徽州及岭南地区乡村风水林/水口林研究

介绍了风水林/水口林的定义和乡村风水林的发展现状,以及研究乡村风水林的价值和意义。并简单地对徽州和岭南地区的乡村风水林进行了简单的介绍,主要包括风水林的产生和研究价值等。对乡村风水林的保护和乡村规划建设的关系进行了分析和建议。     

北京地区设施西瓜生产技术规程

针对北京地区设施西瓜栽培技术标准化水平低、质量不稳定、商品率不高等问题,满足西瓜产业的优质化和标准化供给能力需求,制定了北京地区设施西瓜生产技术规程,主要包括产地环境条件、栽培技术、病虫害防治及采收等。该项规程可为设施西瓜生产的标准化、规范化提供参考。     

北京地区冬季日光温室鲜切生菜专用品种筛选试验

对14个不同的结球生菜进行了品种比较试验,筛选出了适合北京地区冬季日光温室种植的生菜品种射手101和绿蕾等.这些品种各方面表现均十分突出,具有极高的商品价值和市场推广价值.     

北京2009年10月蔬菜价格走势分析

1蔬菜价格走势的特点2009年10月,是北京地区2009年全年蔬菜价格比较低的月份,也是当年下半年中价格最低的月。该月北京地区蔬菜的价格总体是下降的,且降幅比较明显。由图1可见,2009年10月末与10月初相比,蔬菜的加权平均价下降了17.77%,而2008年10月,菜     

浅议黄土高原地区低效刺槐林的生态种植

本文先简要介绍了"三低林"的界定及低效林的简述,进而对在黄土高原地区低效刺槐林的生态种植做了深入分析,以为其正常生长提供理论支持。     

浅议莲城镇油茶低产林改造技术

莲城镇现有低产老油茶林约2000hm2,但因经营管理水平差,科技含量低,导致经济效益低。如何经营好现有的油茶林,使之在短期内产生良好的经济效益,显得极其重要。本文主要阐述油茶低产林改造技术,使老油茶林从低效益中转变过来提高产量,增加经济收入。     

‘神龙1号’无籽西瓜越夏栽培技术

中果型无籽西瓜在北方种植面积逐渐减小,其主要原因是无籽西瓜种子价格高,发芽率低,嫁接难以成活。尤其在北京地区进入6—7月份温度高、湿度大,是病虫害发生的高峰时期,一旦防控失利就会造成绝收。为了增添北京地区西瓜供应的花色品种,填补7—8月份市场空白,特介绍‘神龙1号’中果型无籽西瓜在北京地区的越夏栽培技术,供瓜农及农技推广工作者参考。     

北京地区园林废弃物资源化利用现状及探讨

对北京地区园林废弃物处理现状进行调研,着重从资源数量、资源化利用方式等方面进行分析与总结。调研结果显示,北京地区园林废弃物资源化利用率低,建设发展较为缓慢。针对以上问题提出对策建议,以期为园林废弃物资源化利用的研究和建设提供参考。     

北京市早春大棚西瓜蜜蜂授粉技术规程要点

为了完善西瓜蜜蜂授粉技术,规范有籽中果型西瓜、地爬小果型西瓜和立架栽培小果型西瓜蜜蜂授粉技术,解决长期以来小果型西瓜立架栽培蜜蜂授粉坐果率低及西瓜在蜜蜂授粉中出现的问题,制定了北京地区西瓜蜜蜂授粉技术规程。规程中对授粉蜂管理者、西瓜蜜蜂授粉使用者提出了详细的要求。从授粉蜜蜂蜂箱的制作、授粉蜂群蜂量标准、蜂箱的摆放、入棚的时间以及瓜农在授粉前的准备、西瓜授粉温湿度的管理、西瓜授粉时间,特别是对小果型西瓜蜜蜂授粉技术作了详细的说明。此操作规程适用于北京地区早春大棚大、中、小果型有籽西瓜蜜蜂授粉,弥补了北京地区西瓜蜜蜂授粉及立架栽培小果型西瓜蜜蜂授粉坐果率低的技术空白。     

