基于超声测距的定高树径测量仪的研究

为了便于对树木直径生长特征的分析,介绍了一种可代替测径围尺的专用于测量树木直径的测量仪。仪器采用超声波测距技术、条码识别技术及光电技术,可实现单株立木测量高度的确定和直径信息的识别,以及测量数据的自动读取和记录,提高了统计效率,方便了对数据的查询与分析。通过实验验证,仪器与围尺测量的相对误差在±1%以内,达到了预期设计指标。

便携式树径生长量测定器推介

介绍了树径生长量测定器的特点和使用方法 。

树径及其环境信息远程动态监测系统的研究

根据直线位移传感器配合机械结构原理、无线传感器网络,并结合太阳能供电系统,建立了一种树径无线遥测及林地环境监测系统。经过初步测试,该系统可以顺利运行,太阳能供电系统的应用大大地延长了系统节点的供电时间。该系统实现对立木胸径、林地温、湿度等信息的实时监测,在实现对林地监测的同时,研究树木直径生长生理特性与其影响因子的相关关系,并可为建立森林资源信息库的提供可靠的数据。

测量树径新工具——测径靠尺

普通的测树工具轮尺和围尺,在测量大径木时,一人难以操作,树干不为正圆时,精度便无保证。吉林省林科院赵彤堂副研究员发明的测径靠尺,不用卡,不用围,一靠便可测量出树径大小。 测径靠尺由角度式尺臂、动尺、读数窗等组成。实际操作时,先将两尺臂靠在树干上,再推动动尺使其顶端也靠至树干,此时在读数窗上即可读出直径值。当遇到椭圆形树干时,将两臂分别靠在长,短径上。

图像测量技术在森林调查中的应用

针对目前森林资源调查中立木测量上存在的问题,提出了一种新的测量方法图像测量.该方法可以同时对树木的树高、树径、树冠进行测量.实践证明该方法简单、可行.

Effect of Continuous Cropping on Leaf Nutrient and Growth of Different Species of Poplar Plantation

[Objective]The paper was to study the effect of continuous cropping on leaf nutrient and growth of different species of poplar plantation.[Method] The tree height,diameter at breast height（DBH）,volume of different generations and species of poplar plantation in poplar production area in northern Jiangsu Province,as well as TN,TP and TK content in their leaves were determined through field investigation and indoor experiment.[Result] With the increasing generation,the changes of TN,TP and TK content in the leaves of different ages of two varieties of forest stand were also different.However,with the increasing tree ages,TN,TP and TK contents in leaves showed decrease trend.With the increasing generation,the changes of tree height of I-69 and I-72 poplar showed the similar trend.The effect of increasing generation on tree height of 7-year-old and 10-year-old poplar was relatively stable,showing decrease trend from generation to generation.The tree height of 4-year-old poplar first increased and then decreased with the increasing generation.The changes of DBH along with different generations were basically consistent with the changes of tree height.With the increasing cultivation generations,the volume of 7-year-old and 10-year-old poplar decreased with significant difference.[Conclusion ] The result provided basis for rational fertilization and management of poplar plantation,improvement of productivity of poplar plantation,and achievement of sustainable management of plantation.

Radial Variation in Sap Flux Density as a Function of Sapwood Thickness in Two Eucalyptus ( Eucalyptus urophylla ) Plantations

Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.

绿化树种及其运输功能对噪音指数的影响——以青岛市为例

对青岛市几个典型道路及小区的噪音指数、温湿度、车流量等进行同步观测,并分析城市绿化树种及其运输功能对噪音指数的影响。结果表明:道路绿化树种减噪能力为:雪松>旱柳>梧桐树>臭椿,小区绿化树种减噪能力为银杏>旱柳>樱桃树>楸树;树间距在合理的范围内对树种减噪能力无影响;同一树种,树径与减噪能力成正相关关系。

龙树湾

在我的故乡浙南龙泉北部山区的双狮村附近，有一处风水宝地，从很远很高的若寮岘奔腾起伏而来似巨龙一样的大山岗，延伸到一个大湾并出现了一个大山坪，叫做龙树湾，那是一块大树成荫、绿竹繁茂的净土。在山坪后壁一字儿排列着一组竖着青石板墓牌的石磊坟墓，正是家族列祖列宗们安息的地方。整个山坪由十余株古树环抱覆盖着，这些大树生机勃勃，铺天盖地，形状各异，树径一般都在二三人合围以上。

