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41.
The article introduces the background and summarises main research findings of the research articles in this special issue. The focus is on the key issues relevant for forest-based entrepreneurship development in small-scale forestry in relation to both wood and non-wood forest products and services (NWFP&S). The article draws special attention to changing forest ownership, changing owners’ motives and values, and the evolving role of forest owners’ associations in Europe. The paper draws attention to the finding that many small-scale forest owners do not treat their forest as an income-generating asset. The ownership of the forests may be more important as symbolic capital than as a source of income. This is quite opposite to the traditional wood production model that for instance most of the Forest Owners Association’s still follow. In relation to NWFP&S, the taxonomy and indicators for NWFP&S are discussed and some conclusions from studies on forest recreation innovation and NWFP&S marketing are presented. The NWFP&S sector is traditionally product-oriented, which is strategically peculiar because the long distances from rural production areas to the customers would suggest highest orientation on marketing. Also surprising is the low level of segmentation in the sector.
相似文献
| B. SleeEmail: |
43.
Participatory National Forest Programmes (NFPs) intend to democratise forest sector policy, but they may suffer from a fundamental democratic legitimisation deficit since the stakeholders involved are neither democratically authorised nor accountable to the population. In order to scrutinise the empirical relevance of this problem in the case of the German NFP, it is analysed how the German population on the one hand and the NFP participants on the other hand assess central forest policy aims of the NFP, and how far both assessments coincide. Two surveys based on identical questionnaires are used as the data base. The respondents assessed the importance of the respective aims as well as at their implementation. Results show that the population considers the majority of the NFP aims to be generally relevant, but assesses the majority of the aims significantly differently from the stakeholders. The formal legitimisation deficit of the German NFP therefore also matters in terms of content. Discussing the NFP among the elected representatives and in the public seems indispensable.Moreover, the differences in the assessment of some policy aims are significantly dependent on how people judge the image of forest enterprises between the opposing poles of profit orientation and nature protection. Public acceptance of those aims could be furthered more appropriately by adjusting the partly incorrect image of forestry rather than by providing more information about the particular aims and their background. 相似文献
44.
《Communications in Soil Science and Plant Analysis》2012,43(1-2):81-100
Abstract Differential thermogravimetry (DTG), differential scanning calorimetry (DSC), and stepwise thermogravimetry (STG), together with two acid hydrolysis methods (hydrolysis with hydrochloric acid in a single step, and hydrolysis with sulfuric acid in two steps), were evaluated to determine the quality of four plant materials (Medicago sativa, Eucalyptus globulus, Quercus ilex, and Pinus halepensis) before and after mixing with a red earth. These quality indices were then compared with the same materials in the field, whether their decomposition could be predicted. All the thermal methods gave poor results. In both DTG and DSC, the presence of the mineral matrix gave rise to strong distortions in the spectra. Since the spectrum of any mixture is not simply the sum of the spectra of the two components (organic matter + mineral matter), these distortions could not be corrected by simply subtracting the spectrum of the red earth alone. STG trials also gave poor results, because the presence of the mineral matrix greatly increased the quality indices, and reduced the ability of the method to distinguish between organic matter qualities. In view of our results, the usefulness of thermal methods in the characterization of soil organic matter would seem to be restricted to certain organic horizons (L, F, and perhaps H). In contrast, methods based on acid hydrolysis were comparatively more satisfactory. Their resolution (ability to distinguish organic matter qualities) was much higher than that of thermal methods. However, they were able to distinguish carbon more accurately than nitrogen. The sulfuric acid method, unlike the hydrochloric acid method, was affected by the presence of a mineral matrix. While both methods could be improved, in their present form they seem to operate as good predictors of carbon and nitrogen mineralization. 相似文献
45.
Vacant land, a product of population and economic decline resulting in abandonment of infrastructure, has increased substantially in shrinking cities around the world. In Cleveland, Ohio, vacant lots are minimally managed, concentrated within low-income neighborhoods, and support a large proportion of the city’s urban forest. We quantified abundance, richness, diversity, and size class of native and exotic tree species on inner-city vacant lots, inner-city residential lots, and suburban residential lots, and used i-Tree Eco to model the quantity and economic value of regulating ecosystem services provided by their respective forest assemblages. Inner-city vacant lots supported three times as many trees, more exotic than native trees, and greater tree diversity than inner-city and suburban residential lots, with the plurality of trees being naturally-regenerated saplings. The urban forest on inner-city vacant lots also had two times as much leaf area and leaf biomass, and more tree canopy cover. The quantity and monetary value of ecosystem services provided by the urban forest was greatest on inner-city vacant lots, with exotic species contributing most of that value, while native taxa provided more monetary value on residential lots. The predominately naturally-regenerated, minimally managed exotic species on vacant land provide valuable ecosystem services to inner-city neighborhoods of Cleveland, OH. 相似文献
46.