江川县低效林现状与改造对策

江川县在查清低效林现状的基础上,自2009年来启动实施低次林改造2666.67hm2,针对不同权属、不同森林类型、不同原因形成的低效林改造,在政策、技术、改造模式上采取了不同的对策,取得明显成效,以供低效林改造市县借鉴。     

芹菜耐抽薹性杂种优势及亲子间相关性分析

以芹菜14个杂种F1及其亲本为试材,采用多个形态指标对其耐抽薹性进行评价分析,选用耐抽薹指数进行芹菜耐抽薹性杂种优势与亲子间相关性分析.结果表明,在多个指标中,耐抽薹指数最为精准,它与耐抽薹力、一级品合格率、二级品合格率、三级品合格率之间存在极显著相关.芹菜耐抽薹性存在超中优势和超亲优势,其中超中优势较为普遍,超亲优势相对较少.F1耐抽薹性与双亲均值存在显著相关,低值亲本对F1的影响力强于高值亲本,前者与F1相关性达到显著水平.     

Modeling vegetation pattern using digital terrain data

Using a geographic information system (GIS), digital maps of environmental variables including geology, topography and calculated clear-sky solar radiation, were weighted and overlaid to predict the distribution of coast live oak (Ouercus agrifolia) forest in a 72 km² region near Lompoc, California. The predicted distribution of oak forest was overlaid on a map of actual oak forest distribution produced from remotely sensed data, and residuals were analyzed to distinguish prediction errors due to alteration of the vegetation cover from those due to defects of the statistical predictive model and due to cartographic errors. Vegetation pattern in the study area was associated most strongly with geologic substrate. Vegetation pattern was also significantly associated with slope, exposure and calculated monthlysolar radiation. The proportion of observed oak forest occurring on predicted oak forest sites was 40% overall, but varied substantially between substrates and also depended strongly on forest patch size, with a much higher rate of success for larger forest patches. Only 21% of predicted oak forest sites supported oak forest, and proportions of observed vegetation on predicted oak forest sites varied significantly between substrates. The non-random patterns of disagreement between maps of predicted and observed forest indicated additional variables that could be included to improve the predictive model, as well as the possible magnitude of forest loss due to disturbances in different parts of the landscape.     

Forest stressors and roadside vegetation management in an exurban landscape

As part of the forest landscape, roadside trees are susceptible to multiple stressors that increase potential for tree damage during storm events and contribute to power outages. In exurban areas, decision-making related to the roadside forest is divided among many land ownerships and management entities with diverse objectives. Our objectives were to (1) identify general forest and roadside vegetation management objectives and challenges, (2) identify forest stressors and assess perceived severity and level of concern for forest stressor impacts to the roadside forest, and (3) evaluate manager interrelationships based on management objectives and challenges. We conducted semi-structured interviews with thirty-nine members of the forest management community who manage non-residential and non-industrial tracts of forest land in Connecticut, USA. Improving overall forest health and resilience, wildlife habitat, and forest products were the three most common general forest objectives. The two most frequently identified roadside objectives were public safety and mitigating hazardous conditions. The most common general forest management challenges included workforce limitations, financial constraints, and public perceptions. Support and satisfaction among the public and other stakeholders was the most frequently mentioned roadside forest management challenge. Although participants recognized the importance of roadside vegetation management, many avoided active management along roadsides. Immediate roadside vegetation issues such as public safety were prioritized rather than long-term planning. Stakeholders are constantly orchestrating a balance of numerous objectives as they integrate roadside vegetation considerations into broader forest management.     

