version was published online in June 2006 with corrections to the Cover Date.     

Threshold responses of songbirds to long-term timber management on an active industrial forest

Forest managers often seek to balance economic benefits from timber harvesting with maintenance of habitat for wildlife, ecosystem function, and human uses. Most research on the relationship between avian abundance and active timber management has been short-term, lasting one to two years, creating the need to investigate long-term avian responses and to identify harvest thresholds when a small change in habitat results in a disproportionate response in relative abundance and nest success. Our objectives were to identify trends in relative abundance and nest success and to identify landscape-scale disturbance thresholds for avian species and habitat guilds in response to a variety of harvest treatments (clear-cuts, heavy and light partial harvests) over 14 years. We conducted point counts and monitored nests at an industrial forest in the central Appalachians of West Virginia during 1996-1998, 2001-2003, and 2007-2009. Early successional species increased in relative abundance across all three time periods, whereas interior-edge and forest-interior guilds peaked in relative abundance mid-study after which the forest-interior guild declined. Of 41 species with >10 detections, four (10%) declined significantly, 13 (32%) increased significantly (only three species among all periods), and 9 (22%) peaked in abundance mid-study (over the entire study period, four species had no significant change in abundance, four declined, and one increased). Based on piecewise linear models, forest-interior and interior-edge guilds’ relative abundance harvest thresholds were 28% total harvests (all harvests combined), 10% clear-cut harvests, and 18% light partial harvests, after which abundances declined. Harvest thresholds for the early successional guild were 42% total harvests, 11% clear-cut harvest, and 10% light partial harvests, and relative abundances increased after surpassing thresholds albeit at a reduced rate of increase after the clear-cut threshold. Threshold confidence intervals for individual species overlapped their guild threshold intervals 91% of the time. Even though relative abundance of most species (80%) did not decline as the area affected by timber management increased, implementing management at or below our approximate forest-interior and interior-edge harvest thresholds would reduce the number of declining species by half, maintain higher relative abundances of four species with a net decline in abundance but that peaked in abundance mid-study, and maintain higher relative abundances of ten additional species. In contrast, this management strategy also would prevent the increase in relative abundance of seven species and limit the increase in abundance of three species that increased throughout the study.     

弱度抚育对青海云杉胸径与材积生长变化的数学分析

生长量是评估立地条件及经营措施效果好坏的重要指标。正确研究分析林木生长规律以及采取相应的经营管理措施，对改善林分状况，森林环境和提高林木生长量具有重要的意义，研究表明，强度为１０％的抚育措施，可使西营河试验区树木胸径定期平均生长量提高８４．８５％，相当于２２％，的强度抚育措施使哈溪试验区树木胸径定期平均生长量提高６９．２０％，材积定期平均生长量提高６５．３３％，经Ｆ０．０５检验，两试验区胸径生长与     

27个木槿品种的数量分类和主成分分析

通过观测27个木槿品种的17个数量和质量性状,探究了木槿品种分类的等级和标准,便于为木槿品种的选育与资源研究等提供参考依据。首先对17个性状指标进行R型聚类分析和主成分分析,根据分析结果再对27个木槿品种进行Q型聚类分析。R型聚类分析结果表明,各性状选取是合理的;主成分分析结果表明,17个性状可综合为6个主成分,其累计贡献率达88.096%。Q型聚类结果表明,27个木槿品种根据有无丹心、花型、丹心基部形状、花瓣指数、花径、叶形、丹心线与丹心的关系可被分为2大类、3大类或8大类。16个性状对木槿品种的划分贡献较大。综合而言,有无丹心、花型、花瓣指数、丹心线与丹心的关系是木槿品种分类的主要标准和依据。     

Nutrient dynamics in a mangrove creek (North Brazil) during the dry season

During the dry season, dissolved inorganic nutrients and organic carbon (DOC) in a mangrove tidal creek (Bragança, North Brazil) presented a clear tidal signature: silicate, phosphate, ammonium and DOC covaried with salinity, with minima at high tide and maxima at low tide. Hydrodynamical calculations explained most diel variability as dilution of nutrientrich groundwater input by estuarine water. Creek nutrients tended to lower concentrations towards the end of the dry season, probably due to changes in groundwater dynamics. Ammonium was about 44% higher in the night than during the day, while silicate, phosphate nitrate + nitrite showed differences < 5%, indicating preferential autotrophic uptake of ammonium as nitrogen source. Nitrification and/or nitrogen fixation are probably sources of nitrate + nitrite, which contributed only 12% to the dissolved inorganic nitrogen pool. Dissolved oxygen (7%) and DOC (11%) were lower during the night, suggesting the existence of a labile, algalderived DOC pool. There is a loose coupling between aquatic primary production, groundwater dynamics and tidal regime.