绥宁县林木采伐伐区调查设计工作探讨

通过总结和分析绥宁县林木采伐伐区调查设计工作,充分认识到保护和合理采伐利用森林资源的重要性,认为做为林木采伐伐区调查设计工作者要熟练掌握伐区调查设计技术规程、具体内容,用法律法规政策约束自身行为,正确处理伐区调查的各种关系,加强林木采伐伐区质量管理,切实提高伐区调查设计精度,达到合理采伐利用森林资源的目的。     

合理利用伐区剩余物浅析

论述了伐区剩余物的利用前景，提出合理利用伐区剩余物的措施。     

伐区剩余物收集成型设备压缩装置的研究

合理利用伐区剩余物是解决能源短缺的有效手段，伐区剩余物收集成型设备可自动高效收集利用伐区剩余物。压缩机构是伐区剩余物收集成型设备中一个重要的组成部分，它的功能直接影响装置的运行。介绍伐区剩余物收集利用技术的现状；通过对木捆运动状态的分析，得出压缩机构螺旋轨道的枉坐标方程，是装置工作效率、螺旋轨道圈数及柴油机选取的依据。     

森工企业伐区剩余物的利用

广泛利用伐区剩余物,提高木材利用率是林区治危兴林的关键措施。文章介绍了伐区剩余物利用现状及存在的问题、潜力和优势以及前景。桃山林业局利用伐区剩余物已获得了可观的经济、社会和生态效益。     

浅谈地理信息系统技术在伐区采伐作业调查设计中的应用

利用森林资源管理与监测地理信息系统,实现伐区设计、伐区生产管理与地理信息系统及GPS定位相结合,实现图形库与档案库的互查联动,全面掌握伐区情况。伐区设计的图文材料一次同时完成,形成从采伐许可、组织伐区作业到伐区验收一整套严格的采伐作业管理程序。     

搞好伐区剩余物生产是缓解林业“两危”的主要途径之一

据伊春林区调查,仅有85％的小规格材和60％的枝丫材运出伐区利用,其余部分都遗弃在伐区。伊春林区一年约有60多万 m~3的采伐剩余物,所以搞好伐区剩余物生产具有重要意义。伐区剩余物利用的主要途径有小规格材的加工利用、枝丫材生产和利用、发展林化产品、改革烧材结构等。     

关于加强伐区区划和伐区调查工作的意见

伐区区划与伐区调查是合理利用森林资源,保证森林更新的重要措施之一。正确的伐区区划不仅明显地体现出既能充分利用森林资源,又能适应森林更新,保持水土的“统筹兼顾,集约经营”的原则。通过伐区调查,给进     

利用地理信息系统进行伐区采伐作业调查设计

为实现资源数据与图面资料的系统管理,利用森林资源管理与监测地理信息系统,经过一定的组织和定期的统一更改,实现数据和林相图的更新以及在此基础上的伐区调查设计工作.伐区设计、伐区生产管理与地理信息系统及GPS定位相结合,实现图形库与档案库的互查互动,全面掌握伐区情况.伐区设计的图文材料一次完成,形成从采伐许可、组织伐区作业到伐区验收一整套严格的采伐作业管理程序.     

采伐区调查设计精度控制措施确保合理利用森林资源

指出了伐区调查(cutting area inventory)是在森林采伐区范围内,为满足伐区作业设计而进行的森林资源、立地条件和专业项目的调查。在全国森林资源调查分类中,属于作业设计调查,即三类调查。伐区调查成果资料是伐区生产工艺设计的基础。主要分析了伐区调查设计存在的问题,提出了伐区调查设计精度控制措施,以确保合理利用森林资源。     

浅谈伐区架杆装车场的合理位置设置

利用成本分析法，根据伐区的生产条件，确定出架杆装车场吸引的最佳伐区长度。     

Estimates of residual fibre supply and the impacts of new bioenergy capacity from a forest sector transportation model of the Canadian Prairie Provinces

Increasing interest in making use of forest sector processing residuals for renewable energy production has led to the need for careful analyses of fibre supply, and the ways in which existing forest sector firms could be affected by new sources of fibre demand. In this paper we present a forest sector transportation model of the three Canadian Prairie Provinces, and use the model to estimate residual fibre production, utilization and surpluses, as well as some potential forest sector impacts from bioenergy capacity additions. Under our base-case assumptions and using 2010 product prices, we estimate that 6.9 million cubic meters (round-wood equivalent) of processing residuals would be traded over the course of a year, with sawmills being the most significant source and pulp and paper mills being the most significant user. Approximately 33% of residuals would be used to produce bioenergy-related products (wood pellets, electricity sold to the grid, or internal electricity and power at pulp mills). Results show that some surpluses of processing residuals may be present in the existing supply chain, though the availability of these residuals is sensitive to lumber prices. At the same time, new bioenergy capacity itself may trigger higher sawmill output, making additional fibre available for both new and existing users. Roadside harvesting residuals are not an economically viable source of fibre under our base-case assumptions; however, their viability is sensitive to roadside processing costs and electricity prices.     

