Field sampling of cork value before extraction in Portuguese ‘montados’

The assessment of cork quality and the estimation of cork value are very important to forest landowners, for management purposes and for cork commercialisation. The Forest Producers Associations have been using a sampling scheme with the objective of estimating cork value (price per unit of weight, usually kg) before extraction, based on the sampling of individual trees along a zigzag transect that covers the entire stand. The sampling error is usually too high, but, from a practical standpoint, it is difficult to increase the sampling intensity if it would imply an increase in sampling costs. The aim of this work was to propose, from data collected in six stands representative of the cork oak stands in Portugal, an alternative sampling methodology with a more efficient precision/cost ratio. Precision and costs of alternative sampling designs based on clusters of different sizes, complemented with analysis of the intracluster correlation coefficient, were studied in order to propose the most adequate sampling strategy. Single-stage cluster sampling with clusters of 5–7 trees guarantees a reasonable sampling error (10–15%) and can be conducted without a large increase in cost.     

Characteristics of bird communities between slope and valley in natural deciduous forest, South Korea

本研究在弄清韩国桂坊山(374030N,128301E)天然落叶阔叶林斜坡和山谷中鸟类群落间的特征差异。调查结果表明:两地鸟类群落的种类组成、丰富度、鸟种多样性及群落结构都有不同。森林的垂直结构特别是林下覆被度及胸高直径分布多显不同。两地生境结构的不同必然影响着鸟类对可利用生境的选择。表6图2参19。     

The importance of the surroundings: are bird communities of riparian galleries influenced by agroforestry matrices in SW Iberian Peninsula?

Context

The remaining riparian stretches are often the unique suitable habitats for forest breeding birds in Mediterranean landscapes undergoing long-term changes. Understanding the interactions between riparian zones and their surroundings is critical to establish successful management actions.

Aims

We assessed the influence of surrounding matrix on riparian bird communities and the use of riparian galleries as surrogate habitats for the forest passerine communities of southwestern Iberia.

Methods

We used point counts in three simultaneous sampling stations, one in the riparian gallery and two in the adjacent matrix. Three matrix types were selected with a decreasing tree density gradient: dense montado, sparse montado, and open agricultural areas. Data were analysed with redundancy analysis and differences in species’ occurrences were tested with one-way ANOVA.

Results

In riparian galleries, we found bird species belong to three ecological guilds: riparian, woodland, and edge guilds. The richness of bird guilds and the occurrence of some species depended on the surrounding matrix type. Riparian bird richness was constant in all surrounding matrices, woodland bird guild was richer in galleries embedded in dense montados, and edge guild in riparian galleries surrounded by sparse montados. Five among 19 assessed species were influenced by matrix type, within particular a few strictly riparian species. Species richness increased close to riparian galleries, due to the increase in habitat heterogeneity and resource availability for birds in densely vegetated riversides. However, the occurrence of some bird species differed according to the type of surrounding matrix.

Conclusion

The matrix type explained most of the variance in riparian bird assemblages. Some woodland birds have used riparian galleries as surrogate habitat. Our study suggests that land use in the surrounding matrices must be taking into account for the management and rehabilitation of watercourses and bird conservation actions.     

Increasing Tree Cover in Degrading Landscapes: ‘Integration’ and ‘Intensification’ of Smallholder Forest Culture in the Alutilla Valley,Matiranga, Bangladesh

Research was conducted in Alutilla Valley in eastern Bangladesh to identify the nature of existing agroforestry systems and to identify potential agroforestry models that could ameliorate currently degrading forest resources Data were collected through farmer participatory research and a structured quarterly survey in two villages. Qualitative and supplementary quantitative analysis methods were used to assess the financial potential of agroforestry systems. Various patterns of agroforestry exist in the study site, but all have two common principles, namely ‘integration with agriculture’ and ‘multi-functionality’. Two agroforestry models suitable for adoption by farmers have been identified. Multi-strata agroforestry, based on a fruit and timber tree canopy with vegetables and tuber species in the understorey, can be practiced in the shifting cultivation fields near settlements. Fruit and timber tree-based conservation agroforestry is well suited to manage large-scale biologically depleted landscapes. Both systems yield early financial returns, facilitating the change from shifting cultivation to multi-strata agroforestry or fruit and tree-based conservation agroforestry.     

