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文章通过对100个树种进行嫩枝扦插试验,结果选出了易生根树种(34种)、不易生根树种(6种)、难生根树种(7种)、爆发性生根树种(10种)和不生根树种(8种),为工厂化育苗开发提供了试验数据。
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研究合肥市区不同功能区景观林组成与结构,共记录102个样方。结果表明:景观林主要组成种有111种,分属45科、81属;主要优势种是香樟、枫杨、水杉、杨树、桂花、石楠等;不同功能区景观林树种相似性系数分别为0.4(公园与居住区)、0.24(高校与居住区)、0.22(公园与高校);林分平均密度560株/hm2,平均基盖度18.83 m2/hm2,平均胸径16.99 cm,平均树高10.13 m,均为正态分布。群落类型可归纳为5个植被型、16个群系及69个群丛,以落叶阔叶型与常绿落叶阔叶混交型为主。建群树种主要有香樟、广玉兰、女贞、雪松、水杉;群落外貌较整齐,树木整体较为健康,景观效果较佳;但层次结构、树种多样性不高,应丰富树种,增加群落的垂直层次,采用近自然经营。
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采用抽样调查的方法,对济南市的6个主要公园黄河森林公园、千佛山公园、环城公园、大明湖公园、五龙潭公园、趵突泉公园的树木进行调查。通过树种数、树种丰富度、树种多样性、树种均匀度4个指标对济南市各公园的树种组成结构进行分析,同时通过上述6个公园的树木总数、树木种类和胸径分布关系对公园树木结构特征进行分析。结果表明,大明湖公园的树种数最多,趵突泉公园的树种丰富度最大,千佛山公园的树种丰富程度最高,黄河森林公园树种最均匀。国槐(Sophora japonica)出现比例最高,占全部树木的10.69%。前20位树种总数占全部树木的75.06%,树木的数量构成具有明显的聚集性,出现少数树种主导整个群落的现象。从树木株数随胸径的分布看,同天然林存在差异,表现为近似的抛物线状。从不同胸径等级树种数分布上看,小径级的树种数多,大径级的树种数少,反映出济南市城市公园树种丰富度不断增加的趋势。
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上海植物园典型群落景观美景度评价 总被引：1，自引：0，他引：1
在全面调查上海植物园植物群落的基础上,采用美景度评判法(SBE)对33个典型群落进行美学价值评价,结果表明其美景度值为-1.38~1.37。得分值≥ 0的有16个群落,其建群树种几乎全为落叶阔叶树、且多为3层结构,得分较高的群落建群树种主要包括栾树、旱柳、乌桕、香樟、银杏、柿树、合欢等,下层以彩叶或观花树种如红花檵木、海棠、杜鹃、日本晚樱、八仙花等为主。影响群落景观美学特点的因素主要有树种组成、色彩、垂直结构、群落与周围环境的协调度、树木的健康状况及林冠线变化度等。植物园的植物群落美景度评价是构建城市绿地群落的重要参考。
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采用人工模拟低温处理,通过对樱花、樱桃、黄栌、胶东卫矛1年生休眠期枝条的游离脯氨酸、丙二醛(MDA)及可溶性糖含量的测定和冷冻后恢复萌芽试验,对它们的抗寒性进行分析与比较。结果表明,随着低温胁迫的加剧,4种灌木绿化树种的游离脯氨酸、丙二醛、可溶性糖含量大体呈上升趋势,萌芽数呈下降趋势,且3种生理指标测定结果与冷冻恢复萌芽试验的结果基本一致。4种灌木绿化树种的抗寒性强弱依次为黄栌 > 胶东卫矛 > 樱桃 > 樱花。
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在对上海12个城市林荫道树种多个性状指标观测的基础上,用灰色关联度分析方法求得各性状指标的关联系数及各树种与最优树种(理想树种)的关联度,评价城市林荫道树种。结果表明,上海城市林荫道树种表现较好的是悬铃木和珊瑚朴。
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干旱是树木生长过程中一种常见的逆境。树木为了适应干旱,在叶形态及解剖结构、叶片内含物质、渗透调节及酶调节等方面产生一系列生理变化,以保持渗透势的平衡和清除自由基,避免或者减轻细胞受到伤害。文中综述了干旱对树木叶片形态及解剖特性、比叶面积及叶面积指数、叶片气孔调节及光合生理、叶片内含物质、抗旱生理和叶片脱落及衰老等方面的影响。未来的研究热点是在大尺度上长期研究叶性状和抗旱生理的关系,对叶片性状及其环境进行协同研究,强化常见树木的主要栽培品种和珍稀树种的叶片抗旱研究,通过基因工程和分子育种技术筛选抗旱品种。 相似文献
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We present prediction models for estimating tree mortality resulting from gypsy moth, Lymantria dispar, defoliation in mixed oak, Quercus sp., forests. These models differ from previous work by including defoliation as a factor in the analysis. Defoliation intensity, initial tree crown condition (crown vigour), crown position, and species grouping classes were highly significant in categorical analysis of variance for mortality. Heavy defoliation intensity was shown to have a strong, consistent influence in increasing the probability of tree mortality. Classification and Regression Tree (CART) analysis, a binomial decision tree procedure, was used to