The perceived scenic effects of clearcutting in the White Mountains of New Hampshire, USA

The scenic effects of clearcutting have been a volatile issue for the American public for much of the past century. A better understanding of the scenic perceptions associated with the cumulative visible effects of clearcutting should contribute to better decisions about its use. This study evaluates the scenic impacts of simulated alternative clearcutting management systems for the White Mountain National Forest. Alternatives represented an unharvested view, and views with removal of 1–5% of the timber every 12 years using either scattered or concentrated clearcut units of 5, 15 and 30 acres in two viewsheds. A random sample of local citizens, four groups of opinion leaders, and US Forest Service employees evaluated these alternatives. Each factor accounts for significant differences in scenic value. All groups rated the scenic value of unharvested scenes very high. All groups find a large drop in scenic value with the introduction of even the least intense harvesting activity. All groups indicated a statistically significant decrease in visual quality as the intensity of harvesting increases. This effect continues throughout the range of harvesting intensities until the level of sustainable yield is reached. In addition, patches 12–15 acres in size were preferred to larger and smaller ones.     

括苍山淡竹森林公园旅游资源特征及开发设想

淡竹森林公园地处括苍山脉中部,保存有括苍山脉最好、最完整的常绿阔叶林,是浙中和浙东沿海区域原生性最强的原始次生森林。在系统调查的基础上,分析得出淡竹森林公园旅游资源的6大特点——风景资源品味较高,天然常绿阔叶林景观较典型,水体景观多姿多彩,山体和岩体景观奇妙,森林环境优异,山区风情较淳厚;提出了淡竹森林公园旅游开发的5条基本思路,即依法开发、保护为先,体现特色与周边景区互补相结合,突出重点与循序发展相结合,旅游产品应以自然性休闲型为主导,塑造主题旅游形象,强化宣传促销。     

Measuring individuals’ valuation distributions using a stochastic payment card approach: application to solid waste management in Nigeria

The objectives of this study are twofold. First it aims to establish empirical grounds for pricing the services of a new environmental management initiative in Enugu state, Nigeria. A joint initiative of the UK Department for International Development (DfID), Enugu State Environmental Protection Agency (ENSEPA) and the State and Local Government Programme (SLGP). The second is to test the empirical performance of a new approach to the contingent valuation method (CVM) i.e., the Stochastic Payment Card (SPC) design proposed by Wang (Contingent valuation of environmental resources: A stochastic perspective, 1997a, Journal of Environmental Economics & Management, 32:219–232, 1997b). The SPC design unlike many of the conventional CVM elicitation formats, takes into account the stochastic nature of individuals’ valuation decisions. The data for the analysis were obtained from a random sample survey of a district in Enugu metropolis. The results show that, on average, households in this city are willing to pay (WTP) 215 Naira ($1.6) monthly as against 200 Naira ($1.5) currently charged for the service by ENSEPA. Analysis of individual’s valuation distribution function indicates that this amount is positively and significantly related to the gender of the respondent, household income and the respondent’s perception of environmental quality.

潮汐河网水环境随机容量研究

根据潮汐河网水环境模型中水文及水质参数具有明显随机性的特点,本文建立了潮汐河网水环境随机模型,给出了随机参数的分布函数形式。用Monte-Carlo随机抽样法求解水项模型 当只抽一个样本时,随机模型的算法与确定性模型的算法一样。计算结果为水环境容量的分布函数,容量结果与保证率成一一对应关系。最后还对随机参数的分布函数形成进行了敏感性讨论。      

氯化钾交换—中和滴定法测定森林土壤交换性酸的研究

用Ⅰｍｏｌ／Ｌ氯化钾交换－中和滴定法测定森林土壤交换性酸含量时，氯化钾淋洗液淋洗土壤时间建议定在５０ｍｉｎ左右，且用中速滤纸过滤淋洗液。     

Emission patterns of biogenic volatile organic compounds from dominant forest species in Beijing, China

Biogenic volatile organic compounds (BVOCs) have significant effects on atmospheric chemistry, ozone formation and secondary organic aerosol formation. Considering few investigations about BOVCs emissions in north China where is facing serious air pollution in recent years, emissions of various BVOCs from 24 dominant forest species in Beijing were measured from June to September in 2018, using a dynamic headspace sampling method. More than one hundred BVOCs in the collected samples were identified by using an automatic thermal desorption-gas chromatography/mass spectrometry, and their emission rates based on leaf biomass were calculated. Isoprene and monoterpenes were verified to be the dominant BVOCs emitted from the tree species, accounting for more than 50% of the total BVOCs. Generally, broad-leaved species displayed high isoprene emission rates, especially the Platanus occidentalis (21.36 µg/(g?hr)), Robinia pseudoacacia (11.55 µg/(g?hr)), and Lonicera maackii (9.17 µg/(g?hr)), while coniferous species emitted high rates of monoterpenes, such as Platycladus orientalis (27.18 µg/(g?hr)), Pinus griffithii (23.11 µg/(g?hr)), and Pinus armandii (7.42 µg/(g?hr)). High emission rates of monoterpenes from the broad-leaved species of Buxus megistophylla (13.07 µg/(g?hr)) and Ligustrum vicaryi (5.74 µg/(g?hr)), and high isoprene emission rate from the coniferous tree of Taxus cuspidata (5.86 µg/(g?hr)) were also observed. The emission rates of sesquiterpenes from each tree were usually 10–100 times smaller than those of isoprene and monoterpenes. Additionally, relatively high emission rates of oxygenated volatile organic compounds and other alkenes than isoprene and monoterpenes were also found for several tree species.     

China’s Classification-Based Forest Management: Procedures,Problems, and Prospects

China’s new Classification-Based Forest Management (CFM) is a two-class system, including Commodity Forest (CoF) and Ecological Welfare Forest (EWF) lands, so named according to differences in their distinct functions and services. The purposes of CFM are to improve forestry economic systems, strengthen resource management in a market economy, ease the conflicts between wood demands and public welfare, and meet the diversified needs for forest services in China. The formative process of China’s CFM has involved a series of trials and revisions. China’s central government accelerated the reform of CFM in the year 2000 and completed the final version in 2003. CFM was implemented at the provincial level with the aid of subsidies from the central government. About a quarter of the forestland in China was approved as National EWF lands by the State Forestry Administration in 2006 and 2007. Logging is prohibited on National EWF lands, and their landowners or managers receive subsidies of about 70 RMB (US$10) per hectare from the central government. CFM represents a new forestry strategy in China and its implementation inevitably faces challenges in promoting the understanding of forest ecological services, generalizing nationwide criteria for identifying EWF and CoF lands, setting up forest-specific compensation mechanisms for ecological benefits, enhancing the knowledge of administrators and the general public about CFM, and sustaining EWF lands under China’s current forestland tenure system. CFM does, however, offer a viable pathway toward sustainable forest management in China.     

森林生态系统在碳循环中的作用

描述了森林生态系统的碳循环及其在全球碳循环中的作用，说明了森林生态系统在碳循环中的作用主要取决于森林生态系统的生物量、林产品、植物枯枝落叶和根系碎屑以及森林土壤。最后，阐明了中国森林生态系统碳循环的研究现状和趋势。