CVM评价森林景区游憩价值的理论效度——以福州国家森林公园为例

【目的】以福州国家森林公园为例,检验CVM评价森林景区游憩价值的理论效度,为CVM评估中国森林景区游憩价值的适用性提供有效证据与调研方案。【方法】在有效性改进的基础上,运用多种回归模型对CVM评价森林景区的理论效度进行详细探讨。【结果】1)福州国家森林公园每年人均游憩价值为37.930元,总游憩价值为18 016.750万元,由于森林景区游憩价值构成相对单一,福州国家森林公园的游憩价值明显低于大型风景名胜区。2)CVM评价森林景区的理论效度良好,检验结果与经济学理论基本一致,且可以在现实生活中给予合理解释。无论剔除样本选择偏差时的支付意愿还是全样本的支付金额均受到收入水平的约束;由于存在奉承偏差,游客的支付金额比支付意愿更容易受到游客和评价对象特征的约束。城市居民相对于农村居民来说,较高的生活水平使得城市居民有较多的可供选择的高质量游憩替代品,导致对森林公园的支付意愿和支付水平较低。政府及事业单位人员的边际支付意愿表现最为强烈,同时边际支付金额也处于最高值,可能是最为真实支付意愿。退休人员由于受到收入限制,其边际支付意愿和支付金额相对其他人员均为负数;游客距离森林公园越远,对森林公园的支付意愿和支付金额越低。【结论】从理论效度来说,在有效性改进的基础上,可以将CVM引入到森林景区游憩价值评估中,但CVM其他效度的评价标准也应该充分考虑。     

北京市高保护价值森林价值评估理论与方法初探

结合现行经济学理论界对森林价值的评估，针对高保护价值森林的特征，从生物多样性和生态服务功能两方面对北京市高保护价值森林的价值评估方法进行探讨。结合效用论、边际效益论等理论，根据实地情况，运用支付意愿法、补偿法、替代法等，从森林的实用价值和精神文化价值等方面作了评估方法概述。     

外生激励和价值认同对农户持续参与森林碳汇项目意愿的影响

【目的】森林碳汇减排量是国家碳市场的重要组成部分,农户作为森林碳汇项目的执行者和利益相关者,识别农户持续参与森林碳汇项目的内、外生因素对于项目的稳定推进和减缓全球气候变化具有重要意义。【方法】在内、外生激励理论的基础上,探究影响农户持续参与森林碳汇项目的内、外生因素,构建外生激励的"政策关注""项目补贴""榜样效应"和"增汇培训"4个维度以及价值认同的"林地价值最大化""碳汇产业认可"和"减缓气候变化"3个维度;基于全国首批开展国家核证自愿减排量(CCER)竹林经营碳汇项目的浙江省遂昌县和景宁县,利用417份已参与首期碳汇项目农户的实地调查数据,通过统计性描述定性分析了外生激励、价值认同与农户持续参与意愿的关系;采用二元Probit模型和中介效应模型,实证分析外生激励、价值认同对农户持续参与森林碳汇项目影响的方向和程度以及价值认同的中介作用。【结果】交叉分析结果表明:外生激励、价值认同因素对农户持续参与意愿有促进作用的比例均达到98%以上,不同的外生激励、价值认同因素均在5%的显著性水平下通过了卡方检验,说明对农户持续参与森林碳汇项目意愿具有显著影响。实证分析结果表明:1)外生激励中"政策关注"在10%的显著性水平下正向影响农户持续参与意愿,"项目补贴""榜样效应""增汇培训"均在5%的显著性水平下对农户持续参与具有正向影响; 2)价值认同中"减缓气候变化"在1%的显著性水平下对农户持续参与森林碳汇项目具有正向影响,"林地价值最大化""碳汇产业认可"对农户持续参与意愿的影响并不显著; 3)外生激励对价值认同具有显著正向影响,价值认同在外生激励和农户持续参与森林碳汇项目之间存在显著的部分中介效应,占比为25.99%。【结论】农户持续参与森林碳汇项目是外生激励、内生价值认同各自作用和共同作用的结果。外生激励中的"政策关注""项目补贴""榜样效应""增汇培训"和价值认同中的"减缓气候变化"是影响农户持续参与的重要因素。外生激励对价值认同具有显著正向影响,价值认同在外生激励和农户持续参与之间存在显著的部分中介效应。     