Differences between coarse woody debris and leaf litter in the response of heterotrophic respiration to rainfall events

Heterotrophic respiration strongly influences carbon cycles at the ecosystem and global scales. We used an automated chamber system to measure the heterotrophic respiration of coarse woody debris (CWD) and leaf litter in a secondary broadleaved forest in southern Kyoto Prefecture. This system, which targeted only organic matter, could detect heterotrophic respiration responses to changes in environmental factors, especially rainfall events. The temporal trends and responses of respiration to environmental factors differed dramatically between CWD and leaf litter. CWD respiration showed a clear diurnal change corresponding to changes in CWD temperature and a clear decrease during rainfall events. Leaf litter respiration did not change clearly but increased at the beginning of rain events and returned to pre-rain rates when soil water content declined. The temporal patterns of the residuals between the observed respiration and baseline respiration, developed from the temperature?Cresponse curves under pre-rain conditions, differed between CWD and leaf litter respiration. The typical trend in CWD respiration response to rainfall events was a clear decrease and then gradual increase in the residuals after the event. The response of leaf litter respiration to wetting was an increase in the residuals during rainfall events and then a gradual decrease during drying. The difference in the responses of these respirations to wetting and drying processes are likely caused by differences in the physical characteristics of the CWD and the leaf litter layer. Measurements targeting only organic matter using an automated chamber system could detect the responses of heterotrophic respiration to environmental factors.     

Long-term trends in dominant-height growth of black pine using dynamic models

Black pine (Pinus nigra Arn.) is a pan-Mediterranean species of high ecological importance and one of the most important timber species in the area. We compare several site dependent height–age models for the species in three regions along its natural distribution area in Spain. The best model was a generalized algebraic difference approach (GADA) polymorphic model with variable asymptotes (Cieszewski, C.J., Bailey, R.L., 2000. Generalized algebraic difference approach: theory based derivation of dynamic site equations with polymorphism and variable asymptotes. For. Sci. 46, 116–126). There was no significant increase in error when a reduced model common to the three regions was tested instead of a full model with region-specific parameters. To study possible biases of the proposed model along the trees’ lifespan we carried out a LOWESS analysis of residuals in time. We detected deviations in the model residuals, and a patent growth reduction in the 1960s and 1970s, which might be related to climate and/or changing stand characteristics. Departures from estimated mean past growth should be monitored in the future to adapt models to a changing environment.     

南五味子在柞水县适宜性研究

柞水县地处秦岭南麓,五味子野生资源极为丰富,尚待开发利用。本文对柞水县南五味子的品种资源及分布情况进行调查求证,对当地气候环境因子进行分析,对环境安全因子进行检测,对照《药典》载南五味子生长环境进行比对分析,结果证明:柞水县南五味子生长环境与《药典》载南五味子相吻合,是南五味子的适生区;柞水南五味子生长地土壤、水、空气含重金属、农药残留符合规定,是南五味子的优生、安全区域。     

食用菌有毒有害物质及控防技术研究进展

综述了食用菌生产中有害重金属的富集规律，农药、甲醛、二氧化硫的残留情况，并提出了食用菌有毒有害物质的减轻或消除措施。     

榆林沙区盐渍化土地防治技术研究

针对榆林沙区盐渍化特点,在沙区采用不同植物种进行不同的整地方式、栽植技术以及生化制剂处理试验,并对这几种防治措施进行比较分析,认为沙棘、柽柳、河北杨和旱柳是盐渍化土地适宜树种;不同整地方式中沟垄低床效果较好,但费时费力;植物残体填充和深栽避盐造林成活率高、生长良好,操作简单,是盐渍化土地防治的有效措施。     

木质炭化物高效开发利用研究综述*

木质炭化物的高效开发利用 ,对解决废弃物资源化、环保、生态环境等问题将起到十分积极的作用。文中综述了木质炭化物高效开发利用的国内外研究和开发进展 ,涉及到木质炭化物在环境净化方面的应用和木质系碳素新材料的研发等。     

Accounting for serial correlation and its impact on forecasting ability of a fixed- and mixed-effects basal area model: a case study

Successfully accounting for serial correlations has always been a vital part of growth and yield modeling when using repeated measurement data. In this case study, 16 alternative functions addressing the serial correlations of errors from a basal area model of black spruce (Picea mariana (Mill.) B.S.P.) were examined and compared. Results from this study showed that functions incorporated into the fixed and mixed models to account for the serial correlations improved model fit. The serial correlation of the residuals from the fixed model with directly modeled error structure was significantly lower than that from the fixed model without a modeled error structure. For the mixed model, modeling error structure resulted in only a moderate reduction in serial correlation of residuals. The comparison of the fixed and mixed models with and without directly modeling the error structure showed that for fixed model, a substantial improvement in forecasting ability was achieved when the error structure was directly modeled to account for serial correlation, and when the forecasts were adjusted based on the estimated correlation. But for the mixed model, further modeling of the error structure to account for more serial correlation resulted in worsened or comparative forecasting ability of the fitted model.     

材积方程中异方差的检验和校正

本文提出了通过检验剩余绝对值和自变量的等级相关系数,检验材积方程模型异方差性的方法。用加权最小二乘法估计异方差的材积方程参数,有效地克服了村积的异方差性,提高了材积方程的适用精度。     

Prediction of near-view scenic beauty in artificial stands of hinoki (Chamaecyparis obtusa S. et Z.)

The Analytic Hierarchy Process was used to identify the evaluation criteria of near-view scenic beauty in artificial hinoki (Chamaecyparis obtusa S. et Z.) forests. A multiple-regression model and a neural-network model were developed to predict near-view scenic beauty with the physical features of forests in this paper. With the multiple-regression model as the benchmark, the neural-network model using genetic algorithms performed better in scenic beauty prediction with respect to the predictive capability and the predictive residuals. A part of this paper was presented at the 47th Annual Meeting of the Central Branch of Japanese Foresty Society (1998).