免炼山与炼山造林对当年生桉树幼林生长的影响

试验对免炼山与炼山造林对当年生桉树生长的影响进行实地调查。结果表明:免炼山造林不影响桉树当年的生长量,具有操作方法简单,成本较低,符合可持续发展经营的要求。     

秸秆捆烧清洁供暖技术评价

中国北方地区秸秆资源丰富,将秸秆打捆转化为能源实现清洁取暖,既能解决秸秆过剩问题,又能有效替代煤炭,对改善大气质量和人居环境具有重要意义。为探究秸秆捆烧清洁供暖技术的能源效率、经济效益和温室气体排放,采用3E（Economic,Energy and Environment）评价模型,从作物种植收获到秸秆捆烧供暖应用全过程开展系统评价。结果表明,秸秆捆烧供暖技术的能源和经济效益较好、温室气体排放少,适于居住较集中的村镇地区冬季供暖,也可用于农业、工业园区等区域供热。供暖面积0.5×104～10×104m2范围内,供暖面积越高,能源和经济环境效益越好,秸秆捆烧供暖的净能量10 512～10 774.8 MJ/t,能量产出投入比8.4～8.5,能源转化率较高,温室气体CO2当量排放量为9.67～11.21 g/MJ;经济成本391.1～560.5元/t（折合16.2～23.8元/m2）,按基准收益率8%计算,供暖规模应不小于2×104 m2,若不考虑折旧只考虑运行成本,则供暖面积应不小于1×104 m2。与秸秆成型燃料和秸秆炭气联产供暖技术比较,均具有较好的经济效益,秸秆捆烧供暖技术的能量效益最优,温室气体排放量最少。与煤炭供暖技术相比,3种秸秆供暖技术的净能量产出不如煤炭,但温室气体排放仅为煤炭的1/10～1/7,秸秆清洁供暖技术的环境效益显著。     

计划火烧对区域森林燃烧性的影响

[目的]利用燃烧概率模型模拟计划火烧前后两种情景下的森林燃烧概率,在景观尺度上定量评估计划火烧在林火预防中的作用。[方法]利用SPOT6卫星数据提取大兴安岭部分区域在2016年火险期前进行计划火烧处理的可燃物状况,基于研究区附近地面气象观测数据利用R软件计算2016年火险期每日的火险指数,通过BURN-P3模型分别模拟计划火烧前后的森林燃烧性,评估计划火烧对森林燃烧概率和火行为的影响。[结果]2016年火险期前该区域进行计划火烧的面积为44 931 hm²,占区域总面积的20.8%。计划火烧后,研究区平均燃烧概率从0.016 4降到0.012 4,落叶针叶林、常绿针叶林、针阔混交林、草地和落叶阔叶林平均燃烧概率分别降低4.2%、3.5%、5.9%、2.3%和0.6%。计划火烧前研究区的平均火烧强度和平均蔓延速度分别为548.9 kW·m^-2和2.2 m·min^-1,通过计划火烧处理,火烧强度和蔓延速度分别降低17.9%和24.3%。落叶针叶林和针阔混交林是发生树冠火的主要类型,火强度高、火蔓延速度快。计划火烧处理后研究区...     

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。     

The effect of timing of forest fire on phenology and seed production in the fire-dependent herbs Geranium bohemicum and G. lanuginosum in Sweden

The seasonal distribution of fires is one fire regime variable which has received little attention with regard to its effects on plants. For species with a short life-span that recruits after fire, the seasonal timing of a fire can be expected to be important due to effects on potential growth period and reproduction. We observed phenology and reproductive output in two annual and fire-dependent Geranium spp. in the southern part of the European boreal forest. In a garden experiment with the two species under two levels of nutrition, we established cohorts of seedlings at several dates over three summers. Time from germination to flowering and first mature seed differed little between the two species and levels of nutrition; i.e. plant size or level of nutrition had almost no effect on phenology. However, emergence time controlled the timing of reproduction. Most plants emerging before the second week of July in the garden experiment bolted the same year. Plants emerging later behaved as winter-annuals and started to flower in June the following year. A similar dichotomy was observed for populations of Geranium spp. at a number of burnt forest sites that differed in date of fire. This response is likely controlled by photoperiod. Nevertheless, at sites that burnt early some plants did not bolt in the same season; probably an effect of variable seedling emergence dates in the populations. In both the field and garden experiment, there were plants entering reproduction too late to produce mature seeds. Our results indicate that management fires should be conducted either very early, or during July and August to achieve a high seed production in these rare forest plants.     

Effect of burning and brush treatments on nutrient and soil physical properties in young longleaf pine stands

Over a period of 16 years, unburned longleaf pine (Pinus palustris Mill.) pole stands grew an average of 27% more volume than similar stands regularly burned. Treatments included biennial burns in winter, spring, and summer plus an unburned check, each of which was combined with three supplemental treatments, namely, initial herbicide injection of all hardwoods, repeated handclearing of all woody stems, and no treatment. All unburned and winter-burned plots were paired to study this growth reduction relative to treatments. The status of nitrogen, phosphorus, available moisture holding capacity, bulk density, and macropore space was determined in both surface and subsurface soils. Foliage from pines on sampled plots was analyzed for N, P, K, Ca, Mg, Mn, Cu, Fe, and Zn. Burning did not significantly affect either soil N and P or foliar nutrients. However, burning reduced available moisture holding capacity and macropore space and increased the bulk density of surface soils, and also reduced the moisture-holding capacity of subsurface soils. The results from this and other studies suggest that growth losses are due, at least in part, to increased moisture stress associated with changes in soil physical properties.     

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.