桉树短周期人工林施用基肥试验

以尾叶桉U6为试材 ,开展桉树施用不同基肥试验研究。结果表明 :施基肥能明显促进桉树的生长 ,是营造桉树速生丰产林的一项关键性措施。在桉树 1a生之前的幼树期 ,与化肥类基肥相比 ,有机无机混合基肥的施用优势不很明显 ,但随着有机无机混合基肥肥效的控释作用 ,其促生效果显著 ,同时能明显改善林分质量且肥效持续时间长达 5a以上。有机无机混合肥做基肥虽然投资成本高些 ,但产出也高 ,经济效益较好。     

Carbon stock changes of forest land in Finland under different levels of wood use and climate change

Context

Prediction of the effect of harvests and climate change (CC) on the changes in carbon stock of forests is necessary both for CC mitigation and adaptation purposes.

Aims

We assessed the impact of roundwood and fuelwood removals and climate change (CC) on the changes in carbon stock of Finnish forests during 2007–2042. We considered three harvest scenarios: two based on the recent projections of roundwood and fuelwood demand, and the third reflecting the maximum sustainable cutting level. We applied two climate scenarios: the climate was in the state that prevailed around year 2006, or it changed according to the IPCC SRES A1B scenario.

Methods

We combined the large-scale forestry model MELA with the soil carbon model Yasso07 for mineral soils. For soils of drained, forested peatlands, we used a method based on emission factors.

Results

The stock change of trees accounted for approximately 80 % of the total stock change. Trees and mineral soils acted as carbon sinks and the drained peatland soils as a carbon source. The forest carbon sink increased clearly in both of the demand-based scenarios, reaching the level of 13–20 Tg C/year (without CC). The planned increase in the use of bioenergy reduced the forest sink by 2.6 Tg C/year. CC increased the forest carbon sink in 2042 by 38 %–58 % depending on the scenario. CC decreased the sink of mineral soils in the initial years of the simulations; after 2030, the effect was slightly positive. CC increased the emissions from the drained peatland soils.

Conclusions

It is likely that forest land in Finland acts as a carbon sink in the future. The changes in carbon stocks of trees, mineral soils, and peatland soils respond differently to CC and fuelwood and roundwood harvests.     

谈森林的二种生态效益

本详细论述了森林在保护生态环境、防灾、防雪方面的作用,从而提出只有加大森林面积,才能更好的发挥森林的生态效益。     

不同生境油茶林油茶史氏叶蜂的发生与危害程度比较

通过比较不同生境油茶林区油茶史氏叶蜂幼虫危害程度、同一种生境距林边不同距离油茶史氏叶蜂的危害程度,分析了油茶史氏叶蜂对油茶春梢发育、夏梢发育、花芽分化率、花芽数目、落果率等的影响。结果表明:油茶史氏叶蜂对油茶的春梢发育、夏梢发育、花芽分化率、春梢上花芽数目、同期的落果率等有显著危害,且危害程度和林区的生态多样性相关;不同生境下,生态多样性越低,危害越严重;同一生境下,距混合林区距离越远,危害程度越重,说明保护油茶林区及周边生境的生态多样性,对防治和控制油茶史氏叶蜂是必要的。另外通过间接证据,提出了白头鹎Pycnonotus sinensis和伯劳Lanius schach等食虫鸟类是油茶史氏叶蜂幼虫重要捕食性天敌的初步结论。     

不同采伐方式对阔叶林物种多样性的影响研究

对阔叶林皆伐人促更新和择伐人促更新对物种多样性影响的研究,结果表明不同采伐方式对群落物种丰富度、物种多样性指数和物种多样性均匀度指数均有一定的影响.皆伐人促更新林分物种比择伐人促更新少10种,乔木树种少了14种;不同采伐方式对群落的物种多样性指数和物种多样性均匀度指数影响不大,但对各层片有较大的影响,皆伐人促更新的乔木层物种多样性指数和物种多样性均匀度指数均比择伐人促更新林分低,但草本和藤本层物种多样性指数和物种多样性均匀度指数均比择伐人促更新林分高.     

