Assessing 3D point clouds from aerial photographs for species-specific forest inventories

In this study we assessed the potential of using photogrammetric data for species-specific forest inventories. The method is based on a combination of Dirichlet and ordinary linear regression models. This approach was used to predict species proportions, main tree species, total, and species-specific volume. Structural and spectral variables were used as predictors. The models were validated using 63 independent validation stands. The results from airborne laser scanning (ALS) data combined with spectral data and photogrammetric data obtained using aerial imagery with different forward overlaps of 80% and 60% were compared. The best photogrammetry-based models predicted species proportions with a relative root mean square error (RMSE) of 21.4%, classified dominant species with 79% accuracy, predicted total volume with relative RMSE of 13.4%, and predicted species-specific volume with relative RMSE of 36.6%, 46.5%, and 84.9% for spruce, pine, and deciduous species, respectively. The results were similar for the three point cloud datasets obtained from aerial imagery and ALS and the accuracies of the predictions were comparable to methods used in operational FMI. The study highlights the effectiveness of forest inventories carried out using photogrammetric data, which – differently from ALS, can include species-specific information without relying on multiple data sources.     

Derivation of stumpage value and logging costs for individual forest stands using aerial photographs and cartographic modelling

A procedure for calculation of stumpage value and logging costs of individual mature forest stands using aerial photo‐interpretation and a grid‐based geographical information system (GIS) is presented. The stumpage value may be computed from characteristics related to the trees, i.e. site index, stand mean height, crown closure, and tree species distribution, using price equations. By means of cost equations, the logging costs may be calculated from the tree characteristics and the terrain characteristics of slope gradient and skidding distance. The practical application of the procedure was demonstrated by a case study in a 710 ha forest area in southern Norway. The tree characteristics were determined by photo‐interpretation of individual stands. Skid paths for wood transportation from the stands to landings along the forest roads were delineated by photo‐interpretation of the ground conditions. Slope and skidding distances were derived by a digital elevation model and cartographic modelling. Finally, the photo‐interpreted tree characteristics and the computed slope and skidding distances were used for calculation of the stumpage value and the logging costs of each stand. According to previous tests, the accuracy of the procedure corresponded to the accuracy that could be achieved by the field‐survey methods used most frequently.     

"3S"技术在广西国有雅长林场森林资源规划设计调查中的应用研究

以广西国有雅长林场为例，介绍遥感、地理信息系统、全球定位系统在森林资源规划设计调查应用的技术线路和技术关键。     

浅议卫星遥感在森林资源清查中的应用

本文综述了卫星遥感在我国森林资源调查中的应用概况,并结合实践讨论了卫星遥感应用于森林资源调查的可能性.     

城市森林的规划设计调查探索

通过上海市森林资源规划设计调查的实践,总结探索城市森林调查的技术、方法要点及工作流程,为城市森林进行调查提供借鉴。     

森林二类调查中蓄积量遥感估测方法应用实例

探讨了用在ＴＭ数据中与地面对应的样点上测得的密度值和波段比，并加上定性因子与地面样地中分别测得的蓄积量进行多元回归，从而估测森林二类调查中所需的林业局、场、林班之蓄积量的方法，并与实测结果进行了对比，证明这一方法是可行的，为遥感在二类调查中的应用提供了必要依据。     

森林资源规划设计调查中小班区划方法探讨

针对目前森林资源规划设计调查中小班区划方法存在的问题，提出了连续小班区划方法，并分析了连续小班区划方法的优点及应用前景。     

Airborne laser scanning-based decision support for wood procurement planning

We present a decision support tool for guiding the selection of marked stands based on airborne laser scanning (ALS) data. We describe three stages, namely (1) wall-to-wall mapping of the stands matured for cutting using low-density ALS data; (2) tree-level inventory of these stands using high-density ALS data and (3) theoretical bucking of the imputed tree stems to produce detailed information on their characteristics. We tested them in a Scots pine dominated boreal forest area in Eastern Finland, where 79 sample plots were measured in the field. The detection of the stands matured for cutting had a success rate of 95% and our results demonstrated a further potential to limit the result towards stands dominated by certain species by means of intensity values derived from the low-density ALS data. The applied single-tree detection and estimation chain produced detailed tree-level information and realistic diameter distributions, yet the detection was highly emphasised on the dominant tree layer. The error levels in the estimates were generally less than standard deviations of the field attributes. Finally, plot-level accumulations of saw-log volumes were found rather similar, whether the input was based on the imputed tree data or trees measured in the field. The results are considered useful for ranking the stands based on their properties, whether the aim in the wood procurement is to focus on certain species or to select stands suitable for production needs.     

