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1.
1.1.2 降水年降水量全州各地时空分布不均（图1），景洪为991.7mm，勐腊1 979.8mm，勐海1 578.5mm，与多年平均值相比，景洪偏少14.6%，勐腊、勐海分别偏多30.7%和19.3%；与1999年相比，景洪偏少 0.9%，勐腊和勐海分别偏多32.2%和22.7%。其中，勐腊年降水量比1978年的1 943.9mm多35.9mm；勐海比1970年的降水量偏少63.1mm，成为降水次多年。年内，雨季（5～10月）降水量，景洪、勐腊、勐海分别为 902.8mm、1 703.3mm和1 452.7mm，占年总量的91%、86%和92%。其中，主汛期（6～8月）降水量，景洪、勐腊、勐海分别为522.8mm、 1 022.0mm和959.7… 相似文献
2.
试验设造林密度和追肥2因素，每个因素6个水平，4次重复，在参试的处理范围内，初植密度越大，其数量成熟和轮伐期的年龄越小；密度处理从1到6达到数量成熟的年龄分别为5.5、6.2、6.6、6.7、6.8、6.4a；最佳轮伐期分别为5、6、7、7、7、6a，这时的内部收益率分别为24.8%、23.9%、23.5%、22.8%、21.6%、24.1%。施肥处理1到6的数量成熟年龄分别为6.3、6.6、6.5、6.5、6.5、6.6a，全部在6.3-6.6a之产，而轮伐期分别是6、7、6、6、6、7a，这时的内部收益率分别为20.4%、21.5%、23.6%、25.0%、26.6%、23.1%。所有施肥和密度处理在4a时均可进行采伐，这时采伐各处理的内部收益率都已超过18％，经济效益十分可观。 相似文献
3.
【目的】为核桃种植区土壤养分管理和施肥决策提供参考。【方法】采用野外调查和室内分析的方法，对永平县7个乡镇19个村庄76株漾濞泡核桃优株15项土壤养分指标进行测定分析。【结果】土壤pH值处于核桃正常生长范围的有42.1%的样本，有57.9%土壤样本的pH值处于偏酸性范围；有85.4%土壤样本的有机质含量处于适宜及以上范围；土壤全氮、全磷含量丰富，有13.2%的样本处于缺乏全钾的状态；土壤碱解氮、有效磷和速效钾处于中等及以上水平的样本比例分别为96.1%、98.7%、100.0%，有效磷含量属于中等偏上变异，有1.3%的样本处于极缺乏有效磷状态；土壤中量元素交换性钙、交换性镁含量均较为丰富，分别有96.0%、85.5%的样本表现为中等及以上水平；微量元素中，100.0%样本的有效铁含量处于较丰富及以上水平，100%样本的有效锰含量处于中等及以上水平，有96.0%、92.1%样本的有效锌、有效铜含量处于中等及以上水平，但有效铜、有效锌含量的变异系数高达97.28%、80.85%，属于强变异，分布极不均匀，3.9%样本的有效铜含量处于缺乏水平，7.9%样本的有效锌含量处于极缺乏水平，土壤有效... 相似文献
4.
为探究1 a年生木榄[Bruguiera gymnorhiza(L.)Lam.]苗木对光照适应能力，采用光照强度模拟控制试验对木榄苗木进行处理，经20%,40%,60%,80%,100%光照强度处理后，测定木榄苗木株高、基径、叶绿素总含量、净光合速率、丙二醛含量、脯氨酸含量、超氧化物歧化酶活性，通过相关性和主成分分析木榄苗木受光照影响情况。结果表明：1)60%光照强度环境木榄苗木株高生长最快，100%光照强度环境木榄苗木基径生长最快；2)在遮阴环境下，叶绿素总含量随光照强度增大而减少，但净光合速率随光照强度增大，表现为先增大再减少，且60%光照强度与80%,100%光照强度叶绿素总含量、净光合速率没有显著差异；3)60%光照强度环境下，木榄丙二醛含量、脯氨酸含量均显著低于20%光照强度环境，但超氧化物歧化酶活性显著高于20%光照强度环境；4)60%光照强度环境下，净光合速率、丙二醛含量、脯氨酸含量与100%光照强度相比均无显著差异，但超氧化物歧化酶活性显著高于100%光照强度环境；5)通过相关性和主成分分析发现，60%光照强度环境木榄苗木生长最佳。因此，1 a生木榄苗木对60%光照强度... 相似文献
5.