香花之王白兰花

白兰花（Michelia alba）为木兰科常绿大乔木。树高可达30米，树径40～60厘米。唯一般栽培者多尽量让植株呈横向生长，长得低矮．不仅采集花朵较容易，而且长出来的花朵也较多；

北港有棵下雨树

最近,在江西省靖安县北港林场的深山林区,发现一棵奇树,说它奇,是因为它有一种特殊的"能耐"——会下雨,树下雨这一奇观,不仅使人们叫绝称奇,也令林业专业人员百思不得其解。这棵"下雨树"属槭树科,树径约18厘米,树高约7-8米,生长在山谷中的山溪旁。

Effect of Ryegrasses on Soil Runoff and Sediment Control

Living plants and plant roots can reduce runoff and soil erosion. Using a rain simulator, a series of soil erosion experiments were conducted to study the influence of living roots and canopies of ryegrasses （Lolium perenne L.） during the growing season on sediment yields and runoff of a silt loam soil. The results indicated that during the growing season, decrements in runoff and sediment yields increased with time. Sediment yields （τ^2 = 0.999） and decrements in runoff （τ2 = 0.946） were closely related to the root surface area density. The contributions of roots and canopies of ryegrasses to the reductions in runoff and sediment yields were different. Canopies usually contributed more to the runoff decrement than the roots, whereas roots contributed up to 96% of the decrease in sediment yields in the late stage of the growing season.

On the Laplacian Spectral Radius of Trees

Some sharp upper bounds of Laplacian spectral radius of trees in terms of order,diameter,pendant vertex number,covering number,edge covering number or total independence number are given.And the ninth to thirteenth largest values of Laplacian spectral radius over the class of trees on a given order are also given.

Comparing the model forms estimating generalised diameter-height re-lationships in Tecomella undulata plantations in hot arid region of India

Four generalised diameter-height equations were developed and compared for pure and even-aged stands of Tecomella undulata in hot arid region of Rajasthan State in India. The data used to fit the equations consisted of 1 540 diameter-height observations collected from the plots laid out in uniformly stocked stands of varying age and density. The performance of four equations was tested by non-linear least squares regression and evaluated using different statistical criteria. Finally, these equations, with the same values of coefficients ob- tained during the fitting phase, were validated by an independent data set consisting of 854 diameter-height observations. Overall, equation （4） （Hui and Gadow function） was found to perform best for both the fitting data set as well as validation data set.

Fitting and evaluation of height-diameter models for Alnus japonica in La Trinidad, Benguet, Philippines

The study was conducted to develop height-diameter at breast height(HT-DBH) models for Alnus japonica in La Trinidad, Benguet,Philippines and evaluate their predictive capability.The six widely used nonlinear growth models that were selected in this study were the ChapmanRichards, Schnute, Modified logistic, Korf/Lundqvist,Weibull and Exponential. A total of 208 Alnus japonica trees were measured using standard diameter tape for DBH(1.3 m above the ground) and Vertex and transponder was used for the total height measurement. The performance of the developed models were evaluated using the fit statistics including coefficient of determination(R^2), root mean square error(RMSE), mean bias(ē), absolute mean difference(AMD), and Akaike Information Criterion(AIC). The lack-of-fit statistics was also performed for further evaluation of the performance of the models.Based on the evaluation criteria, all six models were able to determine the DBH-height relationships and fitted the data well. Using the rank analysis, the Weibull HT-DBH model had the best performance among the six commonly used nonlinear growth models. The results of this study will help forest managers especially in La Trinidad, Benguet to easily predict the total height using the Weibull model for Alnus japonica utilizing the DBH as the predicting variable.

Effect of heating methods on drying quality of small-diameter birch lumbers

Following a normal low temperature drying schedule, the small-diameter Birch lumbers （ 1 000mm× 45mm ×30mm） were dried with consecution-heats or intermittent-heating, visual drying defects （bow, crook, twist, check along grain and end check） were measured, and then statistical analyses were performed. It was found that the drying quality of small-diameter Birch lumbers could be improved with intermittent-heating, but the intermittent time should be prolonged. Prolonging intermittent time helped to weaken or even avoid wood distortion and drying checks. It wash＇ t helpful in avoiding crook. The drying quality of small-diameter Birch lumbers with all kinds of drying methods reached the second class of the Chinese National Standard. The drying quality reached the first class of the Chinese National Standard with the intermittent-heating in the area of visual wood defects.

