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杨树短轮伐期集约栽培的新进展 总被引：8，自引：0，他引：8
本文介绍了参加18届国际杨树会议的17个会员国的杨树栽培新进展、杨树育种和短轮伐期集约栽培的研究动态和成果,还报道了与会外国专家的观感。 相似文献
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南斯拉夫共有杨柳树林地15万公顷,仅占森林面积的1.5%,但其木材产量却占全国木材总产量的8%。杨木产量由1950年的10立方米,提高到1985年的120万立方米,增加了11倍,成为当今国际杨树委员会的重要成员国之一。该国杨树发展速度之所以快,与其有一支稳定的科研队伍密切相关。本文较详细地介绍了南斯拉夫杨树育种的成就和经验,并结合我国的实际情况,提出了作者的看法和建议。 相似文献
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瑞典柳树能源林的研究及发展概况 总被引：12，自引：0，他引：12
本文介绍了瑞典柳树能源林在矮林作业系统、专家系统和土壤生态、集约生产生态、林分生态、土壤微生物、遗传育种、病虫害、生物物理学、环境效果和经济效益等方面的研究进展及瑞典柳树能源林的发展概况,旨在为今后我国研究和发展柳树能源林提供思路和方法。 相似文献
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杨树、柳树是中原地区主要的速生树种,为充分利用速生林软质木材,研究其改性工艺,提高木材品质。作者通过对杨、柳木干燥改性实验,对软质木材进行改性。改性后木材尺寸稳定性增强、硬度大幅增大,杨树、柳树硬度分别提高49.2%、40.1%;木材的抗弯强度分别提高49.0%、51.5%。 相似文献
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To improve the productivity and wood quality of poplar plantations, effects of four planting spacing on canopy characteristics, biomass production and stem roundness in poplar plantations were evaluated over 8 years. Planting spacing influenced canopy characteristics of the plantations, and further affected the understory vegetation and plantation productivity. Understory vegetation biomass and Shannon-Wiener index were negatively correlated with leaf area index, but both diversity indexes and aboveground biomass of understory vegetation were higher in stands with a wider spacing. Tree diameter growth increased with increasing planting spacing, while the increment in plantations of square configurations (5?×?5 m and 6?×?6 m) was higher than those with rectangular configurations (3?×?8 m, 4.5?×?8 m). The highest poplar biomass production was achieved in the plantation with 5?×?5 m spacing at age 8. Moreover, poplar trees showed a tendency with better stem roundness in a square configuration. The results suggest that planting spacing not only affect canopy characteristics, understory vegetation and tree growth but also wood quality, and square configurations (5?×?5 m and 6?×?6 m) could be a better option for poplar plywood timber production at similar sites. 相似文献
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涂干剂防治杨树天牛成虫试验 总被引：4，自引：0，他引：4
用0．5％BL—1和0．25％BL—4涂干剂处理柳树，施药30d后使天牛成虫接触5s，24h死亡率分别是80％～93．2％。施药后33d内平均每株树杀死天牛分别是30．3和39．8头，而同期对照组仅为0．6头。用0．5％BL—6和0．25％BL—8涂干剂处理杨树，施药52d后使天牛成虫在毒环上爬行一次。24h防治效果均达100％，平均每株施药树杀死天牛成虫分别是7．8和7．4头，对照组为0．3头。用凡士林配制涂干剂，防治效果更佳，成本更低。用涂干剂防治杨树天牛施药方法简便，机动灵活，可以处理生长在各种环境的杨、柳、榆等树木，特别适合小级杨树和已经截干处理的诱饵树。 相似文献
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以长江中游芦苇滩地为研究对象,利用微生物分离培养计数方法和PCR-DGGE技术重点研究了人工杨树林对芦苇滩地土壤细菌种群的影响。结果表明：与芦苇地相比,人工杨树林根际土、根表土和0-10cm土层中的氮、速效磷和总有机碳的含量都明显降低;人工杨树林下根际土中的微生物数量都比芦苇地的低,而其根表土中则是细菌、真菌数量低于芦苇地,放线具比芦苇地高;就4种功能细菌来说,人工杨树林根际土的纤维素菌、反硝化菌、硝化细菌和氨氧化细菌的数量则比芦苇地低,而根表土中除了氨氧化细菌外,其他3种功能细菌含量又比芦苇地的高。4种功能细菌数量在不同的土壤剖面中的分布也各不相同：在0-10cm土层中,人工杨树林的纤维素菌和氨氧化细菌的数量高于芦苇地,而其余2种功能茵则低于芦苇地;在10-25cm土层中,人工杨树林的纤维素菌和硝化细菌含量低于芦苇地,反硝化菌的含量却高于芦苇地,而氨氧化菌含量相同;在25-60cm土层中,除了纤维素菌,其他3种功能细菌含量都是人工杨树林低于芦苇地。通过系统进化树分析发现,滩地中普遍存在的细菌类群为α变形菌纲、β变形茵纲和硝化螺旋菌纲,而人工杨树林和芦苇地的根表土、根际土和0-10cm土层均存在各自专有的细菌种群,表明人工杨树林对芦苇滩地土壤中细菌种群产生了一定的影响。 相似文献
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The response of hybrid poplar plantations established on former agricultural land in Saskatchewan to competition from weeds
