共查询到19条相似文献,搜索用时 62 毫秒
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为了保证日本落叶松造林后林相整齐,减少苗木分化,提高林分质量,确保尽快郁闭成林。2009~2011年间,开展了苗木分类造林对比试验。结果表明:无论用哪个类别的苗木造林其成活率和保存率没有太大区别;造林后连续3 a地径、树高新生长依次为:1 a生超级苗>2a生Ⅰ级苗>2 a生混合苗>2 a生Ⅱ级苗。造林时,一定将苗木进行分类,在2 a生Ⅰ级苗用完后,可采用1a生超级苗造林,不提倡混合苗造林。 相似文献
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小陇山林区日本落叶松良种繁育现状与策略张宋智马建伟赵文杰(小陇山林业实验局林科所天水741000)科学技术是生产力,林木良种在某种意义上亦是一种物化了的生产力。选用良种,实现造林良种化,这是当今世界提高人工林质量和产量最主要的方法和途径。林业部在1... 相似文献
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该文从森林经营角度阐述了日本落叶松商品林的经营特点,系统提出不同经营目标的定向培育技术措施,同时对日本落叶松人工林的更新技术要点进行归纳总结,用于指导日本落叶松商品林的定向培育,为今后辽东山区日本落叶松商品林经营提供了科学依据和对策。 相似文献
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日本落叶松是本地区林业产业建设的首选树种.种子受种源、自然条件、基础建设等诸多因素的影响,出现了严重短缺的现象,与快速发展的林业建设需求形成尖锐矛盾.为了解决这一矛盾,适应现代林业建设的发展,文章对该树种从良种选育、发展现状、存在问题等方面进行了较为客观的论述,并根据国内外解决这一矛盾采取的对策及成功经验,提出了今后对日本落叶松良种选育,提供充足造林苗木的经营措施. 相似文献
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小陇山林区日本落叶松的现状与前景李嘉珏,牟真1993年底,我们在小陇山林业实验局负责同志陪同下,到该局沙坝种子园、麻沿、高桥林场对日本落叶松用材林营造情况进行了初步考察,所见所闻,深受鼓舞。我们似乎看到了小陇山林区的未来和希望。在长期实践中总结出的发... 相似文献
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通过华北落叶松与日本落叶松的杂交,在22个控制授粉杂交组合中,球果长在1.74 cm~2.92 cm之间,球果径在0.98 cm~1.46 cm之间;在30个组合中,单粒球果质量介于0.52 g~1.63 g之间;球果种鳞数在23枚~47枚之间;种子连翅长在0.75 cm~1.07 cm之间;种子千粒重在2.6 g~5.0 g之间。 相似文献
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Test samples of Japanese larch (Larix leptolepis) heartwood and Japanese beech (Fagus crenata) sapwood were heated for 22 h at constant temperatures (50°–180°C) under three water content conditions. Raman spectra of
the samples were recorded before and after the heat treatments, and spectral changes in the range from 1000 cm−1 to 1800 cm−1 were evaluated using the difference spectrum method. For both wood species, the Raman band intensity at 1655–1660 cm−1 due mainly to the C=C and C=O groups in lignin clearly decreased with increasing heat-treatment temperature (HTT). The spectral
change was thought to reflect the progress of condensation reactions of lignin molecules during the heat treatment. Moreover,
the decrease in band intensity was considerably facilitated by the presence of water in the cell wall, suggesting that the
condensation is closely related to the softening of lignin. From the spectral changes in the wavenumber region of 1200–1500 cm−1, it was considered that wood constituents are partially decomposed at the higher HTT.
Part of this article was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, March 2003 相似文献
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Twelve-year-old Japanese larch (Larix kaempferi [Lamb.]Carr.) trees of 20 different progenies and/or provenances were sampled at one site in the Mauricie region of Quebec. Two standard samples were obtained at breast height and closer to the bark from each tree. Partial and total radial, tangential, and volumetric shrinkages, and tangential/radial (T/R) shrinkage ratios were assessed. All of these variables were significantly affected by the progeny/provenance. Drying defects are one of the main reasons for downgrading larch lumber; thus, T/R shrinkage ratio was considered for the selection of progenies/provenances for lumber production purposes. Lowest partial and total T/R shrinkage ratios were obtained with progenies/provenances 8964, 8904, 8962, 8957, 8907, 8927, 7283, and 7795. Among them, lowest partial and total tangential, radial, and volumetric shrinkages were found in progenies/provenances 8964, 8962, and 8907 as well. Other physico-chemical (mechanical properties, density, extractive content) and silvicultural (growth rate) attributes should also be taken into consideration for an adequate selection of progenies/provenances according to the specific final utilization. 相似文献
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通过分析建水县林业生态建设现状及存在的问题,结合我县当前的生态环境形势,提出林业生态建设的奋斗目标及发展对策,以期为更好推动建水县林业生态建设的可持续发展提供一定的指导依据。 相似文献