基于CEBERS-WFI遥感数据的森林生物量估测方法研究

以中巴卫星CEBERS-WFI遥感数据为基础,结合东北三省的地理、气象因子及森林资源连续清查固定样地信息,构建BP人工神经网络森林生物量估测模型,对我国东北三省的森林生物量进行估测,并反演了森林生物量的空间分布图像。结果表明,基于CEBERS-WFI遥感数据的BP人工神经网络应用于森林生物量估测简单实用,是一种快捷、有效的估测方法。     

森林碳储量遥感估测模型构建研究——以闽江流域杉木林为例

以福建省闽江流域为研究对象,利用年均降水、温度数据,结合改进NPP模型构建基于气象因子的森林生产力估测模型,并通过森林生产力与二类调查结果对应的小班年龄曲线建立森林生物量模型,以此获得遥感估测模型所需的样地生物量,在此基础上利用遥感影像和杉木平均含碳率可以成功构建森林生物量非线性遥感估测模型和碳储量遥感估测模型。本研究不仅能建立森林碳储量模型,而且避免了繁杂的森林生物量野外实测,节省了大量的人力物力,且不需砍伐森林树木。实验计算结果:闽江流域杉木林碳储量2003~2012年从10 337 774 t增加到19 624 374 t。     

高分一号遥感影像下崂山林场林分生物量反演估算研究

以高分一号遥感影像为数据源,结合外业实测数据,通过提取植被指数因子、波段组合因子以及地形因子等19个因子,建立崂山林场生物量多元线性反演模型,进而分析该反演模型的精度和优缺点,估测崂山林场森林生物量。结果表明:应用多元线性回归法建立的生物量模型平均反演精度达到80.75%;根据反演出的林分生物量估测模型,估测崂山林场2013年的林分生物量为402 485.44 t。     

基于不同立地质量的杉木生物量遥感估测

[目的]研究不同立地质量对杉木生物量遥感估测精度的影响,为进一步提高和完善森林生物量遥感监测体系提供一种新的思路和方法。[方法]以2007年建德市森林资源二类调查数据和TM影像为研究材料,采用蓄积量—生物量换算因子连续函数法计算杉木林生物量和地位级法评价立地质量等级,比较杉木立地质量好、中等、差和不分地位等级4种生物量遥感估测模型,并进行精度检验。[结果]表明:(1)以TM遥感影像主成分分析中第一主成分为自变量的模型拟合效果最好,决定系数R2均在0.69以上,最高0.855。(2)利用预留独立样本对模型精度进行验证,不分地位级总体估测精度为87.78%,分立地质量等级好、中、差3种类型总体估测精度分别为97.37%、95.82%、98.23%。分不同立地质量类型可以提高杉木生物量遥感估测精度。[结论]研究结果为森林生物量遥感估测提供一种改进的思路,且为提高森林生物量和碳储量遥感估测精度提供一种参考方法。     

基于不同立地质量的松树林分生物量遥感估测

基于2007年建德市森林资源二类调查数据和TM影像数据,采用蓄积量—生物量换算因子连续函数法计算松树生物量,对松树树种分立地质量等级和不分地位等级2种类型建立生物量的遥感估测模型,并进行精度检验。结果表明:(1)以TM遥感影像主成分分析中第一主成分为自变量的模型拟合效果最好,决定系数R2均在0.6以上,最高0.773。(2)利用预留独立样本对模型精度进行验证,不分地位级总体估测精度为92.51%,分立地质量等级好、中、差3种类型总体估测精度分别为97.66%、96.56%、97.32%,分不同立地质量等级建模精度明显优于统一建模的精度。研究结果为森林生物量遥感估测提供一种改进的思路,且为提高森林生物量和碳储量遥感估测精度提供一种参考方法。     

基于地理加权回归模型的思茅松生物量遥感估测

通过调查云南省景谷县思茅松林120株单木数据,构建思茅松单木生物量模型。结合2005年景谷县TM影像数据及2006年森林资源二类调查小班数据,采用普通最小二乘模型(OLS)和地理加权回归模型(GWR)的方法构建思茅松生物量遥感估测模型。结果表明:地理加权回归模型比普通最小二乘模型具有更好的拟合效果,其决定系数(R2)显著高于OLS模型,Akaike信息指数(AIC)相比降低7.832;两种模型通过独立样本检验可以看出,模型预估精度从OLS模型的72.70%提高至GWR模型的75.06%;通过GWR模型反演计算,研究区内思茅松林单位面积生物量为49.02t/hm~2,比实测数据低1.229%,与实测数据基本吻合,且估算误差优于OLS模型;基于GWR模型估算的景谷县思茅松林总生物量为2.101×107t。可见基于地理加权回归方法估测森林地上生物量的方法是有效的,能提高森林生物量遥感估测模型的拟合和预估精度,可以用于思茅松林的生物量的遥感估算。     

