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为给枸杞春季霜冻预报和预警提供参考,以3年生盆栽宁夏枸杞‘宁杞1号’为研究对象,于2016、2017、2018年在MSX-2F型霜冻箱内进行人工模拟霜冻试验,处理温度为-3、-4、-5、-6、-7、-8℃,处理时间为1、2、3h,研究不同温度和持续时间处理下宁夏枸杞花蕾期、初花期、盛花期的霜冻率,最终确定宁夏枸杞的霜冻等级。结果表明:根据霜冻率,将霜冻程度划分为3个等级,轻度为霜冻率低于40%,中度为霜冻率40%~80%,重度为霜冻率高于80%;不同低温和持续时间对宁夏枸杞花蕾期、初花期、盛花期的影响程度不同,温度越低、持续时间越长,宁夏枸杞的霜冻率越大;同一温度和持续时间处理下,花蕾期的耐霜冻性最强,初花期的次之,盛花期的最弱。 相似文献
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Forest and livestock management puts pressure on forests and the wildlife they support. Although many species may be negatively affected by these human activities, the abundance of other species may be promoted, although this has perhaps received less attention in livestock, logging, and conservation management plans. Wild boar and red fox, two common mammals distributed throughout Europe, occupy a wide variety of Mediterranean environments. Little is known about how increases in logging and livestock management have changed their status. This work models the response of wild boar and red fox to these pressures in the human-altered Mediterranean forest landscapes of the central Iberian Peninsula (NHR), where the predominant land uses in the last hundred years have focused on livestock and logging (thinning and selective cutting). We collapsed land use and habitat structure variables into independent habitat vectors using principle component analysis (PCA) and then used a general linear model (GLM) to explain the relationships between red fox and wild boar abundance and the independent habitat vectors observed in human-altered forests. Livestock and logging activity was positively correlated with wild boar abundance, and negatively correlated with red fox abundance, although red fox tolerated open scrubland that had been logged. Red fox abundance remained negatively correlated with the same variables when boar abundance was added as an environmental predictor in the model, but some additional variance was explained, demonstrating the need to include indirect interspecific relationships in the habitat-species models. The combined effects of wild boar, logging and livestock are indirectly important factors which modify habitat structure and negatively affect red fox. Therefore, common mammal species are influenced by livestock and logging in different ways which necessarily may be taken into account in management and conservation decisions in Mediterranean human-altered forests. 相似文献
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本文结合实例.深刻地分析了绥化地区道路翻浆的主要特征及成因.处治方法和各种处治方法的经济比较.证实翻松凉晒法处治道路翻浆是一种切实可行的方法. 相似文献
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以遭受霜冻的麻竹（Dendrocalamus latiflorus）为试验材料,研究在2016—2018年3种霜冻恢复措施对麻竹立竹生长和竹笋生长特性的影响,运用主成分分析对3种霜冻恢复措施进行综合评价。结果表明：3种霜冻恢复措施对竹高、胸径、丛幅、笋地径、笋高、笋质量及出笋数量均具有影响。皆伐后常规经营模式下的立竹生长指标和笋生长特性指标均逐年增大,其中2017年和2018年竹丛丛幅、笋总质量和笋数量大于其他2种模式;持续常规经营模式下的麻竹立竹竹高、胸径和平均笋基径最大;无人工经营模式下的立竹各生长指标和笋生长指标最小。主成分分析表明,麻竹遭受霜冻后,采取持续常规经营措施能够保证麻竹生长和笋产量的增加,带来更高的经济效益。 相似文献
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季节性冰冻地区路基聚冰防治措施浅析 总被引：1，自引：0，他引：1
我国东北季节性冰冻地区的路基若土体中含有较多的水,在温度下降的时候,会发生程度不同的聚冰、冻胀现象。由于土体含水量、土体毛细作用的强弱及温度变化速度的不同,又将产生轻度冻胀直至翻浆等不同程度的病害。本文对季节性冰冻地区聚冰现象提出了一些防治措施及建议。 相似文献
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Frost resistance and ice nucleation temperatures of leaves, from bud swelling until after full expansion, were measured in situ for five major woody timberline species with recently developed field freezing equipment. Frost resistance determined in situ on leaves of attached twigs was significantly higher than values determined on detached leaves in laboratory tests (e.g., the temperature at which incipient frost damage was observed (LTi) was 1.2 degrees C higher for detached leaves than for attached leaves of Picea abies (L.) Karst.). Frost resistance of leaves of all species changed significantly during shoot expansion (e.g., changes of 7.2 and 11 degrees C for Rhododendron ferrugineum L. and Larix decidua Mill., respectively). Expanding leaves (between 0 and 60% of full expansion) were the most sensitive to frost, with LTi values ranging from -3.4 degrees C in R. ferrugineum to -6.3 degrees C in L. decidua. Among the studied species, P. abies and R. ferrugineum were the most frost sensitive throughout the shoot elongation period. In situ freezing patterns of leaves of attached twigs also differed from those of leaves of excised twigs. During leaf expansion, two distinct freezing exotherms were always registered in situ. The first freezing event (E1, high-temperature exotherm) was recorded at -1.5 +/- 0.2 degrees C and reflected extracellular ice formation. Exposure of leaves to temperatures at which E1 occurred was, in all cases, noninjurious. The low-temperature exotherm (E2) mostly coincided with frost damage, except for some stages of leaf expansion in R. ferrugineum and P. abies, indicating that in situ freezing exotherms were not accurate estimators of frost damage in these species. 相似文献
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Climate warming and the risk of frost damage to boreal forest trees: identification of critical ecophysiological traits 总被引：1，自引：0，他引：1
