樟子松人工林鼠害防治的探讨

根据樟子松人工鼠害发生特点和以往防治实践,提出了“以营林为基本措施”,生物,化学防治,人工和机械防除为辅助措施,综合防治樟子松鼠害”的方针,并着重阐述了营林防治措施及营造防鼠混交林的可行性和方法。     

Beyond reduced-impact logging: Silvicultural treatments to increase growth rates of tropical trees

Use of reduced-impact logging (RIL) techniques has repeatedly been shown to reduce damage caused by logging. Unfortunately, these techniques do not necessarily ameliorate the low growth rates of many commercial species or otherwise assure recovery of the initial volume harvested during the next cutting cycle. In this study, we analyze the effect of logging and application of additional silvicultural treatments (liana cutting and girdling of competing trees) on the growth rates on trees in general and on of future crop trees (FCTs) of 24 commercial timber species. The study was carried out in a moist tropical forest in Bolivia, where we monitored twelve 27-ha plots for 4 years. Plots received one of four treatments in which logging intensity and silvicultural treatments were varied: control (no logging); normal (reduced-impact) logging; normal logging and low-intensity silviculture; and, increased logging intensity and high-intensity silviculture. Tree growth rates increased with intensity of logging and silvicultural treatments. The growth rates of FCTs of commercial species were 50–60% higher in plots that received silvicultural treatments than in the normal logging and control plots. Responses to silvicultural treatments varied among functional groups. The largest increase in growth rates was observed in FCTs belonging to the partially shade-tolerant and the shade-tolerant groups. These results indicate that silvicultural treatments, in addition to the use of RIL techniques, are more likely to result in a higher percentage of timber volume being recovered after the first cutting cycle than RIL alone.     

影响营造林质量的主要因素及改善措施研究

营造林具有防止水土流失、抵抗自然灾害、净化空气等重要作用,可以有效地改善生态环境,促进我国林业的健康发展。其中营造林质量对林业的发展起到了至关重要的作用。基于此,文章阐述了营造林的重要意义,详细分析了影响营造林质量的主要因素,并提出了保证营造林质量的有效措施,以期为我国的林业研究提供理论参考。     

Estimation of sequestered carbon in Article-3.4 private planted forests in the first commitment period in Japan

The purpose of this study was to predict the likely amounts of carbon sequestration on a national scale for Japan in the Article-3.4 private planted forests of the Kyoto Protocol during the first commitment period. We regarded the planted forests that had undergone silvicultural practices such as weeding, pruning, and thinning since 1990 as Article-3.4 planted forests in accordance with the definition given by the Forestry Agency of Japan. Regression models were developed to predict the forest areas that had undergone silvicultural practices, employing silvicultural subsidies and forest workers' wages as predictor variables. Then the time series changes in the predictor variables were provided by extending their recent trends, with the result being that the forest areas that have undergone silvicultural practices were predicted on the basis of the three scenarios of the variables. Thus, the Article-3.4 forest area was calculated considering overlaps of silvicultural practices over fixed stands, and the area was converted into the amount of carbon sequestration by multiplying it by coefficients such as a volume table, biomass expansion factor, and others. The result implied that Article-3.4 private planted forests were expected to sequester 8.16–8.87 Mt-C year⁻¹ during the first commitment period. These amounts cover 63%–68% of the carbon sequestration goal by land-use change and forestry activities capped under the Marrakesh Accords. To realize this prediction, it is important to provide a sufficient silvicultural subsidy to last until the end of the first commitment period and to implement silvicultural practices on the forest stands that have not undergone such practices since 1990.     

Productivity and Costs in Shelterwood Harvesting

Harvesting costs have a significant influence on the application and potential use of the shelterwood system. These costs are strongly related to the time needed for the logging operations. In this study, which was carried out in Norway spruce [Picea abies (L.) Karst.] stands in northern Sweden, the effective time (E ₀) of a single-grip harvester in shelterwood cutting, thinning of shelterwoods and clearcutting was measured. Based on these data the costs of shelterwood harvestings and clearcutting were calculated and compared. It was found that (1) the time per tree in shelterwood cutting and thinning of shelterwoods was greater than in clearcutting, (2) the time per cubic metre was higher in sparse shelterwoods than in dense shelterwoods, (3) most of this increase was due to longer driving time because fewer trees were harvested, and (4) the longer time and higher logging costs in the shelterwood system (compared with the clearcutting system) were mostly related to the establishment of the shelterwood. It was concluded that the shelterwood alternative is especially competitive when it is desirable to maximize the share of saw logs at the expense of pulpwood.     