Temporal change in fragmentation of continental US forests

Changes in forest ecosystem function and condition arise from changes in forest fragmentation. Previous studies estimated forest fragmentation for the continental United States (US). In this study, new temporal land-cover data from the National Land Cover Database (NLCD) were used to estimate changes in forest fragmentation at multiple scales for the continental US. Early and late dates for the land-cover change data were ca. 1992 and ca. 2001. Forest density was used as a multi-scale index of fragmentation by measuring the proportion of forest in neighborhoods ranging in size from 2.25 to 5314.41 ha. The multi-scale forest density maps were classified using thresholds of 40% (patch), 60% (dominant), and 90% (interior) to analyze temporal change of fragmentation. The loss of dominant and interior forest showed distinct scale effects, whereas loss of patch forest was much less scale-dependent. Dominant forest loss doubled from the smallest to the largest spatial scale, while interior forest loss increased by approximately 80% from the smallest to the second largest spatial scale, then decreased somewhat. At the largest spatial scale, losses of dominant and interior forest were 5 and 10%, respectively, of their ca. 1992 amounts. In contrast, patch forest loss increased by only 25% from the smallest to largest spatial scale. These results indicate that continental US forests were sensitive to forest loss because of their already fragmented state. Forest loss would have had to occur in an unlikely spatial pattern in order to avoid the proportionately greater impact on dominant and interior forest at larger spatial scales.     

Tropical deforestation and species endangerment: the role of remote sensing

Initial results of a pilot study to link remotely-sensed information on tropical forest loss to field-based information on species endangerment are reported here. LANDSAT multispectral scanner (MSS) imagery from 1973 and 1988 were used to estimate net forest removal (29% of forest area), regrowth (7% of forest area, including possible artifactual errors), and forest edges in Mabira Forest in southeastern Uganda during the 15-year period. Of the forest remaining, the percentage that was heavily disturbed increased from 18% to 42%. This change in forest density was observable with the MSS imagery. The total forest edge-to-area ratio (including edges interior to the forest boundary) increased by 29% over the period. Although four distinct types of closed tropical forest, based on structure or dominance, could be recognized on the ground, the types could not be distinguished by differences in spectral reflectance in the four MSS bands. Closed tropical forest could be readily distinguished from exotic conifer plantations, banana plantations, and other non-forest vegetation types. Field measurements in Mabira and other Ugandan rain forests, and in rain forest isolates on the Atherton Tableland of North Queensland, are being made to relate changes in forest fragmentation to resulting changes in species abundance, structural form of the forests, and morphological diversity of target populations. Possible applications of conservation biology theory and modeling to these data are briefly discussed.     

Edge and area effects on avian assemblages and insectivory in fragmented native forests

Disentangling the confounded effects of edge and area in fragmented landscapes is a recurrent challenge for landscape ecologists, requiring the use of appropriate study designs. Here, we examined the effects of forest fragment area and plot location at forest edges versus interiors on native and exotic bird assemblages on Banks Peninsula (South Island, New Zealand). We also experimentally measured with plasticine models how forest fragment area and edge versus interior location influenced the intensity of avian insectivory. Bird assemblages were sampled by conducting 15?min point-counts at paired edge and interior plots in 13 forest fragments of increasing size (0.5?C141?ha). Avian insectivory was measured as the rate of insectivorous bird attacks on plasticine models mimicking larvae of a native polyphagous moth. We found significant effects of edge, but not of forest patch area, on species richness, abundance and composition of bird assemblages. Exotic birds were more abundant at forest edges, while neither edge nor area effects were noticeable for native bird richness and abundance. Model predation rates increased with forest fragmentation, both because of higher insectivory in smaller forest patches and at forest edges. Avian predation significantly increased with insectivorous bird richness and foraging bird abundance. We suggest that the coexistence of native and exotic birds in New Zealand mosaic landscapes enhances functional diversity and trait complementation within predatory bird assemblages. This coexistence results in increased avian insectivory in small forest fragments through additive edge and area effects.     

