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1.
本文描述了森林火灾扑救成本构成与核算体系，扑救成本就是扑救消耗的价值量，含活劳动量和物化劳动量，它由直接成本和间接成本构成，利用计算机确定扑救决策优化方案，不但是科学的，而且也是迅速的。 相似文献
2.
3.
地图制作是指用户将输入和编辑过的图形数据用各种说明性的地图要素加以说明，构成完整的地图，最终通过打印机或绘图仪获得实物图纸资料。地图要素是地图构成的基础，在地图制作中，需要各种地图要素，如文字说明、符号、线型、填充模式、图例、参考图等等。用户通过地图制作模块，将地图要素按一定方式有机地组合而成一幅具有各种属性信息的丰富多彩的地图。本文主要对地理信息系统ＷＩＮＧＩＳ中的地图制作模块的设计原理和功能做一简要介绍。 相似文献
4.
勘察设计质量成本是将勘察设计成果质量保持在规定的水平以上所需的费用，通过分析质量成本项目的构成，确定质量成本项目，收集质量成本数据，统计、核算质量成本，可以有效地进行质量成本管理，保证勘察设计成果质量，增强竞争能力，提高经济效益。 相似文献
5.
农林系统经济评价方法的探讨 总被引：9，自引：2，他引：7
本文从经济学角度对农林系统的经济评价方法进行了探讨和研究。介绍了农林系统的涵义及其经济特征,农林系统经济评价的目的、内容及其特点,并重点讨论了收益成本分析、生产函数边际分析和经济可行性分析在农林系统经济评价中的具体应用。 相似文献
6.
浅谈如何降低胶合板成本曲忠良（哈尔滨松江胶合板厂）在森林工业处于“两危”的状况下，木材加工企业充分利用现有森林资源、努力降低产品成本、扭亏为盈具有深远的现实意义。结合成本的构成要素，降低成本的途径主要有以下几个方面。１节约原材料、燃料和动力消耗在胶合... 相似文献
7.
从绿色建筑项目施工技术造价与成本节约两个方面，分析了绿色建筑项目的经济效益，指出了绿色建筑项目实施的合理性和经济性，也是未来发展所必需的。并将绿色建筑项目带来的经济效益作为绿色建筑项目技术经济评价的关键内容，为科学、合理地选择方案提供了一定参考。 相似文献
8.
提出了住宅小区景观生态设计的基本原则，对小区主要景观构成要素的生态设计分别进行了阐述，并指出了低碳设计和人性化设计结合在一起才是完整意义上的生态设计。 相似文献
9.
邓健民 《中南林业调查规划》1992,(1)
1 引言在进行森林经营方案的营林设计和用材林基地设计的投资效果分析时,都会遇到用材林投资项目的经济评价问题,通过用材林投资项目的经济评价问题的研究与方案比选,选择最恰当的投资方案和对生产要素的利用方式,充分地利用用材林的经济效益、社会效益、生态效益,以最少的投资获取最 相似文献
10.
针对道路运输企业营运车辆运行过程中燃油消耗状态难以监控的实际情况,本文设计了以单片机STC89C52为核心的车载油耗实时监测系统.提出监控系统的总体设计方案,搭建由电源处理模块、单片机主控模块、油耗数据采集模块、GPS定位模块、GPRS无线通信模块和数据存储模块构成的硬件系统,开发系统控制软件和上位机油耗管理软件.该车载油耗实时监测系统操作方便,成本较低,兼容性强,具有广阔的应用前景.能够对营运车辆行车过程中的实时耗油量进行统计分析,结合生产计划进行燃料供给管理工作,能够有效改善道路运输企业的燃油浪费现象,实现节能增效的目的. 相似文献
11.
