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2009—2010年对拉萨半干旱河谷地带新植林采用堵洞与夹日法进行了鼠(兔)种类和密度调查,结果表明鼠(兔)种类有黑唇鼠兔Ochotona curzoniae Hodgson和白尾松田鼠Pitymys leucurusBlyth,在新植林地洞口密度为905.07洞/hm2,有效洞口率是31.66%,有效洞口系数为0.18,鼠(兔)密度为50.64只/hm2。饲养和实地监测发现,两种鼠(兔)对新植林地的金丝垂柳、白榆、藏青杨、北京杨4种树的危害株率均在25%以上。选用P-1拒避剂、0.2%莪术醇抗生育剂和克鼠星1号杀鼠剂单独、交叉施药进行防治实验,结果表明单独施用克鼠星杀鼠剂的效果是暂时的,单独施用拒避剂和莪术醇抗生育剂的效果是缓慢的,同时混合施用3种药剂18个月后捕鼠(免)率、有效洞数、植株受害率分别下降了90%,81.23%,85%,效果较持久。 相似文献
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近年来,我国中西部退耕还林工程区内,鼠、兔害频频发生。据统计,陕西省今春鼠害发生面积达14.2万公顷,兔害发生面积达12.4万公顷,林木被害株率普遍在30%以上,严重的可达70%。今年内蒙古全区共发生突发性森林鼠、兔害面积达94万公顷。森林鼠(兔)害已成为制约造林绿化成果和退耕还林工程顺利实施的一个重要因素。森林鼠(兔)害在我国发生范围广泛,涉及北京、河北、山西、内蒙古、辽宁、吉林、黑龙江、福建、河南、湖北、湖南、海南、四川、重庆、贵州、云南、陕西、甘肃、宁夏、青海、新疆等21个省、自治区、直辖市以及龙江森工集团、内蒙古森… 相似文献
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通过在不同海拔高度设置样地调查分析,祁连山区分布的36种啮齿动物形成4大类群7个亚群落.中华鼢鼠是林业生产的主要害鼠,因掘洞取食树木根系对幼林造成危害,年被害株率在10%～40%,平均18%.依据森林有害生物可持续控制原理,提出了祁连山自然保护区森林害鼠、兔的可持续控制策略,总结了区内主要森林害鼠中华鼢鼠的综合治理措施,进行了大面积推广防治. 相似文献
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呼和浩特市退耕还林区棕背鼠平生物防治技术研究 总被引：1，自引：0，他引：1
《陕西林业科技》2017,(1)
在武川县15a生油松林内,按密度0.3只·hm~(-2)释放年龄1.5~2a银狐,和沿山脊线两侧分别栽植2行(行距200m,桩距300~500m)招鹰桩,进行了释放银狐和栽植招鹰桩捕杀棕背鼠平技术试验,结果为释放银狐可使林地棕背,鼠密度由19.16只·hm~(-2)降低到4.83只·hm~(-2)、被害株率由22.82%降低到7.81%、植株死亡率由6.13%降低到4.01%;栽植招鹰桩可使鼠口密度由18.97只·hm~(-2)下降到4.94只·hm~(-2),被害株率由22.96%降到7.68%,死亡率由6.03%降到4.02%,既达到了控制鼠害的目,又具有绿色、高效、持续等优点,可大面积推广。 相似文献
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中华鼢鼠是山西省低山丘陵区的主要害鼠之一,对林业生产危害极大.大同市大同县从上世纪80年代开始大面积种植针叶树纯林,给中华鼢鼠的繁衍生息创造了有利条件,每年发生面积为2～3万亩,被害株率在12％左右,每亩鼠口密度约为1只.由于中华鼢鼠危害严重,导致造林地缺苗断垄,甚至高2米左右的幼树枯死,严重阻碍了大同县荒山造林和林业生产. 相似文献
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陇南地区退耕还林地鼠(兔)害现状及预防对策 总被引：1，自引：0，他引：1
论述了陇南地区退耕还林工程区森林鼠(兔)害发生危害现状，系统分析了发生原因，并提出了加强退耕还林区森林鼠(兔)害防治工作对策。 相似文献
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辉南林区森林鼠害的调查结果表明:害鼠种类主要是棕背鼠平,约占全部森林害鼠种类的72%,其余为红背鼠平、大林姬鼠等。害鼠密度与林木被害程度显著相关,当铗日捕获率在1%~5%时,林木被害率在3%~10%之间;当铗日捕获率在6%~15%时,林木被害率在11%~30%之间;当铗日捕获率在16%以上时,林木被害率超过30%。森林害鼠的种群数量具有明显的季节与年度变化规律,且与气候条件、地形和土壤、植物、天敌、人类经济活动等密切相关。 相似文献
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据河北省各市(省直属单位)“2005年林业有害生物防治统计报表”统计,全省主要林业有害生物发生面积341532.67hm2,同比上升10.42%。其中森林虫害318760hm2,同比上升10.7%,病害16446.67hm2,同比持平,鼠(兔)害6.320hm2,同比上升17%。此外,荒漠林、灌木林、天然次生林有害生物发生4 相似文献
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《Journal of Sustainable Forestry》2013,32(3-4):313-345
Abstract In 250 20 m X 20 m permanent plots in the Craigie-burn Range, Canterbury, New Zealand, 1970 stem density was 2,191/ha, basal area was 52.4 m2/ha, and stem biomass was 178.1 Mg/ha. Net production of stemwood (1974-1987) was 2.0 Mg/ha/yr; mortality was 3.5 Mg/ha/yr. By 1987 density had decreased by 30%, basal area by 12%, and stem biomass by 13%. Stands with many short trees of small mean dbh were common at high elevation, whereas stands with fewer, taller trees with large mean dbh were common at low elevation. Stemwood production