城市森林环境对正负情绪状态影响的Meta分析

明确城市森林环境对正负情绪状态的影响程度及影响因素，为城市森林建设提供科学依据。对Web of Science和CNKI数据库进行检索，对最终纳入的文献采用Meta分析的方法，研究城市森林环境对正负情绪状态的影响。结果表明，纳入的17篇文献中有13项随机对照试验，21项自身前后对照试验，文献质量一般；进入森林对积极情绪影响的总效应量SMD=0.33,I²=33%,95%置信区间Cl[0.23,0.44];进入森林环境对消极情绪影响总效应量SMD=-0.35,I²=0,95%置信区间Cl[-0H46,-0.25];与城市环境相比，处于城市森林对积极情绪状态总效应量SMD=0.59,I²=42%,95%置信区间Cl[0.44,0.75];对消极情绪的影响总效应量SMD=-0.45,I²=0,95%置信区间Cl[-0.61,-0.30],城市森林对积极情绪影响效果的异质性来源主要为心理健康程度和城市森林自然环境。综上所述，城市森林环境对人的心理健康有积极促进效果，进入森林环境后可降低人的消极情绪，心理健康状态和城市森林自然环境影响城市森林对积极情绪的提升效果。     

国家森林公园建设发展情况及其空间格局

为探索国家森林公园建设发展情况并揭示其空间分布规律,本研究采用知识图谱及GIS空间技术对我国国家森林公园的研究进展和空间格局进行了可视化的探索分析.结果 显示:(1)国家森林公园、生态旅游、森林旅游、风景园林、生物多样性、自然保护区、评价、群落结构等是我国森林公园的历史研究热点领域.(2)我国国家森林公园总体呈现东密西疏的空间格局,东北区域及西南区域公园分布较为集中,青海及西藏地区相反.(3)1992-2017年期间国家森林公园的面积得到了更为显著的提升,黑龙江、西藏、新疆、内蒙古4省贡献的面积较多,天津、上海、宁夏、海南4省市对全国国家森林公园建设面积的贡献较小.西部地区国家森林公园的数量有待提升,宁夏、海南2省的国家森林公园总面积有较大理论拓展空间,未来可以加强国家森林公园动态监测评价、森林公园管理制度保障、森林公园建设成效评价、智慧森林公园等方面的研究,以此来推动全国森林公园的全面健康发展.     

Divergent effects of tropical forest fragmentation and conversion on leaf litter decomposition

Context

In tropical landscapes, dominant land-use changes involve conversion of intact forest to an agricultural matrix with embedded fragments of remnant forest. However, most research to date has focused on how these land-use changes affect species within the fragmented ecosystem, rather than the flux of energy and nutrients within these different landscape elements.

Objectives

We examined how forest fragmentation and conversion to orange fields impact the potential for litter decomposition in a Costa Rican landscape, in particular via effects on macroinvertebrates (MIs) and microclimate.

Methods

We measured mass losses of a standard leaf litter in four habitats: orange fields, small forest fragments, large forest fragments and intact forest. Litter bags were constructed of mesh that either excluded or allowed MIs. Decomposition rates were measured in wet and dry seasons, and at different distances from the forest edge.

Results

Forest fragmentation and forest conversion had divergent effects on decomposition rates. Decomposition rates were 7 % slower in forest fragments during the dry season than in intact forest, and this result was mediated by forest fragmentation effects on MIs. Decomposition rates were 9 % higher in orange fields during the wet season, relative to intact forest, and this pattern was explained by effects of the litter microenvironment on leaching rates or smaller invertebrates. Fragment area and distance from forest edge had minor or undetectable effects on decomposition in fragments.

Conclusions

We conclude that land-use changes affect decomposition processes in both forest and agroecosystems, and these effects can vary in mechanism and direction across disturbed landscapes.

     

城市森林绿地空气负离子生态效益评价研究

对长兴县三种功能类型森林绿地空气负离子浓度进行测定,结果表明:城郊森林绿地的空气负离子浓度为1 823个/cm~3,城区公共绿地为1 296个/cm~3,单位、居住区绿地为958个/cm~3;在森林植物生长期间,空气负离子浓度从城区向城郊呈增加趋势;在郊区以高大乔木为主的近自然林,空气负离子浓度高,生态效应明显。综合上述分析,本文提出应按照近自然森林群落建设理念,推广种植乡土树种、乔木树种,营造城区核心林地,改善城市生态环境,提高城镇居民的生活品质。