基于移动最小二乘法的点云叶面三维重建

利用地面激光扫描仪获取户外树木的大量点云数据,从中截取树叶点云数据并以此进行曲面拟合,构建树叶真实的三维模型。主要针对空间散乱点云数据的曲面拟合方法进行研究,并利用Delaunay三角剖分构建树叶三维模型。在移动最小二乘法的二维曲面拟合方法基础上,针对空间散乱点云数据,提出了新的曲面拟合方法。通过移动最小二乘法对点云数据曲面拟合,得到了理想的效果后再利用三角剖分重建叶面三维模型。     

基于卷积神经网络和树叶纹理的树种识别研究

利用计算机图像工程技术和卷积神经网络将大量树叶图像叶脉信息提取并分类,主要研究单一背景下阔叶树叶脉纹理特征。本实验采用卷积神经网络在图像信息识别准确率高,无需人工定义树叶纹理特征减少繁琐的人工成本。将网络在Caffe平台上面进行定义,使用符合标准正态分布的一组随机参数初始化网络。对卷积神经网络使用BP神经网络反向传播算法和随机梯度下降算法训练。经过对于网络的训练最终识别率达到95%以上,超过了人眼的识别率,为树种识别研究提供有效的分类方法。卷积神经网络在树叶纹理中省去了人工定义树叶特征的工作。最终多次实验得到可观的识别效果,卷积神经网络适用于树叶图像的识别,其识别率基本达到可以应用的要求。     

异尾华枝虫生物学特性及防治

异尾华枝 虫 Sinophasma mirabile Günther在华东地区是一种新发现的危害壳斗科树木的重要食叶害虫。在浙江泰顺 1年发生 1代 ,以卵越冬 ,若虫和成虫大量取食寄主树叶造成树木生长衰弱甚至枯死。该文介绍了该虫的年生活史、发育过程、生活习性、取食量、天敌种类和防治方法 ,采用燃放烟剂、树干注药、地面喷药等措施 ,防治效果显著     

异尾华枝Xiu生物学特性及防治

异尾华枝ＸｉｕＳｉｎｏｐｈａｓｍａ ｍｉ３ｒａｂｉｌｅ Ｇｕｎｔｈｅｒ在华东地区是一种新发现的危害壳斗科树木的重要食叶害虫。在浙江泰顺１年发生１代，以卵越冬，若虫和成虫大量取食寄主树叶造成树木生长衰弱甚至枯死。该文介绍了该虫的年生活史、发育过程、生活习性、取食量、天敌种类和防治方法，采用燃放烟剂、树干注药、地南药等措施，防治效果显著。     

英国研究测量施肥量新技术

英国土壤学家托尼·哈里森和约翰·戴顿博士研究了一项测量林木施肥量的新技术,施肥量的确定是通过测量树根吸收营养的速度来实现的。常规的测量方法是对树叶和土质进行分析,但是由于树木对营养的需求并不能完全直观地反映在树叶上,因此通过观察树叶来分析氮、磷、钾的含量是靠不住的,施肥量的多少不易掌握,施少了不起     

估测树木需肥量新方法

通常采用的树木需肥量估测方法是对树叶或土壤进行分析,但两者都不十分可靠。现在,美国两名土壤学家研究出一种能可靠测定树木需肥量的新方法,其速度快、成本低。该方法是通过测定树根对营养成分的吸收率来测定树木的需肥量,从而使农民能准确地计算出需肥量。具体做     

树叶在饲料中的应用

树木种类繁多。除少数树叶不能作饲料用以外,绝大多数树木的叶子(包括青叶和秋后落叶)。都可作畜禽饲料。合理的采摘利用。不但不会影响树木的生长。还可以开发利用资源,提高经济效益,现介绍几种常见树叶的饲用价值,以供广大农民选择。 一、松针粉:松针粉是由马尾松、黑松、湿地松、火炬松、赤松、五针松等树种的针叶,洗净切碎。放在80℃高温箱中,经过几十秒钟的快速烘干处理,再粉碎而成。松     

近年来在我国严重为害森林的毒蛾种类鉴别

毒蛾科昆虫是林业上的重要害虫。目前已知为害森林的毒蛾有80余种,其中很多种类能造成森林大面积受灾。树木受灾后,轻者使树叶枯黄脱落,芽梢枯萎,树木长势衰     

树木形态结构的三维建模方法研究

树杆与树叶是构建树木3D模型的2个要素,相关的建模方法很多,但普遍存在建模的真实度不高和建模效率较低等不足,或是难以同时解决存在的二者兼顾的问题。本项研究提出了基于少量特征参数和变量控制,构建任意变形与光滑连接的树干方法,以及基于树叶图像处理的树叶精细智能绘制和简易表达模拟方法,这些方法为树木的精准和高效建模提供了一个有效的途径。结果表明,本项研究提出的方法建模速度快,构建的树木模型真实度高,效果更好,并具有很强的建模灵活性和很好的可交互性。     