世界私有林概览与芬兰私有林探究

对我国研究人员而言,私有林研究还是一个不十分熟悉的领域,对私有林命题的准确把握还有一定难度。该文通过对世界私有林发展道路的概览性介绍和对芬兰私有林发展模式的典型介绍,希望对我国私有林的发展能够起到借鉴的作用。     

Estimating leaf area index in different types of mature forest stands in Switzerland: a comparison of methods

Leaf area index (LAI) was estimated at 15 sites in the Swiss Long-Term Forest Ecosystem Research Programme (LWF) in 2004–2005 using two indirect techniques: the LAI-2000 plant canopy analyzer (Licor Inc.) and digital hemispherical photography, applying several exposure settings. Hemispherical photographs of the canopy were analysed using Hemisfer, a software package that offers several new features, which were tested here: (1) automatic thresholding taking the gamma value of the picture into account; (2) implementation of several equations to solve the gap-fraction inversion model from which LAI estimates are derived; (3) correction for ground slope effects, and (4) correction for clumped canopies. In seven broadleaved stands in our sample set, LAI was also estimated semi-directly from litterfall. The various equations used to solve the gap-fraction inversion model generated significantly different estimates for the LAI-2000 measurements. In contrast, the same equations applied in Hemisfer did not produce significantly different estimates. The best relationship between the LAI-2000 and the Hemisfer estimates was obtained when the hemispherical photographs were overexposed by one to two stops compared with the exposure setting derived from the reading of a spotmeter in a canopy gap. There was no clear general relationship between the litterfall and the LAI-2000 or the hemispherical photographs estimates. This was probably due to the heterogeneity of the canopy, or to biased litterfall collection at sites on steep slopes or sites subject to strong winds. This study introduces new arguments into the comparison of the advantages and drawbacks of the LAI-2000 and hemispherical photography in terms of applicability and accuracy.     

Estimating biomass in northern lower Michigan forest stands

Forest biomass data are now being sought by many forest managers and specialists. These data have been accumulating rapidly in recent years, but numerous gaps remain for various forest types, locations, and site quality levels. This paper illustrates how available information was carefully synthesized to generate biomass data for the evaluation and management of forest stands in northern lower Michigan. The basic approach involved the integration of published specific gravity and biomass distribution data with bolewood volumes predicted from regression equations relating these volumes to stand height and basal area. Preliminary evaluations of the data thus generated indicate that the approach should produce reasonable estimates of stand biomass in this region.     

Goshawk breeding densities in relation to mature forest in southeastern Norway

Forest harvesting practices have been assumed to be the main reason for the decrease in Goshawk Accipiter gentilis populations in Fennoscandia during the late 1900s, by reducing prey density, especially grouse and Red Squirrel (Sciurus vulgaris), and preferred hunting habitats (mature forest). In Norway, the highest breeding densities are now found in areas with a high proportion of farmland and urban areas where corvids and pigeons are important prey. To assess the importance of mature forest for Goshawk populations in southeastern Norway, we compared breeding densities from 20 municipalities with different percentages of farmland and mature forest. In multiple regression models, regional breeding densities were positively related to both the percentage of mature forest, and the percentage of farmland and urban areas. We conclude that the recommendation of establishing buffer zones around nest sites will not be sufficient to maintain Goshawk populations if the proportion of mature forest is reduced at a landscape level.     

Estimating forest cover in the presence of missing observations

Abstract

In the first sample-based Danish National Forest Inventory (NFI) initiated in 2002, measurements were not obtained for some plots owing to there being insufficient time to complete the measurements for the inexperienced measurement crews and lack of access to some plots on privately owned land. Nationally, the percentage of missing observations ranged from 1.8 to 7.8% in different years. Missing observations may cause the complete case estimator of forest cover mean and variance to be biased. An unbiased estimator of forest cover for NFI data with missing observations was derived, which is almost as efficient as the full data estimator. The estimator of the standard error of the estimate is unbiased, giving the correct coverage when calculating the 95% confidence interval (CI). Applied to the Danish NFI data, the estimator gave a forest cover estimate of 12.4% with an estimated standard error of 0.002576, resulting in a 95% CI of 11.9–12.9%. This corresponds to an estimated total of 534,888 ha forest land with confidence limits of 513,159–556,618 ha.     

