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昆明地区华山松球蚜发生规律研究 总被引：3，自引：0，他引：3
１９８９年３月～１９９２年８月工嵩明县大吸及白邑两乡的５～７年生华山松幼林内设立标准地１０块、结合室内饲养，观察华山松球蚜的发生规律及各环境因子对基人种群消长的影响。结果是：华山松球蚜在昆明地区１年发生８代，２月上蟾当日均温达到８℃左右时越冬雌成虫开始产卵繁殖，１１月，当日无温降至５℃以下时雌虫停止产卵，雌成虫分别３月中旬、５月下旬、１０月中旬出现３次产卵高峰，降雨强度、天敌是影响林间球蚜种群种的 相似文献
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竹箩舟蛾是竹子的重要食叶害虫,分布于我国南方产竹各省,在浙江省１ａ３～４代,均以蛹于土表下越冬。成虫发生期分别为４月上旬～５月上旬、６月上旬～７月上旬、７月下旬～８月下旬、９月下旬～１０月中旬。幼虫危害期分别为４月下旬～６月中旬、６月中旬～８月上旬、８月中旬～１０月上旬,以第３代蛹越冬者幼虫可延至１０月下旬,第４代为１０月中旬、１１月下旬。第３代幼虫各龄食叶量分别为１．５７、７．７３、１６．３６、５７．０２、５７９．７８ｃｍ＾２,幼虫期共取食竹叶６６２．４６ｃｍ＾２。雌性幼虫期食叶量比雄性多１２％～１５％,每头成虫产卵量为１６１～２８６粒。天敌有赤眼蜂、黑卵峰、姬蜂、寄蝇等。并提出了相应的防治方法。 相似文献
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作者于１９９４～１９９８年研究表明，双棘长蠹是石家庄市的一个新害虫，仅危害国槐细枝干，１年发生１代，每代有４个虫态。成虫期近１０个月，卵期５～８ｄ，幼虫期３０～４０ｄ，蛹期７ｄ左右。４月中旬～５月上旬是成虫产卵、蛀食危害盛期，１０月上旬～１１月中旬新成虫开始迁移、蛀食危害、越冬。幼虫、新成虫具有群居和固守的习性。依据这些生物学特性，提出了加强检疫、清理受害枝以消灭越冬成虫、幼虫、新成虫的无公害新防治策略，并收到了显著效果。 相似文献
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华竹毒蛾生物学特性及防治方法的初步研究 总被引：2，自引：0，他引：2
华竹毒蛾是毛竹的食叶害虫，在安福武功山区一年发生３代，以蛹在竹杆上的地面灌木杂草叶背越冬，翌年４月中旬开始羽化产卵。１、２、３代幼虫发生危害期分别为：４月下旬－６月下旬，７月上旬－８月上旬，８月中旬－１０月中旬。以第２代发生整齐且危害最烈。在幼虫１－３龄期用ＤＤＶＰ插和烟雾剂进行熏杀，效果可达８０％，蛹期寄生虫较多，可利用于防治。 相似文献
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栗绛蚧的寄生蜂有８种，６种育自雌蚧，１种育自雄蚧，１咱育自雌蚧及雄蚧。每年发生１代，营内寄生，寄生雌蚧的蜂种。发生期集中于３月中旬至５月中旬，林间成蜂有三个羽化期，３月中旬至４月上旬，４月中旬至下旬，５月中旬。林间寄生率３．２％～６２．７％。 相似文献
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草履蚧在陕西１年发生１代,一般情况下越冬卵 孵化盛期为２月中下旬,若虫２月中旬至３上旬上树危害,雌成虫４月下旬至６月中旬下树,下树雌虫在树干周围的地面杂物下、土缝、疏松土层内产卵越夏和过冬。蚧虫卵在树完下土壤中的分布规律、分布量与距树干的距离远近有关,集中分布于距离树干６０ｃｍ范围内地面以下－～５．６～１０ｃｍ的土层中。以土壤中草履蚧的卵量作为该虫的防治指标时,指标值确定为树冠下在离树干６０ｃｍ范 相似文献
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《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
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《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
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《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
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《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
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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
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《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献