虚拟森林资源信息三维可视化中树模型的生成方法

根据树木形态特征的相似性,应用IFS(Iterated Function System,迭代函数系统)方法,采用面向对象的分析和设计方法,将树的建模分为树干建模和树叶建模,建立了树的三维模型,并将其加入到虚拟森林资源信息三维可视化中。     

Diversity of deciduousness and phenological traits of key Indian dry tropical forest trees

? In seasonally dry tropical forests deciduousness (leaflessness) is an important strategy of trees to survive in water stress period during summer. Deciduousness is a reflection of interacted effect of seasonal drought, tree characteristics and soil moisture conditions.

? The present study aims to document the diversity in leaf pheno-phases in terms of duration of deciduousness (which is reciprocal to growing season length), wood density, leaf mass per area (LMA) and leaf strategy index in 24 important tree species growing in the Vindhyan dry tropical forest in India.

? On the basis of phenological observations, the tree species were categorized into two main groups: leaf exchanging species exhibiting overlapping periods of leaf fall and leaf flush, and deciduous species whose timings of leaf flush and leaf fall differ resulting in a time lag (deciduousness) between the completion of leaf fall and initiation of leaf flush. Presence of wide range of deciduousness duration (from ca. a week to 7 months) among dry tropical trees indicates large variations in their growing season length. In the tree species studied, as the duration of deciduousness increased, leaf flushing period decreased significantly but leaf fall period showed little variation.

? Differing deciduousness in tree species exhibited substantial differences in their leafing (vegetative growth) pattern, as reflected by ratio of durations of leaf flush to leaf fall (leaf strategy index). Across different species, duration of deciduousness was significantly positively correlated with leaf strategy index, and significantly negatively correlated with both wood density and LMA.

? Wide variations in deciduousness, leaf strategy index, wood density and LMA in the 24 species investigated indicate considerable functional diversity in tree species growing in Vindhyan dry tropical region. Variation in seasonal duration of deciduousness among species is reflections of differences in tree functional traits like stem wood density, leaf strategy index and LMA.

     

林木病原真菌——赤黏壳科(Erythrogloeaceae)的识别与鉴定

赤黏壳科Erythrogloeaceae包含了多种植物枝干溃疡病菌及叶斑病菌,是间座壳目Diaporthales中一类重要的林木病原菌。本文分析了赤黏壳科的分类学历史和研究现状,总结了赤黏壳科4属21种的分类学特征,编制分种检索表,并构建了该科适用的系统发育树,对后续相关研究工作以及林木病害防治工作提供技术支撑。     

鄂西北半干旱地区多季节造林技术研究

试验结果表明:鄂西北秋季造林比春季造林成活率可提高30%左右,差异显著;苗木高生长可提高1.6～6.0倍,地径生长变化不大;对于不同树种,中、晚秋造林成活率不同,针叶树种如湿地松、杉木等中、晚秋造林成活率变化不大,而阔叶树如刺槐、沙棘等晚秋造林成活率则明显高于中秋造林。因此,鄂西北地区造林应根据造林树种不同而选择相应的造林时间,尤其是阔叶树种应在10月中旬造林效果最佳,针叶树种造林时间可以提前到9月中旬。     

Quantitative Classification of Plant Functional Types Based on Photosynthesis

Classifying plant functional types by a general and quantitative technique is important for sustainable forest management. Here, the time series of diurnal net photosynthetic rate and other related external and internal factors of 11 tree species in a young mixed broadleaf and coniferous Korean pine forest in Northeast China were recorded during the growing season. All time series data were analyzed by a newly proposed model, by which the relative importance of external environmental factors and internal factors on leaf photosynthetic rate among tree species was evaluated. The analysis showed that this method can be useful to identify environmentally sensitive tree species and to quantitatively classify plant functional types. Photosynthetic rate in most pioneer tree species is less sensitive to variation in environmental conditions than in late successional species. The photosynthetic rate of all 11 tree species was mainly determined by their internal factors. The results may also have implications for tree species selection in forest plantations and forest restoration.     