Hänninen H 《Tree physiology》2006,26(7):889-898
According to a hypothesis presented in the mid-1980s, climate warming will, paradoxically, increase the risk of frost damage to trees in the boreal and temperate zones. Dehardening and even growth onset may occur in trees during mild spells in winter and early spring, resulting in damage during subsequent periods of frost. In the present study, ecophysiological traits critical to the occurrence of frost damage in trees in the boreal zone were identified. Diagnostic computer simulations were performed to examine why one simulation model of frost hardiness in an earlier study predicted heavy frost damage as a consequence of climate warming, whereas another closely related model did not. The modeling comparison revealed that the response of ontogenetic development to air temperature during quiescence is a critical factor determining the risk of frost damage. As the response can be readily determined in growth-chamber experiments, the findings of the present study can be used to guide experimental work on the environmental regulation of the annual cycle of frost hardiness in trees. 相似文献
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通过对黄金间碧玉竹的繁殖和适应性试验，认为黄金间碧玉竹繁殖容易，适应性强．在亚热带轻霜地区种植，生长良好，可作观赏和材用。影响其生长发育的主要限制因子是霜冻，若定檀当年和次年采取防护措施，待其根系、地下茎和茎杆抗性增强后，便可抵御一定程度的寒窖。 相似文献
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《Forest Ecology and Management》2001,141(3):223-235
Damage to Norway spruce (Picea abies (L.) Karst.) seedlings by summer frost was monitored on 10 clear-cuttings of various ages to which slash removal and four types of site preparation had been applied. The clear-cuttings were established on two sites (5 on each) in southern Sweden from 1989 through 1993 and planted each year from the year of cutting until 1993. In total, 7680 seedlings were analysed for frost injuries during the first three years following planting. The site preparation methods evaluated were: application of herbicide to ground vegetation; mowing of ground vegetation; scarification (mounding); and control. Two seedling types, bare-rooted and containerised seedlings, were evaluated.Periods of frost susceptibility were calculated using data on bud and shoot development during 1997 together with weather data for each of the studied years and sites. The date of flushing was well correlated to the air temperature sum (+5°C threshold value) in spring. Frost damage varied considerably between sites and study years. The lowest measured minimum air temperature and the frost-day sum during the frost-susceptible period were correlated to the frequency of frost damage. Soil scarification reduced frost damage in the first growing season. Bare-rooted seedlings had a considerably lower frequency of frost injury compared with containerised ones, possibly because flushing of the former was delayed. There was no statistically significant effect of herbicide application, mowing or slash removal on the frequency of frost damage. Seedling growth was significantly reduced by frost injury, especially in cases where injuries were sustained during several years. Survival was only slightly affected by frost damage. 相似文献
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Forking is a frequent flaw in beech which can adversely affect the formation of high quality logs. Even though the hypothesis that late frosts increase forking is widely accepted by forest managers, it remains to be proved and quantified experimentally. Damage caused by a late frost on 15 May 1995 to young beech trees in an experimental site at Lyons-La-Forêt (France) and the consequences on the development of forking were analysed. The beech trees were 17 years old with heights between 1.5 and 9 m. Of all the plantation densities tested only the lowest density (625/ha) showed various and severe frost damage. Three levels of immediate damage to the growing terminal shoot were observed, with increasing intensity from: (1) no trace of frost damage, (2) reddened leaves and (3) frost-nipped shoots. The intensity of visible damage to the terminal shoot appeared to be very dependent on the height of the plant which justified our original experimental approach, based on an evaluation of the damage for each individual. Almost all of the beech trees less than 4 m high suffered frost damage and all those taller than 7 m were unaffected. Three-year-old forks due to frost which occured in May 1995 were recorded at the end of 1997 using an objective definition based on dendrometric and age criteria. The worst frost damage resulted in a significant increase in the risk of fork emergence (71.7% of the plants were forked). With a risk related to forking in the presence of frost-nipped shoots equal to 2.15 and a fraction of the attributed risk of 0.36 it was concluded that the late frost observed played a significant role in the degradation of the shape of the beech affected by frost and the overall quality of the stand. 相似文献
