The interaction between organic layer and forest growth and forest development on former heathland

Heathland soils are characterized by high acidity and poor nutrient contents. Nutrient availability could then be an important factor in forest growth and development on these soils. The hypothesis to be verified was 1. The enduring change in vegetation composition and production is of great influence especially on the development of the organic layer and on the nutrient distribution between this compartment and the mineral soil, and 2. As a result, forest nutrition and water supply will change during forest growth with consequences for forest development itself. In NW Germany heathland forest development are dominated by heathlands as the initial stage of the succession, naturally established pioneering pine dominated woodlands, and oak and beech dominated forests as the terminal stages. In a comparative study, within these stages of forest succession the nutrient and water supply in the organic layer were investigated with regards to the nutrient and water supply in the mineral soil and to the morphology of the organic layer itself. The successional development was associated with an increased productivity and a marked enrichment of organic material and nutrients in the organic layer, whereas the nutrient storage in the mineral soil was unchanged. The nutrient storage in the organic layer in the forested sites amounted to up to 80% of the plant-available nutrients within the organic layer–mineral soil system. The water supply increased too due to higher water storage and increasing root penetration within the organic layer. However, the increase in water supply was less marked than the nutrient enrichment. Especially the beech-dominated broad-leaved forests depend on higher nutrient and water supply of the organic layer. They have better growth conditions in the late stages of succession, due to an intense humus accumulation by the pioneering birch–pine woodlands. Consequently, the development of the organic layer facilitates the change of coniferous woodlands to forests and woodlands dominated by broad-leaved trees. Using pine as first planted tree is recommended to support this development.     

土壤养分状况系统研究法在油茶林地养分管理上的应用

为了明确平衡施肥对土壤养分状况的影响,应用土壤养分状况系统研究法,研究江西省樟树市的油茶林平衡施肥前后的土壤养分状况。结果表明:油茶林未施肥土壤主要养分限制因子根据亏缺严重程度由高到低排序依次为:Ca、N、P、Mo、K、B、Mg、Cu;平衡施肥后,油茶林土壤主要养分限制因子根据亏缺严重程度由高到低排序依次为:Ca、N、P、Mg、B。通过试验,可以看出合理施肥对于土壤养分状况的改善是具有明显效果的。     

森林分类经营的论述与实践

森林分类经营是对森林使用价值的一次重新认识,是对森林生态效益、社会效益、经济效益三者位置的重新界定。是实施天然林保护工程的基本依据     

Ecological studies on subtropical evergreen broad-leaved forest in Okinawa, Japan: Litter production and nutrient input

Patterns of litterfall and nutrient input in a subtropical evergreen broad-leaved forest in northern Okinawa, Japan, were studied during May, 1996–April, 1999. The mean annual rate of litterfall in the five sampling plots ranged from 6.84 to 8.93 Mg ha⁻¹ yr⁻¹, of which 63.3–68.5% were leaves; 22.4–29.1% woody parts (including branches < 5.0 cm in diameter and bark); 2.8–5.0% sexual organs and 4.6–6.3% miscellaneous material. Significant differences were found among plots and among years. Significantly monthly differences pronounced seasonal patterns in litterfall were observed. Total litterfall and leaf litter showed negative correlations with relative basal area of the dominant species,Castanopsis sieboldii; and showed positive correlations with mean height of the stands. The dominant species,C. sieboldii produced an average of 2.36 Mg ha⁻¹ yr⁻¹ of leaf litter, which covered 30.5% of the annual litter production, and the nutrient input from those litterfall contributed 32.3, 28.3, 30.2, 22.2, 32.5, and 30.5% of total N, P, K, Ca, Mg, and Na, respectively. Nutrient use efficiency in litter production was high, especially for P and K compared with other broad-leaved forests in Japan indicating that P and K may be limiting in Okinawan evergreen broad-leaved forest.     

Economic consequences of sustainable forest management regimes at non-industrial forest owner level in Norway

Consequences for net present value, net income and harvest related to ‘sustainable forest management regimes’ at non-industrial forest owner level in Norway are discussed. The following indicators of a sustainable forest management have been analysed: existing old forest set aside for preservation, maintaining minimum target levels for area covered by old forest through time, restricted treatments for border zone areas around water bodies, retention of trees at final harvest and restricted options with respect to regeneration. The consequences were analysed according to individual as well as co-operative management for eight different properties. GAYA-JLP, a large scale forestry scenario model applying simulations and linear programming, was used for the calculations. A regime with a ‘medium’ intensity of the environmentally oriented constraints, and a real rate of discount of 2.5%, reduced the net present values by 8% to 20%. The results indicated that the consequences for individual properties might vary considerably if the regimes for a sustainable forestry are designed generally without considering the heterogeneity among the properties with respect to the initial forest state. Assuming co-operative management, the net present value of the entire forest area (all properties) increased. At the same time it was possible to increase, respectively, the proportion of old forest set aside for preservation and the area covered by old forest through time. The differences compared with individual management were relatively small for all these parameters, and most likely not large enough to cover up for the transaction costs related to co-operative management. Whether the gains of co-operation will exceed transaction costs, can probably only be answered through cost-benefit analyses of the actual project.     

