林分密度研究评述──关于3/2乘则理论*

通过回顾近３０ａ来对植物种群自然稀疏规律──３／２乘则理论的研究结果，全面评价了这一密度理论及其对林分自然稀疏上限线的适合性，并得出结论：林分生长发育过程中，由于树冠形状及林隙发生动态变化，因此不满足３／２乘则。建议采用同一林分的林木大小及林木株数之间动态变化规律，重新建立林分密度理论。     

洛阳市行道树种类及生长状况调查与分析

对洛阳市区主要街道行道树的种类、胸径、高度、冠幅等进行了抽样调查，分析了洛阳市区主要行道树的生长状况、景观效果以及存在的问题，并尝试提出了一些建设性的意见，以期呈现出古都洛阳市区行道树的风貌，为城市发展提供一定的参考和依据。     

用最大树种数测度森林群落树种丰富度

目的 试图给出确定森林群落树种丰富度的方法,解决物种丰富度测度问题,完善森林生物多样性研究的方法。 方法 采用Monod模型表达种-面积曲线,通过数学手段确定最小森林群落面积和最大树种数。 结果 用本研究提出的方法对不同气候带森林物种丰富度进行测算,结果表明：热带森林群落具有更高的最大树种数和更大的群落最小面积,物种丰富度随气候带由热带到寒温带逐渐减少。 结论 用最大树种数能够确切表达不同气候带森林群落树种丰富度,克服了现有研究中直接把不同大小调查面积上的树种数量视为树种丰富度的弊端。     

Phytosociological characteristics and diversity of trees in a comanaged protected area of Bangladesh: Implications for conservation

ABSTRACT

The Chunati Wildlife Sanctuary (CWS), a degraded protected area in southeastern Bangladesh, had been under comanagement since 2004. This study examined phytosociological characteristics and diversity of trees in CWS and discussed villagers’ opinions on the impact of comanagement on forest conservation. Following a stratified and systematic sampling 140 circular plots, 17.84-m radius each, were laid out in seven forest beats for the assessment of phytosociological characteristics and tree diversity. Several key-informant interviews and 15 focus group discussions were held to explore the impact of comanagement on forest conservation and on villagers’ livelihood. A total of 93 tree species were identified having a diameter at breast height (dbh) of ≥ 5 cm in 36 plant families. The dominant species were Acacia auriculiformis, Dipterocarpus turbinatus, Ficus hispida, and Tectona grandis. The average density of trees was 239 trees/ha of which 60% was composed of planted exotic species. Nearly 90% trees were belonging to 5- to 15-cm dbh class and the Shannon-Wiener index was 3.15. The comanagement governance had brought positive changes in forest conservation. However, to sustain the engagement of poor villagers in the comanagement and conservation of degraded CWS, more collective efforts are needed to support their living.     

Analysis of the relationship between DBH and crown projection area using a new model

Relations of DBH-crown projection area (CPA) were studied for deciduous and coniferous trees with different models, one of which is newly derived this time. For DBH-CPA relations, a proposed power-sigmoid function was the most suitable one among four models because of its good fit and mechanistic meaning. This model contains the feature that CPA grows with the second power relation to DBH, and the increasing rate of CPA slows as DBH increases. With transformation, the power-sigmoid function for DBH-CPA relation can be applied for individual basal area (IBA)-CPA relations as single-saturate function, and these two functional models have high compatibility. Next, the differences of DBH-CPA between deciduous and coniferous tree groups were analyzed with power-sigmoid function. The initial increasing rates of CPA against DBH for each group were similar, though the CPA's increasing rate for the coniferous group tended to decrease earlier than for the deciduous group. Because the power sigmoid function has mechanistic meanings, one can separately analyze the attributes of the DBH-CPA relation: the initial increasing rate of CPA and final tree form.     

Low- to moderate-severity historical fires promoted high tree growth in a boreal Scots pine forest of Norway

Abstract

Fire is the most important ecological factor governing boreal forest stand dynamics. In low- to moderate-severity fires, the post-fire growth of the surviving trees varies according to fire frequency, intensity and site factors. Little is known about the growth responses of Scots pine (Pinus sylvestris L.) following fires in boreal forests. We quantified changes in tree growth in the years following 61 historical forest fires (between 1210 and 1866) in tree-ring series collected from fire-scarred Scots pine trees, snags and stumps in Trillemarka nature reserve in south-central Norway. Basal area increment 10 years pre-, 5 years post-, and 11–20 years post-fire were calculated for 439 fire scars in 225 wood samples. We found a slight temporary growth reduction 5 years post-fire followed by a marked growth increase 11–20 years post-fire. Beyond 20 years post-fire, the long-term tree growth declined steadily up to approximately 120 years. Our results indicate that recurring fires maintained high tree growth in remnant Scots pines, most probably due to a reduction in tree density and thus decreased competition.     