Forest precipitation chemistry is a major issue in forest hydrology and forest ecology. Chemical contents in precipitation
change significantly when different kinds of external chemical materials are added, removed, translocated and transformed
to or in the forest ecosystem along with precipitation. The chemistry of precipitation was monitored and analyzed in a 31-year-old
Pinus tabulaeformis forest in the West Mountain of Beijing. Movement patterns of nutrient elements in hydrological processes can be discovered
by studying this monitored data. Also, the information is useful for diagnosing the function of ecosystems and evaluating
the impact of the environment on the ecosystem.
Samples of rainfall, throughfall and stemflow were collected on the site. In the lab, Ca2+ and Mg2+ were analyzed by flame atomic absorption and K+ and Na+ by flame emission. NH4
+-N was analyzed by indophenol blue colorimetry and NO3
−-N was analyzed by phenoldisulfonic acid colorimetry. The results showed that: 1) The concentration gradient of nutrient elements
clearly changed except for Na+. The nutrients in stemflow were significantly higher than those of throughfall and rainfall as the precipitation passed through
the P. tabulaeformis forest. The monthly patterns showed distinct differentiation. There are indications that a large amount of nutrients was
leached from the canopy, which is a critical function of intra-ecosystem nutrient cycling to improve the efficiency of nutrient
use. 2) The concentrations of NO3
−-N and K+ changed more than those of the other nutrient elements. The concentration of NO3
−-N in throughfall and stemflow was 4.4 times and 9.9 times higher than those in rainfall, respectively. The concentration
of K+ in throughfall and stemflow was 4.1 times and 8.1 times higher than those in rainfall, respectively. 3) The leaching of nutrient
elements from the stand was an important aspect of nutrient return to the P. tabulaeformis forest, which returned a total amount of nutrient of 54.1 kg/hm2, with the contribution of Ca2+ and K+ much greater than that of other elements. Also, K+ was the most active element in leaching intensity. 4) Nutrient input through precipitation was the main source in the West
Mountain of Beijing and the amount of nutrient added was 66.4 kg/hm2, of which Ca2+ and N contributed much more than the other nutrient elements. When precipitation passes through the P. tabulaeformis forest, 121 kg/hm2 of nutrient is added to the forest floor. Ca2+ recorded the greatest nutrient increase, with 61.2 kg/hm2, followed by N (NH4
+-N and NO3
−-N), K+ and Mg2+, with 31.3 and 16.5, and 8.11 kg/hm2, respectively. The least was Na+, 3.34 kg/hm2.
Translated from Acta Ecologica Sinica, 2006, 26(7): 2,101–2,107 [译自: 生态学报] 相似文献
12.
生物量受坡面环境条件变化影响而有坡面变化与尺度效应。本文在六盘山半湿润区的香水河小流域选择了33 a生华北落叶松人工林的一个斜坡长480 m,水平长398 m的典型坡面,在整个坡面上建立了宽30 m的调查样带,均匀分为空间连续的16个样地,在2014年生长季中期调查不同坡位的样地生物量,分析其坡面变化规律。结果表明:生物量存在明显的坡位差异。坡面生物量t·hm-2平均值为118.59,其变化范围为96.19 139.18,变幅为42.99,变异系数为0.12;随着离坡顶距离的增加,生物量总体上呈现先升高后降低的变化趋势,在坡面的中上部(水平坡长为87.71 m)达到最大。生物量存在坡面空间尺度效应,即随着相对坡长(X1)的增加,生物量的顺坡滑动平均值(Y1)先增大后减小,其回归关系式为:Y1=23.004X13-60.834X12+31.786X1+123.43(R2=0.84),坡面尺度效应表现为每100 m水平坡长生物量变化的数值为6.12 t·hm-2;各样地生物量与整个坡面平均值的比值(Y2,小数)随相对坡长有很好的非线性关系,基本上呈先增加后下降、后趋于稳定的变化趋势,其关系式为Y2=1.722 6X13-2.844 5X12+1.033 8X1+1.000 1(R2=0.57),可基于此将特定坡位样地的生物量换算成整个坡面的估算值。造成生物量坡面变化的主要原因是太阳辐射和光照时间随海拔的变化等多种因素造成的。 相似文献
13.
