Factors driving natural regeneration beneath a planted urban forest

Cities around the world are investing in urban forest plantings as a form of green infrastructure. The aim is that these plantations will develop into naturally-regenerating native forest stands. However, woody plant recruitment is often cited as the most limiting factor to creating self-sustaining urban forests. As such, there is interest in site treatments that promote recruitment of native woody species and simultaneously suppress woody non-native recruitment. We tested how three, common site treatments—compost, nurse shrubs, and tree species composition (six-species vs. two-species)—affected woody plant recruitment in 54 experimental plots beneath a large-scale tree planting within a high-traffic urban park. We identified naturally regenerating seedling and sapling species and measured their abundance six-years after the site was planted. This enabled us to examine initial recruitment dynamics (i.e. seedlings) and gain a better understanding of seedling success as they transition to the midstory (i.e. saplings). Seedling and sapling recruitment (native and total) was greater in areas with higher canopy cover. The combination of the nurse shrub treatment with compost and species composition (six-species) treatments increased seedling recruitment by 47% and 156%, respectively; however, the nurse shrub treatment by itself decreased seedling recruitment by 5% and native seedling recruitment by 35%. The compost treatment alone had no effect on the total number of recruits but resulted in 76% more non-native seedlings. The sizes of these treatment effects were strongly dependent on whether the forest plantings were in open areas, versus areas with existing tree canopy, the latter condition facilitating recruitment. Our findings therefore suggest that combinations of site treatments, paired with broad canopy tree species, may be most effective for promoting regeneration of native species resulting in more self-sustaining urban forests.     

Public perceptions of ecosystem services and preferences for design scenarios of the flooded bank along the Three Gorges Reservoir: Implications for sustainable management of novel ecosystems

The newly formed extensive flooded land associated with the Three Gorges Reservoir hold great potentials to provide ecosystem services (ESs) for surrounding cities and communities. Conflicting values and conventional management strategies may complicate and inhibit broad-scale decision-making for this novel ecosystem. Public attitudes are a crucial influence in the way this process plays out. This study was conducted to assess how the reservoir bank is perceived by the general public of Chongqing Municipality in terms of importance of riparian ESs, and preference for corresponding landscape design styles through photo-questionnaire interviewing. Although Chongqing citizens know little of the “ecosystem services” concept, they do recognise riparian environmental and ecological benefits especially the bank protection and pollution interception functions, while benefits of habitats for wildlife and flood attenuation were of less concern. Recreational values were least appreciated, which is inconsistent with other studies. This may be attributed to a wider, intensive environmental education in various social media in today’s China. But publicity has been dominated by toxic air, water and soil pollution control rather than the benefits of nature conservation and personal contact with nature. In line with recognition of ESs, there is quite strong preference for the forested design scenario and particularly vegetation components across the socio-demographic spectrum. Overall, socio-demographic variables have very low explanatory power for the perceptual responses. Our study also revealed misunderstandings around riparian functions and a gap between public expectations and special abiotic and biotic prerequisites in restoring novel ecosystems. Finally, we discuss the relevance of this research to urban novel ecosystems in general, and implications for raising public awareness, engaging appropriate public values in sustainable design and management of such ecosystems.     