营林生产管理工作探析

做好营林生产管理工作,对于推进我国林业工程的可持续发展有着至关重要的作用,可以有效促进林业产业经济效益和社会效益的提升。然而,由于种种原因所限,我国目前的营林生产管理工作并不尽如人意,亟需改进。文章先分析目前营林生产管理工作的现状,接着提出一套有针对性的解决措施,以期能促进我国林业工作持续稳定的发展。     

营林措施对萧氏松茎象种群的控制作用

在信丰林区连续2 a研究了营林措施对萧氏松茎象种群的控制作用。结果表明：2010～2011年试验区萧氏松茎象当年虫口密度平均分别下降85.3%%和85.0%;相对防治效果平均分别为85.9%和86.0%;而对照区当年虫口密度分别上升4.4%和29.4%。这说明营林措施能明显抑制萧氏松茎象种群的上升。     

The increasing scarcity of red oaks in Mississippi River floodplain forests: Influence of the residual overstory

Red oaks – cherrybark oak (Quercus pagoda Raf.), willow oak (Quercus phellos L.), water oak (Quercus nigra L.), and Nuttall oak (Quercus texana Buckley; aka: Quercus nuttallii Palmer) – are not regrowing in Mississippi Delta river floodplain forests in the southeastern United States in sufficient numbers to sustain the former species composition and timber and wildlife values. Even if vigorous red oak reproduction becomes established, partial harvesting that does not remove the taller trees will suppress understory red oak height growth more than it will suppress height growth of such other species as sugarberry (Celtis laevigata Willd.), American elm (Ulmus americana L.), cedar elm (Ulmus crassifolia Nutt.), swamp dogwood (Cornus foemina Mill.), green ash (Fraxinus pennsylvanica Marshall), and sweetgum (Liquidambar styraciflua L.). Consequently, the red oaks in these partially harvested stands become increasingly suppressed and probably die; and there is a shift in species composition to the other species. In addition to ensuring vigorous oak reproduction, silvicultural clearcutting or rapid removal of the residual trees following shelterwood or seed tree harvesting to provide full sunlight is needed to ensure red oaks become a dominant part of these future river floodplain stands.     

Can the impact of deer browsing on tree regeneration be mitigated by shelterwood cutting and strip clearcutting?

Silvicultural treatments creating large canopy openings failed to restore regeneration of balsam fir (Abies balsamea (L.) Mill.) due to browsing pressure from white-tailed deer (Odocoileus virginianus Zimmermann). Consequently, we tested two alternative silvicultural treatments aimed at improving balsam fir establishment on Anticosti Island (Québec, Canada). In 1998 and 1999, we set up shelterwood seed cutting using three harvest intensities (0, 25 and 40% of basal area) and strip clearcutting with scarification using three different strip widths (15, 30 and 45 m), both with fenced and unfenced regeneration plots, in balsam fir stands. After 8 years, shelterwood seed cutting did not allow the establishment of new balsam fir seedlings, nor the development of unbrowsed balsam fir seedlings. In the strip clearcutting, deer browsing suppressed growth of palatable species in all strip widths. This favoured the development of unpalatable species, especially white spruce (Picea glauca (Moench) Voss). Our study demonstrates that the use of silvicultural treatments alone is unlikely to restore balsam fir regeneration on Anticosti Island, as long as the deer population remains higher than 20 deer/km².     

青杨脊虎天牛防治技术

针对黑龙江省青杨脊虎天牛发生面积大、蔓延快、危害重的现实,对其防治技术进行了研究。结果表明,小叶杨与落叶松混交林被害株率为14%~16%,而小叶杨纯林被害株率则为42%~56%;小青杨与樟子松混交林被害株率为8%,小青杨纯林被害株率为35%~84%。8%的绿色威雷微胶囊剂和3%的氯氰菊酯微胶囊水悬浮剂喷雾防治成虫,效果在75%以上(100液);大力士和氧化乐果树干基部注射防治幼虫,效果达70%以上;10g/m3以上剂量磷化铝片剂熏蒸受害原木,防治效果可达100%。