常绿阔叶树叶面积指数与其形态特征的相关性分析——以上海地区主要常绿阔叶树种为例

以LAI-2000冠层分析仪的应用为基础,对上海园林几种主要常绿阔叶树木黄杨Buxus sinica、桂花Os-manthus fragrans、广玉兰Magnolia grandiflora和香樟Cinnamomum camphora单株植物的树高、枝下高、冠幅、基径/胸径、三维绿量等形态特征数据和叶面积指数(ILAI)进行测量分析。结果表明:4种植物的形态特征数据之间均有显著性正相关;黄杨受修剪影响,单株ILAI与形态特征数据无显著相关性,但叶总量与树高、三维绿量有极显著正相关;桂花和广玉兰单株ILAI与树高、三维绿量有极显著正相关;香樟随树木成长枝干横向生长的影响,单株ILAI与树高呈显著负相关,但其叶总量与形态特征数据呈极显著性正相关;平均单株ILAI灌木类大于乔木类,而平均单株叶总量却恰恰相反;反映出不同生活型的植物其树枝叶片的空间分布是有明显差异的。同时,根据上海植物园多年的单位叶面积生态效益数据,结合相关ILAI方程,建立了单株植物生态效益模型公式。     

唐棣无性系生长量与结实量的调查报告

通过对引进6个唐棣无性系树高、地径、果实直径、单株结实量、单果质量的调查与分析,结果表明,各无性间树高、单株结实量差异均显著,唐棣无性系6号树高、单株结实量最大,分别为138.20 cm、177.00 g,分别为无性系总体平均值的138.20%和108.92%,确定出唐棣无性系6号为面向吉林地区推广的优良无性系。     

坡地生态经济林水分研究

研究表明，黄土丘陵区旱坡地生态经济林在年降雨量达到331mm时，经济林(枣树)生长期的水分供需在理论上达到平衡状态。降雨量低于331mm时，经济林园水分出现亏损，水量平衡向负值倾斜。由于雨量分布不均，某一时期的旱害会影响整个生育过程。实际观测表明，当生态经济林平均单株土壤水分净集蓄量达到树体蒸发量的2倍时，经济林才能正常生长结果，而要达到这个集蓄量，年降雨量需大于400mm。当降雨量为298mm时，林地缺水随密度的加大而增加，4种密度株均缺水依次为—249．14kg、—354．56kg、—453．50kg和—640．95kg。     

用电阻应变法测定木材顺纹抗压弹性常数的研究

用电阻应变法测定木材顺纹抗压弹性常数的研究龚蒙（南京林业大学南京２１００３７）关键词木材，电阻应变法，弹性模量，柔量木材弹性常数是反映木材刚性的指标，也是木结构设计和木质复合材料设计的重要参数。电阻应变法（简称电测法）在木材科学中的应用是最近二、三十...     

牛角瓜3个居群的结实特性研究

调查分析东川、元江和元阳3个干热河谷居群的牛角瓜结实等特征。结果表明,1元阳居群的牛角瓜单株结实量、单位冠幅结实量和单枝结实量最高,分别为102.4个/株、35.1个/m2和34.6个/枝,且3个居群间这3个指标差异极显著;2居群内单株、单位冠幅和单枝结实量3个指标差异极显著;3各居群的单株结实量与单枝结实量、单位冠幅结实量和分枝相关性状间呈线性相关。元阳是牛角瓜人工栽培的首选区域,通过对结实量大的优良单株进行选育,可极大地提高其果实产量。     

竹炭营养颗粒在花卉中的应用

竹炭营养粒是一种新的室内花卉较理想的栽培基质，它的球径可以加工成2～15mm大小各种规格，以满足不同植物生长的需要。它具有以下几个特点：（1）竹炭营养颗粒表面和内部有大量且均匀的毛细微孔，具有透气吸潮的特点。加水后，植物的毛细根可以直接吸收颗粒内的营养元素。（2）竹炭营养颗粒含有生物生长所需的各种矿物质，可保持良好的营养平衡。     

绿巨人组织培养的激素调控

通过对观叶植物绿巨人在不同生长阶段、不同状态下培养基中激素的调控、筛选，选出了５种分别适用于愈伤组织团块、丛生芽苗团、单株苗生长，在不同生产时期使用的培养基配方。     

