人工混交林的营林技术要点分析

随着经济的发展,我国植树造林工作取得了斐然的成绩。不仅带来一定的经济效益,还在一定程度上促进了社会的发展。尤其是在营造林建设中应用的人工混交林技术,不仅解决了林业病虫害发病率高的问题,还大大地提高了树木的成活率。本文章探讨了人工混交林技术的重要作用,并着重分析了人工混交林的种植模式和技术要点。一方面,希望可以给相关领域的从业者带来一些参考意见。另一方面,希望促进我国人工混交林技术的发展,进而为社会的发展进步贡献一点微薄力量。

27年生福建柏多树种混交林生长分析

对27a生福建柏、杉木、马尾松和木荷混交林生长进行分析。结果表明:在1005株·hm^(-2)保留密度下,混交林平均树高、胸径和单株立木材积为13.71m、17.2cm和0.18381m^3,分别比福建柏纯林大13.03%、1.18%和30.70%。混交林中小径木、中径木和大径木比例分别为52.5%、25.0%和22.5%。福建柏纯林中无大径木,小径木和中径木分别占42.5%和57.5%。混交林蓄积量183.8115m^3·hm^(-2),比福建柏纯林大30.07%。福建柏、杉木、马尾松和木荷对混交林蓄积量的贡献率分别为37.3%、25.37%、12.22%和25.07%,小径木、中径木和大径木对混交林蓄积量的贡献率分别为26.52%、31.19%和42.29%。混交林中福建柏平均树高、胸径和单株立木材积分别比福建柏纯林大17.64%、8.24%和50.16%,其中混交林中23.08%的福建柏为大径木。

闽中山地福建柏多树种混交林生长效果

调查福建省永安国有林场2000年营造的福建柏、马尾松与天然更新杉木、阔叶树多树种混交林生长效果,结果表明:多树种混交林的林分生长量大、中大径材比例多,20 a林龄平均树高10.9 m、胸径15.8 cm、单株立木材积0.12172 m^(3)、单位面积蓄积量155.43 m^(3)/hm^(2),分别比纯林大21.1%、10.5%、35.1%、32.0%;小、中、大径材蓄积量分别占23.19%、68.64%、8.17%。混交林中福建柏林木生长量大、尖削度小,平均树高10.8 m、胸径14.8 cm、单株立木材积0.10728 m~3,分别比纯林大20.0%、3.5%、19.1%。

在多代杉木林地上营造多树种混交林以防止地力衰退试验初报

多代杉木林地的地力衰退是围绕杉木产区林业发展的一个不容忽视的问题。该试验是在多代杉木人工低产林地上营造杉木优良种源子代苗、马尾松、桤木、泡桐、毛竹等多种树种混交林，以期通过生物自身的力量，改善林地土壤理化性和水肥条件，达到提高土壤肥力的目的。

Distribution Patterns and Associations of Dominant Tree Species in a Mixed Coniferous-Broadleaf Forest in the Changbai Mountains

In 2012 a plot was established with 1-ha area in a mixed coniferous-broadleaf forest in the Changbai Mountains, northeastern China for examining local forest processes, structure and succession. A method of O-ring statistics （pair- correlation function） was applied to analyze the spatial patterns and associations of the dominant species within different vertical layers. After the evaluation by their importance values, six tree species （or group） （i.e. Abies nephrolepis, Picea jezoensis, Pinus koraiensis, Tilia amurensis, and species group of Betula ssp. and species group of Acer ssp.） were determined as dominant trees species. It was found that some of these species exhibited closely clustered distributions at fine distances. As spatial distance increased, a random or even regular distribution gradually appeared with the exception of the upper layers of A. nephrolepis and P. koraiensis, and the lower layers of P. jezoensis, P. koraiensis and Betula ssp., which were substantially randomly distributed. Intra- and inter-species spatial associations varied in accordance with species, tree height and reciprocal distances. Positive associations were observed between the lower and upper height classes of trees of the same species （except for that of P. jezoensis） at fine distances. This may be owing to limited seed dispersal and geological heterogeneity. The aggregation intensity declines with increasing distances and this consistent with the predictions of self-thinning. Some coniferous trees （e.g. Pinus koraiensis） in the lower height class were positively associated with T. amurensis and group of Betula ssp. of the upper height class at some distances, suggesting that saplings of coniferous trees occupy a broader niche and can grow well under the canopy of the adult of broad-leaved trees. Negative associations were observed between upper coniferous trees and lower broad-leaved trees and between upper P. jezoensis and lower P. koraiensis, suggesting that a canopy of these trees might not provide suitable environment for the survival, establishment, and growth of o lower individuals, corresponding well to Janzen-Connell hypothesis.

光泽县残次天然阔叶林改造试验

根据生态学原理，把天然更新和人工改造更新相结合，对光泽县林业试验场残次天然阔叶林进行改造，通过改造可很快地形成多树种的混交林，林木材积提高１１４．６％～２１８．６％，土壤物理性质比杉木纯林好，土壤蓄水量比杉木纯林提高８０．７％～９１．５％，有良好的生态经济效益，实践证明，残次天然阔叶林改造是加速培育森林资源的好途径。

Vegetation Dynamism in the Mixed Conifer/Broadleaves Species Artificial Stands Crossed by Fire： The Arci Mountain Case Study in Sardinia

Immediate cutting and logging of mixed conifer/broadleaves species in a man-made forest crossed by fire in 2009 in the Arci Mountain in Sardinia can not guarantee as the best post-fire regeneration. The study case reports the differences in the density and in the height of seedlings. The release of damaged Pinus halepensis Mill. stems seems to confirm the tree seeder role of this species.

上窑大队营造薪炭林的调查

一、概况云霄县上窑大队有山地830亩,属沿海低山丘陵区,坡度15—25℃,多花岗岩发育的砖红壤性红壤,土层一般在50—100厘米。无腐殖质层或者腐殖质层极薄,质地从中壤至轻粘土,沙石含量多,水肥条件差,由于人为的活动频繁,植被常遭破坏。年平均温度21℃左右,年降雨量约1800毫米,多集中在5—8月份,冬、春常干旱。

创建绿色营区

中央军委批准印发的《全军环境保护和绿化工作“十五”计划》,要求军队环保绿化工作要走在社会的前列,其中一个很重要的内容就是要提高营区绿化美化水平。创建绿色营区,我们一定要认真贯彻落实,早日实现军委提出的绿化目标。 一、把创建绿色营区上升到保障力、战斗力的高度来认识。营区绿化不仅能美化环境,使官兵在四季如春的营区生活、训练、工作,陶冶情操,激发工作热情。