两种林龄中山杉(Taxodium hybrid 'Zhongshanshan')林地土壤质量评价

以江苏省靖江市牧城公园和东湖公园两种种植年限分别为5 a和9 a的中山杉(Taxodium hybrid'Zhongshanshan')人工林土壤和无林地为研究对象,对0~15 cm、15~30 cm和30~45 cm深度土层土壤理化性质、养分含量和微生物生物量进行了分析。典型相关分析表明,土壤微生物生物量的变化是一个复杂的过程,是土壤各因子共同作用的结果,3种土壤U、V值均表现出层次性,随着土壤深度的增加逐渐降低;不同取样点相同深度土层U、V值为9 a林5 a林对照;单相关分析表明,土壤微生物生物量与速效磷、速效钾、有机质和全氮呈极显著正相关(P0.01),因此土壤微生物可以作为评价中山杉人工林在促进林地土壤质量改善过程中的重要生物指标;主成分分析表明,综合得分最高的9 a林为2.993,其次是5 a林为0.748,作为对照的无林地则为-3.742,说明9 a林地土壤质量最高。可见,中山杉对林下土壤质量有显著提高作用。     

Transect relascope sampling for assessing coarse woody debris: The case of a π/2 relascope angle

In transect relascope sampling, a wide‐angle relascope is used along survey lines for selecting a sample of objects that extend linearly in the plane, e.g. downed logs. The method is closely related to line intersect (intercept) sampling. In this article, a special case of the transect relascope technique is studied. Using a π/2 radian relascope angle, the method becomes invariant to the orientation of the line objects in the population. The reason is that the area of inclusion around objects, through which a survey line should pass for an object to be included, turns out to be circular. In analytical studies and Monte Carlo simulations, the cost‐efficiency of transect relascope and line intersect sampling is evaluated. It is found that transect relascope sampling is a competitive alternative to line intersect sampling in inventories of the total volume of coarse woody debris (in the form of downed logs) in forest compartments.     

我国橡胶林碳汇贸易潜力的实证分析

依据气候减缓项目选择可贸易的碳库，利用森林蓄积量扩展法，计算了2008年和2011年橡胶林碳汇量，进而以2011年为基期，测算了2015年我国橡胶林的碳汇贸易潜力。计算结果表明，到2015年，我国橡胶林碳汇贸易潜力为248.61万t，占现有碳储量的10.62%，碳汇量年均增长速度呈下降趋势，显示出我国橡胶林碳汇贸易潜力的后劲不足。最后提出了依靠内涵式增长途径来提升碳汇潜力的几点建议。     

大兴安岭新林林业局森林资源可持续发展的技术体系

以大兴安岭林区具有典型代表性的新林林业局为研究对象，在对其自然资源、经济和社会调查后，建立了森林资源可持续发展的配套技术体系。包括种苗培育、资源调查与监测、资源采伐、资源更新、资源抚育技术体系以及资源效益评价体系等。     

Site classification of the eastern forest region of Daxing''''an Mountains

StudysiteThestudysiteislocatedintheeasternslopeofDaxing'anMountains(47"25'~49'37'N,119'37'-122"45'E),whichbelongstotheBalinForestryBu-reauofNeiMenggol.ThemaintopographyislowermountainsandhilIs.Thealtitudeis4oo~1ooom.Theannualaccumulativetemperature(>=1oC)isabout1845oC.AnnuaIprecipitationis42omm.Annualaveragetemperatureis-15t.Thefrost-freeperiodis97d.lnthisarea,thezonalsoilisbrownconiferousforestsoil,theothertypeofsoilismeadowsoilandbogsoiI.ThemainfundamentaIrockisgrinite.ThebasaItisse…     

关于皆伐的思考

本文从景观层次上对皆伐的应用进行了分析 ,得出皆伐是森林主伐的一种行之有效的方式。在森林主伐中 ,应根据立地条件和景观格局 ,恰当考虑皆伐的应用。     

天然白桦林的特点与经营

通过白桦林样地调查,对白桦林进行了径级分析、死亡木分析和经营分析。结果表明,白桦林是一个不稳定的次生林型。在大片次生林中的白桦林天然更新非常好。现在硬阔已进入演替层;死亡木用“一边竞争”的模型进行预测效果较好。根据分析提出对白桦林进行上层疏伐的经营方法。     

Applying Local Measures of Spatial Heterogeneity to Landsat-TM Images for Predicting Wildfire Occurrence in Mediterranean Landscapes

In mountainous Mediterranean regions, land abandonment processes in past decades are hypothesized to trigger secondary vegetal succession and homogenization, which in recent years has increased the size of burned areas. We conducted an analysis of temporal changes in landscape vegetal spatial pattern over a 15-year period (1984–1998) in a rural area of 672.3 km² in Eastern Spain to investigate the relationship between local landscape heterogeneity and wildfire occurrence. Heterogeneity was analyzed from textural metrics derived from non-classified remote sensing data at several periods, and was related to wildfire history in the study area. Several neural network models found significant relationships between local spatial pattern and future fire occurrence. In this study, sensitivity analysis of the texture variables suggested that fire occurrence, estimated as probability of burning in the near future, increased where local homogeneity was higher.     

Do coarse resolution U.S. presettlement land survey records adequately represent the spatial pattern of individual tree species?

Presettlement land survey records (PLSRs) are a valuable and unique source of information for the reconstruction of presettlement forest patterns. The purpose of this study was to determine whether coarsely resolved PLSRs are adequate to characterize the spatial patterns of individual tree species over large areas. The General Land Office Survey records of the PLSRs of Minnesota were used and species selected in the analysis were based on their abundances and degrees of clustering. A geostatistical procedure was developed to analyze observations of bearing-tree point-locations, at progressively coarser resolutions from 1×1 mile to 24×24 miles, to create spatially continuous probability surfaces of species occurrences across the landscape. Statistical and visual analyses of the geostatistical predictions indicated that coarsely resolved PLSRs, as coarse as 24×24 miles, can adequately represent the spatial pattern of individual species over large areas. Mean errors in predictions increased as more coarsely resolved data were used, primarily in response to the decreased abundance of a species and minorly in response to the degree of spatial clustering of a species. The results indicate that coarsely resolved township-level data of 6×6 miles can be used for presettlement vegetation reconstruction of large areas of several counties.     

祟仁余干两地封山育林控制松毛虫效果初探

本文通过对祟仁、余干两地封山育林控制马尾松毛虫效果的研究。揭示了封山育林是一种安全、经济、有效的控制松毛虫的技术措施,通过封山育林,改变了松林生态环境,增加了松林的生物多样性,提高了松林的抗虫能力。