Trees

树木
  • 文章类型: Journal Article
    临床管理很少基于一个数据项的收集。相反,它的典型特征是持续收集和评估临床数据(症状,标志,实验室,成像测试,等。)建立进一步管理决策的平台。
    Clinical management is rarely based on the collection of one data item. Instead, it is typically characterized by the continuous collection and evaluation of clinical data (symptoms, signs, laboratory, imaging tests, etc.) to establish a platform for further management decisions.
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  • 文章类型: Editorial
    最近发布了新的胸痛指南文件。最大的变化是对已知和未知CAD的中危和高危患者的建议。冠状动脉CT血管造影已被推荐为<65岁胸痛患者的首选影像学检查。本文将审查文件中促使该建议的主要证据和遗漏,并就未来的潜在行动提供想法。
    The new chest pain guideline document was recently released. The biggest changes are in the recommendations for intermediate and high-risk patients with known and unknown CAD. Coronary CT angiography has been recommended as the preferred imaging test for patients < 65 years old with chest pain. This paper will review the major evidence and omissions in the document that prompted that recommendation and provide thoughts on potential actions going forward.
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  • 文章类型: Journal Article
    例如,城市树木和绿地对城市的重要贡献,气候适度和公共卫生已经得到认可。本文讨论了促进观看绿色的好处的指南和规范,生活在绿色之中,并方便进入绿色空间供娱乐使用。从家里看到树木和其他植被,工作地点,或学校有重要的心理健康和表现的好处。当地的树冠覆盖与降温和气候适度的其他方面呈正相关。随着公共绿地靠近一个人的家,刺激了这些区域的定期使用,并对精神产生积极影响,物理,和社会健康。在分析了现有的城市绿地规划和提供的指导方针和规则后,一个新的,提出了全面的指导方针,被称为城市林业的“3-30-300规则”。本指南旨在通过设定从每个家庭观看至少3棵完善的树木的门槛,提供对树木和绿地的公平访问及其好处,学校,和工作地点,每个社区不少于30%的树冠;距离每个住宅最近的公共绿地不超过300米。讨论了这一新指南的当前实施情况,以及使用这种循证规则的优点和缺点,但也明确和简单。
    The important contributions of urban trees and green spaces to for example, climate moderation and public health have been recognized. This paper discusses guidelines and norms that promote the benefits of viewing green, living amongst green, and having easy access to green spaces for recreational use. Having trees and other vegetation in sight from one\'s home, place of work, or school has important mental health and performance benefits. Local tree canopy cover is positively associated with cooling and other aspects of climate moderation. With public green spaces in proximity to one\'s home stimulates regular use of these areas and results in positive impacts on mental, physical, and social health. After analyzing existing guidelines and rules for urban green space planning and provision, a new, comprehensive guideline is presented, known as the \'3-30-300 rule\' for urban forestry. This guideline aims to provide equitable access to trees and green spaces and their benefits by setting the thresholds of having at least 3 well-established trees in view from every home, school, and place of work, no less than a 30% tree canopy in every neighbourhood; and no more than 300 m to the nearest public green space from every residence. Current implementation of this new guideline is discussed, as well as the advantages and disadvantages of using this evidence-based but also clear and simple rules.
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  • 文章类型: Editorial
    暂无摘要。
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  • 文章类型: Journal Article
    Forests are a major supplier of renewable energy; however, gleaning logging residues for use as woody biomass feedstock could negatively alter habitat for species dependent on downed wood. Biomass Harvesting Guidelines (BHGs) recommend retaining a portion of woody biomass on the forest floor following harvest. Despite BHGs being developed to help ensure ecological sustainability, their contribution to biodiversity has not been evaluated experimentally at operational scales. We compared herpetofauanal evenness, diversity, and richness and abundance of Anaxyrus terrestris and Gastrophryne carolinensis among six treatments that varied in volume and spatial arrangement of woody biomass retained after clearcutting loblolly pine (Pinus taeda) plantations in North Carolina, USA (n = 4), 2011-2014 and Georgia (n = 4), USA 2011-2013. Treatments were: (1) biomass harvest with no BHGs, (2) 15% retention with biomass clustered, (3) 15% retention with biomass dispersed, (4) 30% retention with biomass clustered, (5) 30% retention with biomass dispersed, and (6) no biomass harvest. We captured individuals with drift fence arrays and compared evenness, diversity, and richness metrics among treatments with repeated-measure, linear mixed-effects models. We determined predictors of A. terrestris and G. carolinensis abundances using a priori candidate N-mixture models with woody biomass volume, vegetation structure, and groundcover composition as covariates. We had 206 captures of 25 reptile species and 8710 captures of 17 amphibian species during 53690 trap nights. Herpetofauna diversity, evenness, and richness were similar among treatments. A. terrestris abundance was negatively related to volume of retained woody biomass in treatment units in North Carolina in 2013. G. carolinensis abundance was positively related with volume of retained woody debris in treatment units in Georgia in 2012. Other relationships between A. terrestris and G. carolinensis abundances and habitat metrics were weak or absent. The lack of consistent community or population responses suggests the addition of a woody biomass harvest to a clearcut in pine plantations does not impact herpetofauna use of Coastal Plain loblolly plantations in the southeastern United States. We recommend additional research to examine relationships between woody biomass harvesting and rarer species or amphibians with high desiccation risk, particularly in other regions and harvesting systems.
