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Forest regeneration can be improved by matching seedling stock with reforestation site environmental conditions. To achieve this improvement, one must characterize seedling performance potential with anticipated field site conditions. A theoretical performance potential index (PPI) has been developed to forecast seedling field performance during the first growing season on a reforestation site. PPI includes material and performance attribute tests that characterize seedling performance potential under optimum and limiting environmental conditions. Test results are standardized and then integrated resulting in a comprehensive assessment procedure. The PPI concept is demonstrated using containerized western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings subjected to a series of dormancy induction treatments and the results are compared with actual seedling performance during the first growing season on a reforestation site. Results indicated that PPI values for western hemlock seedlings treated with various dormancy induction treatments corresponded to field performance. Possible use of PPI in stock selection is discussed. 相似文献
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Roger A. Sedjo 《Forest Ecology and Management》1984,9(4):245-257
Industrial forest plantations are playing an increasingly important role in meeting world wood requirements. Recent successes with plantations in the tropics and Southern Hemisphere suggest potential for considerable expansion. The results of a detailed investigation of the comparative economics of industrial forest plantations in twelve regions of the globe, including nine in the tropics and Southern Hemisphere, are reported. The important factors are identified and discussed and formal investment criteria are applied. In general, the analysis suggests that the economics of plantation forests in the regions of the Southern Hemisphere examined are quite favorable, provided that the development costs, which may be substantial, can be adequately covered. 相似文献
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Francesca Camilli Andrea Pisanelli Giovanna Seddaiu Antonello Franca Valerio Bondesan Adolfo Rosati Gerardo Marcos Moreno Anastasia Pantera John E. Hermansen Paul J. Burgess 《Agroforestry Systems》2018,92(4):849-862
This paper reports the results of a study conducted in Italy, within the AGFORWARD (2014–2017) project, aimed at promoting innovative agroforestry practices in Europe. Agroforestry offers a means for maintaining food production whilst addressing some of the negative environmental effects of intensive agriculture. This study aims to elicit the positive and negative points of view and perceptions of local stakeholders in Italy in relation to three types of agroforestry systems. The Participatory Research and Network Development was implemented in three workshops conducted in Sardinia, Umbria, and Veneto regions, and applied adopting a common methodological protocol. Qualitative data were obtained using open discussions with stakeholders on key issues, challenges and innovations. Quantitative data were obtained from stakeholders completing questionnaires during the workshops. A statistical analysis was applied to elicit the differences in stakeholders’ positive and negative perceptions in relation to production, management, environment and socio-economy aspects. Although the participants in the study came from different geographical and socioeconomic contexts with varied educational and cultural backgrounds, the different professional groups (farmers, policy-makers and researchers) and the three workshops generally shared similar perceptions of the benefits and constraints. The effects of agroforestry on production and the environment were generally perceived as positive, whilst those related to management were generally negative. The process of bringing the groups together seemed to be an effective means for identifying the key research gaps that need to be addressed in order to promote the uptake and maintenance of agroforestry. 相似文献
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Predicting field performance using seedling quality assessment 总被引:2,自引:0,他引:2
Seedling quality is defined as fitness for purpose. Attributes for assessing seedling quality are grouped in material attributes that can be rapidly assessed by any number of direct or indirect methods, and performance attributes that are assessed by subjecting whole seedlings to certain environmental regimes and evaluating their growth response. Material attributes comprising morphology, bud dormancy, water relations and nutrition and performance attributes comprising frost hardiness, vigour and root growth potential are discussed with regard to relevance for predicting field performance. Measurement techniques and relevance in assessing seedling quality are presented for different physiological attributes: electrolyte leakage, enzymatic activity, water potential, water conductance, mineral nutrition, food reserves, mitotic index, gas exchange, chlorophyll content, plant growth regulators, stress-induced volatile emission, and nuclear magnetic resonance. Methods with future potential in improving the prediction of field performance are identified and discussed. The methods presented in this respect are chlorophyll fluorescence, infrared thermography, machine vision systems, integrated approaches and ecophysiological evaluations. 相似文献
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Local-level criteria and indicators: an Aboriginal perspective on sustainable forest management 总被引:1,自引:1,他引:1
Sherry Erin; Halseth Regine; Fondahl Gail; Karjala Melanie; Leon Beverly 《Forestry》2005,78(5):513-539