基于峰谷分析算法用针刺仪测定树木年龄的可行性分析

目的 介绍峰谷分析算法在树木针刺仪抗钻阻力数据中的应用,推进微损测定树木年龄方法的研究进程。 方法 以吉林省汪清县林业局金沟岭林场天然林中红松、冷杉为研究对象,钻取树木生长芯,同时使用针刺仪获取104组抗钻阻力数据。利用峰谷分析算法,根据树芯的实测年龄选定恰当的阈值Det,记录抗钻阻力的峰和谷的个数为估算的树木年轮数。 结果 根据树芯的实测年龄选定阈值后,利用峰谷分析算法估计树木年龄与实际年龄很接近。该算法估计年龄平均绝对误差是−2,范围在−5年至5年之间,平均相对误差为−2.69%,范围在−6.73%至6.73%之间。经过成对数据t检验得到t值为1.31,说明该算法估计树木年龄均值与真实年龄均值之间无显著差异。 结论 峰谷分析算法应用于针刺仪抗钻阻力序列来估计树木年龄是可行的,确定存在恰当的阈值使针刺仪估计树木年龄精度很高,阈值的选择依据是下一步研究的重点内容。     

银盏林场海南榄仁试验林活立木生长调查与分析

海南榄仁（Terminalia nigrovenulosa Pierre ex Lanessen）是原产于海南岛热带林区的一类商品用材树种,银盏林场于1976年从海南引进进行试种,现保存46株,通过活立木物候观察和树干解析结果发现,海南榄仁在银盏林场表现较强的适应性;能完成开花和结实的完整生殖生长过程;林下自然更新良好,表明该树种能适应当地的立地和气候条件。在清远银盏的引种成功,表明该物种可作为珍贵用材树种在清远市南部地区及以南的广东南部区域种植和发展。     

林木良种化的经济政策分析

林木良种具有公共物品的特征, 需要政府扶持。但林木良种化是一项复杂的系统工程, 涉及良种选育、繁殖、生产、市场供需、利益分配机制等, 每个阶段和环节都有不同的特点, 要从公共财政现阶段的实际状况出发, 给予相应的政策支持。     

绿化带大树主要病虫害调查分析

通过对丹东市主要绿化树种病虫害的调查分析,结果表明:危害行道树和绿化带的病虫害很多,病害主要是流脂病、腐烂病、干腐病和黑斑病,其中流脂病和腐烂病发生的面积大,发病率较高;高温、高湿和栽植过密是导致病虫危害的主要因素;混交度较差,纯林比例大,给病虫害传播创造了条件;生长势较弱的区段病虫危害相对较重。     

基于Sentinel-2影像的火烧迹地快速提取方法比较研究

利用Sentinel卫星数据,特别是其中对植被敏感的红边波段与短红外波段,针对提取灾后火烧迹地研究不足的问题,选取四川省冕宁县4月20日森林火灾发生前后的Sentinel-2卫星数据,使用不同的提取方法探究识别火烧迹地的潜力,并进行对比研究。实验结果表明,决策树分类法识别火烧迹地的能力最好,提取精度最高,BAI指数次之;其余方法均受道路、房屋和裸体不同程度的影响;用红边波段替换可见光红波段的效果相比原有指数提取效果并无明显提升。研究证明在各类方法中,采用决策树分类法能快速高精度地将火烧迹地准确提取出来。     

Water consumption of a single tree from the main afforestation tree species in Western Shanxi Province, a loess area

Water is the key factor in vegetation growth in a loess area. Researchers have been keen on the study of tree transpiration for a long time. To provide a scientific basis and practical instruction for vegetation reconstruction and recovery in a loess area, the paper measured and calculated the water consumption of potted Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis separately during the growing season (from Apr. to Nov.). The four were the main afforestation species in a loess area of western Shanxi based on the principle of water balance. Using data on soil water dynamics and the range of available moisture on potted mature trees, the relationship between water supply and consumption and soil moisture availability and deficit state were analyzed. Several conclusions are listed as follows: 1) In the dry year (2002), during the growing season the precipitation was 430.7 mm and the water consumption of potted trees was from 430 to 490 mm. More water consumption and less available water supply occurred, showing a serious water deficiency. In the rainfall-rich year (2003), during the growing season the precipitation was 870.2 mm and the water consumption of potted trees was from 480 to 515 mm. Due to the uneven distribution of rainfall, the water budget balance was slightly affected in May and November. 2) The curves of soil water content of different species had similar annual changes, although the trends were different in the same month, and those of the same tree species in different test plots also had different trends in the same month. 3) Non-available soil water content of Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis was less than 8.0%, 8.4%, 9.2% and 9.7% respectively, which indicated that Pyrus orentalis used water more efficiently than the others. In the dry year (2002), for several months, soil water content of potted trees was lower than its threshold value for non-available soil water content, which could influence the healthy growth of trees. After supplements of precipitation of winter in the year and spring in the next year, soil water content was higher than the lower limit of soil readily available moisture content, which implied that a balance between inter-annual water supply and consumption could be maintained. __________ Translated from Scientia Silvae Sinicae, 2006, 42(9): 18–23 [译自: 林业科学]     

《江西省森林资源转让条例》对促进林木林地流转的成效分析

《江西省森林资源转让条例》的颁布实施活跃了江西省的林木林地转让交易,推动了林木林地的资产化、产业化经营,增加了林农的收入。但随着林业产权制度改革的深入,一些新的问题还有待于进一步明确。本文对《条例》促进林木林地流转的成效及有关问题进行分析,并提出相关的建议。     