and mortality rate were higher in tall stands. Mortality was well distributed among plots, indicating small, frequent canopy openings; stand turnover calculations were 66 year (based on 2.2% annual biomass loss) to 83 year (based on 1.2% annual stemwood production). Larger canopy openings were also evident, but were more infrequent, so stand turnover times due to 'catastrophic' disturbances were in the range of 350-4000 yr. Consequently, the small, high-frequency disturbances blurred effects of larger disturbances on stand structure and also constrained the fluctuation in forest biomass. 相似文献
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Gopi Chand 《Journal of Sustainable Forestry》2013,32(6):604-625
The study was undertaken to develop agrotechniques for raising short-rotation, high-density (SRHD) energy plantations as a renewable energy source by using planting densities of 10,000 and 14,000 plants/ha. Under Species × Spacing × Fertilizers (N:P:K), the effect of fertilizers was more evident on plant height than on stem diameter. The species as Grevillea robusta, Bauhinia variegata, and Eucalyptus showed the most statistically significant vertical and radial growth in both of the spacings. The N:P:K::50:25:25 kg/ha produced statistically significant growth. The photosynthesis rate, as recorded, showed that Salix tetrasperma had high rates of CO2 assimilation but poor aerial growth.The photosynthetic rate under varying fertilizer treatments remained unchanged, but the biomass improved significantly. In G. robusta, excellent aerial growth was observed despite a low rate of photosynthesis (even at low water potential). The dry weight of Eucalyptus was recorded (60 and 233 t/ha; spacing 1 m × 1 m and 1 m × 0.71 m) after 3 yr. After 10 yr, the highest dry weight was recorded again in Eucalyptus at 1,471.44 t/ha. The lowest moisture content (36–38%) was recorded in Morus alba, while the highest moisture content was recorded in Eucalyptus (66–70%). In all tested species, G. robusta (26%) showed the maximum calorific value. 相似文献
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Productivity and economics of mixed two-storied spruce and birch stands in Southern Finland simulated with empirical models 总被引：7，自引：0，他引：7
The profitability of growing a naturally emerged birch (Betula pendula Roth or Betula pubescens Ehrh.) overstory in a young Norway spruce (Picea abies (L.) Karst.) plantation was examined with empirical stand structure, growth and yield, logging cost, and logging damage models. In the projected alternatives, an overstory of either birch species was thinned to 200–1000 stems per ha at the age of 15 years and retained for another 15 years. Development of the remaining spruce stand was simulated up to rotation age (70–85 years). Alternative treatments included removing the overstory completely at 15 years, and managing a pure spruce stand that was kept free of birch throughout.
