炼山对二代5年生杉木幼林生长的影响

在福建南平对炼山和不炼山的第2代5年生杉木幼林生长进行对比研究,结果表明,2种处理杉木平均胸径年均生长量均在1.70 cm以上,平均树高年均生长量均在1.00 m以上;炼山处理杉木的生长量略高于不炼山,但它们之间的差异不显著。     

等养分条件下稻草还田替代双季早稻氮钾肥比例的研究

【目的】研究等量氮磷钾养分投入条件下,长期稻草原位全量还田配施化肥对双季早稻氮 (N)、磷 (P)、钾 (K) 养分吸收累积、转运及养分利用的影响,为南方稻区稻草资源有效利用,维持并提高土壤肥力及水稻合理施肥提供理论依据。【方法】以江西温圳国家级耕地质量监测点长期定位试验为研究对象,陆两优 996 为供试材料,在不施化肥和施用化肥基础上设稻草还田、稻草烧灰还田和稻草不还田共 6 个处理,除空白对照外,所有处理养分投入量相等。于 2015 年在早稻移栽期、分蘖期、幼穗分化期、抽穗期和成熟期取地上部植株样,分析水稻植株不同部位的 N、P、K 含量和累积量以及转运比例,并计算 N、P、K 养分利用效率。【结果】稻草还田提高了水稻产量,施肥条件下稻草还田处理比稻草烧灰还田和稻草不还田处理平均增产 2.9%～ 6.4%,比不施肥区产量增幅高达 23.8%～ 26.0%,且差异达显著水平。无论是施肥区处理,还是无肥区处理,与稻草烧灰还田和稻草不还田处理相比,稻草还田植株中 K 含量及 N、P、K 积累量在整个生育期均较高,而 N、P 含量在生育后期较高,N、P、K 积累量以施肥区处理大于相应的无肥区处理;稻草还田提高水稻 N、P、K 养分农学效率、回收率和养分偏生产力,且 N、K 差异达显著水平,同时显著增加 K 的收获指数;稻草还田还提高了抽穗至成熟期茎鞘中 N、P、K 的转运量、转运率及转移养分对籽粒的贡献率,而叶片各处理间差异不显著。【结论】稻草还田配施化肥能提高水稻产量,同时还可以调节 N、P、K 养分的积累和转运,提高养分的吸收利用效率。本试验条件下,稻草还田可替代化肥氮肥 (N) 29.5%、磷肥 (P₂O₅) 4.0% 和钾肥 (K₂O) 50.0%。综合考虑,稻草还田相比稻草烧灰还田而言是南方稻区土壤养分管理实现高效利用的有效途径之一。     

Rural land-use and wildland fires in the tropics

Tropical forest land is increasingly influenced by man-caused wildfires. The vast majority of the forested area burnt and cleared annually is in the tropics. The use of fire in rural land-use systems is the major cause of the wildfires. Five broad causative agencies of wildfires are presented, shifting cultivation, grazing, non-wood forest products, migration programs and the wildland/residential interface. Integrated concepts of prescribed burning and prescribed grazing may offer solutions to the tropical wildland fire problems.     

浅谈阻燃中密度纤维板

介绍了中密度纤维板的生产现状和前景，阻燃中纤板所用阻燃剂的种类。阻燃的机理和处理方法。同时，论述了中纤板阻燃的必要性和紧迫性。并讨论了阻燃中纤板的发展方向。     

Ten-year responses of ponderosa pine growth,vigor, and recruitment to restoration treatments in the Bitterroot Mountains,Montana, USA

Little is known about ponderosa pine forest ecosystem responses to restoration practices in the Northern Rocky Mountains, USA. In this study, restoration treatments aimed at approximating historical forest structure and disturbances included modified single-tree selection cutting, with and without prescribed burning. We compared the effectiveness of restoration treatments on growth, vigor, and composition of recruitment responses with untreated controls. We used a randomized block design to detect treatment differences in mean individual tree basal area increment (BAInc10), growth efficiency (GE), and recruitment abundance between two restoration treatments (Cut-only and Cut-burn) and a Control. We further examined treatment effects by tree age-class (Young, Mature, Presettlement) using a spatial ANOVA model that incorporates the spatial autocorrelation among trees within experimental units. Ten years after implementing restoration treatments, mean individual tree BAInc10 and GE were significantly higher for treated units relative to Control units; all three age-classes benefited similarly from restoration treatments relative to the Control, with the greatest response in the Cut-only and moderate response in the Cut-burn. When treated units were compared, Cut-burn negatively affected BAInc10 and GE relative to Cut-only. Presettlement trees responded positively to treatment relative to the Control, particularly for BAInc10, demonstrating the potential of these old trees to respond to reduced competition. The Cut-burn treatment, in contrast, negatively affected the BAInc10 and GE response of postsettlement trees when compared to Cut-only. Restoration treatments did not reduce the amount of Douglas-fir recruits. In addition, the recruitment of both ponderosa pine and Douglas-fir species was associated with the proximate cover of woody debris in Cut-only and Control treatments. Finally, special consideration needs to be taken for spring Cut-burn treatments, which appeared to dampen growth and vigor, relative to Cut-only, particularly for Young and Mature trees, and increased recruitment of ponderosa pine and particularly Douglas-fir.     