Conversion of native forest ecosystem to cropland has considerably degraded the soil nutrient levels in the Bale Mountains, south-eastern highlands of Ethiopia. This study investigated the effects of land use change through conversion of native forest to cropland and/or grazing land on soil pH (H2O), base cations (Ca2+, Mg2+, K+, Na+), CEC and percentage base saturation (PBS) in three adjacent land-use types: cropland, grazing land and native forest. A total of 108 soil samples (3 replications × 3 land-use types × 4 profiles × 3 soil depth layers, 0–0.2, 0.2–0.4 and 0.4–1.0 m) were collected for laboratory analyses. Results showed that soil pH, Na+ and K+, CEC, and PBS varied significantly with respect to land use and soil depth while Ca2+and Mg2+ varied with soil depth (ρ < 0.05). Conversion of native forest ecosystem to cropland during a 15-year period significantly increased soil pH and PBS while reducing Na+ and K+. The CEC in the cropland was reduced by 37.7% (2.6% per annum) compared to the native forest, which could be attributed to the decline in organic matter concentrations. If such rapid declines in soil nutrient concentrations continue unabated, the soils will reach at the point of no return within a few decades. Although the effect of grazing on most of the properties was found to be minimal, adapting the number of stock to the carrying capacity of the land and thereby enhancing the natural regeneration, combined with proper cropland management practices could help restoring soil nutrients for sustainable agricultural production and ecosystem functions. 相似文献
14.
[目的]探讨不同造林密度对米老排人工林生长的影响规律,为米老排人工林定向培育过程中的密度控制提供参考。[方法]以广东省云浮市造林后6年生米老排人工林为研究对象,对不同造林密度(625、833、1 111、1 667、2 500株·hm~(-2))林分平均树高、优势木高、胸径、保留率和枝下高等生长指标进行连续4年调查。[结果]表明:随着造林密度的增大,米老排林分平均胸径、胸径连年生长量、保留率、单株材积和材积连年生长量均显著减小,而枝下高、林分蓄积量和蓄积连年生长量显著增加。在一定密度范围内,造林密度对林分高生长的影响比较小。造林后第6年,密度1 667株·hm~(-2)林分的平均树高最大(11.4 m),优势木高以密度1 111株·hm~(-2)林分的最大(13.3m),树高连年生长量以密度625株·hm~(-2)林分的最大(1.5 m·a~(-1));密度625株·hm~(-2)林分的平均胸径、胸径连年生长量、单株材积和材积连年生长量均最大,分别为14.3 cm、2.5 cm·a~(-1)、0.097 3 m~3和0.038 2 m~3·a~(-1),比密度2 500株·hm~(-2)林分的分别增加27.7%、81.0%、49.0%和82.4%;密度2 500株·hm~(-2)林分的枝下高、蓄积量和蓄积连年生长量均最大,分别为6.0 m、149.4 m~3·hm~(-2)和44.8 m~3·hm~(-2)·a~(-1),分别是密度625株·hm~(-2)林分的2.61、2.52、1.95倍。[结论]分析了造林密度对米老排初期生长的影响,对米老排人工林的培育具有理论指导意义。 相似文献
15.
