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移动式喷灌育苗设计实例吴威,吴贵成,赵林清,梁湘玉(辽中县苗圃110200)喷灌是一种先进的灌水方法,它具有省水、增产、保土保肥的优点,而移动式喷灌又比固定式喷灌投资少、寿命长、适应性强,目前已逐渐用于营林苗圃的育苗中.笔者承担了1992年辽中县苗圃... 相似文献
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作者通过多年的苗圃工作实践,对苗圃地下害虫的综合防治进行了一系列试验研究,取得了一定成效,并对其预防措施及防治方法做了介绍,为苗圃的生产和管理,提供了参考。 相似文献
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关于建立果树苗圃技术档案的意见 总被引:1,自引:0,他引:1
果树苗圃技术档案是科学技术档案的一种,笔者通过多年从事果树生产的实践,总结各地的经验,针对目前国内各地大多数苗圃尚未建立和健全树苗圃技术档案的实际状况,论述了建立果树苗圃技术档案的意义,提出了建立果树苗圃技术档案的主要内容和要求,为发展苗圃生产,提高育苗技术水平和经营管理水平,提高果树经济效益提供科学依据。 相似文献
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前 言 林业育苗应用化学除草是苗圃生产中的一项新技术。筛选出一批适合于林业苗圃使用的化学除草剂,并了解掌握它的适合浓度和使用方法,乃是目前当务之急。实践证明,应用化学除草,是消灭圃地杂草,提高劳动效率,减轻劳动强度,降低育苗成本,提高苗木质量,实现苗圃机械化、系列化的重要措施。我场于七九年春,开始采用部份除草剂在苗圃进行除草试验,取得了一定成效。 相似文献
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随着苗圃基地的建立,苗圃生产档案也应运而生。苗圃生产档案是苗圃生产历史和现状的真实记录,也是总结生产经验的真实依据。苗圃从规划设计、土建施工之日起,就应有专人从不间断地对苗圃的各项生产活动及其结果,按照一定的计划或项目,规范地记录下来,并在一定时期内将这些原始材料整理成册,归类为科技档案。苗圃生产档案通常分为五大类别。基建档案该档案记录了苗圃立项,规划设计,项目可行性研究报告的起草、定稿,专家论证意见,上级机关的批复;苗圃规划设计情况(包括生产区和非生产区的设计、图纸)工程预算、说明和土壤改良、灌… 相似文献
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苗圃改造型休闲观光农业园规划设计的实践探索——以安徽芜湖天鹰苗木生产基地为例 总被引:2,自引:0,他引:2
休闲观光苗圃以苗木生产为基础.兼顾休闲观光功能的开发.构建休闲观光苗圃景观的核心是观赏植物。本文从主题定位与规划构思,总体布局、功能分区,项目设计和道路系统优化等几个方面对天鹰苗圃进行了改造规划设计的实践探索。提出了苗圃旅游开发规划依据的6大原则和3大功能分区的划分方法.对同类休闲观光农业园区的规划设计具有借鉴意义。 相似文献
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我区现有国有苗圃101处,总经营面积41万亩,职工总数4400人。在计划经济时期,国有苗圃采取国营形式经营,取得了较好的经济效益。随着经济体制改革的不断深入,许多苗圃在计划经济体制下长期形成的思想观念一时无法跟上急剧变化的形势,经营与市场脱节,仍然是单一林业,单一经营,追求单一经济效益,严重影响了国有苗圃的经济发展,致使苗圃陷入了“一穷二死”的状态,苗圃生产、生活步履艰难,部分苗圃到了难以维持的地步。赤峰市巴林右旗良种苗圃面对新形势做出了新的选择,对苗圃内部的经营管理体制进行了大刀阔斧的改革,对… 相似文献
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This article investigates the role of local knowledge in the policy approach of neo-endogenous rural development, which may be held by local and regional actors such as municipal and county level politicians, local and regional level administration, entrepreneurs as well as local third sector representatives. The main question addressed is whether local knowledge under this approach is merely mobilised or if rural development processes are even based on such knowledge, placing it at the centre of such policy. The relevance of this approach to forestry is also explored. The types of forest owners for which the neo-endogenous rural development approach is appropriate and the types that may have difficulties in coping with this cross-sectoral and area-based approach are especially examined. Using a case study design on the German Active Regions funding program it is shown that the neo-endogenous approach is most relevant to large private forest owners and small-scale corporate enterprises, but also has potential for small- and medium-sized private owners. Concerning the role of knowledge held by local and regional actors, the approach is shown to largely build on the use of local expertise, and hence policy acceptance increases. However, scientific knowledge as well as politics are found to play a major role in the use, production and interpretation of local knowledge. 相似文献
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Tsuyoshi Kajisa Takuhiko Murakami Nobuya Mizoue Neth Top Shigejiro Yoshida 《Journal of Forest Research》2009,14(4):203-211
Information about forest biomass distribution is important for sustainable forest management and monitoring fuelwood supply.