Long-term response of weed control intensity on Scots pine survival, growth and nutrition on former arable land

The effects of post-planting weed control intensity on the cover and composition of ground vegetation, and on growth, survival and foliar nutrient concentrations of 4-year old bare-rooted Scots pine (Pinus sylvestris L.) seedlings were studied over a 15-year period with experimentation on former arable land. Weed control treatments with terbuthylazine and glyphosate were carried out 1?C3 times during successive years, either as overall or as spot applications. The vegetation cover and the shading effect of vegetation decreased with increasing weed control intensity. The more intensive the weed control was, the better was the afforestation result in terms of tree seedling growth and survival. Overall application repeated three times increased seedling survival by 79 percentage points, and their final height, breast height, diameter, and stand volume after 15 years were increased by 183, 19, 15, and 822%, respectively. Weed control did not affect the foliage nutrient concentrations, except for magnesium. However, increase in weed control intensity was reflected in larger needle size 5 years after planting.     

Influence of forest clearing methods on nutrient uptake of some tropical food crops

The adverse effects of forest clearing on crop yield have often been directly ascribed to decline in soil fertility. However, the effect of various forest clearing methods on crop nutrient uptake as reflected by the content in the leaf tissues has been the subject of few scientific investigations. A study to determine the effect of forest clearing on nutrient content of some arable crops was, therefore, carried out in the tropical rainforest of south-western Nigeria. Three forest clearing methods—mechanical, semi-mechanical and manual clearing—were used, while maize, cowpea, and cassava were the test crops. Nutrient content in the tissues of these crops was assessed by sampling maize ear leaves at silking, youngest mature leaves (YML) of cowpea at flowering and YML of 3-month-old cassava for analysis. Correlation analysis was carried out to establish the relationship between nutrient content and crop yield. The method of forest clearing had no significant effect on the nutrient content of maize and cowpea during the first cropping cycle. However, nutrient content of maize in the manually cleared plots was higher than those in the semi- and mechanically cleared plots for all elements analyzed except Mg. Nitrogen content of cowpea was much higher than that of maize. Except for P and K, the nutrient content of cassava was not markedly different among the forest clearing methods. Calcium and P content in the leaves of maize and cassava varied inversely with their levels in the soil, implying that crop uptake could have accounted for the differences in their availability within the soil. Nitrogen, P and K had significant positive correlations with maize yield (r = 0.77, 0.89, and 0.71). Potassium content also had significant positive correlation with cassava root yield (r = 0.69). This is not surprising because compared with other crops, cassava requires large amounts of K for starch formation and root development. It is concluded that differences observed in crop yields under different forest clearing methods are a function of nutrient uptake and availability within the soil. However, the uptake of some nutrients does not seem to be determined by the level of soil availability alone. This study was supported with a research grant from the International Foundation for Science (IFS), Sweden.     

长白山北坡阔叶红松林林冠对降雨及其养分的影响

在2001年森林生长季(6-9月),通过测量降雨各分量,分析了中国吉林省长白山北坡红松阔叶林冠层对降水分配各分量的影响。结果表明:干流量(37.39 mm),透流量(326.02 mm)和截留量(105.67 mm),分别占同期降雨量(469.08 mm) 的7.97%、69.50%和22.53%。林冠对降雨的月份分配规律是:树干茎流率的月变化为七、八月份大于其它月份,穿透率从6-9月份有逐渐减少的趋势,而截留率的变化正好与穿透率相反,从19.43%增加到31.02%。林内降雨中的养分元素浓度发生显著变化,除Ca、Mg外,其它元素的浓度都有所增加。经分析得出,大气降雨中养分元素的浓度序列为:Ca> Mg> N> K> Fe > P> Cu > Mn;而穿透雨中养分元素的浓度序列为:K>N>Mg>Ca>P>Fe>Mn>Cu;在林冠淋溶中各养分元素的浓度序列为:Mn> P>K>Cu>Fe>N>Mg>Ca。图1表5参13。     

不同树种幼林生长差异及对土壤营养的影响

通过调查不同树种新造林树高生长量及其林地土壤有机质和速效氮、磷、钾含量,研究其生长及对土壤营养的影响.结果为：光皮桦、四川桤木、楸树、栾树、湿地松6年生树高分别为8.2、7.7、7.4、7.0、5.3 m;不同树种造林后对土壤营养物质含量的提高有明显差异,5个树种造林后效果排序的先后次序为光皮桦、四川桤木、栾木、楸树、湿地松;新造林均表现为造林当年土壤营养含量明显下降,第2年起逐年增加,第3～5年超过造林前水平.     

