共查询到19条相似文献，搜索用时 359 毫秒
1.
【目的】树高是森林经营决策中最重要的一个参量,常用于估计森林生长、年龄、材积、生物量和碳储量等立木参数,其精度对立木质量的评价及森林生长的预测分析影响重大。为解决传统的树高量测仪器移动不便,测量周期长,人力耗损大等问题。【方法】以近景摄影测量为基础,构建了一种以登山杖绑定安卓智能手机为测量平台的便携、快捷的树高测量装备;针对立木生长环境有无坡度,拍摄是否产生倾角等情况建立了树高量测模型。在手机环境下,研制了立木树高测量软件APP。APP采用上下分屏技术,利用手机成像系统以及坐标系转换,使屏幕与待测立木建立关联,从而自动解算立木的深度信息;结合手机内部方向传感器的强大性能,单站作业可实时获取树高估计值。在北京市平谷区红石门村选取不同坡度的307株立木作为研究对象,使用该装备分别在上坡位和下坡位对其进行量测,将测定结果与全站仪多次量测求得的平均值进行对比分析。【结果】结果表明,树高估计值平均绝对误差为0.21 m,平均相对误差为2.11%,整体精度达到97.89%。当处于下坡位观测时,树高估计值平均绝对误差为0.11 m,平均相对误差为1.16%,树高精度高达98.84%。当处于上坡位观测时,树高估计值平均绝对误差为0.32 m,平均相对误差为3.07%,树高精度达到96.93%。智能手机倾斜角较大时,精度达到95.19%,智能手机倾斜角较小时,精度高达99.03%,说明手杖式测树仪观测时所产生倾角越小,精度越高。量测同一株立木时,下坡位观测的精度优于上坡位。【结论】此装备的研发满足国家森林资源连续清查中的测量精度要求,且装备成本低、灵活性强、不依赖其他设备获取深度信息、携带方便、具有较高利用价值,未来可作为森林资源调查树高测量装备。 相似文献
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《林业资源管理》2017,(2):103-109
为提升林业调查的技术水平,研究小型无人机搭载非测量相机在林业调查中的应用技术。选择北京十三陵林场开展低空航拍试验,针对非测量相机的镜头畸变和小型无人机相机云台外方位元素误差较大的特点,分别通过相机检校算法和外方位元素逆向求解,进行内外方位元素定向,生成立体像对和正射影像;用地面控制点对相片整体进行几何精校正,采用3D量测工具测量立体区域树高,用地面控制点测量图像拼接区域面积和周长,用现地实测树高、面积和周长对图测结果进行检验和模型拟合。结果表明,通过适当的校正和调整,小型无人机搭载非测量相机基本能够满足林业调查对树高、面积及周长等的量测精度要求,应用前景广阔。 相似文献
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对全站仪测树原理进行了研究分析,应用全站仪与PC-E500袖珍计算机或PDA连接,可自动测算伐区或样地内每一株立木的树高、胸径或树干任意高度处直径,进而可自动而精准地计算出单木材积和伐区立木蓄积.理论上,树高的量测精度可达1/1 400.直径的量测精度可达1/200.实测结果表明:全站仪重复测量数据比较稳定,直径的量测误差在毫米级以内,树高的量测误差控制在厘米级,材积测定精度可优于1%,均高于测树的需要精度.全站仪测树技术实现了实时、快速、精准测定立木材积,不用材积表推求蓄积量,克服了传统测树方法的缺陷,其实测数据可作为伐区设计立木蓄积的测算依据. 相似文献
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本文对比了传统的道路横断面积量测方法与电子求积仪法的优缺点,通过对电子求积仪法在量测速度上、精度上以及操作的繁简程度上的分析,阐述与论证了电子求积仪法量测道路横断面积的可行性,并就量测过程中应注意的问题加以说明. 相似文献
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该项研究采用吉林长白山林区1：2600比例尺黑白航片，进行主要测树因子量测试验。为解决航片量测与实验结果的可比性，该试验在样地野外每木检尺的同时，划定树木生长级并排序。以航片量测株数为准，取等量实测立木对比（从上层顺取） 这样，不仅对比株数相等，对比用的单株也大体在同一范围，并在查明样地被压木数量与航片漏测立木的比率后，根据航片立木漏测规律，编制漏测木蓄积量补偿表，以提高森林蓄积量估测精度。本试验测高业均方误±1．07m，蓄积量估测精度均方误±6．0m^8。展示了用大比例尺航片量测的实用前景。 相似文献
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图形面积量测是地籍测量及农业、林业、海洋等部门经常遇到的工作内容,目前量测面积的方法和仪器有解析法、网格法、平行线法、称量法和数字长度面积仪、密度分割仪、光电扫描面积仪及机械求积仪、电子求积仪等多种。经多年的工作实践,结合国家科技攻关课题——黄土高原重点治理区遥感调查与系列制图中面积量算工作的要求,我们对常用的网格法、机械求积仪、电子求积仪及较高精度等级的数字长度——面积仪的量测精度进行了测定与比较,以供量测面积时参考。 相似文献
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生态旅游环境容量的确定与量测 总被引：17，自引：0，他引：17
生态旅游环境容量是进行生态旅游规划与管理的重要依据。生态旅游环境容量的确定与量测要运用唯物辩证法为指导，采取实证论、规范论和形式化等方法来进行，在具体操作上可采取经验量测法、理论推测法等进行，并注重定性与定量相结合，以确定生态旅游环境容量的阈值范围或者最适容量，保证生态旅游环境良性循环，促进旅游业可持续发展。 相似文献
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花榈木人工林主要测树因子回归模型的研究 总被引：1，自引：0，他引：1
根据花榈木人工林样木的胸径、树高、冠幅、冠长测定数据,应用多方程选优法建立以胸径为辅助因子的树高、冠幅、绝对幅长、相对冠长以及树冠系数等因子的回归预估模型,旨在为生产应用提供定量依据。研究表明:主要测树因子间存在不同程度的线性或非线性关系,视测树因子而定。以相关系数来看,胸径与主要测树因子相关紧密程度从大到小依次为:冠幅、树高、绝对冠长、树冠系数和相对冠长。 相似文献
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巨尾桉立木测树因子关系的研究 总被引：1，自引：0，他引：1
根据长泰县岩溪国有林场凤山工区巨尾桉引种试验林皆伐标准地的120株样木材料,对巨尾桉胸径与树高,胸径、树高与材积,胸径、树高与生物量间的内在关系,采用数理统计和现代计算技术进行分析研究,用数学模型反映立木测树因子之间关系的规律性,为编制巨尾桉测树数表提供理论依据。 相似文献
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南酸枣为我国南方的多用途优良阔叶树种。依据3年和5年生的5种南酸枣林分类型林木的根系及树高、胸径的观测数据,应用分形理论,探讨了南酸枣人工幼林林木的根系与其树高、胸径的分形关系特征,揭示了林木根系的生长过程及其生物量的积累与空间分布规律。结果表明:根系与树高、胸径之间存在极显著的分形关系,说明南酸枣人工幼林根系生物量的累积及其空间分布是一个分形生长过程,它服从分形维数D值规律增长;根据分形模型可以估算林木根系的生产力。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):482-499
