广州城市广场建设随谈

初步的分析与研究了广州市城市广场建设的体系、文化、功能及环境,总结存在的问题,提出相关建议。     

Forest road design with soil sediment evaluation using a high-resolution DEM

In this study, we combined a program to optimize forest road alignments with a method for prediction of surface erosion and related sediment delivered to streams. Combining the forest road design program with the high-resolution digital elevation model made it possible to estimate soil sediment based on a standard methodology, because a relatively accurate road prism could be generated. The combined program properly places and spaces drainage structures based on the Washington State Forest practice board manual. We applied the program to a part of Capitol State Forest in Washington State and optimized horizontal and vertical alignments while estimating movement of soil sediment from roads to streams. We discussed the effects of road surface materials, near-stream culvert distance to stream, and out-sloped forest road template on total road costs and soil sediment delivered to streams. Using lower quality rock surfacing reduced total costs, but the amount of soil sediment from lower quality rock surfacing was 1.5 times more than that on a higher quality rock traction surface. Therefore, lower quality rock surfacing should not be used near the stream. The placement of near-stream culverts 15 m upstream and out-sloped road template were examined using a traction surface on 15-m sections upstream and lower quality rock surfacing on other sections in order to reduce soil sediments to the stream and total costs. As a result, placing near-stream culverts 15 m upstream and using an out-sloped road template significantly reduced total road cost and soil sediment. Finally, we optimized horizontal and vertical alignments while limiting soil sediment to a specified maximum level. The model successfully optimized forest road alignments, which reduced total road cost as well as soil sediment.     

德州市区园林树木调查及评价

德州市区园林树木调查及分析表明,德州市园林树木少,共45科145种,不能满足城市绿地类型多样性要求及植物多样性的要求,城区绿化存在注重视觉效果,忽视改善环境质量的生态功能,对此提出建议。     

园林绿化对降低城市热岛效应的作用

城市热岛效应作为现代城市气候的主要特征之一,目前在大部分地区城市有日渐严重的趋势.基于当前城市热岛研究现状,根据城市园林绿化植物生态作用的有关原理,结合长沙市城市中心区与城市郊区两地的气候测量数据,选取城市典型地段的绿地小气候进行实测分析.结果表明:城市园林绿化可从根本上大大改善城市下垫面热力学特性,是有效改善城市热岛效应的重要措施之一;合理的绿化结构和植被类型,能使城市园林绿化充分发挥其综合效益.     

浅论景观生态学在城市绿地系统规划中的初步应用

简单介绍了景观生态学并初步论述其在城市绿地系统规划中的应用。     

浅谈惠州市东征主题公园规划设计

以惠州市东征主题公园规划设计为实例,初探城市旧公园的景观重塑,尊重历史和人文特色,突出纪念性的文化主题,重视对文物和历史遗址的保护,建设具有鲜明特色和主题的公园,推进惠州市历史文化名城的建设步伐,提升城市文化品味。     

广州市城市森林体系规划建设探讨

针对广州市林分质量差、林种结构不合理和龄组比例不协调等城市森林现状,阐述了广州市城市森林体系规划建设的基本原则和目标,构建了广州市内环、中环和外环分项规划框架,重点讨论了市域林带(包括主干道绿化带、市域生态廊道、市域滨水林带)和城市林区(包括生态景观林区、水源涵养林区、商品林区)、城区花园式单位、自然保护区与野生动物栖息地等重点项目的规划建设问题.     

论城市林业的生态经济特征与产业发展对策

城市林业建设能为城市提供多方面的社会经济效益 ,其空间区域特性有利于发展广泛的公众参与 ,形成发展现代林业所要求的社会基础。发展城市林业有利于推动现代林业理论与实践的发展 ,有利于现代林业产业体系的培育及科技创新。从资源利用与产业化发展方向等方面探讨了我国现代城市林业的产业发展对策。     

Tabu search optimization of horizontal and vertical alignments of forest roads

This article describes a program for optimizing horizontal and vertical alignments of forest roads using Tabu search, a modern heuristic technique. Once a series of intersection points (IPs) is selected manually, the program generates alternative horizontal and vertical alignments. The program precisely generates ground profile and cross sections using a high-resolution digital elevation model (DEM) derived from light detection and ranging (LiDAR) data. It accurately calculates earthwork volumes for curved roadways using the Pappus-based method. The program also estimates construction and maintenance costs. Tabu search optimizes forest road alignments based on the total costs. The application of the program to part of Capitol State Forest in Washington State, USA, indicated that the program successfully found better alignments than manually selected initial alignments. The effect of initial solutions and the number of iterations on the Tabu search process was examined. The result showed that the solutions were improved using the best solutions with the smaller number of grade change points as the initial solutions. It also showed that a small number of iterations could be used to reduce computation time due to the fact that Tabu search is based on a gradient search technique. Finally, the Dijkstra method was examined to find initial solutions without manually initialized solutions. The program, when combined with the Dijkstra method, could find similar-quality solutions from manually initialized solutions. The program will become useful with further tests and verifications.     

Assessing and Managing Soil Quality for Urban Agriculture in a Degraded Vacant Lot Soil

Following the decline of industrial manufacturing, many US cities have experienced severe population reductions that have resulted in large areas of vacant land. Urban agriculture has emerged as a desirable land use for these spaces, but degraded soils are common. Therefore, we measured soil and plant responses to amendments and management in urban lots where vacant houses had recently been demolished in Youngstown, OH, USA. Soil degradation was observed following demolition activities in the form of compaction (bulk density of 1·5–1·8 Mg m⁻³) and low soil microbial biomass C (21 mg C kg⁻¹ soil). Our split‐plot experiment measured the effects of organic matter (OM) amendments produced from yard wastes and the use of raised beds on soil properties and vegetable crop yields. Two years after their application, OM amendments resulted in significant improvement to a number of soil physical, chemical, and biological properties. Vegetable crop yields were improved by OM amendments in 2011 and by both OM amendments and the use of raised beds in 2012. A soil quality index, developed using factor analysis and the Soil Management Assessment Framework, produced values ranging from 0·60 to 0·85, which are comparable to those reported for rural agricultural soils. All results indicate that urban agriculture can be productive in vacant urban land and that amendments produced from urban yard wastes can improve soil quality at previously degraded sites and increase crop yields for urban agriculture. Copyright © 2015 John Wiley & Sons, Ltd.