Multipurpose tree species （MPTs） were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2 m × 2 m （2500 stems·hm^-2） could have the potentiality to meet the timber/fuelwood requirement due to its high wood production of 635 m^3·hm^-2 with mean annual increment （MAI） of 2.54×10^-2 m^3.treel.a^-1 in a short rotation period of 10 years. Thus, A. auriculiformis is a short rotation forest tree species suitable to grow in subtropical humid climate. On the other hand, at 16 years of age, Eucalyptus hybrid and Michelia champaca in spacing of 3 m × 3 m （1111 stems.hm^2） produced appreciably high timber volume of 315 m^3.hm^-2 and 165 m^3.hm^-2 with MAI of 1.77×10^-2 m^3.tree^-1·a^-1 and 0.92×10.2 m^3.tree^-1.a^-1, respectively. At 16 years of age, Gmelina arborea produced a timber volume of 147 m^3.hm^-2 with MAI of 1.47×10^-2 m^3.tree^-1.a^-1 followed by Samania saman （140 m^3.hm^-2）, Albizziaprocera （113 m^3·hm^-2） and Tectona grandis （79 m3.hm^-2） with MAI of 1.40, 1.13 and 0.78 × 10^-2 m^3 .tree^-1a^-1, respectively in 4 m × 4 m spacing （625 stems.hm^-2）. Gliricidia maculata and Leucaena leucocephala could be used as live fences around the farm boundary to supply their N-rich leaves for mulch as well as manure to crops. In agroforestry arboretum, direct seeded upland rice （Oryza sativa - variety, AR-11）, groundnut （Arachis hypogaea - variety, JL-24） and sesamum （Sesamum indicum - variety, B-67） were grown during the initial period upto 8 years of tree establishment. Under other MPTs, there was a reduction in crop productivity as compared to open space. After 8 years of tree establishment, horti-silvi and silvi-pastoral systems were developed and pineapple （Ananas comosus - variety Queen）, turmeric （Curcuma longa -variety RCT -1） and cowpea （Vigna sinensis - variety Pusa Barsati） as forage crop were raised. The productivity of p 相似文献
16.
对海南岛尖峰岭35年生鸡毛松人工林生物量的结构与分布特点、净初级生产力和林分生长的动态变化进行了研究。结果表明,鸡毛松人工林乔木层生物量达285 53t·hm-2,其中树干为190 82t·hm-2,树皮为19 19t·hm-2,树枝为35 93t·hm-2,树叶为7 96t·hm-2,根为31 63t·hm-2,鸡毛松不同器官生物量的比例为树干∶树枝∶根∶树皮∶树叶=24 0∶4 5∶4 0∶2 4∶1 0。12～22cm径级的立木生物量占总生物量的70 9%,而8m以下的树干生物量占其总生物量的80%以上。1～25a内生物量增长迅速,年平均净生产量随年龄的增加而增大,25a后生物量增长相对较慢,进入生长的平稳期。35a鸡毛松人工林乔木层年平均净生产力可达10 34t·hm-2·a-1,最大可达13 99t·hm-2·a-1,表现出较高的生产力。 相似文献
17.
Xingliang Liu Qinyan Ma Dongsheng Yang Zuoming Shi Yiming Su Shiqiang Zhou Shirong Liu Yupo Yang 《Frontiers of Forestry in China》2006,1(4):379-386
This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots
(Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m×25 m plot located
on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the
4 plantation types. To estimate the root biomass of an individual tree using D
2
H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm2 varied among plantation population types following the order: L. kaempferi (37.832 t/hm2) > A. fabri (24.907 t/hm2) > L. maxteriana (18.320 t/hm2) > P. balfouriana (15.982 t/hm2). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population
types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88%
for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0–20, 20–40, and 40–60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm2·m) for P. balfouriana, 8.230 t/hm2·m) for L. maxteriana, 24.546 t/(hm2·m) for A. fabri, and 13.211 t/(hm2·m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm2·year) for P. balfouriana, 0.83 t/(hm2·year) for L. maxteriana, 0.71 t/(hm2·year) for A. fabri and 1.64 t/(hm2·year) for L. kaempferi population, respectively.
__________
Translated from Acta Ecologica Sinica, 2006, 26(2): 542–551 [译自: 生态学报, 2006, 26(2): 542–551] 相似文献
18.