从水量平衡角度探讨沙地樟子松人工林的合理密度

本文从水量平衡角度，分析了可供不同年龄沙地樟子松人工林利用的有效水量；在保证土壤供水充足的条件下，估算出不同年龄单株樟子松的年蒸腾水量，据此推算出不同年龄单株樟子松的合理水分营养面积及合理密度，为建立稳定的沙地人工林提供科学依据。最后讨论了该结果在生产实践中的应用问题。     

如何提高石榴的坐果率

石榴花具有开放时间一致、花期长、坐果率低的特点。自然坐果率仅占总花量的0．9％-7．82％，少数单株最高达到15．18％。提高坐果率是实现石榴丰产的关键。主要措施如下：     

不同种源香椿苗期生长差异比较

采用14个产地种子所育的1 a生香椿播种苗为测定材料,研究了各种源苗期生长差异,发现各种源香椿苗的苗高、地径与生物量等生长性状均存在显著差异,同一种源内不同单株之间也存在较大差异.7～9月是香椿苗高生长的主要时期.香椿种源的地理变异规律主要表现为南一北变异趋势.综合其生长表现,初步选出江苏南京和湖南洞口2个种源为苗期优良种源.     

用回归正交设计建立柳杉人工林单木生长模型

将柳杉人工林单株木的胸径、树高、材积 3个因子的生长量作为年龄、地位指数、竞争指数的函数 ,用回归正交设计法建立单木生长模型。误差计算表明 ,该方法是可行的 ,在林业生产上有其实用价值     

Accurate single-tree positions from a harvester: a test of two global satellite-based positioning systems

Accurate positioning of single trees registered automatically during harvesting operations opens up new possibilities for reducing the field sampling effort in forest inventories utilising remotely sensed data. In the present study, we propose to use a harvester to collect single-tree data during regular harvest operations and use these data to substitute or supplement traditional measurements on sample plots. Today’s harvesters are capable of recording single-tree information such as species and diameter at breast height, and a cut-to-length harvester was equipped with an integrated accurate positioning system based on real-time kinematic global satellite positioning, as well as a low-cost global navigation satellite system (GNSS) receiver mounted directly on the harvester head. Positions from 73 trees were evaluated and compared to coordinates obtained using a total station. At the single-tree level, the mean error for the integrated positioning system was 0.94?m. The low-cost GNSS receiver mounted on the harvester head yielded a mean error of 7.00?m. The sub-meter accuracy obtained with the integrated system suggests that data acquired with a harvester using this positioning system may have a great potential as a method for single-tree field data acquisition.     

全国立木生物量建模总体划分与样本构成研究

结合全国生态地理区域和行政区域,并兼顾立木材积表的建模总体划分,提出了全国立木生物量建模总体划分方案,将全部树种分为34个树种组,全国分为6大地理区域,共划分70个建模总体;通过对已有立木生物量数据进行建模分析,将立木生物量模型的预估精度确定为95%以上,同时根据变动系数分析结果提出合适的建模样本单元数应该在150以上,且要按划定的10个径阶均匀分配,保证每个径阶的样本单元数不少于15个;以第七次全国森林资源清查数据为基础,确定了每一个建模总体的样本结构,将样本单元数全部落实到了各省和各级径阶。研究成果可为推进全国森林生物量调查建模工作提供参考依据。     

基于三维激光扫描的单木胸径和树高提取

为了提高林分尺度下单木参数的识别精度,研究了基于三维激光扫描的单木胸径和树高的辨识方法。在东北林业大学实验林场,采用Trimble S60三维激光扫描仪,对104株蒙古栎进行多测站扫描,获得样本树的点云数据。在对点云数据进行配准、去噪、地形数据提取、切片栅格化等一系列处理基础上,基于霍夫变换和连续生长法分别构建了胸径和树高的提取方法,对林分尺度下单木定位识别、胸径和树高提取精度进行了对比分析。研究结果表明:所构建方法单木定位识别精度均值为87.50%,胸径和树高提取的均方根误差分别为2.88 cm、2.61 m。     

Final results from a trial to test the effect of plot size on Eucalyptus hybrid clonal ranking in coastal Zululand,South Africa