Growing a birch overstory of 200–1000 stems per ha up to age 30 years resulted in a 61–93 m3 ha−1 or 9.1–16.8% yield loss for the spruce stand due to growth retardation, and a mortality of 382–498 out of 1900 stems per ha through logging damage. This was compensated for or exceeded by the additional yield of the birch (54–173 m3 ha−1) except for the lowest stocking (200–400 stems per ha) alternatives with B. pubescens. Treatment regimes with a birch overstory were clearly the most profitable alternatives, yielding up to 151% (B. pendula) and 113% (B. pubescens) of the net present value of the pure spruce alternative, at 4% interest rate. Removing the birch overstory already at 15 years was the least profitable alternative with 79 and 83% net present values, respectively. The most profitable treatment with current technology, price, and cost structure appears to be to grow 500–800 birch per ha up to about age 40 years for B. pendula and 45–50 years for B. pubescens. 相似文献
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Tamarind (Tamarindus indica) is a valuable tree species Uganda and elsewhere in semi-arid Africa—for fruit, timber, leaves and shade—but like other indigenous species has been subject to decline in recent years. The success of steps to assist natural regeneration and rehabilitation will depend on the net financial benefits to the rural households, hence there is a need for improved financial information on the costs and returns of growing tamarind trees. This paper compares the financial performance of T. indica production in the open woodland and cropland areas in Uganda. Household surveys were carried out in Kamuli and Kaliro districts in eastern Uganda from July 2004 to February 2005. The estimated mean production of T. indica was 127 and 84 kg/ha/year from open woodland and cropland areas, respectively, a statistically significant difference. The net present value from T. indica products was US$ 893/ha in woodland and US$ 684/ha in cropland. In terms of foreign export earnings, T. indica juice from woodland and cropland was estimated to generate US$ 0.03/ha and US$ 0.02/ha, respectively. Returns from alternative land-use activities of agricultural cropping were highest for maize and lowest for finger millet in both open woodland and cropland sites. Sensitivity analysis revealed that an increase in the real discount rate from 9.86% (base case) to 15% decreases the financial NPVs of both the open woodland and cropland areas by 24%. 相似文献
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The effect of sulfometuron (Oust) on the root growth of loblolly pine (Pinus taeda L.) seedlings was studied in the field and in two soil types in the greenhouse. In the greenhouse study sulfometuron was applied to the foliage only, the soil only, and to both foliage and soil at the rates of 0.10, 0.21, and 0.42 kg ai/ha. Twenty-eight days after application root growth significantly decreased for all methods of application and with increasing rates e.g., 0.10, 0.21, and 0.42 kg ai/ha sulfometuron reduced new root length by 42%, 53%, and 64%, respectively. Application in the field at the rate of 0.30 kg ai/ha resulted in a 68% reduction in root growth. However, by the end of the growing season treated seedling root and shoot biomass were 115% and 64% greater, respectively. To ensure earlier season survival the rate of sulfometuron applied should be kept at a minimum level that will allow both weed control and adequate root growth. Low rates would be particularly important during a dry planting season. 相似文献
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J. H. Heering 《Agroforestry Systems》1995,30(3):341-350
The forage, wood and seed production of sixSesbania sesban accessions was assessed under irrigated conditions for two cutting frequencies and heights. Control trees were left uncut to measure their seed production potential. The trial was conducted over an 18-month period. The fastest growing accession produced almost 10 t/ha total dry matter (DM) after six months of growth, 40% of it being leaves. Total DM yield was higher at the six-month cutting interval compared to the three months' interval with yields between 25–42 t/ha/year. Some accessions could not sustain their high level of production but showed drastic drops in yield after repeated cutting. In general leaf DM production increased with increased cutting height. When cut at 150 cm the DM leaf yield at the three-month cutting interval ranged form 9.7–18.2 t/ha. More plants survived at the three-month cutting frequency. Seed yields varied considerably between accessions (0.02–1.56 t/ha at the six months' interval). After 18 months of undisturbed growth the trees yielded 36.5–83.7 t/ha total DM comprising 21% leaves. Fresh wood biomass ranged between 56.4–138.0 t/ha and seed yields 2.7–6.6 t/ha. 相似文献
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泡桐人工林生态系统养分循环的研究 总被引：11，自引：0，他引：11
桐粮间作生态系统在黄淮海平原地区具有广泛的代表性。研究比较泡桐的养分循环律,对挖掘其生产潜力,保证高产高效益,维持系统的稳定和平衡具有重要意义。一、试验地概况试验地位于河南省扶沟县江村乡泡桐试验场,东经114°32′,北纬32°0′,属暖温带季风气候,年均日照2361h,年均太阳辐射59.48kcal/cm~2,年均温度14.4℃,年均降水量678.5mm。≥0℃积温5272.8℃,≥10℃积温4692.6℃,年无霜期215d。该区属黄河冲积平原,土壤为沙壤土,pH为7.5,土层深厚,地势平坦,土壤肥沃,距地面1m左右有一粘土间层,厚30cm,保肥保水,对深根性的泡桐生长十分有利。 相似文献