基于条件价值评估法的居民参与城市森林生态服务供给的实证分析

采用条件价值评估法调查牡丹江市居民对于城市森林生态服务的支付意愿情况,通过描述性统计分析、影响因素关联性分析方法,探讨公众对生态服务收费的态度、支付意愿情况及影响公众支付意愿的因素,并得出影响居民参与城市森林建设的主要因素为居民人均月收入、受教育程度,最后提出的相应建议对于解决我国城市森林建设资金投入不足问题具有现实意义.     

基于意愿调查价值评估法的居民对自然保护区环境支付意愿研究——以白石砬子国家级自然保护区为例

意愿调查价值评估法是目前西方广泛采用的一种环境物品经济价值的评估方法。本文以白石砬子国家级自然保护区为例,利用意愿调查法来设计调查问卷并评估居民对自然保护区森林生物多样性的支付意愿,对白石砬子国家级自然保护区周边的居民进行问卷调查,获知公众的支付意愿影响因素。     

基于CVM法的陕西长青自然保护区游憩价值评估

以陕西长青国家级自然保护区为研究区域,采用条件价值评估法对其游憩价值进行量化评估,得出针对保护区资源的游憩价值人均支付意愿值为80元/年,总游憩价值为3 560万元/年。同时,通过对受访者特征与支付意愿和支付意愿值进行相关性分析可知:支付意愿与其年龄、职业、受教育程度、月收入水平、环境保护意识、景观满意度、周边旅游次数显著正相关;支付意愿值与其年龄、受教育程度、职业月收入水平、旅游倾向、保护区了解程度和景观满意度显著水平上正相关。     

北京市高保护价值森林价值评估理论与方法初探

结合现行经济学理论界对森林价值的评估,针对高保护价值森林的特征,从生物多样性和生态服务功能两方面对北京市高保护价值森林的价值评估方法进行探讨.结合效用论、边际效益论等理论,根据实地情况,运用支付意愿法、补偿法、替代法等,从森林的实用价值和精神文化价值等方面作了评估方法概述.     

国外森林文化价值评价指标研究现状及分析

在社会对良好生态环境和优质精神文化需求不断增长的情况下,森林文化价值对国民福利水平的影响越来越显著。由于分析角度的不同,国外与森林文化价值相关的评价体系大致可分为“森林资源资产评估研究”和“森林可持续经营管理框架” 2类。文中在对比分析国外相关研究的基础上,汇总32个国外典型的森林文化价值评价指标,包括各个典型指标的计量单位、指标类型和分析角度。     

管涔山国家森林公园森林旅游资源资产评估研究

对山西省管涔山国家森林公园的森林旅游资源资产进行了评估,结果认为:旅游者的年支付意愿为62.9万元,旅游时间价值为176.07万元。     

CVM法在森林生态旅游产品价值评估中的运用——以黑龙江省平山生态旅游区为例

研究CVM评估法在我国森林生态旅游产品价值评估中的可行性,从CVM评估法的优越性和局限性出发,以在哈尔滨市进行的关于对黑龙江省森工总局平山生态旅游区的支付意愿的调查研究为例,设计森林生态旅游产品价值评估调查方法、问卷内容、问卷流程及实施应注意的问题.探讨CVM评估法在我国进行森林旅游产品价值评估实践中的实用性与局限性,得出了这一方法在我国森林生态旅游产品价值中具有推广前景的结论.     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.