共查询到20条相似文献，搜索用时 250 毫秒
1.
王长富 《绿色中国(A版)》1983,(5)
森林资源清查,也称森林资源调查,它是查清森林资源现状及其动态规律的方法,是林业生产的一项基础工作,也是森林经理,或者叫森林经营计划的一个工作内容。通过森林资源清查,可以精确的测定林区各种土地和森林的面积、树种别林木生长量、枯损量、树种组成,径级分布以及灌木、下草等,林木总蓄积量及其质量(包括各林分、树种别蓄积量)和出材量(包括材种别出材量)以及森林更新等数据,各种林副产品的数量和质量,森林资源的地理分布和林区各部分的地形以及立地条件的特点并绘制森林分布图,为制定林业计划与经营、开发利用森林资源,为考虑维持生态平衡,确定森林 相似文献
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《中南林业科技大学学报(自然科学版)》2019,(8)
森林蓄积量是评价森林资源数量的一个重要指标。结合遥感影像和地面调查数据估测森林蓄积量受遥感影像、遥感因子、预处理方法、估测方法等多方面的影响。为研究国产GF-1遥感影像估测森林蓄积量的最佳遥感因子组合方式和较优估测方法,并绘制森林蓄积量空间分布图,为我国森林蓄积量的研究提供理论基础和科学依据。为研究GF-1遥感影像估测森林蓄积量的遥感因子和估测方法,以湖南省醴陵市为研究对象,以国产GF-1遥感影像为数据源,通过对遥感图像预处理,获取光谱信息、纹理因子、植被指数作为特征变量,结合同时期的二类调查样地数据,从GF-1遥感影像像元与样地不匹配角度出发,应用移动窗口的方法解决像元与样地的对应关系,采用多元逐步回归、偏最小二乘回归和随机森林模型对研究区森林蓄积量进行估测,采用建模精度和估测精度进行分析评价。实验结果表明:1)3个模型选择的因子都包含了NDVI、 Band2、DI3、CO1和DVI等5个遥感因子,说明其对森林蓄积量的估测比较敏感;2)随机森林模型优于偏最小二乘回归和多元逐步回归,其决定系数R2为0.73、估测精度为83.69%。利用GF-1遥感影像结合随机森林模型应用于森林蓄积量的估测结果趋于真实分布,效果较理想;采用移动窗口法,利用国产GF-1遥感影像并结合随机森林进行森林蓄积量估测具有较好的应用前景。 相似文献
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本文对森林调查中蓄积量、株数和平均胸径等数据采用计算机编程计算。可减轻外业工作量,能快准地得到小班调查材料。 相似文献
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森林生态系统蓄积量的空间分布及反演研究对碳储量估测、生物多样性保护以及全球气候变化研究起着至关重要的作用,然而,由于森林植被类型的多样性,尤其是对人力所不能及的热带原始林区,森林调查数据缺失,森林蓄积量的估测和反演存在巨大挑战。以巴布亚新几内亚西塞皮克省18.80万hm~2的热带原始雨林区为研究区,利用高分遥感影像RapidEye,QuickBird与Landsat TM,结合野外地面调查数据,对研究区土地覆盖类型进行分类。基于遥感影像得到森林植被参数信息,提取各波段地表反射率、各种植被指数和其他光谱变换形式等遥感因子,利用多元线性逐步回归构建森林蓄积量遥感反演模型,估算研究区森林蓄积量,并结合GIS技术分析其小班尺度上的空间分布特征。结果显示:1)研究区土地覆盖类型可以分为低海拔平原森林、低海拔高地森林、低山森林、稀疏森林、沼泽森林和其它类型共6种,分类精度达79.2%;2)蓄积量遥感反演模型的多元回归模型R~2为0.694,对森林蓄积量有较好的反演精度;3)研究区森林蓄积量的分布特点表现为中部高于周边、北部和中东部山区明显高于西北和东南地区,其与研究区的土地覆盖类型分布相对应。构建的森林蓄积量反演模型对全球热带原始林区的森林资源蓄积量估测具有重要的参考价值。 相似文献
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利用东北林区云冷杉林、落叶松林、樟子松林、红松林、栎树林、桦树林、杨树林、榆树林、椴树林和水胡黄林10种森林类型的1947个样地的激光雷达数据和地面实测蓄积量数据,首先通过多元线性回归和非线性回归方法,分别建立基于机载激光雷达数据的森林蓄积量回归估计模型,并通过对比分析,确定统一形式的基础回归模型;然后利用哑变量建模方法,建立基于不同森林类型参数和相同激光雷达变量的蓄积量模型。结果表明,研究建立的10种森林类型的线性蓄积量回归模型的解释变量个数在2~7之间,确定系数在0.460~0.858之间;非线性蓄积量回归模型的解释变量个数在2~4之间,确定系数在0.461~0.846之间。基于点云平均高度和平均强度建立的10种森林类型的二元蓄积量模型(研究称之为标准模型),其确定系数在0.440~0.815之间,平均预估误差在2.88%~4.42%之间,平均百分标准误差在16.76%~25.52%之间,预估精度基本达到森林资源规划设计调查技术规定要求。依据研究建立的10种森林类型的蓄积量模型,可以编制基于激光雷达数据的航空林分材积表,在森林资源调查实践中推广应用。 相似文献
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《林业科学》2021,57(2)
【目的】建立变量相同、结构稳定、具有普适性的基于机载激光雷达数据的森林蓄积量预估模型,为规范森林蓄积量建模与评价提供科学参考,为森林资源调查提供计量依据。【方法】利用东北林区落叶松林、红松林、杨树林和桦树林4种森林类型790块样地的激光雷达数据和地面实测蓄积量数据,首先采用多元线性回归和非线性回归方法,分别建立基于机载激光雷达数据的森林蓄积量回归模型,通过对比分析,确定具有相同变量和统一结构形成的普适性模型;然后采用哑变量建模方法,建立基于相同激光雷达变量的不同森林类型蓄积量模型。【结果】4种森林类型线性蓄积量回归模型的解释变量个数在2～6之间,确定系数(R~2)在0.701～0.827之间;非线性蓄积量回归模型的解释变量个数在2～4之间,R2在0.707～0.818之间。基于点云平均高度和平均强度的落叶松林、红松林、杨树林、桦树林非线性二元蓄积量模型,其R~2分别为0.679、0.814、0.698和0.703,平均预估误差分别为4.26%、2.90%、3.68%和3.83%,平均百分标准误差分别为24.44%、18.23%、21.47%和23.26%。【结论】基于机载激光雷达数据估计森林蓄积量,非线性模型优于线性模型;基于点云平均高度和平均强度的二元蓄积量模型具有普适性,可作为森林蓄积量估计的标准模型;本研究建立的4种森林类型蓄积量模型,其预估精度均达到森林资源调查相关技术规定要求,可在实践中推广应用。 相似文献
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刍议管涔林区生态效益王忠贵管涔林区是山西省的九大林区之一。森林面积７４万亩（包括集体林），总蓄积量７７７万立方米。除了明显的经济效益，还有着巨大的生态效益。参照国内外对森林生态效益的调查测算方法，采取重点调查、典型调查与普查相结合，经实地调查和理论... 相似文献
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森林资源清查的主要任务是查清各类土地和森林面积,查清各类森林蓄积量,查明各类森林的生长量和消耗量等。调查完毕除提交以上数据外(主要是以表格形式体现),为了更清晰、直观、明了地表示整体的趋势和情况,还必须提交图面材料,如地形图、林场林相图、林业局林相图、林业局区划略图及经营方案附图、野生动植物和森林病虫害分布图等 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):65-73