Forest variable estimation using photogrammetric matching of digital aerial images in combination with a high-resolution DEM

Abstract

The rapid development in aerial digital cameras in combination with the increased availability of high-resolution Digital Elevation Models (DEMs) provides a renaissance for photogrammetry in forest management planning. Tree height, stem volume, and basal area were estimated for forest stands using canopy height, density, and texture metrics derived from photogrammetric matching of digital aerial images and a high-resolution DEM. The study was conducted at a coniferous hemi-boreal site in southern Sweden. Three different data-sets of digital aerial images were used to test the effects of flight altitude and stereo overlap on an area-based estimation of forest variables. Metrics were calculated for 344 field plots (10 m radius) from point cloud data and used in regression analysis. Stand level accuracy was evaluated using leave-one-out cross validation of 24 stands. For these stands the tree height ranged from 4.8 to 26.9 m (17.8 m mean), stem volume 13.3 to 455 m³ ha^?1 (250 m³ ha^?1 mean), and basal area from 4.1 to 42.9 m² ha^?1 (27.1 m² ha^?1 mean) with mean stand size of 2.8 ha. The results showed small differences in estimation accuracy of forest variables between the data-sets. The data-set of digital aerial images corresponding to the standard acquisition of the Swedish National Land Survey (Lantmäteriet), showed Root Mean Square Errors (in percent of the surveyed stand mean) of 8.8% for tree height, 13.1% for stem volume and 14.9% for basal area. The results imply that photogrammetric matching of digital aerial images has significant potential for operational use in forestry.     

“十二五”木本粮油树种研究领域科技成果推广示范的立项分析

为给木本粮油树种研究领域科技成果推广示范提供参考依据,依托中央财政林业科技推广示范项目数据库,分析了"十二五"期间核桃、油茶、枣、栗、香榧、榛子、油橄榄、柿等木本粮油树种研究领域的科技成果在不同省(区、市)推广的主要技术和内容。结果表明:核桃领域的研究成果在全国20个省(区、市)进行了推广示范,推广区域较广,但成果的技术推广能力仍处于较低水平;油茶研究领域的先进科技成果在全国15个省(区、市)进行了应用,推广内容全面,成果水平较高;枣、栗、香榧、榛子、油橄榄、柿等树种的研究成果只在特定区域进行了推广示范,成果水平和推广能力尚需进一步提高。文中指出,不同木本粮油树种研究领域科技成果具有区域推广特征,今后应加大和拓宽不同木本粮油树种、同一树种不同技术在全国推广示范的力度和范围。     

防火林带迎风面风速分布规律的风洞试验

采用风洞模拟方法,对通风结构、疏透结构和紧密结构3种防火林带迎风面的风速进行测定,绘制了3种结构防火林带迎风面的相对风速等值线图;根据风速的分布特征,采用多模型选优的方法,确定了山脊防火林带迎风面的相对风速预测模型。结果表明:紧密结构与疏透结构的防火林带迎风面的阻风性能比较好,最小相对风速达到70%以下,而通风结构的阻风性能最小,迎风面的最小相对风速在80%左右。如考虑其综合防火效能则以疏透结构的防火林带阻火性能最佳。     

南昌市植物多样性分析、保护与规划

在对南昌市主城区园林植物应用现状调查的基础上,分别对不同生活型（习性）植物的多样性、主城区各应用类型的植物多样性、不同绿地类型的植物多样性、不同的行政区的植物多样性及珍稀植物与古树名木的多样性进行分析,并就其现状问题提出南昌市植物多样性的保护与规划策略,以期为南昌市的绿化建设提供理论参考。     

川西亚高山箭竹-岷江冷杉原始林优势树种的空间格局分析

箭竹-岷江冷杉林是川西亚高山暗针叶林的重要类型,研究其优势树种的空间分布格局和空间关联性对其恢复和保育具有参考意义。采用林木定位调查法,分别用Ripley’s L(t)和L12(t)函数分析群落中优势树种的空间分布格局和空间关联。结果表明:群落的优势树种为岷江冷杉(Abies faxoniana)、红桦(Betula albosinensis)和云杉(Picea asperata),群落层次结构分明。3个优势树种在小尺度上均为聚集分布,其分布格局随尺度增大而变化。岷江冷杉种群在0~11m的尺度上呈聚集分布,而在11~20m的尺度上呈随机分布;红桦种群在0~14m的尺度上呈聚集分布,而在14~20m的尺度上呈随机分布;云杉种群在0~20m尺度上均呈聚集分布。3个优势树种间的空间关联性在0~20m尺度上均呈显著的相互独立关系,表明它们相互之间作用微弱。     

大理市古树名木资源及特点分析

对大理市城区及周边乡镇的古树进行实地调查结果,这一区域共有古树名木215株,其中古树212株,名木3株.经鉴定隶属23科30属35种.分析了大理市古树名木种类与资源的关系,树龄结构与分布及文化特色等特点,并提出了古树名木保护中存在的问题.