集体林管理与采伐工作中的几点建议

本文对集体林的管理与采伐提出了建议。     

城市森林火灾隐患及其管理

人为纵火、林区吸烟、施工用火、闪电、林区建筑物以及不合理的城市森林规划等是城市森林火灾发生的重要隐患,常常导致城市森林火灾的发生,给城市居民的生命和财产造成了巨大的损失。加强对城市森林火灾发生原因的研究,合理规划城市森林布局和结构,加强对火灾隐患的管理,减少城市森林火灾的发生,是维护城市生态可持续发展的必然要求。       

槐花黄 举子忙——透视槐树文化与科举制度

文章探讨了槐树文化与中国科举制度之间丰富的文化内涵。槐树（Sophora japonica Linn）．又称国槐,在我国分布广泛,它枝干茂密,淳朴厚重,是人们喜爱的一个乡土树种。     

Tracing drought effects from the tree to the stand growth in temperate and Mediterranean forests: insights and consequences for forest ecology and management

European Journal of Forest Research - How drought affects tree and stand growth is an old question, but is getting unprecedented relevance in view of climate change. Stress effects related to...     

Differences in C and N release from Alliaria petiolata leaves and stems: consequences for nutrient cycling in forest ecosystems

European Journal of Forest Research - Garlic mustard (Alliaria petiolata (Bieb.) Cav. et Grande) is a widespread forest edge plant species in the European temperate zone and also one of the most...     

对辽宁省森林分类经营的问题分析及管理措施的探讨

通过对森林分类经营存在的问题进行分析，提出了如何科学地经营和管理公益林、商品林。阐述了必须建立科学的管理体制和有利于森林分类经营健康发展的政策、制度；尽快实行公益林补偿机制，通过征收生态补偿基金、减免税收等进行补偿；对商品林实行贸工林一体化生产经营型发展模式，完善林业产权交易体系，广辟商品资金渠道，使商品林经营快速走向市场经济轨道。     

Influence of seed-borne fungi on the nutrient composition and growth of conifer seedlings

Seed-borne fungi induce conspicuous changes in the concentrations of various nutrients (N, P, K, Mg, Na, Ca, Fe, Zn and Mn), thus affecting the growth in height and biomass of seedlings of two conifer species. The data indicates that the changes may be caused by interference in the physiology of the infected seeds and seedlings. The response of the change in the nutrient levels and total height growth towards the pre-chilling treatment of the seeds was not consistent to indicate any trend.     

森林文化与现代森林可持续经营关系的探讨

森林文化与森林可持续经营密不可分,本文阐述了森林文化与森林可持续经营的内涵,并对这二者关系进行了探讨,指出森林文化与森林可持续经营之间是唇齿相依、一脉相承、和谐发展、相互促进的关系。森林文化是现代林业建设中实现森林可持续经营管理的重要动力,是实现生态文明的必然要求。     

Loblolly pine growth and soil nutrient stocks eight years after forest slash incorporation

Incorporation of forest slash during stand establishment is proposed as a means of increasing soil carbon and nutrient stocks. If effective, the increased soil carbon and nutrient status may result in increased aboveground tree growth. Eight years after study installation, the impact of forest slash incorporation into the soil on soil carbon and nutrient stocks, foliar nutrients and loblolly pine growth are examined on mineral and organic sites on the North Carolina Lower Coastal Plain. Treatments include leaving forest slash on the surface and flat planting (control); V-shear and bedding (conventional), mulch forest slash followed by bedding (strip mulch) and mulch forest slash and till into the soil followed by bedding (strip mulch till). After eight years, mulching and/or tillage did not have a significant impact (p > 0.05) on soil bulk density or soil chemical properties (pH, cation exchange capacity, soil nutrients). Additionally, neither tree foliar nutrients nor stand volume were significantly impacted. However, significant effects were observed for soil phosphorus contents and stand volume between the control plots and the other treatment plots. For example, the mean stand volumes on the mineral site were 24.49 ± 1.28, 38.16 ± 2.90, 44.59 ± 3.07 and 46.96 ± 2.74 m³ ha⁻¹ for the control, conventional, strip mulch and strip mulch till plots. These observations are more likely due to the effect of bedding rather than mulching or tillage of the forest slash. These results are consistent for the mineral and the organic sites. Considering the greater expense to install the mulch and tillage treatments, the lack of a treatment effect on soil carbon and nutrient stocks and tree growth does not justify these treatments on these sites.     

Community-based forest management and its role in improving forest conditions in Nepal

The status of forest conditions before and after intervention of the forestry projects in community forest in three districts of Nepal is examined. Benefits are observed from the adoption of adaptive collaborative management and collective learning and action research in three sampled districts. The adoption of regular silvicultural treatments has increased the availability of forest products to local users. Moreover, improved forest condition and smallholder livelihoods have improved, as has environmental sustainability. However, the community forestry program has several limitations and shortcomings. Elite capture, social disparity, inequitable benefit-sharing and exclusion of poor and marginalized groups from the community forestry program are notable challenges to be solved in coming years. Special attention is needed to make community forestry inclusive with equitable benefit-sharing and a pro-poor focus.     

直干桉能源林高效经营技术及其多效益研究

通过直干桉能源林不同密度的造林试验,表明采用合理密植和短轮伐期的经营技术,可以获得较高经济效益。