0.5M分辨率航摄数字影像数据在森林资源规划设计调查中的应用

以0.5 M分辨率航摄数字影像数据为基础,结合以往调查设计及经营资料,对森林资源规划设计调查小班的部分因子进行判读,探讨高分辨率航摄数字影像数据在森林资源规划设计调查中的应用,结果表明:利用0.5M分辨率航摄数字影像数据进行小班因子判读,可以作为小班因子调查的辅助手段,并可显著提高小班调查质量及效率。     

Uncertainties of mapping aboveground forest carbon due to plot locations using national forest inventory plot and remotely sensed data

Abstract

Forest carbon sinks significantly contribute to mitigation of atmospheric concentrations of carbon dioxide. Thus, estimating forest carbon is becoming important to develop policies for mitigating climate change and trading carbon credits. However, a great challenge is how to quantify uncertainties in estimation of forest carbon. This study investigated uncertainties of mapping aboveground forest carbon due to location errors of sample plots for Lin-An County of China. National forest inventory plot data and Landsat TM images were combined using co-simulation algorithm. The findings show that randomly perturbing plot locations within 10 distance intervals statistically did not result in biased population mean predictions of aboveground forest carbon at a significant level of 0.05, but increased root mean square errors of the maps. The perturbations weakened spatial autocorrelation of aboveground forest carbon and its correlation with spectral variables. The perturbed distances of 800 m or less did not obviously change the spatial distribution of predicted values. However, when the perturbed distances were 1600 m or larger, the correlation coefficients of the predicted values from the perturbed locations with those from the true plot locations statistically did not significantly differ from zero at a level of 0.05 and the spatial distributions became random.     

湖南省森林资源连续清查遥感应用研究

森林资源连续清查是全国森林资源监测体系的重要组成部分,是掌握森林资源宏观现状、消长动态,制定和调整林业方针政策、规划、计划等的重要依据.随着现代遥感技术,特别是卫星遥感的发展,为准确、快速地获取森林资源相关信息提供了新途径.以2004年湖南省森林资源清查遥感样地的目视解译为例,探索了目视解译在森林资源连续清查中的应用.结果表明:采用遥感样地调查比人工调查节省时间,在某些调查因子方面可获得比人工调查更为准确的数据;目视解译结果精度较高,经实地验证,其加权精度达到85.31%.     

基于RS和GIS的云南省森林火险预报研究

基于遥感、GIS技术,选取不同植被易燃等级、植被干燥度、森林气象火险预报等级作为森林火险预报因子,采用因子加权叠置法,计算得到云南省森林火险预报指数,划分为没有危险、低度危险、中度危险、高度危险和极度危险5个等级。研究结果表明,较之传统的森林火险气象预报,该预报模型能够更为准确地预测林火发生的可能性,更好地满足森林防火业务的需求。     

Combining ALS and NFI training data for forest management planning: a case study in Kuortane,Western Finland

Forest inventories based on airborne laser scanning (ALS) have already become common practice in the Nordic countries. One possibility for improving their cost effectiveness is to use existing field data sets as training data. One alternative in Finland would be the use of National Forest Inventory (NFI) sample plots, which are truncated angle count (relascope) plots. This possibility is tested here by using a training data set based on measurements similar to the Finnish NFI. Tree species-specific stand attributes were predicted by the non-parametric k most similar neighbour (k-MSN) approach, utilising both ALS and aerial photograph data. The stand attributes considered were volume, basal area, stem number, mean age of the tree stock, diameter and height of the basal area median tree, determined separately for Scots pine, Norway spruce and deciduous trees. The results obtained were compared with those obtained when using training data based on observations from fixed area plots with the same centre point location as the NFI plots. The results indicated that the accuracy of the estimates of stand attributes derived by using NFI training data was close to that of the fixed area plot training data but that the NFI sampling scheme and the georeferencing of the plots can cause problems in practical applications.     