Incorporating agroforestry practices in the management of walnut plantations in Dauphiné, France: an analysis of farmers‘ motivations

The Dauphiné province in south-eastern France is a major area for walnut orchards. Growers manage their orchards with some specific agroforestry features: grafted walnut trees may be pruned to form a bottom log with a timber end use (dual purpose trees), and intercrops may be grown between the tree lines. These agroforestry practices are however only partially adopted. Three surveys were conducted in 1993, 1995 and 1996 to elicit the farmer motivations for adopting or rejecting agroforestry management features. The walnut industry is a key activity in two parts of Dauphiné: the Isère valley, and the Diois basin. The reasons for adoption of agroforestry practices are discussed. In the Isère valley, the priority is given to walnut production in specialised farms, and the extension services are opposed to agroforestry practices. In the dryer Diois area, the main explanations for agroforestry adoption were the welfare of the farmer family, the age of the farm manager, and the contribution of walnut production to the family income. Dual purpose management schemes were characterised by extended investment return delays, but proved to be the most rewarding schemes when practised with intercrops. A very extensive tree management with few pest control operations improved the profitability. Intensive orchards had a low bequest value at the time of inheritance, in contrast to dual-purpose orchards. The age of the farmer at planting time appeared to be a key criterion for agroforestry management adoption. This revised version was published online in June 2006 with corrections to the Cover Date.     

Hidden in the woods? Meaning,determining, and practicing of ‘common welfare’ in the case of the German public forests

This article addresses the German debate on the issue of the common welfare designation of public forests. In the first part, drawing on two case studies, the political discourse on the issue is introduced. Two major competing ‘story lines’ can be made out that are both based on a long tradition of controversially discussed concepts of regulatory forest policy. While they both emphasise that common welfare services in forestry run counter to profit orientation, they fundamentally differ with regard to the consequences for forest policy, e.g., considering the degree of state intervention. Afterwards, an overview on the scientific debate on common welfare in the German context is given, and different concepts of common welfare determination are distinguished. Existing approaches of common welfare determination in German forest policy are related to these concepts and discussed. It is argued that the common welfare designation of the public forest is only insufficiently implemented by the actual governance arrangements. Based on this consideration, eventually, the implementation of a procedural concept of common welfare operationalisation in Germany’s public forests at the local level is proposed. While such a concept will not solve all complex problems related to the determination of common welfare in public forestry, it would notably contribute to a more operational definition of common welfare in public forestry and a more informed public debate on the issue.     

Overview of restoration and management practices in the degraded landscapes of the Sahelian and dryland forests and woodlands of East and southern Africa§

The highest deforestation and forest degradation rates in Africa occur in the dry forests and woodlands where pressure for land is increasing, poverty is rampant, livelihood options are few and climate change effects are severe. This paper examines factors that cause land and forest degradation in the Sahel and dry forests and woodlands of eastern and southern Africa and highlights some successful restoration practices, technologies and approaches. In the Sahel, enclosures are used to protect young growing trees while in East Africa enclosures are implemented on degraded land as a mechanism for environmental rehabilitation with a clear biophysical impact. The choice of techniques for rehabilitating specific degraded areas depends first on the priorities and management objectives of stakeholders followed by the costs and benefits associated with available rehabilitation techniques and the economic, social, and environmental values of the land resources in their current and desired future states. In the Sahel, sustainable land management is considered to be an imperative for their sustainable development and the practices include soil and water conservation activities and structures. In all regions, natural forest rehabilitation has used both natural and assisted regeneration to promote the growth of especially indigenous species through coppice regrowth and root suckers rather than seeds. Assisted regeneration was especially prevalent in the Sahel where indigenous tree species have been identified to dominate the degraded sites during early stages of secondary forest succession. The success of any rehabilitation activities depends on community-based natural resources management. In addition, the forest policies and their related policies need to be enabling in order to address issues of concern, including (1) the full participation of communities, (2) clear land and tree tenure and (3) equitable benefit sharing.     

Fleshy Fruits Eating Birds and Their Role in the Seed Dispersal of Plants in of Plants in Maoer Mountain,NE China

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Length of cuttings in establishment and production of short-rotation plantations of Salix ‘Aquatica’

The effect of length of cuttings, 10 to 50 cm long, on establishment and productivity of short-rotation plantations was investigated in five trials, for periods of 2 to 9 years. The trials were established on abandoned agricultural fields planted with unrooted Salix Aquatica cuttings. The effect of cutting length was very similar in all five trials: the longer the cuttings (up to 30–50 cm), the better the survival and growth. In most trials the greatest difference in survival was between cutting lengths of 10 and 20 cm, especially in unfavorable growing conditions. In an annually harvested trial during the 9-year test period, a cutting length up to 30 cm affected biomass production per stool positively. In two trials grown with 5-year rotation, the longest cuttings produced 7 times the above-ground biomass of the shortest ones. Results of these trials also emphasize the importance of establishment for the future success of willow plantations.     