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  • 文章类型: Journal Article
    提倡将集合预测作为减少物种分布建模(SDM)不确定性的一种方法。这是因为期望平衡SDM模型的准确性和鲁棒性。然而,关于不同共识方法生成的组合分布图的空间相似性的可用数据很少。这里,使用八个基于利基的模型,九个分裂样本校准回合(或九个随机模型训练子集),和九种气候变化情景,在当前和未来的气候条件下,模拟了中国32种森林树种的分布。使用三种简单的共识方法(平均,频率,和中位数[PCA])。物种地理范围因气候变化而变化(面积变化和移动距离),但是三个共识预测在多少或哪个方向上没有显着差异,但是在三个共识预测的空间相似性方面,它们确实存在差异。主要在物种范围的边缘观察到不一致的区域。多元逐步回归模型显示了三个因素(生态位边缘化和专业化,和生态位模型准确性)与共识方法中共识预测图的观察变化有关。当生态位模型精度较高,边缘度和专业化较低时,预测图之间的空间对应关系最高。空间预测的差异表明,在根据地图输出做出有关专业物种的任何决定之前,应更加注意空间不确定性的范围。利基特性和单模型预测性能提供了有希望的见解,可以进一步了解SDM中的不确定性。
    Ensemble forecasting is advocated as a way of reducing uncertainty in species distribution modeling (SDM). This is because it is expected to balance accuracy and robustness of SDM models. However, there are little available data regarding the spatial similarity of the combined distribution maps generated by different consensus approaches. Here, using eight niche-based models, nine split-sample calibration bouts (or nine random model-training subsets), and nine climate change scenarios, the distributions of 32 forest tree species in China were simulated under current and future climate conditions. The forecasting ensembles were combined to determine final consensual prediction maps for target species using three simple consensus approaches (average, frequency, and median [PCA]). Species\' geographic ranges changed (area change and shifting distance) in response to climate change, but the three consensual projections did not differ significantly with respect to how much or in which direction, but they did differ with respect to the spatial similarity of the three consensual predictions. Incongruent areas were observed primarily at the edges of species\' ranges. Multiple stepwise regression models showed the three factors (niche marginality and specialization, and niche model accuracy) to be related to the observed variations in consensual prediction maps among consensus approaches. Spatial correspondence among prediction maps was the highest when niche model accuracy was high and marginality and specialization were low. The difference in spatial predictions suggested that more attention should be paid to the range of spatial uncertainty before any decisions regarding specialist species can be made based on map outputs. The niche properties and single-model predictive performance provide promising insights that may further understanding of uncertainties in SDM.
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  • 文章类型: Journal Article
    BACKGROUND: Commercial forestry programs normally use locally collected seed for reforestation under the assumption that tree populations are optimally adapted to local environments. However, in western Canada this assumption is no longer valid because of climate trends that have occurred over the last several decades. The objective of this study is to show how we can arrive at reforestation recommendations with alternative species and genotypes that are viable under a majority of climate change scenarios.
    RESULTS: In a case study for commercially important tree species of Alberta, we use an ecosystem-based bioclimate envelope modeling approach for western North America to project habitat for locally adapted populations of tree species using multi-model climate projections for the 2020s, 2050s and 2080s. We find that genotypes of species that are adapted to drier climatic conditions will be the preferred planting stock over much of the boreal forest that is commercially managed. Interestingly, no alternative species that are currently not present in Alberta can be recommended with any confidence. Finally, we observe large uncertainties in projections of suitable habitat that make reforestation planning beyond the 2050s difficult for most species.