A method is presented for prediction of the present net value (PV) of timber production, based on satellite data and subjectively inventoried forest stand data. Multiple regression analysis was used for predicting the PV. This method has the advantage that predictions of the PV can be made using any kind of existing stand data. The precision of the estimate of the PV, however, depends on the information available in the forest stand database. In the study a combination of Landsat TM data and subjectively inventoried site‐index explained about 75% of the variance, which was equal to the case when all subjective ground stand data, excluding TM data, were used to predict PV. This result and results from other data combinations suggest that Landsat TM data might be useful for forest management planning. 相似文献
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Forestcontractors,loggersandengineershavebeenpayingahighattentiontotimberextractionoperationssince1990's.Sincetimber-extractingoperationproducesthehighestproportionofoperationcosts,largestareadisturbedandmostresidualstandsdamagedamongalloperationsofsmalltreeharvesting,manytechniquesweredevelopedtomeettherequirementsoftimberextractioninsmalltreeharvesting.Animalskidding13Animalskidding,oneoftimberextractionmethods,usessomespecialdevicessuchassledgesandcarriagesasshowninFig.1toreducetheresistanc… 相似文献
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木材储备基地及其多功能森林经营建设对策 总被引：2，自引：2，他引：0
木材战略储备基地作为林业产业发展的重大举措被列入我国“十二五”林业发展规划,以应对我国木材自产不足、外供不济的安全保障问题,但面临速生丰产林用地有限、社会对森林综合需求增加、生产成本上升、效益低下等因素制约。文中在分析木材储备的特征及其森林经营需求的基础上,提出以林分状态存在的活立木储备是低成本、环境友好型、有战略意义的木材储备,而且木材储备基地是一种以物质生产功能为主导的多功能用材林模式;在此基础上,进一步提出了通过建设有生命活力和结构稳定的用材林生态系统来实现有经济效益的木材战略储备基地的多功能森林可持续经营对策。 相似文献
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This study examined the potential use of low-cost consumer-grade smartphone technology to perform and improve field data collection in support of small-scale forest management. This proof-of-concept exercise for day-to-day forester operations focused on the effectiveness of the smartphone platform (form factor and functionality) rather than any particular smartphone software. An electronic data acquisition system for a smartphone was developed that combined a simple custom timber cruise application and mobile commercial mapping software to record and process forest stand and geospatial information, and transfer these to a small-scale operator’s existing desktop geographic information system. Workflow efficiency and system performance of the smartphone system was then measured and compared with paper-based methods presently being used in the managed forest. The smartphone greatly increased workflow efficiency by reducing data transfer and processing times, and eliminated the need to carry separate global positioning system (GPS) device, map, paper forms and digital camera. The GPS accuracy of the smartphone was more than adequate to meet operational requirements, and provided a capacity to map forest features on an ad hoc basis that is not easily done through the paper-based process. However, initial data entry using the smartphone takes longer than using paper-based notes, there is a greater chance of data entry error through inadvertent keypad touches on the small screen, and there is the potential for a device malfunction. Overall, it is concluded that smartphones offer an opportunity for small-scale operators to create electronic field data management systems that are affordable, operationally robust, compatible with existing management systems, capable of increasing data management efficiency and, in particular, expanding the types of data that can be collected during silvicultural operations. 相似文献
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《Forest Policy and Economics》2000,1(1):27-40