Time dependence of Poisson’s effect in wood IV: influence of grain angle

Off-axis tensile creep tests were conducted on woods taken from Japanese cypress and Kalopanax by changing the angle of load to the grain direction in the longitudinal–tangential (LT) plane. The dependence of the Poisson’s ratio and trend of the viscoelastic Poisson’s ratio on grain angle were investigated. The Poisson’s ratios were found to reach their extrema when the grain angle was around 30°. Moreover, the Poisson’s ratio in the LT plane was observed to be negative when the grain angle was in the range of 15°–45°. Comparing the experimental results with theoretical values obtained from the theory of orthotropic elasticity, it was revealed that, although the Poisson’s ratio reached an extremum in both cases, the specific values did not match, especially when the angle was between 15° and 45°. Furthermore, the temporal variation of the viscoelastic Poisson’s ratio was found to depend on the grain angle and the measurement plane. It also appeared to be affected by the Poisson’s ratio, showing an increasing tendency above a specific Poisson’s ratio (Japanese cypress: 0.196, Kalopanax: 0.102) and a decreasing tendency below it, regardless of the grain angle and measurement plane. Additionally, the increment in the viscoelastic Poisson’s ratio after 24 h of creep was observed to reach its extremum when the grain angle was around 30°. Finally, by improving the six-element Frandsen–Muszynski viscoelastic model, which simultaneously considers the longitudinal and transverse strains, an eight-element model was presented, and the trend of the viscoelastic Poisson’s ratio was well reproduced by this model.     

Analysis of rural people’s attitude towards the management of tribal forests in South Africa

The management of forests for multiple purposes coupled with a varying socioeconomic profile of forest users can result in attitudinal differences towards forest management. This study examines the attitudes of rural people in South Africa towards the management of tribal forests. Attitude towards forest management was analysed with respect to five forest management objectives: 1, forest management for rural livelihood resilience to climate change; 2, forest management for reduction and management of forest fire risk; 3, forest management for sustainable forest-based livelihood; 4, forest management for household socioeconomic wellbeing; and 5, forest management for community-based climate change adaptation initiative. A household questionnaire survey was used to elicit information from 155 rural households using the proportionate random sampling procedure. Chi-square test was used to analyse data from the household survey. Factorial analysis was used to analyse variance in attitude towards forest management. The results showed that rural people generally have positive attitudes toward the management of tribal forests. Factor analysis isolated 2 major factors that explained 61% variance in attitude. Based on the findings we conclude that centralising forest management around the four management objectives (1, 3, 4 & 5) are likely to promote inclusive forest-based development in the study communities.     

Water harvesting in a ‘runoff-catchment’ agroforestry system in the dry lands of Ethiopia

A major production constraint in arid and semiarid areas of Ethiopia is a lack of water for crop growth. Run off water can be harvested by channeling it into micro- catchments (MC) where it slowly infiltrates into the soil. The increased moisture provides more plant growth in these dry lands. An experiment using MC was conducted in eastern Ethiopia to study the growth of four multipurpose tree species intercropped with grass. Trees and grass were grown in 25 m² and 100 m² MC. Plant height, root collar diameter, and mortality rate of trees were determined 12 months after planting. Dry matter yield of grasses and trees were measured and nutrient analysis of plant tissues was determined. In a separate experiment the biomass of trees was determined after 2.5 years of continuous growth without grass competition. Soil moisture, organic matter, texture and bulk density of the soils were also determined. Mean tree height was 10% greater in the 100 m² than in the 25 m² MC. Root collar diameter and survival rate showed similar increase with 13% and 7.8% respectively. Acacia saligna and Leucaena leucocephala showed better growth in both plot sizes than the indigenous Acacia seyal and Acacia tortilis. The dry matter yield of grass (Panicum maximum) was over 12 tons/ha and 8 tons/ha in the 100 m2 and 25 m2 plots respectively. Soil moisture content was greater in MC than in control plots with no water harvesting structures with 31% and 24% during the wet and dry seasons respectively. The use of water harvesting can improve fodder production and carrying capacity of the dry lands of Ethiopia.     