基于Landsat8影像的汝城县森林地上生物量遥感估算研究

精确估测森林生物量是分析森林碳动态和碳循环的基础。本研究采用汝城县森林资源连续清查数据,结合Landsat 8遥感影像,分析了森林地上生物量的空间自相关和空间异质性,并选取显著相关的植被指数因子,分别构建普通最小二乘模型、空间滞后模型以及地理加权回归模型,并绘制汝城县森林地上生物量的空间分布图。结果表明:通过对森林地上生物量的空间效应分析,发现样地生物量的空间自相关和空间异质性不容忽视。与普通最小二乘回归相比,空间滞后模型和地理加权回归模型可以减少空间效应对森林地上生物量估测的影响。地理加权回归模型可以最大程度地减少过高或过低估计,估测森林地上生物量的精度最高,决定系数达到0.756,均方根误差和平均相对误差最小,分别为17.288 t·hm~(-2)和-8.542%。因此使用Landsat 8遥感影像结合地理加权回归方法在改善森林地上生物量的估测中具有巨大潜力。     

机载激光雷达大区域亚热带森林参数估测的普适性模型式

【目的】针对当前森林参数估测模型受研究区条件、森林类型限制不具备普适性的问题,从森林三维结构分析描述出发,构建森林参数估测多元乘幂模型式,并测试其在不同森林类型不同森林参数估测中的表现,检验其推广能力,以期发现一个适用于不同森林类型不同森林参数估测的模型结构式,为激光雷达森林参数的一致性估测提供实践案例。【方法】以面积2.21万km~2的南亚热带丘陵山地区域为研究区,以面积法为基础,将刻画森林冠层三维结构的7个离散回波Li DAR变量进行组合,构建5个森林参数估测多元乘幂模型式,通过383块样地测试5个模型式在不同森林类型(杉木林、松树林、桉树林和阔叶林)不同森林参数(蓄积量、断面积和平均直径)估测中的表现。【结果】以激光雷达点云平均高、冠层覆盖度、叶面积密度变动系数、激光雷达点云高度变动系数、50%分位数密度为变量的模型结构式表现最好; 4种森林类型蓄积量估测模型的决定系数(R~2)分别为0.667、0.769、0.764和0.602,相对均方根误差(rRMSE)变化范围为18.53%～36.32%,平均预估误差(MPE)变化范围为3.37%～6.95%; 4种森林类型断面积估测模型的R~2分别为0.572、0.582、0.706和0.568,rRMSE变化范围为16.11%～30.82%,MPE变化范围为3.27%～5.89%; 4种森林类型平均直径估测模型的R2分别为0.574、0.501、0.709和0.240,rRMSE变化范围为10.07%～29.01%,MPE变化范围为1.83%～5.55%;最优普适性模型式的R2与各森林类型各森林参数最优模型的R~2的相差小于5%,rRMSE和MPE的相差均小于7%。【结论】本研究提出的模型式变量具有明确的生物物理意义和林学解析意义,可准确刻画林分冠层三维结构,在不同森林类型不同森林参数估测中均取得较好效果,具有良好的普适性,有利于提高不同森林类型估测结果的可比性,可用于机载激光雷达大区域森林资源动态监测。     

崂山林场林分生物量遥感反演估算研究

以Landsat TM影像和高分一号影像为数据源,结合外业实测数据,利用遥感影像和实测数据建立崂山林场生物量多元线性反演模型,比较分析不同数据源下反演出的模型精度,估测了崂山林场森林生物量。研究发现,利TM遥感影像作为数据源的崂山林场森林生物量反演模型平均精度为77.12%。高分一号遥感数据反演的生物量模型平均反演精度达到80.75%,高于TM数据源下的生物量反演模型精度。分别根据TM遥感影像和高分一号遥感影像林分生物量估测模型,估测的崂山林场2009年的林分生物量为401185.62t,2013年的林分生物量为402485.44t。     

大兴安岭南段阔叶次生林生物量遥感模型研究

应用遥感技术对大兴安岭南段次生阔叶林生物量进行估测,融合2009年8月的SPOT及同期TM影像,结合DEM等资料,利用多源信息复合处理方法,在ENVI软件中计算归一化植被指数、比值植被指数,同时引入海拔、坡度、坡向与阔叶林生物量估测相关的因子,依据地面森林样地生物量实测数据,运用多元回归分析方法,建立阔叶林生物量遥感估测模型B=13220.418-(254.645S+7.218A+46.679RVI)。经过模型检验,各统计量均在合理范围之内,建立的多元回归生物量遥感估测值与实测值平均相对误差≤17.14%,模型预测结果合理精度较高,可用于赛罕乌拉国家级自然保护区阔叶林生物量预测,同时为大兴安岭南段阔叶次生林生物量的遥感估测奠定基础。     