on a range of site productivities was studied. The short-term impact of competition control on the growth of juvenile trees
and how tree responses to competition control differed across the productivity gradient was of particular interest, as was
the determination of which resource was most highly competed for and was most important in determining tree growth. Eight
sets of paired plots in juvenile hybrid poplar plantations were established in central Saskatchewan across a range of site
productivities. In each pair, one plot had complete weed control (weed-free) while in the other plot weeds were allowed to
grow. The best soil predictor of tree growth was soil texture, represented by a combination of the percentage silt and clay,
with finer textures showing better growth. Competition control significantly increased tree growth on all sites with the benefit
being greatest on the higher productivity sites. Soil water appeared to be highly competed for between trees and weeds and
was a dominant resource controlling growth. For soil nutrients, nitrogen and phosphorous were highly competed for between
trees and weeds. However, leaf phosphorous concentration of the weed-free plots had a strong positive relation to tree growth
while nitrogen did not, indicating that when trees are free of competition they can access sufficient nitrogen from these
soils. 相似文献
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Forest plantations in the northeastern United States comprise a small proportion of the total forest area. Most plantations are typically softwood dominated and managed for sawlog and pulpwood production, while high-yield hardwood plantations for bioenergy feedstocks have not been as widely investigated. The objective of this study was to compare the biomass production of planted white spruce (Picea glauca (Moench) Voss) and hybrid poplar (Populus spp.) plantations (four clones) in monoculture, and in mixture of the two on a typical reforestation site in Maine. Three years following planting, hybrid poplar height and ground line diameter growth rates began to diverge among clones, and by 6?years, the Populus nigra?×?Populus maximowiczii (NM6) clone clearly outperformed three Populus deltoides?×?Populus nigra clones (D51, DN10 and DN70) both in pure stands and in mixtures with white spruce. In mixture, we found the yield of white spruce to decline as the yield of hybrid poplar increased. Overall, yields of white spruce monocultures were comparable to those reported in eastern Canada, while the hybrid poplar biomass yields were substantially lower than those reported from studies on abandoned agricultural lands, likely due to the harsher soil conditions at our site. The dominance of rocky and poorly drained sites (like the one tested in this study) across Maine will likely limit the feasibility of widespread hybrid poplar plantations, and thus constrains their potential use as a bioenergy feedstock. 相似文献
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"杨、柳、榆、槐"是东北地区园林绿化的主要树种,在东北地区园林绿化中起着举足轻重的作用。文章对"杨、柳、榆、槐"是东北地区乡土树种的笼统提法提出了质疑,对"杨、柳、榆、槐"在东北地区园林绿化中的作用进行了评价,并提出了东北地区园林绿化合理选择、应用"杨、柳、榆、槐"的建议。
相似文献