美国森林管理的特点与启示

通过实地考察,总结了美国森林管理具有严格管理公有森林、鼓励发展私有林业、实行森林集约经营、科学治理沙漠土地、高度重视城镇绿化、重视生态系统保护、依法管理森林行为等七大特点。并以此为鉴,坚持从实际出发,提出我国森林经营管理必须重视强化的六个环节:必须用法律手段调整森林经营行为;切实用生态系统管理理念指导森林经营活动;加大对天然林资源的保护管理力度;坚持把林木种苗生产管理作为森林经营的首道工序来抓;争取把自然保护区和森林公园纳入自然文化遗产管理;努力为非公有制林业发展创造宽松环境。     

Using canopy heights from digital aerial photogrammetry to enable spatial transfer of forest attribute models: a case study in central Europe

This paper describes a workflow utilizing detailed canopy height information derived from digital airphotos combined with ground inventory information gathered in state-owned forests and regression modelling techniques to quantify forest-growing stocks in private woodlands, for which little information is generally available. Random forest models were trained to predict three different variables at the plot level: quadratic mean diameter of the 100 largest trees (d₁₀₀), basal area weighted mean height of the 100 largest trees (h₁₀₀), and gross volume (V). Two separate models were created – one for a spruce- and one for a beech-dominated test site. We examined the spatial portability of the models by using them to predict the aforementioned variables at actual inventory plots in nearby forests, in which simultaneous ground sampling took place. When data from the full set of available plots were used for training, the predictions for d₁₀₀, h₁₀₀, and V achieved out-of-bag model accuracies (scaled RMSEs) of 15.1%, 10.1%, and 35.3% for the spruce- and 15.9%, 9.7%, and 32.1% for the beech-dominated forest, respectively. The corresponding independent RMSEs for the nearby forests were 15.2%, 10.5%, and 33.6% for the spruce- and 15.5%, 8.9%, and 33.7% for the beech-dominated test site, respectively.     

影像解译在贵州省森林资源连续清查中的应用研究

为了提高贵州省森林资源连续清查中各类土地利用类型的监测精度,在Landsat TM遥感影像处理的基础上建立贵州省的土地类型解译标志,综合利用“3S”技术建立能与图形数据库互查的属性数据库,实现全省遥感样地的计算机管理.     

森林资源档案管理系统中数据更新方法的探讨

森林资源档案管理系统主要对森林资源的档案信息进行管理,是林业信息管理中的重要内容。森林资源档案数据具有易变性和时效性,森林资源档案数据的及时更新将有助于林业主管部门对森林资源状况的掌握。本文综合了时空数据模型中基态修正模型、生命周期模型和面向对象模型的特点,建立了增量存储数据更新模型,提出了增量存储数据更新方法,并以甘肃省小陇山林业局党川林场的部分数据为基础,利用增量存储数据更新方法,对数据更新实现过程进行了探讨。     

远程诊断专家系统在城市森林病虫害防治中的应用

本文分析了森林病虫害的现状及危害,提出了森林病虫害的远程诊断专家系统的建设思路、系统结构、逻辑结构以及系统的模块结构。并详细阐述了系统的功能及效果。       

卫星遥感技术在林火管理与研究中的应用(英文)

卫星遥感已经成为森林火险等级预测、可燃物和火烧区制图、林火监测和火生态研究的一个主要数据来源。本文综述了这些研究领域的研究成果,分析了未来林火管理中采用的卫星遥感技术的发展趋势。根据卫星遥感数据制取的可燃物分布图可以满足林火管理在空间和时间尺度上的需要。单独采用遥感数据或结合地面气象数据可以生成一些火险指数,用于森林火险的预报。目前NOAA 和MODIS 卫星由于有高的时间分辨率已被广泛用于林火探测和监测,这些监测结果可以在许多林火网站上见到,这为世界各地的林火管理和研究提供了重要的参考资料。作为低成本的有效工具, 卫星遥感技术在确定火烧面积和过火区制图上发挥了重要作用。遥感技术的发展也可以用来推断火烧时间和估计火烧程度。卫星遥感也非常适合用来估计生物燃烧面积,这是估计全球或区域生物燃烧排放量和理解火对全球变化的影响的基础。本文还讨论了林火研究中采用的卫星类型。文章最后建议中国需要在卫星遥感技术的应用上进一步发展,提高我国的林火管理水平。参71。