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This paper discusses determinants of the historical and current spatial extent of the floodplain forest in Leipzig as well as its tree species composition using a GIS-data based delineation model and historical forest inventories for the floodplain forest in the district of Leipzig in Germany from the 19th to the 20th century. We found that the spatial extent of the floodplain forest remained considerably stable in spite of an overall decline in the entire floodplain area from the period where the city first experienced industrialisation in the 19th century to now. However, with river regulations and the alteration of forest management from coppice-with-standards forest to high forest in the 19th century, major changes can be found in the tree species composition of the floodplain forest. Comparing these findings with references from other European floodplain forests we discuss the impact of historical and current forest management as well as the city location's influence on the extent and tree species composition of urban floodplain forests. For urban forest management in particular there is a great need to integrate biophysical, historical and forestry knowledge when predicting future developmental trends. 相似文献
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Mikko Vehmas Kalle Eerikäinen Jussi Peuhkurinen Petteri Packalén Matti Maltamo 《Forest Ecology and Management》2009
Boreal forest stands with high herbaceous plant species diversity have been found to be one of the main habitats for many endangered species, but the locations and sizes of these herb-rich forest stands are not well known in many areas. Better identification of the stands could improve both their conservation and management. A new approach is proposed here for locating the mature herb-rich forest stands using airborne laser scanner (ALS) data and logistic regression, or the k-NN classifier. We show that ALS technology is capable of distinguishing the ecologically important herb-rich forests from those growing on less fertile site types, mainly on the basis of unique but quantifiable crown structure and vertical profile that characterise forests on high fertility sites. The study site, Koli National Park, is located on the border of the southern and middle boreal vegetation zones in Finland, and includes 63 herb-rich forest stands of varying sizes. The model and test data comprised 274 forest stands belonging to five forest site types varying from very fertile to poor. The best overall classification accuracy achieved with the k-NN method was 88.9%, the herb-rich forests being classified correctly in 65.0% of cases and the other forest site types in 95.7%. The best overall classification accuracy achieved with logistic regression was 85.6%, being 55.0% for the herb-rich forests and 94.3% for the other forest site types. Both methods demonstrated promising potential for separating herb-rich forests from other forest site types, although slightly better results were obtained with the non-parametric k-NN method, which was capable of utilising a higher number of explanatory variables. It is concluded that ALS-based data analysis techniques are applicable to the detection of mature boreal herb-rich forests in large-scale forest inventories. 相似文献
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Effects of multiple factors on plant diversity of forest fragments in intensive farmland of Northern Portugal 总被引：1，自引：0，他引：1
Angela Lomba Joana Vicente Francisco MoreiraJoão Honrado 《Forest Ecology and Management》2011,262(12):2219-2228
The joint and independent effects of dominant tree species, forest patch spatial attributes, and forest structure and management as drivers of plant species richness and composition in small forest patches scattered within an intensive agricultural landscape were addressed.In a landscape with scattered urban and intensive dairy agricultural areas in north-west Portugal, within which small forest patches (dominated by pines, eucalypts, or both) represent semi-natural habitat islands, 50 small forest patches, with areas ranging between 0.3 and 3 ha, were selected and surveyed for vascular plant diversity, within dairy farming landscape mosaics dominated by annual forage crops. Explanatory variables were composed of three datasets derived either from GIS mapping or field observations: forest type (dominant tree species), forest patch spatial attributes (patch area and shape index), and measures of forest management and structure (diameter at breast height, tree density per hectare, and percentage cover of vegetation strata). Variations in these forest patch attributes were assessed across forest types, and related to measures of plant diversity (total, native, alien, woody, and herbaceous species richness). Redundancy analysis with variance partitioning was applied to evaluate the joint and independent effects of the three sets of variables on species assemblages. The recent shift in canopy dominance from pine to eucalypt observed in the region appears to be related to a (nonsignificant) tendency for the increase of patch area and to the decrease of patch complexity, as well as several changes in forest structure and management, expressed as a trend to denser tree canopies and lower cover of understory plants. Dominant tree species and attributes related to forest structure and management were the most important factors determining plant diversity. The joint effect of the dominant tree species and forest structure and management resulted in lower levels of plant species richness in eucalypt plantations. These were also more prone to invasion by alien species, probably due to decreased biotic resistance from unsaturated native plant assemblages. Our results draw attention to the importance of dominant tree species and management practices for the maintenance of plant diversity levels (species richness and composition) in dairy landscape mosaics, highlighting the importance of the remnants of semi-natural forests as refuges for plant diversity in the landscape context. Nonetheless, forest plant diversity could further be fostered by promoting naturalness of pine stands and the regeneration of native oak woodlands in some forest areas. This would also diversify the range of ecosystem services that could be provided by forest areas in these peri-urban farmlands. 相似文献
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竹林区竹类种质保育需要建立避免人为干扰的竹类自然生态系统,但现有的竹林粗放遍及各处的经营策略则直接威胁到竹类种质栖息地的保护。通过对蜀南竹海人工经营和未经营下楠竹林群落环境与种群结构的对比分析,认为保护区内楠竹林经营强度改变了植物群落结构,导致植物物种多样性的丧失,地表灌木、草本和凋落物的盖度降低,生物量减少;考虑天然楠竹林结构演替,楠竹的人工经营(纯林经营)是维持楠竹林生产力和楠竹林的必然途径。基于现代林业理论,提出了县域楠竹林适度经营与保护的空间分工性、集约化策略,以期获得保护区长期的生态经济社会效益与生态安全屏障的优化格局。 相似文献
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Much research effort is being devoted to developing forest management practices with limited impacts on biodiversity. While the impact of poplar Populus sp. plantations on biodiversity is relatively well-known at the landscape scale, the impact of alternative management practices at the plantation scale has received much less attention. Yet biodiversity is likely to be impacted by the choice of the poplar clone, stem density at plantation, type and duration of the understory control, and age at which the poplars are harvested. In this study, we investigated the impact of these factors on herbaceous plant communities with data from plant surveys conducted in 85 young (2–5 years) and 96 mature (11–17 years) hybrid poplar high-forest plantations in northern France. On average, ruderal or generalist plants contributed to 40.5% of the plot species richness; tall herbs (60.2%), forest (26%) and meadow plants (13.8%) contributed to the remaining 59.5% more specialised species. Soil moisture and soil nitrogen were major determinants of plant communities: wet soils were favourable to tall herbs, while meadow and forest species preferred moist soils; a significantly lower diversity of the three species groups was reported in the nutrient richer soils (in mature plantations only for forest plants). Mean species richness decreased with plantation age except for forest species. Plant communities in young plantations showed little differences in composition according to the type of understory control (chemical, mechanical or both). The development of a shrubby layer in mature plantations was restricted to the drier soils and was detrimental to both meadow plants and tall herb species. Effects of previous land use on forest and tall herb species were found only in young plantations, suggesting a rapid reset of plant communities for these two groups. This may not be the case for meadow species as the influence of previous land use was significant in mature plantations only. Finally, clone type and stem density at plantation had no significant impact on plant communities. Adjusting age at which the poplars are harvested seems the only effective way to drive plant communities in high-forest poplar plantations: delaying poplar harvest (probably beyond 15–20 years) would benefit forest plants, while advancing poplar harvest (about 10 years) would benefit tall herbs, especially in wet soil conditions. 相似文献
