望城县五大家领导参加义务植树

3月12日,望城县委、县人大、县政府、县政协和县人武部10多位县级领导率领机关干部70余人．在高乔大道南接线开展义务植树活动,共栽植杜英、桂花、红叶李等树苗200余株。     

市场需求不断扩大肥西苗木销售同期增长三成

今年以来，安徽省肥西县苗木销售明显好于去年，同期增长三成以上。据悉，前几年大量滞销的杨树、马尾松、杉树等造林用苗今年供不应求，做色块用的彩叶灌木苗也销量猛增，桂花、广玉兰、红叶李、女贞、香樟等园林绿化用乔木，大规格的树苗与去年同期相比涨幅达15％；南于蚕茧价格走高，今年桑树苗也出现了紧缺，价格一路上扬。     

红叶李扦插繁殖技术及在园林绿化中的应用

指出了红叶李的生态习性,分析了红叶李扦插繁殖技术,并从孤植、丛植、群植等方面探讨了红叶李在园林绿化中的应用。     

红叶李苗木培育技术

通过山杏、山桃播种培育砧木后进行红叶李嫁接的试验，探索出了太原地区红叶李育苗的一系列技术措施。山杏、山桃需经沙藏处理后播种，嫁接可采用芽接，也可进行枝接，两者成活率均在90％以上。     

著名观叶植物红叶李

著名观叶植物红叶李红叶李，别名紫叶李，系蔷薇科李属的落叶小乔木。株高达２３米。幼枝、叶片、花柄、花萼及果实都呈紫红色。叶卵型或倒卵型，基部圆型，边缘有锯齿。花单生，有时２３朵簇生于叶腋，粉红色或水红色，花期３４月。花后结扁球型果实，６７月成熟。它以红...     

4个李属彩叶树种在河西走廊张掖市引种适应性研究

为丰富河西走廊张掖市城市绿化彩叶树种资源,从辽宁铁岭引种密枝红叶李、红叶李、太阳李、紫叶矮樱4个彩叶树种,对其生长情况、叶色物候期、抗逆性进行观测和评价。结果表明,4个彩叶树种的引种成活率为81%～100%;地径、树高、冠幅年均生长量分别为2.18～2.82 cm、72.21～96.69 cm、58.34～89.29 cm;色叶最佳观赏期为163～170 d,色叶期为163～186 d;抗逆性由强到弱次序为紫叶矮樱、太阳李、密枝红叶李、红叶李。4个彩叶树种中紫叶矮樱、太阳李、密枝红叶李在内陆河流域甘肃省张掖市综合生长表现较好,适应性较强,适宜在张掖市园林中广泛推广和应用。     

干旱胁迫与彩色树生长状况关系研究

以金叶榆、金枝梾木和俄罗斯红叶李3种彩色树2a生苗木为试材,测定了不同程度干旱胁迫下净光合速率、蒸腾速率、细胞膜透性、叶片含水量以及高生长等指标,分析了3种彩色树的抗旱性。结果表明:在轻度干旱胁迫条件下,金叶榆和金枝梾木受到的影响小于俄罗斯红叶李;重度干旱条件下,金叶榆表现出较强的抗旱性,而金枝梾木和俄罗斯红叶李受到的影响较大。3种彩色树的抗旱性强弱排序为:金叶榆金枝梾木俄罗斯红叶李。     

密枝红叶李引种栽培及在园林绿化中的应用

对密枝红叶李(Prunus cerasifera var.atropurpurea Russia)在昌吉地区的栽培技术进行了初步研究,通过大田试验,初步总结出密枝红叶李在新疆昌吉地区的引种栽培技术要点,并对密枝红叶李在昌吉地区引种表现进行了观测。已在南北疆城镇绿化中得到广泛应用,有着极大的开发价值。     

俄罗斯红叶李在宁夏的引种表现

指出了俄罗斯红叶李生长季叶片始终保持鲜红且抗寒性极强,在银川地区表现良好,是难得的红叶耐寒树种。对其物候期,生长特性、观赏性等特点进行了观察,结果表明:俄罗斯红叶李适应本地的气候条件,能正常生长发育,表现出较强的耐寒、耐高温、耐旱和抗病性,具有很高的观赏价值和推广应用价值。     