The Use of Simulation in the Management of Privately Owned Forests in Britain

The use of simulation as a tool in planning, predicting output,and as part of a system of forest management is discussed andillustrated by an example based on thirty-seven privately ownedforest estates in the Dee valley in north-east Scotland. The simulation model is described and the results of a low anda high level of felling and afforestation are compared. Thepredicted outputs from the simulation runs are compared withthe records of actual output from 1970 to 1972. The estimated increment and output were: Annual increment of crops 20 years and older 52,000 m³ Annual output at the ‘high’ level .4,000 m³ Annual output at the ‘low’ level 27,000 m³ Average actual annual output 1970–2 18,000 m³ The conclusions drawn from the results of the management studyin the forests of the Dee valley are:

1. In the past, owners haveaccepted low rates of return from theirforest enterprise, theirprimary object being to re-create andmaintain a forest resourcesimilar to that which existed inthe past.
2. Objective reappraisalsof the forest enterprise are exceptionaland management is constrainedoften by arbitrary, rigid, andsevere decisions that imposeunforeseen consequences on activitiesin both the forest andother parts of the estate.
3. The current situation of the forestis very different from thatof the past and is continually changing.For example, the demandsof modern marketing and harvestingpractices are quite differentfrom those imposed even ten yearsago, and the proposed Wealthand Capital Transfer Taxes mayalter the relative importanceto the owners of forest incomeand capital.

Many forest owners in Britain now require a more objective approachto forest management with continuous reappraisal to ensure thattheir plans continue to serve their needs. As the financialresults of the forest enterprise are especially sensitive tothe felling and afforestation programmes, studies to answerthe following questions may be needed urgently:

1. Can a higheroutput than that harvested at present be sustainedin the future?
2. Should the rate of replacement of mature woods be altered?
3. Does the current rate of afforestation best serve the objectsof management in the light of altered tax commitments and cashliquidity requirements?

Computer simulation can be a useful aid in planning providedthat reliable information on costs, prices, and growth ratesis available. Forest managers must be encouraged to collectthe necessary data.     

基于林分生长模型的森林资源年度档案更新技术探讨——以江西省森林资源年度档案更新为例

森林资源档案是森林经营管理的一项重要内容,准确及时的掌握区域森林资源年度更新数据,是实施科学规划合理经营的依据.在吸取当前我国森林资源监测体系相关成果基础上,通过对影响林分生长的自然因素多项因子综合分析,研建林木生长模型和林分生长模型两个层次模型,建立基于林分生长模型的森林资源年度档案更新技术体系.以期为以林地“一张图”为基础的林地保护利用数据年度变更提供参考.     

基于遥感技术的宜良县云南松蓄积量反演

以云南省宜良森林二类调查数据为样本,基于Google Earth Engine云平台Landsat 8 OLI影像,结合植被因子、纹理特征以及K-T变化为自变量,构建了多元线性回归和随机森林的建模方法,建立了森林蓄积量反演模型.以宜良县云南松为研究对象,运用Landsat8 OLI遥感影像数据结合地面角规控制样地调查数...     

基于气象因子深度学习的森林火灾预测方法

森林火灾一旦发生将对生态系统造成严重的破坏,间接导致气候的变化和极端天气频发。对森林火灾的发生进行准确预测可提前采取有效的防控措施,具有重要意义。传统林火预测模型多为数学方法和浅层神经网络,当数据量增大时易出现建模困难以及预测精度降低等问题。深度学习模型在处理大量非线性数据上具有一定的优势,其模型具有多层网络结构,通过训练大量数据可提取出具有代表性的特征值,发现数据间的隐含关系,达到准确分类预测的目的。因此,本研究提出一种基于深度学习的林火预测方法,将深度信念网络(deep belief network,DBN)作为预测模型,气象因子作为输入数据,以解决传统林火预测模型在面对大量数据时预测效果不佳的问题;同时结合过采样SMOTE(synthetic minority oversampling technique)算法,平衡林火数据集和增加训练数据量,提升了森林火灾的预测准确度。结果表明,在面对更大的数据量时,该模型预测精度明显优于其他传统林火预测模型,证明了将深度学习应用在林火预测的优越性。该研究可为深度学习在林业领域的应用提供参考。     