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Today, most poplar plantations in the temperate region are established on abandoned marginal agricultural land, but there is great potential for planting poplars on forest land as the available area is large and does not compete with food production. The objective of this study was to examine how different planting types (un-rooted cuttings, bare-rooted and containerized plants) affect the establishment and early growth of poplar plants on forest and agricultural sites. Our results suggest that on the agricultural site, survival and growth during the first two years are not influenced by plant type. However, at the forest sites, survival of rooted plants was superior compared to un-rooted cuttings. The height and biomass (stem and root) increment of bare-rooted plants was low; greater height and biomass growth was found for containerized plants. Container sizes had no effect on height growth, but leaf and stem biomasses were higher if the largest containers were used. When using the largest containers, concentrations of macronutrients (N, P) were increased compared to bare-rooted plants. Thus, these results suggest that practices for establishing poplar plantations of agricultural land include planting of un-rooted cutting, but on forest land, a plant grown in a container of 470?ml should be used. Together, this can reduce the cost of establishment, increase the available area for poplar plantations and have an impact on poplar plantation economics in Sweden. 相似文献
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毛白杨生长和收获模型 总被引：3，自引：0，他引：3
本文介绍了根据毛白杨调查数据检验J.L.Clutter的火炬松生长和收获模型的过程和结果。在他的模型基础上,根据毛白杨的生长特点,作了一些修改,分别为该树种成片林和林带制定了生长和收获预测模型,并编制了毛白杨地位指数曲线。 相似文献
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为探明廊坊地区杨、柳、榆、槐四个主要树种适生的土壤类型;本文利用灰色系统理论建立适地适树决策模型,结果表明与实际调查基本相吻合。 相似文献
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朝阳市主要树种组林分平均胸径生长率模型研究 总被引：1，自引：0，他引：1
采用超总体理论编制朝阳市油松、刺槐、杨柳、速生杨4个树种组林分平均胸径生长率通用模型,以2005年森林资源二类调查资料为原始数据,涵盖全市所有地区不同地理位置和不同立地条件的生长水平.建立4种模拟方程,通过拟合与优化及结果精度的检验,选择出各树种组的平均胸径生长率模型. 相似文献
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为进一步了解柳树优良无性系的生长特点,为无性系的合理利用提供依据,对苏柳932,799,795,797和172等5个柳树优良无性系2年生幼林的树高、胸径、材积等生长指标以及生物量和形率进行了测定分析。结果表明,苏柳5个无性系的胸径平均值为4．28cm,其中苏柳172的平均胸径最大（4．71cm）;树高平均值为6．97m,其中苏柳795平均树高最高（7．75m）。苏柳795的形率qo．5、q0．7值分别为0．68,0．44,是各无性系中形率的最高值,主干生物量占单株地上部分总生物量的比例最高（76．02％）,出材率高,是优良的用材林树种;而苏柳932的总生物量最高,为12．35kg／株,枝量、叶量占总生物量的比例最大,为42．0％,14．4％,属于防风防浪和生物能源林的造林良种。 相似文献
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粉煤灰复田立地上杨,柳,榆,刺槐根系的分布和生长特点 总被引：22，自引：0，他引：22
针对粉煤灰复田立地（利用电厂粉煤灰填充采煤塌陷区，在其上再覆３０ｃｍ土壤）营造人工林的可行性和造林树种选择等问题，调查了该立地上生长的４—５年生欧美杨、旱柳、白榆和刺槐人工林根系的分布及生长特点。结果表明：四树种根系分布深达１８０ｃｍ以下，水平延伸达８ｍ。在粉煤灰层中，各树种根系均能正常生长，其中根系长度和根系重量分别占总量的６８％和８７％以上。在３０ｃｍ厚表层土壤中，根系长度和重量分别低于总量的３０％和１３％。欧美杨、旱柳、白榆和刺槐的根系总长度和总重量分别为每株４９．２４、２９．４５、２５．４２、６８．０８ｋｍ和７．４５、７．５４、１０．０５、１３．３７ｋｇ。 相似文献
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Performance of wheat varieties under poplar (Populus deltoides Bartr.) plantations in Punjab (India)
Three varieties of wheat, viz., PBW-222, HD-2329 and PBW-34, were studied for grain yield potential under six-year-old poplar plantations. The order of yield reduction found was: PBW-34 (57.1%)>PBW-222 (19.4%)>HD-2329 (15.3%). The reduction in wheat yield was found to be significant under poplar plantations as compared to crops grown in open condition. Research needs to maintain the increased wheat production by evolving suitable ideotypes for an agrisilviculture system have been suggested. 相似文献