玉龙县计划烧除存在的问题及改进措施

计划烧除是控制和减少森林火灾发生最有效的手段之一。该文通过分析计划烧除的有益作用和可能带来的负面影响,结合玉龙县实施计划烧除存在的问题,提出了改进措施。     

Thinning and prescribed fire effects on dwarf mistletoe severity in an eastern Cascade Range dry forest,Washington

Forest thinning and prescribed fire practices are widely used, either separately or in combination, to address tree stocking, species composition, and wildland fire concerns in western US mixed conifer forests. We examined the effects of these fuel treatments alone and combined on dwarf mistletoe infection severity immediately after treatment and for the following 100 years. Thinning, burning, thin + burn, and control treatments were applied to 10 ha units; each treatment was replicated three times. Dwarf mistletoe was found in ponderosa pine and/or Douglas-fir in all units prior to treatment. Stand infection severity was low to moderate, and severely infected trees were the largest in the overstory. Thinning produced the greatest reductions in tree stocking and mistletoe severity. Burning reduced stocking somewhat less because spring burns were relatively cool with spotty fuel consumption and mortality. Burning effects on vegetation were enhanced when combined with thinning; thin + burn treatments also reduced mistletoe severity in all size classes. Stand growth simulations using the Forest Vegetation Simulator (FVS) showed a trend of reduced mistletoe spread and intensification over time for all active treatments. When thinned and unthinned treatments were compared, thinning reduced infected basal area and treatment effects were obvious, beginning in the second decade. The same was true with burned and unburned treatments. Treatment effects on infected tree density were similar to infected basal area; however, treatment effects diminished after 20 years, suggesting a re-treatment interval for dwarf mistletoe.     

中国秸秆废弃焚烧与资源化利用的经济与环境分析

本研究就农作物秸秆资源废弃焚烧与资源化利用的经济效益与环境效益问题进行了分析和讨论。研究系统归纳了国内学术界有关秸秆焚烧现状、原因、危害以及秸秆资源化利用的经济和环境效益等方面文献。研究显示,秸秆废弃焚烧已成为中国显著的环境和社会问题,而农户之所以会焚烧秸秆是由于收获和利用秸秆的机会成本过高,且收益较低;秸秆发电、秸秆气化集中供气等新型秸秆资源化利用技术的环境效益明显,但经济效益受技术、原料、市场等因素影响存在不确定性;秸秆收储运成本高及相关体系不完善,成为制约秸秆规模化利用的关键因素。总体上看,现有技术的综合效益不明显,这限制了中国秸秆资源化利用水平的提高,急需政府扶持以进一步推动相关领域的技术创新。     

Review on Causes of Forest Decline

Site degradation and yield decline of forest have attracted increasing attention from forest managers and scientists. Studies conducted by researchers from a variety of disciplines and perspectives have led to a variety of competing hypotheses concerning the causes of the problem. In this paper we review evidence of such a yield decline and examine the problem and its possible way to identify the individual contributions of the many determinants of yield decline, and their interactions.     

东北、内蒙古林区物候点烧技术应用的情况分析

物候点烧技术是我国当前开设防火隔离带、国境防火带,降低林内可燃物载量、预防重大森林火灾最有效的技术之一,得到相关部门高度重视。但近年由于计划烧除时跑火造成森林火灾,使人们对物候点烧技术产生争议。本文是在对东北、内蒙古林区开展物候点烧技术相关事宜进行调查的基础上,总结四省（区）开展物候点烧取得的显著成效,阐述点烧的可行性、必要性,分析跑火的主要原因、存在的问题、解决的办法,并对今后如何加强物候点烧技术的安全性、科学性提出了建设性意见。