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Explaining gender differences in private forest risk management 总被引：1，自引：0，他引：1
Louise Eriksson 《Scandinavian Journal of Forest Research》2018,33(7):716-723
In many countries, lower levels of forest management activities have been observed among female forest owners compared to male owners. The present study examined potential explanations for gender differences in private forest risk management among forest owners in Sweden (n?=?1482) using a questionnaire. Results from this study confirmed a slightly lower level of forest risk management among female owners in proactively combating damage caused by climate change and animal browsing when compared to their male counterparts. Further gender differences were revealed on a structural level. For example, female owners displayed higher levels of education and were more often non-resident owners and urban owners, as compared to their male counterparts. In addition, female and male owners differed regarding social-psychological variables (e.g. forest values and threat and coping appraisals). However the greatest gender difference was found in involvement in forest planning and forestry work. Even though gender differences were evident on multiple levels, involvement in forest issues and forest planning were found to be most important for explaining gender differences in forest risk management. By disentangling predictors of gender differences in private forest risk management, this study may contribute to a more strategic gender approach to forest risk governance. 相似文献
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John C. Adams Kenneth W. Farrish Joshua P. Adams 《Journal of Sustainable Forestry》2013,32(4):406-421
Minor stream bottoms (alluvial floodplains) in the southeastern United States contain large areas of hardwood forests which are a potential sink for upstream nutrients. As a sink, they serve an important role in reducing the loss of nutrients from the sites via the watershed. However, little is known about nutrients stored in forest litter that have the potential to be cycled back to the forest or lost through removal from the site. Three hardwood stands of varying management regimens that span common scenarios found in north Louisiana were sampled for nutrient concentration and quantity in falling litter including leaf, woody, and other debris. Across sites, the well-drained site constitutively contributed more nutrients in litter than the poorly drained sites. Also, the sampling time spanning from March to October had the most litter fall and subsequent nutrient discharge from the trees. Of the five nutrients measured, nitrogen was the largest component followed by potassium. These features in nutrient quantity have broad implications for nutrient management based on site and timing of timber removal. This study provides novel nutrient levels in litter fall of hardwood forests typical along minor stream bottoms. 相似文献
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文章通过调查石嘴山市城市绿化现状和园林植物种类,立足石嘴山的市情、林情和立地环境条件特点,对石嘴山市创建"显山、露水、透绿、通畅"的山水园林城市的营林技术进行了一些探讨。
相似文献
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Laima Česonienė Remigijus Daubaras Vytautas Tamutis Vilma Kaškonienė Paulius Kaškonas Vidas Stakėnas 《Journal of Sustainable Forestry》2013,32(8):791-808
Currently, the aim of modern forest management is not only timber production but also the protection of biodiversity. The initial effects of clear-cut logging on forest understory vegetation, soil and the diversity of litter beetles have been studied. We examined unstudied effects of clear-cutting disturbance on understory vascular plant species abundance, forest soils, and understory vegetation nutrients as well as beetle diversity one year after clear-cutting. Substantial changes in the prominence values and above-ground mass of forest-related vascular plant and moss species were detected. Clear-cuttings resulted in fast appearance of new light-loving plant species. The significant decrease in understory plant biomass influenced the reduction of nutrient pools in clear-cut areas after one year. The clear-cut logging negatively influenced the richness of species and the number of individuals of stenobiontic forest-related beetles in the forest litter. However, forest clear-cuttings were beneficial for eurytopic and open land species. 相似文献
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数字图像模式识别技术在植物叶片识别中的应用 总被引：1，自引：0，他引：1
