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以刺槐、樟子松2个树种3种配置方式进行退耕还林造林试验,结果表明:造林树种配置方式对林木生长量有显著影响,刺槐在纯林配置时的生长量优于混交配置,前者的树高、胸径生长量分别是后者的140.2%和129.7%;樟子松混交配置时的生长量要优于纯林配置,前者的树高、胸径生长量分别是后者的119.0%和125.0%。土层厚度对林木生长量有显著影响,刺槐在厚土层立地条件下的树高和胸径生长量分别是薄土层的112.0%和104.0%;樟子松在厚土层立地条件下的树高和胸径生长量分别是薄土层的115.0%和113.0%,林地郁闭度亦提高了1成。 相似文献
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坡向和土壤质地对刺槐生长量的影响 总被引：1，自引：0，他引：1
文章从刺槐造林的坡向和土壤质地入手,研究了不同坡向和不同土壤质地对刺槐根系生长量和树高胸径生长量的影响,结果表明:阳坡、半阴坡向和壤土质地有利于刺槐生长量的提高,而阴坡虽然土壤含水量较高,但生长量高最低。在刺槐造林选择坡向时,应选择阳坡、半阴坡和壤土质地造林。 相似文献
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从刺槐造林的坡向和土壤质地入手,研究了不同坡向和土壤质地对刺槐根系生长量和树高胸径生长量的影响。结果表明:阳坡、半阴坡向和壤土质地有利于刺槐生长量的提高,而阴坡虽然土壤含水量较高,但生长量最低。在刺槐造林选择坡向时,应选择阳坡、半阴坡和壤土质地造林为宜。 相似文献
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不同立地条件下红豆树容器苗与裸根苗造林对比试验 总被引：1，自引：0，他引：1
对红豆树(Ormosia hosiei)容器苗与裸根苗在3种不同立地条件下进行成活率、树高和胸径生长量造林对比试验。结果表明:红豆树在不同处理间造林,成活率、6年生幼树高和胸径生长量差异极显著,立地条件与苗木类型间的互作效应在成活率和胸径上呈极显著差异,在树高上无显著性差异;采用容器苗造林成活率、6年生幼树高和胸径生长量极显著大于裸根苗造林;不同立地条件下造林成活率、6年生树高和胸径生长量呈极显著差异,随着立地条件变差,容器苗与裸根苗之间的造林成活率、树高和胸径生长量差距逐渐拉大,对造林成效的影响依次为:胸径成活率树高。 相似文献
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采用红豆树3年生容器大苗和1年生容器小苗,对不同立地条件下造林成活率、树高、胸径生长量等因素进行调查,结果显示:不同年限容器苗造林对成活率、树高和胸径生长有极显著影响,变幅分别为29.78%、18.62%和43.67%。不同立地条件对容器苗造林成活率、树高和胸径生长影响极显著,变幅分别达到17.59%、68.29%和83.13%。不同年限容器苗和不同立地条件交互作用对造林成活率和胸径生长均有极显著的影响,但在树高生长上无显著性差异。3年生容器大苗加良好的立地条件配置其造林效果优于1年生容器小苗加较差立地条件配置。红豆树造林对苗木和立地条件要求严格,其中立地条件对红豆树造林后的生长起着决定性的作用。选择3年生容器大苗造林比1年生容器小苗造林成本要低,且其树体通直、树型美观、林相整齐,效益优势显著。因此,红豆树造林宜选择3年生以上容器大苗,林地应选择中下坡、土层深1 m以上、土壤肥力条件良好的造林地。 相似文献
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在内蒙古赤峰市敖汉旗小流域选择小叶杨、白榆、油松为研究对象,采用样地法和标准木树干解析木法,对标准地内林木进行每木检尺,同时对标准木树干解析,从而对流域内3种人工造林树种进行树高、胸径以及材积生长过程分析。结果表明:立地条件对不同人工林都存在明显的生长抑制作用。(1)小叶杨在种植19年后,树高、胸径、材积量生长均出现下降或减缓;从材积生长来看,第5~19年时为小叶杨的速生期;(2)白榆在种植后9~10年间树高和胸径生长速度开始降低,树高连年生长量与平均生长量相交于10年。材积量的快速积累可达22年;(3)油松在种植后14~19年开始出现树高和胸径生长降低现象,种植后19年是油松生长的转折期,应在此时实施疏伐调整。从材积生长来看,第7~20年时为油松的速生期。 相似文献
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《中南林业调查规划》2021,(2)
以三个不同海拔区域11年生的四川桤木林为研究对象,对其成活率和保存率、平均树高和平均胸径生长量、林分土壤化学性质进行分析。结果表明:不同海拔高度,四川桤木成活率和保存率均存在显著差异,但两者规律一致,在海拔440～480 m时保存率和存活率最高,分别能达到92.28%和89.38%,平均树高和胸径生长量差异特点也基本一致;海拔在440～480 m时,平均树高最高,为18.46 m,平均胸径也最大,为15.86 cm;四川桤木种植11年后,三个海拔区间的林地土壤化学性质均得到不同程度的提高,在海拔680～730 m时林分生长与林地地力恢复达到平衡状态。 相似文献
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通过在辽西干旱地区1年生刺槐新造林中开展保水剂应用效果的研究,结果表明保水剂对提高刺槐造林成活率有着明显的作用,保水剂稀释蘸根处理中以1%的效果最好,成活率达到了81.3%,与不施保水剂对照的差异显著;穴施保水剂颗粒的处理中以穴施颗粒剂12～19 g/株的刺槐造林效果最好,成活率达到了90%以上,与不施保水剂的对照差异极显;穴施保水剂胶体的处理中以穴施2～4 kg/株的效果较好,成活率达到了94%以上,差异极显著,穴施2 kg/株处理的成活率最高,达到了97.6%;保水剂稀释液蘸根处理、穴施保水剂颗粒剂处理的年生长量与对照相比差异不明显,相对而言穴施保水剂胶体的处理对刺槐年生长量有比较明显的影响。 相似文献
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A. Lehtijärvi H. T. Doğmuş‐Lehtijärvi A. G. Aday Kaya S. Ünal S. Woodward 《Forest Pathology》2017,47(6)
Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m2. One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites. 相似文献
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通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。
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植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。 相似文献
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The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha?1, of which 1700?ha?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches. 相似文献
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Keisuke Kojiro Yuzo Furuta Makoto Ohkoshi Yutaka Ishimaru Misao Yokoyama Junji Sugiyama Shuichi Kawai Takumi Mitsutani Hiromasa Ozaki Minoru Sakamoto Mineo Imamura 《Journal of Wood Science》2008,54(6):515-519
To investigate the changes in microstructures of wood with elapsed time in the environment, CO2 adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years.
The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased
in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores
smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of
that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased
in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were
considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption
and/or temperature variation in the environment. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):530-542
Abstract The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha?1), and 36% were at least satisfactory (≥1300 ha?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting. 相似文献