As tools for improving the sustainability of forest management,criteria and indicator (C&I) frameworks have grown in popularityover the last decade. Such frameworks have been largely derivedfrom top-down approaches to determining critical measures offorest management success. While useful, they fail to capturemany C&I of critical importance to local populations, whoexperience forest management strategies first hand and who havetheir own definitions of sustainability. Using archival materials,our research begins to identify one First Nation's forest valuesand compares these local-level C&I with three well-knownC&I frameworks for sustainable forestry. We demonstratethat local-level definitions can provide additional C&I,as well as additional levels of detail to C&I that theyshare with the national and international frameworks. Both arecrucial to developing strategies for sustainable managementthat meet local as well as broader needs and desires. 相似文献
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Site quality evaluation by classification tree: an application to cork quality in Sardinia 总被引:1,自引:0,他引:1
Cork harvesting and stopper production represent a major forest industry in Sardinia (Italy). The target of the present investigation was to evaluate the classification tree as a tool to discover possible relationships between microsite characteristics and cork quality. Seven main cork oak (Quercus suber) producing areas have been identified in Sardinia, for a total of more than 122,000 ha. Sixty-three sample trees, distributed among different geographical locations and microsite conditions, were selected. A soil profile near each sample tree was described, soil samples were collected and analysed. After debarking, cork quality of each sample tree was graded by an independent panel of experts. Microsites where trees had more than 50% of the extracted cork graded in the best quality class, according to the official quality standard in Italy, were labelled as prime microsites, the others as nonprime microsites. Relationships between a binary dummy variable (0 for nonprime microsites, 1 for prime microsites) and site factors were investigated using classification tree analysis to select the relevant variables and to define the classification scheme. Prime quality microsites for cork production proved to be characterised by elevation, soil phosphorus content and sandiness. Results have been compared with those of the more conventional parametric approach by logistic regression. The work demonstrates the advantages of the classification tree method. The model may be appropriate for classifications at landscape and stand mapping levels, where it is possible to sample a number of microsites and to evaluate distributional characteristics of model output, while its precision is only indicative when estimating the prime quality of single microsites. 相似文献
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This paper discusses a plantation management approach involving a combination of “short” and “long” rotations designed to
allow farmers to receive income from trees as soon as possible after establishment. We present results from two plots that
represent extreme conditions: (a) a seasonally waterlogged, non-saline site (Nahalal), and (b) a saline site (Ginnegar) located
in the Yizre’el Valley, Israel. Six improved seed sources, four of Eucalyptus camaldulensis and two of E. occidentalis, were examined. The local Israeli seed source of E. camaldulensis (HA) performed best at both sites. In Nahalal, the short rotation thinning of the slower growing (50%) plantation trees could
provide economic returns approximately five years after establishment. The calculated mean annual increment (MAI) of these
trees reached 12.2 t ha−1 year−1. The long rotation, or better performing half of the plantation trees, could be used as a source of sawn timber, providing
higher-value products. By nine years after establishment, the average DBH of the various seed sources reached 25.8 ± 1.9 cm.
The calculated MAI of the combined cutting rotations reached 48.3 t ha−1 year−1. Eucalyptus grown under the combined (short- and long-term) management approach at Nahalal was more profitable than many other non-irrigated
local crops. Eucalyptus production in Ginnegar would be less profitable than in Nahalal. However, an additional ecological benefit was provided by
the crop’s ability to lower the water table. When this contribution to regional drainage is taken into account, trees become
economically competitive with other non-irrigated field crops under saline conditions.
Jim Morris–Deceased. 相似文献
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Roger A. Baldwin Ryan Meinerz Gary W. Witmer Scott J. Werner 《Journal of pest science》2018,91(3):1107-1113
Vole (Cricetidae) girdling of tree trunks is a common form of damage experienced by tree and vine growers throughout much of the Northern Hemisphere. Management programs that effectively incorporate chemical repellents and vegetation management would be of substantial assistance to growers that experience such damage. Anthraquinone has proven effective as a repellent against voles in lab trials, yet controlled field tests of combined anthraquinone and vegetation management programs are lacking. Therefore, we established a mesocosm-based study in central California, USA, to test the efficacy of anthraquinone and vegetation management for reducing girdling damage caused by California voles Microtus californicus to Clementine citrus trees Citrus clementine under semi-field conditions. We observed a 90–100% reduction in girdling damage for trees following a single application of anthraquinone during two trials in summer and spring, respectively. Removal of vegetation around the base of trees further reduced damage during the summer sampling period, with no girdling observed on anthraquinone-treated trees that were surrounded by bare soil. We did not observe this same relationship during spring, and we observed no relationship between vegetation management in the absence of anthraquinone treatments in either seasonal trial, suggesting that vegetation management had a lesser impact on vole girdling than anthraquinone applications. We observed no decrease in efficacy of anthraquinone across the duration of both sampling periods (5–6 weeks), indicating substantial longevity for anthraquinone. Anthraquinone appears to have substantial utility for minimizing vole girdling damage. Field testing is warranted for additional mammalian species to determine potential uses for other taxa. 相似文献