提升林业生产动力机制的探讨

本文从林业生产的动力及动能构成要素,简述新的自然和社会经济条件下,推动林业生产动力机制相应发生变化,使工程造林实施面临新的课题。如何调整和适应动力因素的变化,对顺利完成任务,满足其要求,具有重要意义。     

Growth and yield models for uneven-sized forest stands in Finland

Uneven-sized forestry is gradually gaining popularity and acceptability also in the Nordic countries. This is because of the willingness of the public and some forest owners to avoid clear-fellings and pursue more near-nature forest structures. It has also been realized that the profitability of uneven-sized forestry may be competitive with even-aged forestry. In Finland, management of uneven-sized stands is hampered by the lack of information about the dynamics of such stands, and about the yield and profitability of uneven-sized forestry. This study developed models which allow managers to simulate the growth and yield of uneven-sized stands in Finland, making it possible to predict the yield and analyze the sustainability of different management options. The model set consists of individual-tree diameter increment, height and survival models, and a model for ingrowth. The modeling data consisted of two long-term field experiments of uneven-sized forest management, a set of temporary sample plots measured earlier for growth modeling purposes, and the sample plots of the third National Forest Inventory of Finland. The application area of the models covers all growing sites, all main tree species, and the whole surface area of Finland. According to the models, the sustainable harvest of a fertile (Oxalis-Myrtillus site) uneven-sized Norway spruce forest varies between 5.5 and 7 m³ ha⁻¹ a⁻¹ in Central Finland, depending on the length of the cutting cycle, stand density, and shape of the diameter distribution. It is profitable to harvest large diameter classes more heavily than small ones. Due to the large amount of data the models for diameter increment are highly significant and reliably show the growth level of trees in uneven-sized stands. The weakest models are the ingrowth models, which are based on a clearly smaller data set than the other models.     

不同程度马尾松毛虫危害对松林植被群落的影响

采用样点调查法对不同程度马尾松毛虫危害松林的植被群落进行了调查。结果表明:不同程度马尾松毛虫危害对松林林分密度的影响不显著,但对松树生长量有着不同程度的影响,中、重度危害可降低松树的高度和胸径(重度危害三年后高度、胸径分别下降0.34 m和1.8 cm),轻度危害则可促进松林的生长;马尾松毛虫危害可适度改变松林的郁闭度和地表植被的盖度(中、重度危害后三年盖度分别上升15%和20%),对林下植被的恢复与生长有一定的促进作用;松林植被物种多样性分析表明,中、重度马尾松毛虫危害可有效增加林地植被物种的多样性,轻度危害则对林地植被物种多样性影响不大。     

江西省生态公益林5种典型林分类型土壤性质特点分析

以江西省生态公益林5种主要林分类型为研究对象,从土壤水分—物理性质、土壤化学性质方面对5种典型林分类型进行比较,并应用SPSS 18.0软件采用主成份分析法对各林分类型土壤性质进行综合分析评价,结果表明:针阔混交林的土壤具有较好的土壤渗透性,具有较强的持水能力,其土壤养分含量与其他林分相比也更高,采用主成分分析对各林分类型进行综合评价,土壤性质的综合排序为针阔混交林>竹林>阔叶混交林>针叶纯林>针叶混交林.     

Cost analysis of a satellite terminal for forest fuel supply in Finland

As forest fuel demand increases, new logistical solutions are needed. Most of the increase in use is expected to take place in large heat and power production units which set special requirements for the supply as both procurement volumes and transport distances increase. Biomass fuel terminals broaden the spectrum of available supply options by offering cost-effective large-scale biomass storage and processing options for securing the fuel supply in all conditions. This study aimed to study different costs of a satellite terminal and to produce important concept and cost information for developing forest fuel logistics based on future terminals. The figures indicate that terminals do not create direct cost benefits per se: direct supply chains are more economical compared to supply through terminals. However, there are several indirect benefits that can be reached via fuel supply through terminals: regional fuel procurement can be widened to a national scale, security of supply increases through easily available storages, large supply volumes can be delivered by an individual operator, prices remain more stable and a more even quality of delivered fuel can be achieved.     