    CONCLUSIONS: More than 50,000 hectares of forests are commercially planted every year in Alberta. Choosing alternative planting stock, suitable for expected future climates, could therefore offer an effective climate change adaptation strategy at little additional cost. Habitat projections for locally adapted tree populations under observed climate change conform well to projections for the 2020s, which suggests that it is a safe strategy to change current reforestation practices and adapt to new climatic realities through assisted migration prescriptions.
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  • 文章类型: Journal Article
    We conducted an online survey (n = 3321) followed by five focus groups with Forest Service employees involved in compliance with the National Environmental Policy Act (NEPA) to explore agency views of how NEPA should be implemented within the agency. We filter these perceptions through the lenses of different functional groups within the agency, each with its own role in agency compliance with NEPA and its own suite of perceived accountabilities. In doing so, we uncover areas of consensus regarding valued practices as well as tensions between employees with different roles in NEPA compliance. General consensus exists regarding the importance of the effective functioning of interdisciplinary teams, but opinions about what constitutes an effective team vary. Findings suggest that NEPA serves as a playing field for competing accountabilities felt by line officers, disciplinary specialists, and advisory personnel within the agency, as each attempts to exert influence over NEPA processes and their outcomes.
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  • 文章类型: Comparative Study
    Seed dispersal by animals is considered a pivotal ecosystem function that drives plant-community dynamics in natural habitats and vegetation recovery in human-altered landscapes. Nevertheless, there is a lack of suitable ecological knowledge to develop basic conservation and management guidelines for this ecosystem service. Essential questions, such as how well the abundance of frugivorous animals predicts seeding function in different ecosystems and how anthropogenic landscape heterogeneity conditions the role of dispersers, remain poorly answered. In three temperate ecosystems, we studied seed dispersal by frugivorous birds in landscape mosaics shaped by human disturbance. By applying a standardized design across systems, we related the frequency of occurrence of bird-dispersed seeds throughout the landscape to the abundance of birds, the habitat features, and the abundance of fleshy fruits. Abundance of frugivorous birds in itself predicted the occurrence of dispersed seeds throughout the landscape in all ecosystems studied. Even those landscape patches impoverished due to anthropogenic disturbance received some dispersed seeds when visited intensively by birds. Nonetheless, human-caused landscape degradation largely affected seed-deposition patterns by decreasing cover of woody vegetation or availability of fruit resources that attracted birds and promoted seed dispersal. The relative role of woody cover and fruit availability in seed dispersal by birds differed among ecosystems. Our results suggest that to manage seed dispersal for temperate ecosystem preservation or restoration one should consider abundance of frugivorous birds as a surrogate of landscape-scale seed dispersal and an indicator of patch quality for the dispersal function; woody cover and fruit resource availability as key landscape features that drive seedfall patterns; and birds as mobile links that connect landscape patches of different degrees of degradation and habitat quality via seed deposition.
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  • 文章类型: Journal Article
    Invertebrates provide the majority of ecosystem services; thus, it is important that they be inventoried, monitored, and protected. Nevertheless, inventories, monitoring, and management generally focus on vertebrates and flowering plants. Consequently, there are few guidelines or case studies for invertebrates. We present a procedure for developing a monitoring program for species-rich invertebrates that entails (1) characterizing the community; (2) identifying surrogates for biodiversity; and (3) establishing efficient methods to monitor surrogates and any ecologically important or sensitive taxa. We used these procedures, biodiversity-based statistical advances, and a survey of arthropods to develop a monitoring plan for the forests of Shenandoah National Park, Virginia (U.S.A.). Our case study revealed that mixed hardwood and hemlock forests had significantly different compositions of arthropods in their soil and understory strata. Of the 10 orders tested Coleoptera and Hymenoptera were the only two to pass most of the five surrogate tests, and their combination improved predictions of overall arthropod diversity. Because arthropods represent the majority of macroscopic species in most ecosystems, the ability of this assemblage to predict overall arthropod diversity makes it a powerful surrogate. Of the 11 collecting methods used, the beat-sheet method was the most efficient for monitoring this surrogate assemblage. To complement this coarse-filter approach to monitoring at-risk, invasive, or other important taxa (fine filter), we used ordination analyses to match 66 taxa with the methods that most effectively sampled them. Our methods serve as a model for developing an invertebrate monitoring plan and should facilitate linking such monitoring with ecosystem functions and management.
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