为确定樟树叶挥发油最佳的提取方法，采用传统水蒸气蒸馏法、微波辅助蒸馏法、超声波辅助蒸馏法和同时蒸馏萃取法提取樟树叶挥发油，并用GC-MS法对其化学成分进行分析比较。实验结果，MAHD挥发油得率为3.1%，略高于SDE的2.8%。4种提取方法所得挥发油共鉴定出79种化学成分，共有成分达到37种，其主要组成成分相近，主要为芳樟醇（64.156%～69.464%）、石竹烯（3.188%～3.814%）、桉叶油醇（2.559%～3.511%）、樟脑（2.015%～4.215%）等。综合分析，SDE成本投入少，简便，耗时短，是一种高效快速提取植物性挥发油的方法。 相似文献
6.
《技术与市场》2005,(1):6-7
太阳能热水器市场是一个潜力巨大的市场，据中国五拿制品协会的统计资料显示，目前我国城市家庭中，57.4%拥有燃气热水器，31.3%拥有电热水器，而拥有太阳能热水器的只有7.6%，明显落后于其它国家，如美国和日本的太阳能热水器市场占有率都超过了10%，澳大利亚为30%，以色列达到49%，塞浦路斯更是高达90%。在我国城市家庭的购买预期调查中，燃气热水器、电热水器和太阳能热水器的比例将演变为35.8%、30.2%、23.2%，太阳能热水器的比例将大幅增长。专家预测，近两三年，将是太阳能热水器飞速发展的时期，年销售额将达到300亿元。到2008年人类生活热水的80%将来自太阳能。 相似文献
7.
为探索低产油茶伐除更换良种技术，以1970年用实生苗造林的普通白花油茶林和培育2年的长林无性系嫁接容器苗为试验材料，采用30%、50%、70%3种砍伐强度和不砍伐4种方式，比较不同砍伐强度对林下油茶苗存活率、生长量及开花的影响。结果表明：50%的砍伐强度效果最好，与不砍伐的对照比较，存活率造林后第一年增加3.19%，第二年增加7.98%；新梢生长量造林后，第一年增加22.76%，第二年增加61.80%；每株开花数量增加18.62%，开花率增加30.55%。由此可见，在低产老油茶林分批更新改造过程中，50%的砍伐强度可以在生产上推广应用。 相似文献
8.
浙江林业经济总量快速增长 细木工板产量翻番 总被引：1，自引：0，他引：1
《浙江林业科技》2008,28(4)
近日公布的2007年浙江林业公报显示，2007年浙江林业经济总量呈快速增长的态势，林业产业总产值达1 372.9亿元，比前年增长155.3亿，增幅12.8%。其中农村林业收入381.32亿元，比上年增长10.3%，占农林牧渔业收入的28%。对农民增收贡献较大的行业是：茶、桑、果收入170亿元，较上年增长13.6%；花卉、苗木收入87.92亿元，增长9.4%；林产品、竹木采伐收入30.86亿元，增长11.6%。 相似文献
9.
泡桐叶甲天敌资源及其控制作用 总被引：1，自引：0，他引：1
泡酮叶甲的天敌种类主要有黑蚂蚁、中华草蛉幼虫、二星瓢虫、Zhu蝽、二点螂、天牛卵姬小蜂、无脊大腿小蜂、蟹形猎蛛、虎蛛等，天敌综合控制率：卵期为24.1%，幼虫期为17.03%－18.55%，最高可达23.8%，蛹期为8.2%-9.6%，成虫期为5.9%-9.4%。 相似文献
10.
沙地因缺水少肥导致牧草存活率底，生长缓慢。高吸水性竹纤维结合枯草芽孢杆菌对沙化地植被的恢复效果，结果如下：（1）与对照组相比试验组月均土壤湿度高38.06%，月均土温低2.89%,0～10cm处土层细菌、真菌数量比对照组高126.69%和50.25%,(2)试验组牧草全氮、全磷、全钾和产量比对照组增加114.49%、35.74%、44.47%和75.76%，试验组土壤铵态氮、有效磷、速效钾、有机质均高于对照组，但不显著；（3）试验组披碱草存活显著高于对照组，单位面积内植株数量超过对照组345.04%，结果表明高吸水性竹纤维结合枯草芽孢杆菌够有效的提升沙地土壤水分、养分含量，提高沙地上植株存活率。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
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. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
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. 相似文献
13.
Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献
15.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
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. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
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. 相似文献
17.
《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
18.
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。 相似文献
19.
《Scandinavian Journal of Forest Research》2012,27(2):139-149
Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(2):150-157
An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation. 相似文献