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季冻区路基土冻胀主要影响因素对冻深的影响规律 总被引：1，自引：0，他引：1
依托黑龙江省庆安冻土科学试验场,开展了不同土质冻胀量和冻深等的试验观测。根据试验和观测数据,分析土质、土的冻胀率及坡向与路基冻深的关系,得到3个主要影响因素对路基土冻深的影响规律,分析土质、冻胀率及地形坡向对路基冻深的影响程度。基于上述研究结论,提出土质、冻胀率及地形坡向对路基土冻深的修正系数。利用三个修正系数,可以实现对标准冻深的修正,计算路基的实际冻深,作为路基换填以及路面抗冻厚度设计的依据。 相似文献
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Twenty-three Pinus radiata seed orchard clones of the New Zealand 850 series were each control-pollinated with a mix of 10 pollens to produce polycross families. The seed was sown in open nursery beds. Seedlings were potted up at six times of the year and subjected to white advective frosts in controlled-environment rooms, with up to seven frosting runs of variable severities at each time. There were significant differences (p< <0.001) between families in frost injury, such that, although there was statistically significant family × time interaction, some families were consistently more frost resistant (tolerant) than others. No association between frost resistance and growth rate was evident.Individual-tree heritability estimates for frost damage scores were around 0.3 at given times, and 0.20 over all times. Prospective gain in resistance from progeny testing over several seasons of the year, with 2:23 selection, is about 1°C. An additional gain of 0.4°C resistance appears obtainable from 1:90 selection of individuals within pair-crosses in a single frosting run. This additional (within-cross) gain might be increased to around 0.75°C, with the same culling rate but testing one ramet per seedling at each of four times of the year. 相似文献
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Vanessa C. Luis Dunja Taschler Juergüen Hacker María Soledad Jiménez Gerhard Wieser Gilbert Neuner 《Annals of Forest Science》2007,64(2):177-182
Frost resistance and ice formation in different developmental states of needles of P. canariensis seedlings were assessed. Regrowth after frost damage was used to determine the overall frost survival capacity. Two distinct freezing exotherms (E1, E2) were registered. E1 was between ?1.7 and ?2.0 °C. Initial frost damage (LT10) was 1.5–2.7 °C below E1. E2 was between ?5.6 and ?6.0 °C, and either corresponded with LT50 or occurred in between LT10 and LT50. Current year needles were less frost resistant than 1-year-old needles. The overall recuperation capacity of seedlings revealed that frost survival may be underestimated when only needle damage is assessed. Freezing of seedlings with or without roots had no effect on the frost resistance of needles but recuperation capacity was significantly affected. Seedlings survived ?10 °C during summer indicating that they withstand the lowest naturally occurring frosts in Tenerife. 相似文献
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经济林冻害调查及其防冻措施 总被引：2，自引：0，他引：2
对江西1991年冬季经济林冻害情况进行了调查,比较了各树种、品种的抗冻能力,并分析了地形地势、经营管理水平等因素对冻害的影响,依此指出了防冻措施。 相似文献
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绿洲防护林体系缓解霜冻作用的调查研究 总被引：3，自引：1，他引：2
通过对2004年5月3日晨发生在内蒙古河套平原的大面积霜冻调查显示,绿洲防护林在减轻霜冻方面具有明显作用。由于树体降温放热、林网对气流的阻挡作用以及林冠层对热辐射的影响等,防护林结构较完整的区域冻害明显轻于防护林不够完整的区域;寒流进入林网区后,产生霜冻的能力随纵深距离增大而逐步衰减。加强绿洲防护林体系建设、完善林网结构、重视农田周围闲散荒地的造林绿化对缓减霜冻具有重要意义。 相似文献
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J. Kreyling D. Thiel L. Nagy A. Jentsch G. Huber M. Konnert C. Beierkuhnlein 《European Journal of Forest Research》2012,131(3):717-725
Fagus sylvatica, the dominant native forest tree species of Central Europe, is sensitive to late frost events. Advanced leaf flushing due
to climate warming may lead to more frequent frost damage in the future. Here, we explore local adaptation to late frost events
at both continental and regional scales and test how moderate climate warming (+1.5°C) affects late frost sensitivity. Short-term
leaf injury and height growth after a late frost event were quantified in a common garden experiment with 2-year-old F. sylvatica seedlings. The fully crossed three-factorial design consisted of a late frost manipulation, a continuous warming manipulation
and selected provenances (three provenances from western Bulgaria and three from southern Germany). Late frost led to leaf
injury and reduced height growth (−7%). Provenances differed in their late frost sensitivity at the regional scale, and local
adaptation was detected. At the larger scale, the Bulgarian provenances showed reduced height growth (−17%), while the German
provenances did not exhibit growth reduction. The warming treatment prevented late frost damage, while height growth declined
by 19% in the reference temperature treatment. This surprising finding was attributed to advanced leaf maturity in the warming
treatment. The impact of late frost events on F. sylvatica in a warmer world will depend on timing. An event that damages leaves immediately after leaf flushing appears negligible
a few days earlier or later, thereby complicating projections. Local adaptation to late frost is evident at a regional scale.
Management strategies should aim at maximizing genetic diversity to adapt to climate change. 相似文献