Stand parameter extraction based on video point cloud data

Monitoring sample plots is important for the sustainable management of forest ecosystems.Acquiring resource data in the field is labor-intensive,time-consuming and expensive.With the rapid development of hardware technology and photogrammetry,forest researchers have turned two-dimensional images into three-dimensional point clouds to obtain resource information.This paper presents a method of sample plot analysis using two charge-coupled device(CCD) cameras based on video photography.A handheld CCD camera was used to shoot the sample plot by surrounding a central tree.Video-based point clouds were used to detect and model individual tree trunks in the sample plots and the DBH of each was estimated.The experimental results were compared with field measurement data.The results show that the relative root mean squared error(rRMSE) of the DBH estimates of individual trees was 2.1-5.7%,acceptable for practical applications in traditional forest inventories.The rRMSE of height estimates was2.7-36.3%.Average DBH and heights,and tree density and volume were calculated.Video-based methods require compact observation instruments,involve low costs during field investigations,acquire data with high efficiency,and point cloud data can be processed automatically.Furthermore,this method can directly extract information on the relative position of trees,which is important to show distribution visually and provides a basis for researchers to regulate stand density.Additionally,video photography with its unique advantages is a technology warranting future attention for forest inventories and ecological construction.     

金融危机对我国桉树人工林产业发展的影响及对策

本文通过分析世界不同地区在金融危机前后林产品产量、出口和需求等指标,根据联合国欧洲经济委员会和联合国粮食及农业组织2009年8月发布的《林产品市场年度评论》（2008—2009）中相关的公开共享数据,科学地分析金融危机对世界和中国林业产业及中国桉树种植业的影响,并提出克服影响的建议,以解决传统的森林经理学和桉树决策支持系统无法处理的突发事件对桉树生产的影响。     

Mapping tree aboveground biomass and carbon in Omo Forest Reserve Nigeria using Landsat 8 OLI data

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.     

Maximum entropy modeling of mature hardwood forest distribution in four U.S. states

In the eastern United States, mature hardwood forest provides habitat for many species of native flora and fauna, but is much less common now than historically. This study examined the utility of maximum entropy modeling and spatial application to identify ecosystem types like mature hardwood forest. I performed pilot modeling in Charles County, Maryland, where I compared fine-scale geographic data available locally to coarse-scale data available nationally. As expected, a model constructed with the best locally available data, including LiDAR-derived canopy height and fine-scale soil maps, outperformed a model constructed with nationally consistent data. However, the model using national data nevertheless accurately identified most mature hardwood forest sites and excluded most young forest. I then applied the coarse-scale approach to four states: Pennsylvania, Ohio, Kentucky, and Tennessee. Average test AUC (area under the receiver operating curve) based on 10 replicates varied from 0.76 to 0.80 when comparing mature hardwood forest locations to general forest locations. The maximum training or test sensitivity plus specificity threshold, depending on the state, captured 78-79% of positive locations while rejecting 74-81% of negative locations. The maximum entropy approach is versatile, and can be applied to other ecosystems and species.     

Modelling drainage fluxes in managed and natural forests in the Dinaric karst: a model comparison study

Two models for calculating the forest water balance were applied to different development stages of managed and non-managed forests in the Dinaric Karst for two hydrologically contrasting growing seasons. A simple model WATBAL, which calculates water balance on a monthly basis, and the BROOK90 model, which calculates water balance on daily basis, were used. Differences between calculated drainage fluxes between the models were less pronounced in the drier growing season and were lower in the forest stands compared to forest gaps. Average calculated drainage fluxes of the two growing seasons were highest in the gaps and lowest in the stand in the virgin forest remnant, followed by the mature stand in the managed forest. According to model fitting, testing the calibration robustness and sensitivity analysis the BROOK90 model was considered best at simulating the water balance of the various research sites. The difference in model behaviour is considered to be mainly the result of the difference in model time step and the inclusion of macropore flow in BROOK90. The greater complexity of the BROOK90 model meant it could be parameterized to describe more fully the complexity of the horizontal and vertical structure of forest stand and soil properties. A disadvantage of the BROOK90 model is the greater need of input data. WATBAL, however, was useful for obtaining rougher estimates of the water balance components and can be applied to areas where there is less data available. Choice of model is therefore determined by data availability.     

基于TerraSAR-X/TanDEM-X数据的森林高度反演算法研究

基于RVoG模型,对传统三阶段算法及其改进算法进行研究,以云南省西双版纳州勐腊县为研究区,以TerraSAR-X/TanDEM-X数据为数据源进行森林高度反演算法研究,并结合野外实测数据进行结果验证。结果表明,三阶段改进算法对森林高度反演精度优于传统三阶段算法。三阶段改进算法对天然林高度反演精度较高;三阶段算法对橡胶林高度反演精度较高。