The objective of this study is to develop an accurate forest biomass map for Kampong Thom Province, Cambodia. We used a new
technique (object-based approach) and a conventional technique (pixel-based approach) for the estimation of forest biomass
using Landsat Enhanced Thematic Mapper Plus (ETM+). The object-based approach created segments of images, and calculated statistical
and textural attributes. Our results showed that estimation accuracy of the object-based approach, with the use of band 1
and an exponential fit, was the best (R
2 = 0.76), and this accuracy was comparable to that of the pixel-based approach (R
2 = 0.67). Although several textural variables were related to forest biomass, they did not contribute significantly to improvement
of estimation accuracy. However, the object-based method can be used for image segmentation so that the image objects are
spectrally more homogeneous within individual regions than with their neighbors. Hence, they can be regarded as management
units for policy-related spatial decisions. Therefore, it is possible to select either of the two methods depending upon what
the situation demands. 相似文献
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Fuel-breaks function to restrict the spread of wildfire through a forest and thereby reduce the damage to values lost when fires escape. The challenge of selecting optimal locations of fuel-breaks arises from the uncertainty over how future fires might originate and spread spatially in the future. In this research, we evaluate a new approach to addressing this uncertainty through the formulation and application of a decision support model using simulation-optimization. The problem is formulated as a combinatorial simulation-optimization problem with the objective of minimizing fire-risk subject to a limit on the total area to be used as fuel-breaks. A stochastic simulation model of fire-spread was designed to estimate the fire-risk of each candidate solution produced by a metaheuristic search algorithm. The model was tested on a forest of 220,000 ha in north-western Ontario. The objective function (total fire-risk) of the solution found using the simulation-optimization model was significantly lower than the objective function of a solution found using a greedy heuristic—a spatially blind approach, by which the highest risk stands were iteratively removed until the allowable limit on fuel-breaks was reached. This significant difference indicates that the spatial relationships between selected fuel-breaks is an important factor in reducing a forest's total fire-risk. Hence, the spatial layouts of the best solutions were visually analyzed using GIS-software to illustrate patterns that result in reduced fire-risk at the landscape-scale. We conclude that this modeling approach, while computationally intensive, can be used to support improved spatial decisions on the location of fuel-breaks. 相似文献
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周一玲 《中南林业科技大学学报(自然科学版)》2004,24(2):64-69
软件体系结构对软件性能、质量和生命周期的影响是非常关键的,它与具体的开发过程紧密相关.面向对象的有限元程序设计可以大大提高程序的模块化和代码的重用性.在有限元基本数据封装和单元过程设计的基础上,构建了有限元工程软件构架和原型,详细讨论了使用该软件构架进行有限元程序开发的方法.实例应用表明,与传统的方案相比,此方法能更完整地抽象出各类有限元数据的共性,能更好地适应系统的扩充. 相似文献
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The development of a model for the prediction of the evolution of individual tree cork caliber over time, from a measurement taken at a certain point in time, was the main objective of this work. The model includes three sub-models: a model to predict the thickness of complete rings from cork caliber at tc years; a cork growth model (for complete rings) and a model to predict cork caliber at age tc from the corresponding thickness of (tc − 1) complete rings. The algebraic difference approach (ADA) as well as the generalized algebraic difference approach (GADA) were used in modeling cork growth. Several base models with one or two site-tree-specific parameters were fitted to the data using the dummy variable approach. The selection of the cork growth model was based on several criteria: fitting ability, prediction performance evaluated through the PRESS residuals and behaviour screened with available knowledge on the cork growth process. The ADA model derived from the log-logistic function with the asymptote as free parameter was selected. The models developed to predict cork caliber and the corresponding thickness of complete rings were based in the linear relationship between the two variables. The two models were simultaneously fitted using two stage least squares approach. The predicted thickness of cork complete rings in a 9-year old cork is proposed as a cork growth index. The distribution of this index can be used to characterize the potential of a site for cork production. 相似文献