develop prediction models of mortality risk for use by forest managers. The best decision tree had 65 groups that correctly classified 75% of the live trees and 76% of the dead trees. Models were run separately by defoliation class and provided correct classifications between 63 and 78% of the trees. Forest land managers can use these models to assign probabilities of death for moderate and heavy defoliation intensity levels and compare predicted mortality to mortality of undefoliated trees to determine how gypsy moth defoliation will affect their stands. The probabilities can be used to develop marking guides Lased on projected defoliation levels for implementing silvicultural treatments to minimize gypsy moth effects in forest stands prior to infestation. 相似文献
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Gustavo Balmelli Sofía Simeto Nora Altier Virginia Marroni Julio J. Diez 《New Forests》2013,44(2):249-263
Eucalyptus globulus is the most important forest species in Uruguay, with more than 250,000 ha of commercial plantations. Despite its high susceptibility to diseases, production losses caused by foliar diseases have not been properly quantified in this country. This study analyzes the effects of foliar damage on growth and survival using data from a progeny test of E. globulus naturally infected by Teratosphaeria leaf disease and eucalypt rust (Puccinia psidii). The severity of leaf spots and defoliation were quantified 8 months after planting and tree growth and mortality were evaluated 2, 4 and 6 years later. The trial had a high incidence of foliar damage, with a mean leaf spot severity of 28.7% and a mean defoliation of 37%. The greatest impact of foliar damage, both on growth rate and mortality, occurred in the first 2 years after damage was assessed. During this period, leaf spot severity less than 40% and defoliation below 50% did not affect growth, while survival was affected when leaf damage was 70% or greater. By the sixth year both stem growth and survival were affected by severe foliar damage (spotting or defoliation of 80% or more), with a loss of up to 25% in diameter and an accumulated mortality over 70%. It has been established for the first time that under the intensive Uruguayan productive conditions, E. globulus trees can tolerate a relatively high degree of leaf spotting or defoliation but severe foliar damage in the first months can cause considerable production losses, putting at risk the economical viability of this species. 相似文献
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对金沙江干热河谷区8个造林树种的有关生理生态特性进行了研究。结果表明:相思类树种在旱季水分自然饱和亏缺较大,乡土树种坡柳和3种桉树则是雨季水分亏缺较大,具有WSD高而RWC低的植物同样具有很强的抗旱能力;比叶面积增大是植物提高抗旱能力的一个表现方面,但增加干物质积累、提高细胞质浓度也是途径之一;干热逆境可造成叶绿素含量降低,雨季叶绿素含量有较大提高,叶绿素a/b值也随之得到提高;参试树种的糖分含量旱季比雨季高,除马占相思外,其它树种淀粉与糖的比率则旱季比雨季低;在干热逆境胁迫下,7个树种(除尾叶桉)的游离脯氨酸含量有不同程度增加,旱季植株易出现萎蔫现象,有部分或较多叶片脱落的树种积累的游离脯氨酸较多。除造林效果较差的马占相思与其它7个树种有较多差异外,造林效果较好的7个树种在生理生态变化方面有较多相似性;同时,同类树种间有明显的一致性;乡土树种坡柳则在某些方面更近似于相思类树种,在某些方面又近似于桉树类树种;除马占相思外,3个相思类、3个桉树类树种与乡土树种坡柳同样在金沙江干热河谷区表现出较强的生态适应性。 相似文献