Mammalian browsing damage in the Mt. Cole State forest,southeastern Australia: analysis of browsing patterns,spatial relationships and browse selection

Browsing by mammals can have a substantial impact on the survival, growth and form of regenerating forest trees. This study investigated the severity and distribution of mammalian browsing damage, and the degree to which eucalypt seedlings (Eucalyptus spp.) were selected for browsing on three regenerating native forest coupes in southeastern Australia. Damage was greatest 6 months after eucalypt germination and at this time, both messmate (Eucalyptus obliqua) and blue gum (E. globulus) seedlings were browsed at similar intensity. Nine and 12 months after germination, messmate was browsed more heavily than blue gum. Consistent relationships between browsing damage and both distance from the forest edge and wallaby density were not observed. Analysis of use and availability data for messmate, blue gum and manna gum (E. viminalis) seedlings showed that messmate was selected for browsing more than expected by chance while manna gum was browsed less than expected. Mammalian browsing affects a substantial portion of Victorias native forest estate, and could alter the species composition of future forests. Research into the ecology of browsing species and the development of non-lethal browsing reduction strategies is seen as a priority for the management of mammalian browsing in Victoria.     

Estimating annual GPP,NPP and stem growth in Finland using summary models

In this study we introduce and test a new simple approach for estimating annual stand-level gross primary production (GPP), net primary production (NPP) and stem biomass growth based on carbon acquisition and allocation, by combining existing summary models. The focus is on the variation of GPP and NPP across different parts of Finland caused by climate.     

汪清林区天然林食叶害虫危害与林分的关系

为探讨汪清林区天然林中食叶害虫危害与林分特征的关系,在林区选取了针叶林、针阔混交林以及阔叶混交林3种类型林分共36块临时样地,比较了不同类型林分的食叶害虫为害率,分析了食叶害虫危害与立地条件、林分特征的关系.结果表明:不同林分间的食叶害虫为害率存在显著的差异,多重比较显示,食叶害虫为害率在林分间差异非常明显,即阔叶混交林＞针阔混交林＞针叶林;食叶害虫为害率与针叶树比例呈极显著的负相关,与林木Simpson指数呈极显著的正相关,与林木Shannon-Wiener指数呈极显著的正相关,同时食叶害虫为害率与林分郁闭度的关系显著.汪清林区天然林中食叶害虫危害格局符合“联合易感性”假说.     

Estimating the effects of adjacency and green-up constraints on landowners of different sizes and spatial arrangements located in the southeastern U.S.

The maximum clearcut size and green-up period is important for land managers adhering to voluntary and regulatory guidelines. Therefore the impact of actual and hypothetical clearcut size restrictions is a concern for forest landowners who manage land and intend to practice forestry for profit. In this research, the effect of a 97.1 ha (240 ac) clearcut size constraint with a green-up period of 2-yrs is assessed for forest landowners with different forest land sizes, ownership patterns, and age class distributions. A meta heuristic which consists of threshold accepting, 1-opt tabu search, and 2-opt tabu search is used to develop spatially-constrained forest plans for 27 hypothetical forest landowners. These results are compared to a relaxed solution produced with linear programming, and statistical analyses are used to determine significant differences. The analysis provided enough evidence to suggest that two factors (size of ownership pattern and initial age class distribution), and one interaction factor (ownership size × initial age class distribution) are significant in explaining the differences in the percent reduction in forest plan value among the forests managed by the hypothetical forest landowners. From an absolute value reduction perspective, small-sized older forests were most affected. From a percent value point of view, one can conclude from this analysis that landowners with small-sized forests and young initial age class distributions will be significantly more affected by potential adjacency and green-up restrictions in the southeastern U.S. than other types of landowners.