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Estimating forest carbon fluxes for large regions based on process-based modelling, NFI data and Landsat satellite images 总被引:2,自引:0,他引:2
The aim of this study was to develop and evaluate a new approach for estimating forest carbon fluxes for large regions based on climate-sensitive process-based model, national forest inventory (NFI) data and satellite images. The approach was tested for Central Finland and Lapland with NFI field data and daily weather data from 2004 to 2008.The approach combines (1) a light use efficiency (LUE) model, (2) a process-based summary model for estimating gross primary production (GPP) and net primary production (NPP), and (3) the Yasso07 soil carbon model, which together allow the estimation of net ecosystem exchange (NEE). Landsat TM 5 satellite images were utilized to generalize the carbon fluxes obtained for field sample plots for all forested areas using the k-NN imputation method. The accuracy of the imputations was examined by leave-one-out cross validation and by comparing the imputed and simulated values with Eddy covariance (EC) measurements.RMSE of the k-NN imputations was slightly better in Central Finland than in Lapland, the bias staying at a similar level. Based on the EC comparisons, the approach seemed to work rather well with GPP estimates in both areas, but in the north the NEE estimates were remarkably biased. The main advantages of the approach include its applicability to basic NFI data and a high output resolution (30 m).The method proved to be a promising way to produce carbon flux estimates based on large-scale forest inventory data and could therefore be easily applied to the whole of Northern Europe. However, there are still drawbacks to the approach, such as lacking parameters for peat lands. One of the future goals is to integrate the approach with an interactive mapping framework, which could thereafter be utilized, for example, in climate change research. 相似文献
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原木材积检测中的计算机视觉技术 总被引:1,自引:0,他引:1
原木材积的检测在林业研究及造纸工程等领域是十分重要的。本文提出了一种基于计算机视觉的新方法用于材积的 检测。首先,分析了用于检测的硬件系统。然后,给出了检测过程中的详细算法。为了提高原木横截面图像的质量,提出了基于模糊熵的图像增强算法。在许多实际应用问题中,图像中的原木横截面常常是部分不可见的,这一现象已成为材积正确检测的主要障碍。为了克服这一现象,本文提出了一种鲁棒的Hausdorff距离用以恢复完整的原木横截面。实验的结果证明了本文方法的有效性。图5参8。 相似文献
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Since trees record all the environmental factors in the wood, many wood properties are related to the site characteristics.
Despite of this fact, identifying the origin of a timber has always been considered a difficult task, and no effective tools
are presently available for this purpose. The goal of this study was to verify whether significant differences among groups
of the same wood species due to the provenance can be detected with Fourier transform near-infra-red spectroscopy (FT-NIR).
Spruce (Picea abies L. Karst.) samples collected from stands in Finland, Northern and Southern Poland and Italy were analyzed using two different
approaches: for the first approach samples were collected from four provenances scattered in a wide area throughout Europe,
while for the second approach the samples were collected from provenances located in a narrow area within the same region
in Italy. For the first approach, all the specimens were clearly divided into groups by using statistical methods. The separation
among groups from the narrow local area was actual; even though less significant than in the previous case. It was concluded
that trees growing in various locations have somewhat different chemical composition, and FT-NIR is sensitive enough to detect
such differences. The presented method could be used for tracking wood provenances and as a technical tool for detecting logs
harvested illegally from protected areas. 相似文献
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Song Tieying Zhou Wenchao Feng Xiulan College of Forest Resources Environment Beijing Forestry University Beijing PR China 《中国林学(英文版)》1994,(2)
DecisionSupportinSelectionCuttingPlanningofUneven-agedStandManagementSongTieying,ZhouWenchao,FengXiulanCollegeofForestResourc... 相似文献