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《Forest Ecology and Management》2005,219(1):13-28
Carbon budgets are developed to understand ecosystem dynamics and are increasingly being used to develop global change policy. Traditionally, forest carbon budgets have focused on the biological carbon cycle; however, it is important to include the industrial forest carbon cycle as well. The overall objective of this study was to quantify the major carbon fluxes associated with the production of Wisconsin's industrial roundwood, by using life cycle inventory (LCI) methodology to produce an industrial forest carbon budget. To achieve this objective we (1) developed carbon LCIs for the harvest process for three major forest ownerships (state, national, and private non-industrial), (2) developed carbon LCIs for a dimensional lumber and two oriented strand board (OSB) mills and (3) completed a scaled version of 1 and 2 to include more Wisconsin forestlands and to incorporate the other major processes within the industrial forest carbon cycle (e.g. primary mill, secondary mill, product use and product disposal processes of the industrial forest carbon cycle). The carbon budgets for the harvesting process of the Chequamegon-Nicolet National Forest (CNNF), the Northern Highland American Legion State Forest (NHAL), and the non-industrial private forests that participated in the managed forest laws of Wisconsin (MFL-NIPF) were 0.10, 0.18 and 0.11 tonnes C ha−1 year−1), respectively. The dimensional lumber and OSB products were both net carbon sources, and released 0.05–0.09 tonnes C/tonnes C processed). More carbon is sequestered than released within the industrial forest carbon cycle of Wisconsin's national (6 g C m−2 year−1), state (12 g C m−2 year−1) and non-industrial private forests (7 g C m−2 year−1). Using published net ecosystem production data we estimate that the net forest carbon cycle budget (sum of the biological and industrial C cycle, [Gower, S.T., 2003. Patterns and mechanisms of the forest carbon cycle. Ann. Rev. Environ. Resour. 28, 169–204]) for the CNNF ranges between −897 and 348 g C m−2 year−1. Life cycle inventories of wood and paper products should be clear and explicitly state what processes are included, so that results can be used by policy makers and future researchers. 相似文献
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浅谈工业与民用建筑冻土工程地质勘察的质量控制 总被引:1,自引:0,他引:1
由于冻土的复杂性和特殊性认识得不够全面,有时会出现缺漏项情况,从而影响勘察质量。现遵循质量策划控制到质量的原则,对勘察过程的每一道工程程序进行质量把关、质量控制,以达到提高勘察质量的目的。 相似文献
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The purpose of this research is to study the avoidable damage from forest fires in the most affected European Union (EU) Member States (MS) using a quantitative model based on a non-parametric efficient frontier technique, namely data envelopment analysis (DEA). The procedure allows the comparison of forest fire damage in EU countries by computing relative efficiency scores and quantifying improvement targets. The proposed DEA model evaluates a slacks-based measure of efficiency and considers two non-discretionary variables (the forest area of the countries and fire weather index). Data from the most affected EU countries over the period 2005–2010 have been used. An input-oriented model has been considered in order to take into account the number of fire events and total burned area as the fire management targets. The study finds evidence that there is a considerable excess of forest area affected by fire in most of the EU countries. The empirical results also suggest that the mean relative damage efficiency in Southern European MS and Other MS is not significantly different. From the efficiency scores, different clusters, with clear characteristic features, emerge. The next step is to extend the best practices of the efficient EU countries. 相似文献
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Forest machine operators are still experiencing work-related musculoskeletal disorders (WMSDs) despite extensive mechanisation and modernisation of harvesting systems. However, paucity of local ergonomics research and technology transfer problems may affect the use of mechanised systems in South Africa. Consequently, this study was a field-based ergonomic assessment of local forwarding operations. PG Bison's North East Cape Forests (NECF) Eastern Cape operations and Komatiland Forests (KLF) Mpumalanga operations were studied. The main aim of the study was to carry out an ergonomic assessment on local forwarder operator tasks, using Tigercat 1055 forwarders. The study specifically assessed WMSD prevalence and risk factors, investigated the frequency of awkward head postures and evaluated work organisation. A modified Nordic musculoskeletal questionnaire was used to survey WMSD prevalence and work organisation factors. Operators reported hourly, localised work-related musculoskeletal discomfort experienced during the shift. A video camera mounted in the cab was used to capture footage of awkward head postures. The video footage was also used for the WMSD risk assessment using the Health and Safety Executive (HSG60) upper limb disorder assessment worksheets. Operators reported having experienced WMSDs during the last 12 months mainly in the lower back, neck, shoulders and upper back. The studied operators reported lower repetition strain symptoms and higher lower-back disorders than in previous studies. Twenty-three percent of the awkward head postures adopted were extreme. The study results support the assertion that causal pathways of WMSDs are complex and multifactorial. Repetition, awkward head posture, duration of exposure, vibration, psychological factors and individual differences were identified as the main WMSD risk factors. 相似文献