让尺对杉木材积及经济效益的影响

通过调查4m长且直径为4－18cm的杉原木11358株，分别统计国标及不同让尺程度的材积，并与实际材积进行比较，以及经济效益分析，认为国标检尺作为木材交易的尺度是准确的、公平的。让尺检尺、选材既损失大量木材地降低单位经济效益，同时容易滋生行业不正之风和以尺谋私等问题。     

基于深度学习与深度信息的原木材积检测方法

针对工业现场整车木材摆放深浅不一且上下分层而导致的整车木材材积自动检测困难的问题,采用ZED2双目相机获取木材端面图像以及深度图像,在改进的基于掩模区域卷积神经网络(Mask region-based convolutional neural network, Mask R-CNN)实例分割模型完成对木材端面分割的基础上,对木材轮廓进行椭圆拟合,根据木材端面中心坐标以及深度图像获取每根木材的深度信息,利用整车木材上下层深度信息相差较大的特点,解决木材上下分层的问题,同时根据双目视觉视差原理,利用相机参数以及轮廓拟合后椭圆短径端点坐标,测量出木材端面检尺径,将检尺径和检尺长代入原木材积计算公式完成原木材积的检测。实验结果表明,使用本方法计算出的整车原木材积同人工检尺数据对比,材积误差率(偶数)为-1.61%,单根木材检尺径平均绝对误差(偶数)为0.33 cm,符合国家原木检尺要求。最终将模型以及材积计算算法部署于Nvidia Jetson Xavier NX平台,并在PyQt5核心库上设计了操作界面,用户仅需拍摄完整木材端面,即可实现原木材积的计算。利用本研究所提出方法可实现木材整车检尺...     

手机组合测距仪进行原木检尺的方法研究

阐述了手机组合测距仪代替传统木材检尺的理论和方法,在手机获取的影像和测距仪测量的距离数据基础上,应用计算机视觉技术分割出木材端面,并使用摄影测量技术计算端面面积,进而计算得到材积。实例分析表明,该方法测量精度与人工检尺相比误差稳定在3%以内,满足国家对于木材检尺误差的要求,但对于部分企业要求更高的小于1%的误差要求还未达标。该方法可替代传统的木材检尺进行工作,提高检尺工作者的工作效率,降低检尺工作的危险性。     

木材材积速查尺的研制

在木材生产和供销过程中,计算木材材积的主要工具是原木材积表和原条材积表。由于这是一本印制好的表格,使用时需要翻阅查找,而每篇内部都给出与材长和检尺直径对应的一些材积数字,行列较多,查找不便。木材材积速查尺的研制,正是根据木材生产的实际情况,为满足生产管理上的要求,以便给生产和使用提供方便。另外,随着木材生产的发展,现有的材积表范围已经不能满足木材检尺的需要,所以在现有的木材材积表中,增添需要的材积数字,去掉不用的材积数字,这也是实际生产的需要,木材材积速查尺的编制,适应了这一要求。     

大径级原条检尺查表法

林区木材生产中,原条验收是一项很重要的工作。原条检尺时,必须遵照“原条验收规程”用将检量得来的材长和径级去查找原条材积表,即知其材积是多少。但是;当超过六十厘米以上的径级、超过二十五米以上的材长以及材长超过三十五米、径级大于六十厘米等这三种情况时,在国标(GB)198—63原条材积表中无处查找。这样,检尺员只好用公式:     

电子计算机在木材工业中的应用及其展望

计算机技术发展之快,使用范围之广,在人类科学技术的历史上是前所未有的。随着计算机技术向各部门不断渗透,木材工业中已越来越多地应用了计算机。本文对电子计算机在木材工业中的应用实例作一些概略介绍,并对其发展前景及在我国木材工业中进一步开发应用谈一点意见。一、应用概况目前,在木材工业中电子计算机不仅用于一般的数据处理,而且已用于过程控制,实现最优化生产,发挥了显著的效益。其应用涉及有原木检尺及制材,木材干燥、人造板及家具、企业管理以及木材学理论研究等方面。1.原木检尺及制材在木材工业中,原木检尺是一项量大且     

中国与俄罗斯、美国、日本原木检验标准比较研究

木材检验是木材贸易过程中的重要环节,木材检验标准或法规是评价木材材积和质量的重要依据.因采用不同木材检验的检测方法,各国在国际贸易中木材检验结果存在差异.文中对中国《原木检验》、俄罗斯《原木打号印、分类、运输、检量和验收方法》、美国《原木检尺和评等规则》和日本《原木等级和检尺规程》原木检验标准或法规进行比较,分析国内标...     

基于Mask R-CNN的密集木材检测分割方法

针对木材检尺中采用人工检尺的方法存在效率低下且检尺主观性较强的问题,提出一种基于掩模区域卷积神经网络(Mask R-CNN)实例分割模型的木材分割方法,探究实例分割在木材密集堆放场景下对各尺寸木材分割的可行性,以期实现智能检尺,提高检尺效率。应对密集木材检测分割任务,难点在于密集小木材和大木材的检测。本研究在原始Mask R-CNN模型的基础上通过改进优化模型参数,包括多尺度训练、提升样本采样数、提高图片输入尺寸和有效数据增广等技术,进行多组分割对照实验,同时利用OpenCV库对模型输出的木材分割掩码图完成木材轮廓拟合和木材计数,并就实验结果对模型性能进行分割精度、掩码质量和木材真检率等多维度分析。实验结果表明：测试集木材真检率达到97.989%,误检率为0.30%,并且相较基础网络,对小木材和大木材的检测分割能力提升明显,分割精度最佳提升12.9%和5.2%,掩码分割质量最佳提升2.2%。改进后的Mask R-CNN模型对密集场景下的木材分割效果良好,此外算法具有较强的鲁棒性及迁移能力,微调下能适应各种场景下的各尺寸大小密集木材检测分割任务。     

尽快解决原木检尺问题

在木材采运生产中,检尺工作是木材生产、经营管理和调拨使用中不可缺少的重要环节。据统计,贮木场检尺人员数占总人数的15％以上。当前,我国木材检验手段主要靠手工作业,虽然出现了几种类型的原木测量仪器,但都没有被广泛地应用。其主要原因归纳起来主要有以下几点:     

基于云计算木材采伐运输物联网管理系统的设计开发

以福建省将乐国有林场为例分析木材采伐运输过程中木材检尺和运输证办理等业务流程管理,设计开发一个B/S和C/S架构相结合的、基于云计算的木材采伐运输物联网管理系统。该系统能够实时采集处理伐区现场的木材检尺数据,提高林业站点运输证办理效率,并提供数据检验、对账、分析等功能,从而达到信息化处理国有林场伐区作业数据,提高伐区生产作业效率等目的。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.