This article reviews the research and application of airborne laser scanning for forest inventory in Finland, Norway and Sweden. The first experiments with scanning lasers for forest inventory were conducted in 1991 using the FLASH system, a full-waveform experimental laser developed by the Swedish Defence Research Institute. In Finland at the same time, the HUTSCAT profiling radar provided experiences that inspired the following laser scanning research. Since 1995, data from commercially operated time-of-flight scanning lasers (e.g. TopEye, Optech ALTM and TopoSys) have been used. Especially in Norway, the main objective has been to develop methods that are directly suited for practical forest inventory at the stand level. Mean tree height, stand volume and basal area have been the most important forest mensurational parameters of interest. Laser data have been related to field training plot measurements using regression techniques, and these relationships have been used to predict corresponding properties in all forest stands in an area. Experiences from Finland, Norway and Sweden show that retrieval of stem volume and mean tree height on a stand level from laser scanner data performs as well as, or better than, photogrammetric methods, and better than other remote sensing methods. Laser scanning is, therefore, now beginning to be used operationally in large-area forest inventories. In Finland and Sweden, research has also been done into the identification of single trees and estimation of single-tree properties, such as tree position, tree height, crown width, stem diameter and tree species. In coniferous stands, up to 90% of the trees represented by stem volume have been correctly identified from canopy height models, and the tree height has been estimated with a root mean square error of around 0.6 m. It is significantly more difficult to identify suppressed trees than dominant trees. Spruce and pine have been discriminated on a single-tree level with 95% accuracy. The application of densely sampled laser scanner data to change detection, such as growth and cutting, has also been demonstrated. 相似文献
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油桐根腐病是桐区历史性、毁灭性的病害,危害甚烈。病株须根和侧根皮层腐烂,生长停止,终致死亡。桐林年均病株率16.7％,年均株死亡率7.4—7.5％,3—5年将导致桐林毁败。各级病株同工酶谱较健株减少2—6条,活性减弱,反映出病株内部“生化症状”与外部衰亡程度的相关规律。桐林周年发病时期分为初期、初峰期、高峰期和末期。病情与桐区气候因素关系密切,通径植分析,其顺序地温>气温>相对湿度>降水量。经偏回归求算,建立的预测模式为: (?)=0.623+0.457x_1-0.391x_2-0.02x_3+0.005_4 X~2检验,X~2相似文献
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Using permanent sample-plot data, selected tree height and diameter functions were evaluated for their predictive abilities for major tree species in complex (multiple age, size and species cohort) stands of interior British Columbia (BC), Canada. Two sets of models were evaluated. The first set included five models for estimating height as a function of individual tree diameter, the second set also included five models for estimating height as a function of individual tree diameter and other stand-level attributes. The inclusion of the BAL index (which simultaneously indicates the relative position of a tree and stand density) into the base height–diameter models increased the accuracy of prediction for all species. On average, by including stand level attributes, root mean square values were reduced by 30.0 cm. Based on the residual plots and fit statistics, these models can be recommended for estimating tree heights for major tree species in complex stands of interior BC. The model coefficients are documented for future use. 相似文献
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Tree growth and soil physical properties were compared on two grazed plots planted with sycamore at 5 and 10 m square spacing on an upland Scottish site. Both plots received fertilizer and stocking density of ewes and lambs was adjusted to maintain a constant sward height.Mean tree height in 1990 and height increment (1988–90) were significantly greater in the 5 m spaced plot (P<0.05). Although matric potential under the trees was generally greater than in the grassed rows between trees, mean penetration resistance (37–107 mm depth) was significantly greater (P<0.01) under the trees. Even when the soil was close to field capacity, less than 