资源型城市城镇化发展对我国城镇化水平的贡献性

为定量研究资源型城市城镇化水平及其对中国城镇化发展的贡献性,以全国126个地级市(仅限大陆地区)资源型城市为研究对象,分析改革开放以来资源型城市城镇化发展的基本情况,并籍此为基础研究资源型城市城镇化发展对我国城镇化发展的贡献。结果表明:1)四大区域资源型城市城镇化水平发展不平衡,东北地区城镇化率始终保持领先,但增长幅度最小,东部地区城镇化率增长最快,各地区年均增长率呈下降趋势,增速放缓;2)地级市资源型城市城镇化发展对我国城镇化发展的贡献度为0.48～0.90,其中0.79%资源型城市城镇化对我国城镇化贡献度为中,40.48%资源型城市城镇化对中国城镇化贡献度较高,58.73%资源型城市城镇化对我国城镇化贡献度高;3)类型上,均有超过各自总量50%的非金属、金属、煤炭和油气型资源型城市城镇化对我国城镇化的贡献度高,而森工型资源型城市城镇化对我国城镇化贡献度高的城市数量不到其总量的1/3;空间上,东和中部地区资源型城市城镇化对我国城镇化发展贡献度大于东北地区和西部地区。资源型城市城镇化推动了我国城镇化发展,但资源型城市的不同类型和区位,对我国城镇化的贡献度有差异。     

我国农业机械的推广与对策研究

新时期下，由于我国宣传推广的力度不够、当地基层群众综合素养不高、机械使用不当等原 因并没有形成使用农业机械进行耕作的习惯，在我国西南部、东南部等丘陵地带，仍然采用牛拉车等 较为落后的耕作方式，从而导致农业机械化带来的提高种植效率，本文目重点就我国的农业机械推广 存在的问题进行概述，并提出相关对策。     

呼和浩特市大气污染状况的研究及遥感信息的利用

利用遥感技术结合地物波谱测定和叶表面内大气污染元素的含量测定分析研究大气污染是一种有效可靠的方法。克服了常规大气监测的弊病。充分显示了快速、准确的优越性。为城市规划和环境的综合治理提供了可靠的科学依据。     

恩施山地扭叶松的幼树期引种成效

用产于加拿大9个种源的扭叶松种子育苗,在湖北恩施的建始县国有高岩子林场的十字坪、姚家坡进行了扭叶松不同种源地、不同种源的植苗造林试验。其幼树期的试验结果表明:扭叶松能适应两地的环境条件,植苗造林成活率及保存率达91.3%~100%;对14年生的试验林进行高、径生长分析,扭叶松的树高生长和胸径生长受种源、造林地点的影响极显著;种源与造林地点对树高生长的交互作用极显著。进一步对树高进行单点分析,参试的9个种源,在十字坪试点,10577、26230、25730、27084、28476、14726、26153七个种源的树高生长极显著高于25801、25803两个种源,且7个种源两两间差异不显著;姚家坡试点10577种源的树高生长极显著高于其他种源,其下依次是28476、26153、26730、27084、14726五个种源。胸径生长在种源间的极显著差异缘于10577种源与25803、25801种源间的差异,其他任意两种源间的胸径生长差异不显著。     

广东山区开发的理论与实践：—广东山区开发理论与实践研讨会综述

本文述了“广东山区开发理论与实践研讨会”所达成共识的观点：广东山区开发具有重要的战略意义，广东山区开发必须走可持续肆展，农业产业化经营、工业化道路，同时必须搞好基础设施建设，组织好商品流通工作，优化资源配置。     

镜台山公园总体规划构思

通过介绍宁德市镜台山公园总体规划构思 ,论述在城市公园的规划中应遵循以人为本、尊重自然、尊重历史的规划方向 ;结合具有特色的自然山水、人文景观 ,运用各种造园方法 ,形成有序空间 ,实现生态、宗教、文化、娱乐、健身、休闲为一体的综合性功能和环境效益、社会效益、经济效益相统一的目标     

开发城市地下空间前景广阔

本文介绍了开发城市地下空间的必然趋势及前景，阐明开发利用城市地下空间，对节省城市用地、节约能源、改善城市交通、减轻城市污染等都有着重要作用。     

2004年冬成都市外来园林植物冻害调查及建议

作者2005年春调查了成都市外来园林植物冻害情况,发现：（1）外来园林植物受冻害影响较为普遍,41种植物在不同程度上受害;（2）冻害影响存在区域差异,郊区冻害比城区严重.分析了冻害原因,并对园林植物引种提出建议.