This paper addresses the effects of economic transition policies on forestry in China. The effects of de-collectivization and market liberalization on the forest land area and timber harvest are studied using panel data from four provinces covering the period 1978–1995. Fixed effects ordinary least squares models for forest land cover and annual harvests per hectare are estimated, allowing for differences across provinces and prefectures in northern and southern China. The results show that land tenure reform in general has had a positive effect on forest land expansion, but the absolute size of the effects varies from province to province. The positive impact of the reform on timber harvesting has not taken place at the cost of forest land cover. The claim that market liberalization leads to over-harvesting of forest resources in developing countries is not supported by our results. 相似文献
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We investigated a strategy to improve predicting capacity of plot-scale above-ground biomass （AGB） by fusion of LiDAR and Land- sat5 TM derived biophysical variables for subtropical rainforest and eucalypts dominated forest in topographically complex landscapes in North-eastern Australia. Investigation was carried out in two study areas separately and in combination. From each plot of both study areas, LiDAR derived structural parameters of vegetation and reflectance of all Landsat bands, vegetation indices were employed. The regression analysis was carded out separately for LiDAR and Landsat derived variables indi- vidually and in combination. Strong relationships were found with LiDAR alone for eucalypts dominated forest and combined sites compared to the accuracy of AGB estimates by Landsat data. Fusing LiDAR with Landsat5 TM derived variables increased overall performance for the eucalypt forest and combined sites data by describing extra variation （3% for eucalypt forest and 2% combined sites） of field estimated plot-scale above-ground biomass. In contrast, separate LiDAR and imagery data, andfusion of LiDAR and Landsat data performed poorly across structurally complex closed canopy subtropical minforest. These findings reinforced that obtaining accurate estimates of above ground biomass using remotely sensed data is a function of the complexity of horizontal and vertical structural diversity of vegetation. 相似文献
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《Southern Forests》2013,75(4):341-350
Protected areas in Nigeria are important ecosystems for carbon storage. The aim of this study was to estimate and map tree aboveground biomass (TAGB) and carbon (TAGC) within a tropical forest in Nigeria. Stepwise regression analysis was implemented to develop models for predicting TAGB in the forest stand, by integrating field TAGB data with Landsat 8 OLI data. Spectral variables used in the analysis include spectral bands, vegetation indices, tasseled cap indices and principal components. Model validation was performed using independent sample plots. The results showed that incorporating more than one category of spectral variables improved the prediction of TAGB. The best-fit model was applied to map the spatial distribution of TAGB and TAGC. The TAGC was estimated as 52.3% of TAGB, based on the average carbon content of tree species derived in this study. Average TAGB and TAGC estimates for the forest stand were 373.1 ± 165.4 t ha?1 and 194 ± 82.7 t ha?1, respectively. Reliable estimates of TAGB and TAGC for the forest reserve were obtained. This study provides important information required to manage the forest stand for optimal carbon sequestration. 相似文献
19.