Hybrid clones with Eucalyptus grandis as one parent and, generally, E. urophylla as the other parent, are deployed commercially as monoclonal blocks by Sappi in the subtropical region of coastal Zululand, South Africa. In monoclonal blocks genotypes are grown in self-competition. Performance under this scenario may not necessarily correlate well with performance where genotypes are competing for resources with a number of genetically dissimilar genotypes. There is an uncertainty whether plot configuration or size influences clonal ranking and therefore selection of clones for commercialisation. Final results at age eight years of a trial testing eight selected Eucalyptus hybrid clones in single-tree, eight-tree line, and eight x eight tree square plots are reported in this paper. Ranking of the eight clones between the half rotation (44 months) and full rotation (94 months) measurement have remained stable in the single-tree and line plots, but there have been some changes in the square plots. At 94 months, clonal ranking between the single-tree and line plots was consistent (r_p = 0.98) with only two clones changing ranks. When comparing the clonal ranking of the single-tree plots to the large square plots rank changes have been significant (r_p = 0.65). The overall means for the three different plot types are very similar. The range of the clonal means for tree volume in the single-tree plots (0.4042 m³) is more than five times the range for the square plots (0.0709 m³). Gain predictions using data from the single-tree plots overestimated the realised gains measured in the square plots. The top-performing clone in the single-tree plots had a predicted gain of 74% over the trial mean, but only yielded 7% more in the square plots. Similarly, the worst-ranked clone in the single-tree plots did not perform as poorly as what was predicted (?59%) and produced only 13% less than the trial mean on the square plots.     

国外立木生物量模型研究现状与展望

对国外立木生物量模型的研究现状进行了综述, 从样本采集、建模方法、模型评价和模型应用等方面系统总结了立木生物量模型研建的技术要点, 并从开展国家级森林生物量监测的角度提出了建立通用性立木生物量模型的研究重点。     

Single-tree and Group Selection in Montane Norway Spruce Stands: Factors Influencing Operational Efficiency

The operational efficiency of single-tree and group selection with a single-grip harvester was studied in uneven-aged spruce forests at high altitudes in southern Norway. Three harvest intensities of single-tree selection and two group sizes were examined in group selection. Single-tree selection included harvest intensities of 25, 45 and 65% of basal area. Group sizes for group selection were 0.063 and 0.250 ha. Normally, single-tree selection is considered less efficient than group selection or clear-cutting. In this study, because time consumption per cubic metre was primarily dependent upon average harvested tree volume, the large harvested tree size for single-tree selection allowed this treatment to be more efficient than group selection. The two blocks in this study were part of a larger design of five blocks with identical treatments under varying stand conditions. The relative operational efficiency of single-tree selection compared with group selection was greatest in stands of low stocking. Other studies have also shown that mechanical damage to the residual stand is lowest under these conditions.     

Effect of selective cutting type on the chainsaw productivity in Caspian Forests

Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests,the selective cutting performed as single and group selection cutting in the region.The selective cutting was performed on a 42-ha tract with an average slope of 30%.The results indicate that felling time for per tree is most affected by diameter at breast height,the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method.The production rate in single and group selection cutting were 21.2 m 3 h-1 and 28.4 m 3 h-1 for one person,respectively.Considering the gross and net production rate in single and group selection cutting,the unit cost was 1.11 USD m-3 and 0.88 USD m-3,respectively.The results indicate that group selection cutting can be more profitable than single-tree selection method.     

广义干曲线模型在杉木人工林蓄积量测定中的应用

广义干曲线方程是研究林分生产力状况的有效方法.利用所建立的杉木人工林广义干曲线模型模拟不同立地、不同密度、不同年龄杉木人工林单株材积和林分蓄积量,并与杉木二元材积公式(《立木材积表》(Ly208-77))计算的相应单株材积和林分蓄积量进行对照,比较结果高度一致.说明运用该广义干曲线模型模拟不同集约经营条件下的杉木人工林具可行性,在生产实践中有可应用性.     

利用混合模型方法建立全国和区域相容性立木生物量方程

开展全国森林生物量监测和评估,建立适合较大区域范围的通用性立木生物量模型将成为必然趋势,而如何保证不同尺度范围森林生物量估计值的相容性,是必须面临的一个问题。以南方马尾松(Pinus massoniana)地上生物量数据为例,通过利用混合模型方法,同时建立全国和区域性立木生物量方程,为解决不同区域尺度范围内森林生物量估计的相容性问题提供有效途径。从模型反映的结果看,相同直径林木的地上生物量估计值随起源、地域的不同存在一定程度的差异,其差异大小可以通过混合模型中的随机效应来估计。该方法可推广应用于其它通用性模型(如材积方程)的建立。