Forest structure of a maple old-growth stand: a case study on the Apennines mountains(Southern Italy)

In Europe, very small forest areas can be considered to be old-growth, and they are mainly located in Eastern Europe. The typical structures of old growth forests infrequently occur in Mediterranean mountainous environments, since they have been affected by human activities for centuries. This study focused on a remote and almost pure Italian maple stand located in southern Italy, which has not been managed for long time due to its inaccessibility. The effects of natural evolution on the forest stand were evaluated through the analysis of the spatial and chronological structure and the regeneration patterns, then estimating the amounts and quality of deadwood occurrence. Across the whole stand, all the trees with DBH （diameter at breast height） larger than 50 cm （LLT, large living trees） were measured （DBH and height） and age was also determined through a dendrochronological approach. The diameters observed ranged between 50 and 145 cm with ages of 12o to ~5o years. The Latham index calculated for trees within the sample plot highlighted a multilayered canopy with a dominant layer of largeliving trees （age 〉 120 years）. The size-class distribution of stems had a reverse-J shape, and basal area was 52 m2 ha-1. Deadwood was exclusively constituted by standing dead trees and CWD and its volume was on average 31 m3 ha-1. Pure Italian maple forests are generally rare in Europe, and it was unexpected to find a forest stand characterized by a so complex structure with old growth attributes. The study of complex forest stand, even if small, could give precious information on the forest evolution, clarifying also diverse auto-ecological traits of tree species that usually are not common in our forests.

Forest Structure Analysis in the Oban Division of Cross River National Park, Nigeria

Information on forest structure is important for forest management decisions. This is inadequate in many situations, especially where timber is not of primary interest. We analyzed the structure of two forest types in the Oban Division of Cross River National Park, Nigeria. Systematic sampling technique was used to establish two transects measuring 2,000 x 2 m, at 600 m interval in the two forest types in four locations. Four 50 m x 50 m plots were located alternately at 500 m intervals along each transect, constituting 32 plots per forest type and 64 plots in all, Diameters at breast height （DBH）, base; middle and top; crown diameter; total height and crown length were measured on all trees with DBH 〉_ 10 cm. There were 159 stems/ha in the close-canopy forest and 132 stems/ha in the secondary forest. The mean DBH were 34.5 cm and 33.62 cm respectively. The mean heights were 24.79 m and 23.97 m, respectively. Basal area/ha were 41.59 m2 ha~ and 27.38 m2 hal for the two forest types. Majority of the trees encountered in the two forest types belonged to the middle stratum which has implication for small mammals＇ populations. Emergent trees which are otherwise scarce in other parts of the country were recorded, which also has implications for density thinning and seed supplies.

Tree Population Dynamics of Three Altitudinal Vegetation Communities on Mount Cameroon(1989-2004)

Changes in permanent sample plots in the lowland,submontane and montane forests on Mount Cameroon(4,095 m above sea level),an active volcano,are described for 15 years from 1989 to 2004.Throughout the study period,the stocking level of trees with a diameter at breast height(DBH) ≥ 10 cm in the three forests were lower than in pan-tropical stands suggesting a significant impact of volcanic and human-related activities on the vegetation communities on the mountain.Annual mortality rates in the submontane and montane forests were consistent with those reported for comparable altitudinal ranges in the Blue Mountains of Jamaica.The annual mortality rate was higher in the lowland forest than other lowland sites included.Divergence between recruitment and mortality rates was large suggesting that the three vegetation communities have not reached their climax.The seven-year difference in half-life of large trees(with a DBH ≥ 50 cm) in the submontane and montane forests suggests an altitudinal effect on turnover of larger trees that in turn contributes to the frequent small stature of high altitude forests.There was little evidence of an altitudinal effect on species turnover and growth rate.This finding supports generalizations about the zero effect of growth on the stature of high altitude trees.Understanding forest dynamics is crucially important in the management of tropical montane environmentsand in this instance particularly so given the recent creation of the Mount Cameroon National Park.