选择内蒙古大兴安岭林区兴安落叶松天然幼、中龄林、采用生长量分析的方法,对丰产区用立木度的理论编制丰产化培育立木度表,它能够适应兴安落叶松天然幼、中龄林林木分布不均匀、林分密度变化幅度大、生长差异明显、分布地域广等特点。结果表明立木度表易于理解、便于掌握,对于生产作业具有一定的适用性。 相似文献
47.
48.
从地理位置、水质及沉积物、红树林、珊瑚礁海岸等方面介绍亚龙湾生态自然环境特点,分析其生态旅游发展现状、形式及成效,提出对亚龙湾生态环境保护的建议。 相似文献
49.
《Journal of Crop Improvement》2013,27(1-2):5-16
Summary The response of woody plants to freezing temperatures is complex. Species vary greatly in their ability to survive freezing temperatures and the resulting dehydrative and mechanical stresses that occur as a result from the presence of ice. Initially, this is presented by the ability to inhibit the formation of ice (ice nucleation) by supercooling. Significant questions exist about the role of internal and external ice nucleating agents in determining the extent to which any particular plant can supercool. Additionally, little is known about how plant structure can affect ice nucleation and propagation. In this review, the ability of high-resolution infrared thermography to reveal significant details about the freezing process is demonstrated. In general, the presence of effective, intrinsic nucleators appear to be common in woody plants. The nucleators appear to be as effective as external ice nucleators and induce stems to freeze at warm, subzero temperatures. Barriers appear to exist, however, that prevent ice propagation into lateral appendages such as buds, or newly extended primary tissues. Deep supercooling represents a unique adaptation of woody plants to avoid freezing injury by dramatically suppressing ice formation in specific tissues. The extent of suppression is limited by the homogeneous nucleation temperature of water (-38°C) and therefore deep supercooling is characteristic of moderately hardy woody plants. In contrast, it has been proposed that the most cold-hardy woody plants have the ability to form glassed solutions. These solutions are very stable as long as the cell remains below the melting temperature of the glass and so allows tissues to become relatively impervious to the stresses associated with extremely low temperatures. 相似文献
50.
Increasing incidences of drought-induced tree mortality are being recorded worldwide, including Africa. African forests cover a significant proportion of the continent, which implies that African forest sustainability is threatened from a climate-change perspective. This is especially problematic in a developing nation context, because forest ecosystems such as plantation forestry provide important goods and services that sustain human well-being and economic growth. Disentangling the likely triggers of tree mortality (including those linked to drought) in landscapes would not only explain the mechanisms underlying local die-offs, but also better predict future mortality events. Methods applied in the field of ecophysiology are particularly useful to study in situ plant responses to an environment. We consider the status quo of global peer-reviewed publication outputs during the past century that have made use of key ecophysiological research approaches, specifically studies concerning ‘tree xylem anatomy’, ‘tree xylem cavitation’, ‘tree leaf gas-exchange’ and ‘tree xylem hydraulic conductivity’. We highlight the growth and applicability of this research field in understanding tree ecology. We also assess the role that the forestry sector has had in promoting such research to ensure future-proof forest products. Most importantly, we consider how Africa with its vast forested landscapes fits within this research spectrum. The last decade saw an increase of up to 60% in the total number of articles published, particularly with a focus on tree xylem cavitation and conductivity. Although forest research contributed greatly to the global tally of ecophysiological studies, and such studies in Africa have also increased by up to 88% in the past decade, there remains a general lack of this research topic in the continent. It is clear an optimisation of applied ecophysiological concepts and techniques will promote an improved understanding of tree mortality patterns. We argue that ecophysiological data will be crucial to future-proof tree improvement strategies in African commodity production landscapes, especially given future drier climates. 相似文献