植物分类鉴别是森林资源及林下中药资源清查和保护工作的基础, 但现在植物的鉴别主要依靠人为进行, 效率低、主观性强, 且专业人才较少。随着数字信息化技术的发展, 构建计算机化的植物模式识别体系已经成为植物鉴别过程中强有力的工具,可为植物学的定种工作提供便捷、准确的保障。文中从叶片特征选择、常用叶片识别方法及图像识别在手机系统上的应用3个方面综述了叶片模式识别的相关研究成果,并探讨了利用计算机视觉辅助植物分类方面的问题和展望,以期为数字图像模式识别技术在植物叶片识别中的应用和进一步研究提供参考。 相似文献
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The tree structure and regeneration was studied in the buffer zone area comprising lowland evergreen and semi-evergreen forests in the Namdapha National Park, one of the largest remaining tract of pristine rainforests in the Eastern Himalayan biodiversity hotspot in India. The investigations were conducted in the three forest stands, viz. Altingia-mixed species, Shorea-Dipterocarp, and Albizia forests that are most dominant forest types in the lowland areas of the park. A total of 98, 54 and 20 species have been recorded at tree stratrum, while 87, 44 and 15 species at regeneration stratum for three stands, respectively. The cumulative regenerating density (seedlings + saplings) was estimated 17,648, 16,110 and 768 individual ha−1 for respective stands. It was interesting to note that of the total regenerating species, 44–47% species were new to different stands, which mainly comprised middle storey species. Low-dominant and rare species also contributed significantly in the regeneration of the forest stands. The expanding population structure of forest stands indicated higher survival of the mid- and the low-canopy species than the top-canopy species. The data revealed that the future composition of these stands will highly depended on the potential regenerative status of species in each of the stand and such information would be crucial for forest management. Since the park contributed significantly to the regional biodiversity by depicting species assemblages for both wet evergreen and semi-evergreen biomes, such last remnants of rainforest should be integrally protected from anthropogenic disturbances. 相似文献
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Considering the pressures on tropical forests from deforestation and the recent expansion of harvesting through forest concessions in the Brazilian Amazon, it is imperative that forest management systems are scrutinized to ensure sustainability. One of the basic problems in forest management is the correct identification of species within the forest stand. While this is a well known issue, little consideration is given to how to mitigate this problem or its affects on management practices and conservation. This paper examines the current practice of forest inventories in the Brazilian Amazon, as part of the mandatory system of reduced impact logging (RIL), using extensive forest inventory verification. The results show that the RIL management plan implemented in the project area was based on a highly inaccurate forest inventory. At least 132 species or 43.5% of all species identified after botanical checking did not appear in the forest inventory and the common practice of matching vernacular names to scientific ones proved to be severely deficient. In contrast, a high percentage of field identifications based on local people's expertise were correct. We suggest changes to current practices, including the training and use of parataxonomists, the collection of samples for verification, and stricter government control over current practices, which will achieve greater accuracy in data collection and forest management planning. Ultimately, we argue that in the current climate of extensive deforestation and forest use, it is essential that all aspects of RIL systems are reevaluated in order to achieve economic and ecological sustainability. 相似文献
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将森林植物耐污能力划分出4个等级,并依此对闽南地区8个排污1~11 a的养猪场蓄污池、排污沟周边植被进行调查,初步筛选出Ⅰ级耐污植物10种,其中木本1种;Ⅱ级耐污植物有29种,其中木本18种;Ⅲ级耐污植物15种,其中木本5种;Ⅳ级耐污植物1种,其中木本1种.调查结果为闽南地区利用森林生态系统治理养殖污水、试行林畜复合经营提供了参考.本文还简述了森林生态系统具有根系庞大、生长量高、生长周期长、结构复杂、能自行演替、可以更多更长时间更稳定吸收养猪污染物的特点,提出在选择生态治污树种时应首选速生树种、常绿树种、阔叶树种的观点. 相似文献
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高黎贡山自然保护区森林资源丰富,动植物种类繁多,其物种多样性的丰富程度为国内外罕见。由于周边社区集体森林破坏严重,使保护区受到周围村社的"蚕食",给高黎贡山的森林资源管理和生物多样性保护工作带来了巨大的压力。在对村社集体林地的管理与高黎贡山生物多样性保护相关性论述的基础上,提出加强对乡村集体森林的管理,发展社区林业,实行"以林养林",即以发展集体林来保护国有林、保护区,使社区林业的发展既为当地农户提供日常生产、生活和经济发展所需要的非木材林产品、薪材及木材,又为保护区构筑一道以集体林为主的绿色屏障,以实现自然保护区森林资源管理、生物多样性保护和周围农村经济的协调发展。 相似文献
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上海城市"近自然森林"建设的尝试 总被引：15，自引：11，他引：15
这是一个借鉴日本经验,结合上海实际的小试。选择了上海11个乡土树种,面积为3000m2,经过3年的生长,最大植株高度达4.6m,已经初步展现景观效果,预计10~20年可形成近自然森林。 相似文献