The allocation of forestry land in Vietnam: did it cause the expansion of forests in the northwest?

Forests expanded rapidly in northwestern Vietnam in the 1990s. Forest expansion coincided with a new forest policy that mandated the devolution of forest management authority. A cornerstone of the new policy was the allocation of use rights for forestry land and trees to rural households. This paper examines to what extent the new forest policy contributed to the observed forest expansion. The findings of three village studies suggest that the new forest policy had minor effects on actual property rights, as villagers resisted its implementation. Instead, forests expanded, mainly due to the liberalization of agricultural output markets and availability of new technology. Changes in markets and technology motivated farmers to intensify crop production, reducing agricultural pressure on land. The research findings suggest the potential of market-based instruments and technology policy to facilitate forest regeneration. They also demonstrate the benefits of in-depth village studies for forest policy analysis, as it provides an integrated framework for assessing the relative effects of political, economic and technological changes on forests.     

Effects of shade and bird exclusion on arthropods and leaf damage on coffee farms in Jamaica’s Blue Mountains

The effects of overstory trees and birds on coffee pests are poorly understood. This study documents (a) the effect of bird exclusion on foliage-dwelling arthropod abundance and insect-caused leaf damage, and (b) the relationships between vegetation complexity and insect abundance, leaf damage, and prevalence of fungal leaf symptoms on coffee farms in the Blue Mountains of Jamaica, West Indies. Overall arthropod abundance was reduced inside bird-proof exclosures, and this corresponded to reduced insect-caused leaf damage. The reduction in leaf damage increased with greater shade, but fungal leaf symptoms increased with greater shade and proximity to non-coffee habitat patches. There appears to be a trade-off for coffee farmers in our study region: vegetation complexity may attract beneficial insect-eating birds that can reduce insect damage, but it is also associated with the prevalence of fungal leaf symptoms.     

Future orientation and planning in forestry: a comparison of forest managers’ planning horizons in Germany and the Netherlands

Long range (or strategic) planning is an important tool for forest management to deal with the complex and unpredictable future. However, it is the ability to make meaningful predictions about the rapidly changing future that is questioned. What appears to be particularly neglected is the question of the length of time horizons and the limits (if any) to these horizons, despite being considered one of the most critical factors in strategic planning. As the future creation of values lies within individual responsibility, this research empirically explored the limits (if any) of individual foresters’ time horizons. To draw comparisons between countries with different traditions in forest management planning, data were collected through telephone surveys of forest managers in the state/national forest services of the Netherlands and Germany. In order to minimize other cultural differences, the research in Germany concentrated on the federal state of Nordrhein-Westfalen, which has considerable similarities with the Netherlands, e.g. in topography, forest types and forest functions. The results show that, in practice, 15 years appears to be the most distant horizon that foresters can identify with. This is in sharp contrast to the time horizons spanning decades and even generations that are always said to exist in forestry. The “doctrine of the long run”—the faith in the capacity of foresters to overcome the barriers of the uncertain future and look ahead and plan for long-range goals—which in many countries still underlies traditional forest management, can therefore be rejected.

Farmers’ perceptions of tree mortality, pests and pest management practices in agroforestry in Malawi, Mozambique and Zambia

Pest management research within the context of agroforestry is in its infancy, and it is often difficult to say when a particular pest justifies investment in research to establish facts. Understanding the potentials and drawbacks of farmers’ indigenous ecological knowledge (ethnoecology) may form the basis for constructive collaboration between farmers, agroforestry scientists and extension staff. Therefore, the objectives of the study were to (1) assess farmers’ knowledge and perceptions of pests, (2) prioritize pest problems that limit tree planting and maize production based on farmers’ own criteria and (3) to identify farmers’ indigenous pest management practices for priority pests. Data were collected using community meetings, individual interviews and direct observation by the first author. The farmers involved in this study in eastern Zambia had over ten years of experience, while most of the farmers in Mozambique and parts of southern Malawi were new to agroforestry. Farmers perceived insects as the major causes of tree mortality, followed by drought, bush fires and browsing by livestock. Among the biological constraints to maize production, insects (particularly termites and stalk bores) and weeds (particularly Striga asiatica) were more important in farmers’ minds than crop diseases. Fundamentally, the farmers’ perception of the causes of tree mortality and crop pests agreed with researchers’ perceptions and the literature. Both termite and witch weed problems were associated with low soil quality, and farmers use various indigenous control practices to control these pests. Some farmers did not know the causes of tree mortality, and hence do not take action. Farmer’s perception of tree mortality was found to be a function of operator-specific variables such as sex, level of education and years of experience with tree species.     