10% of penetrometer readings were < 1 MPa under the trees, in comparison to 44% in grassed areas between trees. This demonstrates that surface compaction due to preferential treading by sheep near the base of trees was sufficient to have seriously reduced tree root growth. Penetration resistance under the 5 m spaced trees was significantly less (P<0.05) than under the 10 m spaced trees. A technique for estimating the probability of root deflections by stones (in 35 mm depth intervals), Ps, from penetrometer readings was used. A significant relationship (P<0.1) was found between tree height increment and depth to Ps0.4 in the 10 m plot. 相似文献
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Dahurianlarch(Larixgmelinii)isamaintreesPeciesinartificialstandsandManchuriaash(Fnainusma:dehurica)isavaluabIehardwoodsPeciesinti1eforestareaofnortheastChina.SomestUdiesrevealedthatthemixedstandbythetwospecieshadpositivemixedeffectSandnutritionrelationshipwasoneofthemaincausesforthepositiveeffects.lnsomeresearches,itwasfoundthatinline-belttwoflarch-ashmixedstand,theconcentra-tionofavailablephosphorusofsoilinlarchbeltwas2ntimesoftl1atinashbelt.Itisdeducedthatinsuchmixedstandtheashcanabsorbmo… 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):543-553
The aim of this study was to develop prediction models using laser scanning for estimation of forest variables at plot level, validate the estimations at stand level (area 0.64 ha) and test the effect of different laser measurement densities on the estimation errors. The predictions were validated using 29 forest stands (80×80 m2), each containing 16 field plots with a 10 m radius. For the best tested case, mean tree height, basal area and stem volume were predicted with a root mean square error of 0.59 m (3% of average value), 2.7 m2 ha?1 (10% of average value) and 31 m3 ha?1 (11% of average value), respectively, at stand level. There were small differences in terms of prediction errors for different measuring densities. The results indicate that mean tree height, basal area and stem volume can be estimated in small stands with low laser measurement densities producing accuracies similar to traditional field inventories. 相似文献
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Collybia fusipes is a common cause of root rot on oak in the north of France. Collybia fusipes basidiomes can be as frequent on oaks in stands where no decline of the trees occurs compared with stands where the decline is chronic. This might be explained by differences in the amount of roots damaged by the parasite. To test that hypothesis, 430 oak trees, Quercus petraea, Quercus robur and Quercus rubra, located in six forests were selected. Half of them showed C. fusipes basidiomes at the trunk base. The association between presence of basidiomes and decline of affected trees depended on the forest. The level of infection of each tree by C. fusipes, as well as the crown appearance, the tree height : diameter at breast height ratio, age and sapwood width were determined. The presence of C. fusipes basidiomes was always associated with significant root infections. The crowns of the trees deteriorated with increasing level of root infection and the decline was severe only when the root damage was heavy. Although the decline of trees that were heavily damaged by C. fusipes was severe in some of the stands, in others, it was only mild, and so the differences in tree decline between the stands could not be attributed solely to differences in root infection severity. Trees damaged by C. fusipes seemed not to be subjected to more competition than their undamaged neighbour as reflected by a similar tree height: diameter at breast height ratio. 相似文献
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