Mingdong Ma Chengde Luo Hong Jiang Yuejian Liu Xi Li 《Frontiers of Forestry in China》2009,4(2):140-145
Biomass, carbon content, carbon storage and spatial distribution in the 32-year-old Phoebe bournei artificial forest were measured. The mean biomass of the forest stand was 174.33 t/hm2, among which the arbor layer was 166.73 t/hm2, which accounted for 95.6%. Carbon contents of stems, barks, branches, leaves, root, shrub layer, herb layer, lichen layer
and litter layer were 0.5769 g C/g, 0.4654 g C/g, 0.5232 g C/g, 0.4958 g C/g, 0.4931 g C/g, 0.4989 g C/g, 0.4733 g C/g, 0.4143
g C/g, 0.3882 g C/g, respectively. The mean carbon content of soil was 0.0139 g C/g, which reduced gradually along with soil
depth. Total carbon storage of the P. bournei stand ecosystem was 227.59 t/hm2, among which the arbor layer accounted for 40.13% (91.33 t/hm2), the shrub layer accounted for 0.17% (0.38 t/hm2), the herb layer accounted for 0.76% (1.71 t/hm2), the lichen layer accounted for 0.28% (0.63 t/hm2), and the litter layer accounted for 0.29% (0.66 t/hm2). Carbon content (0–80 cm) of the forest soil was 58.40% (132.88 t/hm2). Spatial distribution ranking of carbon storage was: soil layer (0–80 cm) > arbor layer > herb layer > litter layer > lichen
layer > shrub layer. Net production of the forest stand was 8.5706 t/(hm2·a), in which the arbor layer was 6.6691 t/(hm2·a), and it accounted for 77.82%. Net annual carbon sequestration of the P. bournei stand was 4.2536 t/(hm2·a), and the arbor layer was 3.5736 t/(hm2·a), which accounted for 84.01%.
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Translated from Scientia Silvae Sinicae, 2008, 44(3): 34–39 [译自: 林业科学] 相似文献
19.
１９９８年４月至１９９９年３月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测,并测定和分析了林内穿透雨物理量及化学量,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明：（１）广州市酸雨占次数的７９．７％或占降雨量的９５．１％。（２）酸雨通过林冠层后,ｐＨ值明显增加。（３）在马尾松林和常绿阔叶林中,某些单次降雨出现ＳＯ４＾２－、ＮＯ３＾－、ＮＨ４＾＋Ａｌ＾３＋、Ｎａ＾＋的负淋溶现象,说明森林对这些离子（特别是ＮＯ３＾－、Ａａ＾３＋）具有吸收作用;阔叶林全年的ＮＯ３＾－和Ａｌ＾３＋净淋溶为负值,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。（４）雨水酸度增加（即ｐＨ值减小）,明显提高阳离子Ｃａ＾２＋、Ｍｇ＾２＋、Ｋ＾＋和Ｎａ＾＋冠层淋溶面分率。（５）ＮＨ４＾＋、ＳＯ４＾ 相似文献
20.
Inorganic compound leakage and change of carbohydrate were measured in Ulmus parvifolia seeds throughout accelerated aging under 35°C and 75% relative humidity (RH) to investigate whether these indicators can
be used as a rapid vigor test for efficient seed bank management. Accelerated aging seeds treated for 0–14 days exhibited
loss of germinability in the longest aging treated seeds (11%, 14 days) compared to a good performance of 52% for control
(0 day) seeds. Leachate electrical conductivity (EC) increase had strong negative correlation with seed vigor (−0.9). Magnesium
ion concentration in electrolyte leakage from artificial aged seeds showed positive correlation (r = 0.94, P < 0.01). The ratios of inorganic ions showed that K+/Mg2+, Ca2+/Mg2+, and Na+/Mg2+ were inversely correlated with germination (−0.93, −0.82, and −0.91, respectively). Increases in starch and total soluble
sugar content in aged seeds were associated with a decrease in seed vigor. In conclusion, EC, magnesium ion concentration,
K+/Mg2+, Ca2+/Mg2+, and Na+/Mg2+ ratios and starch and total soluble sugar content could provide a sensitive and accurate index for the assessment of U. parvifolia seed vigor. 相似文献