‘Relationships between relationships’ in forest stands: intercepts and exponents analyses

Relationships between diameter at breast height(dbh) versus stand density, and tree height versus dbh(height curve) were explored with the aim to find if there were functional links between correspondent parameters of the relationships, exponents and intercepts of their power functions. A geometric model of a forest stand using a conic approximation suggested that there should be interrelations between correspondent exponents and intercepts of the relationships. It is equivalent to a type of ‘relationship between relationships’ that might exist in a forest stand undergoing self-thinning, and means that parameters of one relationship may be predicted from parameters of another. The predictions of the model were tested with data on forest stand structure from published databases that involved a number of trees species and site quality levels. It was found that the correspondent exponents and intercepts may be directly recalculated from one another for the simplest case when the total stem surface area was independent of stand density. For cases where total stem surface area changes with the drop of density, it is possible to develop a generalization of the model in which the interrelationships between correspondent parameters(exponents and intercepts) may be still established.     

‘Without bamboo,the land dies’: A conceptual model of the biogeochemical role of bamboo in an Indonesian agroforestry system

The ‘talun-kebun’ system consists of a 6–7 year management cycle in which a 4–5 year fallow period of perennial clump bamboo is alternated with 2 years of food crop production. Clearcutting, raking the forest floor and slash into piles for burning, and hoeing the soil to a depth of 25 cm reduces the vigour of the bamboo to the point at which it poses no competitive threat to the first year of planted food crops. These crops are (typically) cucumber, bitter solanum and hyacinth (pole) beans. Ash from the burned slash piles, plus some animal mamure and application of NPK fertiliser (only recently), are used to increase the production of these vegetables. In spite of these nutrient additions, the fertility of the upper soil layers declines during the first year, and the field is planted to cassava (a less nutrient-demanding root crop) the second year after clearcutting. After 2 years of cultivation, bamboo regrowth and declining soil fertility prevent continued food cropping. The field is abandoned and permitted to revert to an unmanaged stand of bamboo for 4–5 years. The historical success of the system appears to be based largely on the ‘nutrient pumping’ action of the bamboo, the slow decomposition of its silica-rich litter, and the extremely high biomass of bamboo fine roots. Studies reported earlier and in subsequent papers support the interpretation that the bamboo recovers much of the nutrients leached deeper into the soil profile during the 2 years of cropping and deposits them at or near the soil surface as above-ground litter and dead fine roots. The biogeochemical role of bamboo in sustaining the productivity of this agroforestry system reflects the rural farmer's saying: ‘without bamboo, the land dies’.     

Effects of habitat type, vegetation structure, and proximity to forests on bird species richness in a forest–agricultural landscape of West Java, Indonesia

To halt biodiversity loss in the humid tropics of developing countries, it is crucial to understand the roles and effects of human-modified landscapes with fragmented forest remnants in maintaining biodiversity while fulfilling the demands of local communities and reducing poverty. To implement appropriate landscape planning for conserving biodiversity and ecosystem functioning, appropriate information is required about parameters of habitat suitability among various anthropogenic habitats with a range of distances to forests and vegetation characteristics, but such information is limited. We examined differences in avian communities between a remnant forest and four types of man-made forest (two mature plantations and two agroforests) in a forest–agricultural landscape of West Java, and we analyzed the effects of both local and landscape factors on various types of species richness in this landscape. The results from non-metric multidimensional scaling revealed avifauna in the two types of agroforest was clustered separately from that in the remnant forest, mainly because drastic declines in the abundance of forest specialists (including IUCN red-listed species) and their replacement with open-habitat generalists. The mixed-tree agroforests were colonized by 30 % of forest specialists and forest-edge species found in the remnant forest, and maintained the highest richness of species endemic to Indonesia among man-made forests, implying that some forest specialists and endemics might have adapted to ancient landscape heterogeneity. High proportion of insectivorous birds was found in the remnant forest (more than 50 %) and drastically decline in man-made forests, although the species richness of insectivores did not decline significantly in broad-leaved plantations. We concluded that protection of remnant forests should be prioritized to conserve forest bird diversity. However, as different environmental factors affected the richness values of different ecological groups, appropriate landscape design and habitat management could improve functional diversity in forest–agricultural landscapes in the tropics.