Helena Mäkelä Hannu HirveläTuula Nuutinen Leena Kärkkäinen 《Forest Ecology and Management》2011,262(8):1345-1359
The sample plot data of National Forest Inventories (NFI) are widely used in the analysis of forest production and utilization possibilities to support national and regional forest policy. However, there is an increasing interest for similar impact and scenario analyses for strategic planning at the local level. As the fairly sparse network of field plots only provides calculations for large areas, satellite image data have been applied to produce forest information for smaller areas. The aim of this study was to test the feasibility of generating forest data for a Finnish forest analysis tool, the MELA system, by means of the Landsat satellite imagery and the NFI sample plot data. The study was part of the preparation of a local forestry programme, where a strategic scenario analysis for the forest area of two villages (ca 8000 ha) was carried out. Management units that approximate forest stands were delineated by image segmentation. Stand volume and other parameters for each forest segment were estimated from weighted means of the NFI sample plots, where the individual sample plot weights were estimated by the k nearest neighbour (kNN) method. Two different spectral features were tested: single pixel values and average pixel values within a segment. The estimated forest data were compared with the forest data based on independent stand-level field assessments in two subareas, a national park and an area of forest managed for timber production.In the national park, the estimated mean volume of the growing stock from both spectral feature sets (about 160 m3 ha−1) was clearly lower than that obtained from stand-level field assessment (186 m3 ha−1). Using average pixel values within a segment resulted in a higher proportion of pine and a lower proportion of spruce volume than using single pixel values. It also resulted in an estimated felling potential nearly 10% higher over the first 10-year period in the scenario analysis of the area dedicated to timber production. However, the maximum long-term sustainable removal was at the same level (about 30,000 m3 year−1) for both feature sets over the simulated 30-year period. The resulting annual felling area in the first 10-year period was 12% lower when the segment averages were applied, but the difference subsequently levelled off. The kNN approach in estimating initial forest data for scenario analyses at the local level was found promising. 相似文献
20.
Karlo Beljan Jura &#;avlovi&#; Josip I&#;tvani&#; Denis Dolinar Kruno Lepoglavec 《Small-Scale Forestry》2020,19(1):19-38
This paper presents a comprehensive financial analysis of the investment potential of seven private forest categories in the Republic of Croatia (total study area of 268,072 ha). It covers the period from 2018 to 2048 and includes forest purchase costs, management simulation, timber transport to mills, timber processing and veneer production, and finally the selling of sawmill, veneer and forest products. Data from the Croatian National Forest Inventory and forest habitats map were used as a basis for analyses. Spatial data on private forests, roads and timber process plants at the national level were also integrated into the analyses. For the forest management simulation, the MOSES 3.0 simulator was used, and the QGis 3.4 software was used for spatial analyses of forests, roads and mils. Based on data from several world stock exchanges that cover companies of the forestry sector, a real (inflation-free) discount rates were used. The financial analyses showed which forest categories have positive investment potential and under which conditions. Results pointed out that multi-aged European beech forests have the highest internal rate of return (8.45%) and are the only one which would meet the expectations of a financially rational investor using criteria of a risk-adjusted inflation-free discount rate of 8%. 相似文献