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辽西地区主要造林树种抗旱性的研究 总被引：23，自引：0，他引：23
辽西地区属于半干旱季风气候区,年平均温度为7.1—8.2℃,年降水量为400—600mm,年蒸发量为1600mm,为降水量的3—4倍。干燥是该区总的气候特点。该区的植物群落主要为旱生的森林灌丛或草本植物群落,针叶树建群种为油松,阔叶树为蒙古栎,元宝槭,黄榆;灌木主要为荆条和酸枣。土壤是在各种岩石风化物残积母质上,以及黄土、红土母质上发育的淋溶褐土和褐色性土,土壤干旱瘠薄。水分是这一地区限制造林树种成活及生长的主要因子,本文试图通过对树种抗旱性的测定和分析,确定树种的抗旱能力,从而为辽西地区的造林提供树种选择的依据。 相似文献
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应用大叶相思、肯氏相思、毛娟相思、马占相思和厚荚相思等相思树种在东山县沿海沙地上营建防护林,并对其抗风、抗台风及抗连续干旱性能进行了测定。结果表明:厚荚相思抗风能力强,生长快,是较好的可在沿海沙地上适生的树种;相思树种抗台风能力较木麻黄弱,台风对相思树种的主要危害是断梢,但在以后的生长中能较快地得到恢复,对相思林分生长并不会产生大的影响;厚荚相思在沿海沙地上造林,不仅成活率高(95%以上),而且在遭受连续8个月的干旱后,旱死率为0,表现出很强的抗旱能力,而且在贫瘠的沙地土壤上生长表现良好,其生长量超过了木麻黄601无性系,是非常好的适合于沿海沙地条件的树种。 相似文献
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以2007—2009年在云南省持续发生的旱灾为例,通过方差分析,检验不同地域、地类、树种和起源的森林是否存在抗旱能力的差异,通过对受灾数据的比较分析,总结出云南省森林资源的抗旱能力和受灾原因。结果表明:不同地类、树种和起源的森林,抗旱能力存在显著差异;不同地域的森林,抗旱能力理论上不存在差异,但实际上从调查数据来看还是存在差异的。 相似文献
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George Matusick Katinka X. Ruthrof Niels C. Brouwers Bernard Dell Giles St. J. Hardy 《European Journal of Forest Research》2013,132(3):497-510
Drought and heat-induced forest dieback and mortality are emerging global concerns. Although Mediterranean-type forest (MTF) ecosystems are considered to be resilient to drought and other disturbances, we observed a sudden and unprecedented forest collapse in a MTF in Western Australia corresponding with record dry and heat conditions in 2010/2011. An aerial survey and subsequent field investigation were undertaken to examine: the incidence and severity of canopy dieback and stem mortality, associations between canopy health and stand-related factors as well as tree species response. Canopy mortality was found to be concentrated in distinct patches, representing 1.5 % of the aerial sample (1,350 ha). Within these patches, 74 % of all measured stems (>1 cm DBHOB) had dying or recently killed crowns, leading to 26 % stem mortality six months following the collapse. Patches of canopy collapse were more densely stocked with the dominant species, Eucalyptus marginata, and lacked the prominent midstorey species Banksia grandis, compared to the surrounding forest. A differential response to the disturbance was observed among co-occurring tree species, which suggests contrasting strategies for coping with extreme water stress. These results suggest that MTFs, once thought to be resilient to climate change, are susceptible to sudden and severe forest collapse when key thresholds have been reached. 相似文献