Tree species classification using deep learning and RGB optical images obtained by an unmanned aerial vehicle

The diversity of tree species and the complexity of land use in cities create challenging issues for tree species classification.The combination of deep learning methods and RGB optical images obtained by unmanned aerial vehicles(UAVs) provides a new research direction for urban tree species classification.We proposed an RGB optical image dataset with 10 urban tree species,termed TCC10,which is a benchmark for tree canopy classification(TCC).TCC10 dataset contains two types of data:tree canopy images with simple backgrounds and those with complex backgrounds.The objective was to examine the possibility of using deep learning methods(AlexNet,VGG-16,and ResNet-50) for individual tree species classification.The results of convolutional neural networks(CNNs) were compared with those of K-nearest neighbor(KNN) and BP neural network.Our results demonstrated:(1) ResNet-50 achieved an overall accuracy(OA) of 92.6% and a kappa coefficient of 0.91 for tree species classification on TCC10 and outperformed AlexNet and VGG-16.(2) The classification accuracy of KNN and BP neural network was less than70%,while the accuracy of CNNs was relatively higher.(3)The classification accuracy of tree canopy images with complex backgrounds was lower than that for images with simple backgrounds.For the deciduous tree species in TCC10,the classification accuracy of ResNet-50 was higher in summer than that in autumn.Therefore,the deep learning is effective for urban tree species classification using RGB optical images.     

云南森林树种种质资源保存策略初探

结合云南自然地理和森林树种植物区系特点,就制订其森林树种种质资源保存策略提出如下建议：开展3种保存方式及建立在分子标记基础之上的样本技术研究;分别气候带和地域实施有侧重的原地和迁地保存,分期建立9个迁地保存中心;配合重大林业生态工程,营造迁地保存林及提供优良种质;在云南“中华生物谷”项目中建立专门的种质低温保存率。     

日本山口的一些景观树对2006、2007年干旱和高温事件的响应

本文依据1967-2007年间的气象资料,对日本山口市的极端天气事件进行了分析,主要用像素分析和光谱分析法对景观树的响应进行了调查研究.结果表明,经过干热、多风的2007年夏季之后,山口市的许多景观树对这些极端天气事件的响应趋于缩减其叶面积和减少辐射能的吸收.一些景观树种出现树叶早期变色或脱落,在许多不利条件下栽培的四照花(Cornus kousa)树上发生叶边叶缘焦枯症状.像素分析结果表明,四照花样树的叶面积平均焦枯率达41.6%,山茶花2007年花季的花量也明显少于2006年.对偏冠变色的美国枫香(Liquidambar styraciflua)树进行的微分分析表明,其树冠颜色呈逻辑斯蒂函数式变化.这表明即使在湿润的山口市,持续的高温少雨天气对一些不利条件下栽植的敏感景观树也是有害的.     

基于数学形态学的立木树枝信息提取方法

立木树枝信息的提取,是进行立木枝桠遮挡识别的基础。本文提出一种基于数学形态学方法的立木树枝信息提取方法。该方法先利用数学形态学基本运算——腐蚀和膨胀来实现树干信息的提取,然后将枝干的二值图像与提取得到的树干图像做差运算,从而得到树枝信息。实验结果表明,此方法能有效的提取立木图像中树枝的信息。     

Quantity of plant leaf area on three major public squares in Kunming City,China

Regressive formulae to calculate the quantity of plant leaf area for 13 species of ornamental plants were set up based on investigation data of 30 species on 3 major public squares (Dongfeng square, Shengli square and Guandu square) in Kunruing City, China, which were applied to calculate quantities of plant leaf area of these 13 species. The quantities of plant leaf area for the other 17 ornamental plant species on these squares were directly measured, and the total quantity of plant leaf area of each studied square was obtained individually. The results showed that the quantity of plant leaf area on Shengli square with ornamental plants structure composed of arbor tree species, shrub tree species and turf grass was highest among the three squares. It is believed that the design model of multi-storied vertical structure and proper tending of plant community could not only increase the quantity of plant leaf area, but also play an important role in generating ecological and landscaping benefits.Some corresponding suggestions were put forward on the basis of comprehensive analyses on the plant leaf area quantity of the three representative squares in Kunming urban area.     

Comparative water use by dryland trees in Parklands in Senegal

Despite the clear evidence of competition for water between trees and crops, there have been very few studies comparing simultaneous water use by differing tree species in drylands. Comparative water use by dryland trees was measured in Senegal using heat balance gauges at the end of the wet season and in the dry season. Significant differences between tree species were found for maximum rates of water use per unit leaf area. Indigenous species may be better adapted to the dry environment than exotic species but the indigenous species Acacia seyal Del. used more water per unit leaf area than all other species. The exotic species Azadirachta indica Adr. Juss. consistently used less water per unit leaf area than most other species. There were significant differences in amounts of water used per unit leaf area by differing provenances of the same tree species. Water use in the dry season varied by a factor of three between two provenances of Acacia aneura F. Muell ex Benth. indicating potential to select provenances for drylands based on their water use characteristics. Absolute rates of water use as well as differences in sapflow between species were greatest when soils were moist suggesting that comparative sapflow studies will be most informative when carried out during the wet season. Water use rankings of the differing tree species were broadly maintained irrespective of season.This revised version was published online in November 2005 with corrections to the Cover Date.