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不同造林密度和混交树种对光皮桦幼林生长的影响 总被引:4,自引:0,他引:4
通过对光皮桦不同造林密度、不同混交树种的试验研究,结果表明:光皮桦不同造林密度林分的生长有较大差异,其胸径、冠幅由大到小依次为:1 100株.hm-2、800株.hm-2、1 600株.hm-2、2 500株.hm-2,树高以1 100株.hm-2的林分最大,其余比较相近。光皮桦与不同树种混交生长有较大差异,各生长指标以杉木×光皮桦混交林最好,其余依次为:福建柏×光皮桦、木荷×光皮桦、马尾松×光皮桦;光皮桦纯林生长指标与福建柏光皮桦混交林比较接近。杉木×光皮桦和福建柏×光皮桦是较好的混交组合。 相似文献
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对11 a生光皮桦不同混交模式造林效果进行试验研究。结果表明:4种混交模式中,光皮桦平均胸径、平均树高、平均单株材积及高径比、造林保存率的差异均达极显著水平,单位面积蓄积生长差异达到显著水平。其中,以光皮桦×杉木混交林效果最好,其余依次为光皮桦×福建柏、光皮桦×木荷、光皮桦×马尾松。在混交林分总蓄积量上,光皮桦×杉木光皮桦×福建柏光皮桦×马尾松光皮桦×木荷,但差异不显著。 相似文献
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杨荣兴 《内蒙古林业调查设计》2012,(4):39-40,43
文章以光皮桦为基础,研究光皮桦与杉木之间进行混交的可能性分析,主要从树高、胸径、材积等方面运用数理统计的方法阐述二者混交的好处和可能性,并且通过南平市郊教学林场的试验得到了证实。 相似文献
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通过秃杉与光皮桦2∶1和4∶1比例及秃杉与杉木1∶1比例行状混交,与营造秃杉纯林进行造林效果对比,结果表明:不同类型林分中秃杉生长量顺序为秃杉+光皮桦2∶1混交林>秃杉+光皮桦4∶1混交林>秃杉+杉木1∶1混交林>秃杉纯林;混交林土壤>0.25 mm的团聚体含量、有机质含量、速效磷含量和速效钾含量等高于纯林,而混交林土壤结构体破坏率低于纯林。秃杉与光皮桦2∶1的比例行状混交的效果最佳。 相似文献
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杉木光皮桦混交林优化模式的研究 总被引:5,自引:0,他引:5
杉木光皮桦混交林,具有针阔叶常绿落叶混交、复层林冠、根系成层分布、林分群体结构稳定等优点,能提高单位面积产量,比杉木纯林增产5.8%,能改良林地土壤,0~60cm土层内有机质年均积累率达0.07%,是杉木纯林土壤的2.35倍。采用梅花状混交方式、7:1混交比例,是杉木光皮桦混交林的优化模式。全面整地、挖大穴造林,埋青抚育,首次抚育间伐时间定为7年生,(但光皮桦原则不间伐)等,是培育杉木光皮桦混交林的技术关键。 相似文献
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从林木生长及其与生态环境之间相互关系入手,对杉木光皮桦混交林与杉木、光皮桦纯林进行调查研究。结果表明:二者混交改善了林内的小气候条件和土壤的理化性状,对林木生长的促进作用明显,有利于地力的维持和形成稳定的人工林群落。营造杉木光皮桦混交林是杉木纯林皆伐迹地更新,防治地力衰退的有效途径之一。 相似文献
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杉木混交林营造试验初报 总被引:1,自引:0,他引:1
通过将杉木分别与檫树等10个树种混交试验,结论明显。檫树、木荷、香樟、光皮桦、马褂木、拟赤杨及马昆松适合与杉木混交;深山含笑混交后生长不良,桤木和银鹊树则全部死亡。从林分生长量看,杉木木荷混交林大于杉木纯林;杉木檫树、杉木香樟及杉木光皮桦混交林大于或相当于杉木纯林;杉木马褂木及杉木拟赤杨混交林生长量略小于杉木纯林。试验证明,混交林对改良土壤、恢复地力及改善林分生态环境有良好的效果,并有明显的抗性效益和社会效益。混交方式以梅花状和网格状为好,混交比例以1:5~1:6为宜。 相似文献
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通过对公路沿线一重山光皮桦等4个景观树种与杉木混交的林分生长因子进行调查,结果表明:9年生混交林分中阔叶树平均胸径、树高、单株材积、单位面积蓄积生长差异极显著,在生长量上米老排>木荷>光皮桦>火力楠;各种混交林分中杉木各生长指标差异不显著。在混交林总蓄积量上4种混交林分木荷>米老排>光皮桦>火力楠,但混交林分总蓄积量差异不显著。 相似文献
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长白落叶松几种酶活力及在种源早期选择中的应用 总被引:7,自引:1,他引:7
不同季节测定了 8个种源长白落叶松 4种酶活力 ,分析了它们与生长的关系。结果表明 ,生长快的种源过氧化物酶、多酚氧化酶活力弱 ,抗坏血酸氧化酶、谷氨酸脱氢酶活力强 ;生长慢的种源则相反 ,4种酶活力与长白落叶松的生长速率密切相关。不同季节各种酶活力的聚类分析结果相似 ,且与生长性状的聚类分析结果相一致。回归分析表明 ,过氧化物酶活力与长白落叶松的生长呈显著负相关 ,抗坏血酸氧化酶、谷氨酸脱氢酶活力与长白落叶松的生长呈显著正相关。多酚氧化酶活力与长白落叶松生长的负相关性较低。初步研究表明 ,过氧化物酶、多酚氧化酶、抗坏血酸氧化酶和谷氨酸脱氢酶可成为长白落叶松种源早期选择的生理生化指标 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):284-295