盐碱胁迫对3种彩色树的影响

该文模拟东北地区苏打盐碱土成分,对金叶榆、密枝红叶李、紫叶风箱果3种彩色树小苗进行不同程度盐碱胁迫,通过测定胁迫中彩色树叶片中的丙二醛含量、可溶性糖含量、生长情况等生理指标,分析3种彩色树的耐盐碱性。结果表明:在盐碱胁迫过程中,金叶榆、密枝红叶李、紫叶风箱果根、冠生物量随盐碱浓度增加均出现不同程度的降低。各项生理指标均表明金叶榆的耐盐碱能力最好,密枝红叶李次之,紫叶风箱果耐盐碱能力最差。     

放牧对幼林地的危害分析

介绍了2个护林成功的典型案例,在探究其成功原因的基础上,分析指出,牛羊为害一般并不会直接致死幼树,但放牧反复为害,会严重削弱幼树的整体光合作用,破坏地上与地下部分的协调性,紊乱营养生长与次生代谢过程相互关系,导致幼树一步步走向衰弱死亡,幼林地永无成林的希望。所以,新造林地必须严格禁牧。     

云南红豆杉实生与扦插人工幼林生长量的比较研究

通过对云南省马关县金城林场云南红豆杉实生苗和扦插苗营造的4年生幼林的生长量进行对比分析,结果表明:实生苗造林幼树的树高、地径、生物量干重指标都大于扦插苗造林的幼树,且表现出明显的生长优势;实生苗造林幼树的地径变异系数是扦插苗造林幼树地径变异系数的1.1倍;扦插苗造林幼树树高变异系数是实生苗造林幼树树高变异系数的2.8倍。     

太行山西侧油松人工林椽材阶段林木密度的探讨

油松是山西太行山区的主要造林树种,现有人工林16.2万ha,由于造林密度不够合理,不少地方成林不成材。确定适宜造林密度的标准和方法是较多的,从太行山区群众生产生活中需求一定数量小径材的实际情况出发,我们认为林分第一次间伐时,大部分间伐木能达到小径材(椽材)标准的密度,是较为适宜的密度,可获得较好的造林经济效益,“七五”期间,我们对太行山西侧的油松人工林密度进行了调查总结。     

林业专用吊运车在大苗移植中的应用和效益分析

为解决大苗出圃运输人抬肩扛难题,提高树木移植机械化水平,河北农业大学教学实验林场根据生产实际需要,结合现代农机的发展成果,研发了适合苗圃林地大苗移植的“林业专用吊运车”。该吊运车在大苗出圃运输中所需人员只2名,是人工搬运的1／2,苗木完好率达到98％以上,高出人工搬运18％左右,每搬运一棵大苗所需的时间为5min,工作效率大为提高。     

Shrubs facilitate recruitment of <Emphasis Type="Italic">Caragana stenophylla</Emphasis> Pojark: microhabitat amelioration and protection against herbivory

Key message

Mature Caragana stenophylla shrubs facilitated intraspecific sapling establishment by two mechanisms: microhabitat amelioration and protection against herbivory. Facilitation was mediated by climate, grazing, and sapling age.

Context

Pre-existing shrubs could facilitate sapling establishment of woody plants; however, how these facilitation vary across abiotic and biotic stress gradients and the underlying mechanisms remain unclear.

Aims

The aim of this study is understanding the facilitation of shrub on sapling establishment and how the two underlying mechanisms, microhabitat amelioration and protection against herbivory, vary across climatic aridity gradients, grazing gradients, and sapling age.

Methods

We conducted field sowing experiments to examine the facilitation of mature Caragana stenophylla Pojark on intraspecific sapling establishment.

Results

Facilitation of C. stenophylla on sapling survival increased as drought stress, grazing intensity, and sapling age increased. Microhabitat amelioration increased as drought stress and sapling age increased. Similarly, protection against herbivory increased as drought stress, grazing intensity, and sapling age increased. Relative importance of microhabitat amelioration increased as drought stress increased, and relative importance of protection against herbivory increased as grazing intensity and sapling age increased.

Conclusion

Facilitation of shrub on sapling establishment involves both microhabitat amelioration and protection against herbivory. Facilitation, the two mechanisms, and relative importance between the two mechanisms would all be affected by climatic aridity, grazing intensity, and sapling age. Shrub establishment has a positive feedback effect.

     

珍稀濒危树种连香树造林试验

本文通过对连香树造林成活率、中幼龄林生长情况调查,结果表明,连香树在前期生长较快,病虫害少,树体大小中等,适宜作为城市行道树和园林、庭院绿化树种,影响栽植成活率和生长量的主导因子是水分,苗期和幼树易发生日灼危害,平原地区栽植应以4～5年生的大苗为主,栽植幼苗应适当遮荫。     

常绿阔叶林的可持续经营

通过对常绿阔叶林研究，努力探索一条发展常绿阔叶林的途径。将阔叶林划分为3个经营类型，分别为：初期幼龄林组成抚育类型、中期幼龄林抚育间伐类型、中龄林密度管理类型。并提出小面积皆伐的采伐方式。同时对常绿阔叶林的生态功能和生产力进行初步研究。     

Six-year time course of light-use efficiency, carbon gain and growth of beech saplings (Fagus sylvatica) planted under a Scots pine (Pinus sylvestris) shelterwood

Two-year-old Fagus sylvatica L. saplings were planted under the cover of a Pinus sylvestris L. stand in the French Massif Central. The stand was differentially thinned to obtain a gradient of transmitted photosynthetically active radiation (PAR(t); 0-0.35). Eighteen Fagus saplings were sampled in this gradient, and their growth (basal stem diameter increment) was recorded over six years. Over the same period, morphological parameters (leaf area, number and arrangement in space) were monitored by 3D-digitization. Photosynthetic parameters were estimated with a portable gas-exchange analyzer. Photosynthesis was mainly related to light availability, whereas sapling morphology was mainly driven by sapling size. Annual stem diameter increment was related to the amount of light-intercepting foliage (silhouette to total leaf area ratio (STAR) x total sapling leaf area (LA)) and light availability above the saplings (PAR(t)). However, light-use efficiency, i.e., the slope of the relationship between STAR x LA x PAR(t) and stem diameter increment, decreased over time as a result of a relative decrease in the proportion of photosynthetic tissues to total sapling biomass.     

Pits and rocky microsites in a subalpine forest stand facilitate regeneration of spruce saplings by suppressing dwarf bamboo growth inside a deer-proof fence

We determined patterns of microsite suppression in dwarf bamboo Sasa nipponica when grazing deer were absent. This bamboo species is able to outcompete Hondo spruce (Picea jezoensis var. hondoensis) saplings under many environmental circumstances. We set up two 10 × 100 m plots inside a deer-proof fence within a subalpine forest on Mt. Ohdaigahara, central Japan, and two similarly sized plots outside the fence. Within the plots, we surveyed microsites where spruce saplings grew. We measured height and shoot elongation of all spruce saplings, and culm height and cover ratios of dwarf bamboo growing around each spruce sapling. Spruce sapling density and average height were higher inside the deer-proof fence than outside, as were bamboo height and cover. Thus, there was a negative effect of deer browsing on vegetation parameters outside the fence and a suppression of the negative effect of bamboo on spruce sapling growth inside the fence. Spruce sapling height was higher in tree-fall pits than in other microsites inside the fence, whereas both dwarf bamboo height and cover were lower in pits and rocky sites than elsewhere. In soil and collar microsites, spruce sapling shoot growth was lower and bamboo height and cover were higher than in pits and rocky sites. Inside the fence, dwarf bamboo cover was high, but pits and rocks suppressed its growth, allowing spruce saplings to flourish. To restore heavily damaged spruce forests with advanced saplings, it will be necessary to construct deer-proof fences and create and maintain microsites with pits and rocks.     

Removing aboveground vegetation facilitates survival but slows height growth of spruce saplings in a fenced, degraded sub-alpine forest in central Japan

The effects of removing aboveground vegetation on survival and growth of Hondo spruce (Picea jezoensis var. hondoensis) saplings were examined in a dense dwarf bamboo (Sasa nipponica) field inside a deer-proof fence built in a degraded sub-alpine forest on Mt Ohdaigahara, central Japan. All bamboo culms were removed within a radius of 1 m from each sapling in a plot of 0.6 ha (removal plot), whereas no culms were removed in two control plots of 0.1 ha. We measured the height, crown depth, and main shoot elongation over 1 year for all spruce saplings, culm height and cover ratios of dwarf bamboo growing around each spruce sapling, and the light levels above each sapling. Removal of dwarf bamboo regulated the culm height and bamboo coverage until the following summer such that light conditions improved. The mortality of saplings smaller than the average culm height was lower in the removal plot (0.89%) than in a control plot (5.9%). After bamboo removal, sapling height growth was reduced with increasing bamboo cover in the previous year. Complete removal of the aboveground portions of covering bamboo improved sapling survival while regulating elongation growth, possibly because of the sudden increase in light intensity. Thus, controlling the extent of dwarf bamboo removal might be necessary to facilitate the growth of spruce saplings to restore the forest.