The purpose of this study was to compare beta and Weibull distributions in describing basal area diameter distributions in stands dominated by Scots pine and Norway spruce. The material of the study consisted of 535 stands located in eastern Finland. Parameters for both two‐ and three‐parameter approaches of the Weibull distribution were estimated using the method of maximum likelihood. Models for these parameters were derived using regression analysis. For the beta distribution, regression models were formed for the minimum, maximum and standard deviation of diameters within individual stands. These models were used when the exponents of the beta distribution were calculated analytically. Also, some parameter models for beta and Weibull distributions from previous studies were compared with the measured diameter distributions. The distributions obtained were compared using diameter sums and an estimate of the proportion of sawtimber. The results did not reveal any major differences between the suitability of the beta and two‐parameter Weibull distributions. There are appropriate models available for both of the distributions and the more similar the original data is to the data of an application, the better are the results. The two‐parameter approach of the Weibull distribution gave better results than the three‐parameter approach. The poorest results for all the predicted distributions were obtained at the extremes of the distributions. 相似文献
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以建始县长岭岗林场17 a生日本落叶松种子园半同胞家系试验林为研究对象,研究不同家系间生长性状的遗传变异和相关性,选择出优良家系并对早期选择的结果进行验证,为日本落叶松遗传改良提供材料。结果表明: 各家系之间胸径、树高和材积的生长差异均达到极显著水平;6 a生与17 a生胸径、树高、材积之间的相关系数在0.541~0.947之间,呈极显著正相关;日本落叶松家系6a生早期选择结果与17 a生选择结果基本一致;以17 a生材积为选择指标,选出排名前10位的优良家系,胸径、树高和材积的遗传增益分别达到3.03%、1.77%和7.11%。 相似文献
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The possibility of using the Iosipescu shear test device to study the combined shear and compression behavior of anisotropic materials was examined. Measurements were made using both an original (Wyoming version) and an in-house modified Iosipescu shear and compression fixture. Numerical simulation of the combined shear and compression test was carried out to verify the reliability of the modified device. The numerical results were compared with data from experiments on a medium-density fiberboard. The numerical results show good agreement with the experimental results for the shear test in all the three material directions tested. The shapes as well as the values of the strain fields were similar in the numerical and experimental results. Different rotations of the combined shear and compression device were studied using the finite element method to find the combinations that gave reliable results in shear and compression. It was found that the 45° rotation gave the most uniform strain fields in the section between the notches. This rotation was tested on the fiberboard. 相似文献