承德市杨柳飞絮综合治理措施

介绍了承德市园林管理局治理杨柳飞絮的多种途径和措施。     

Recent Status of Willow Ptarmigan in China

IntroductionWillowptarmigan(LagOPusI8gOPus),belongingtoGrouse,hasbeenputonthesecond-classofproteCtedanimalinChina.ItlikesHazelgrouseinthebodilyformandsize,butplumagecolorchangesinthefourseasonofoneyearThebodyplumageofmaleandf6maleiswhiteinwinter,onlytailplumeisblack.So,Willowptarmiganhaslongbeenknownastheif.hit.Hazelgroused.WillowPtarmiganiscircumborealspecies.DistributionrangespreadsovertheentireforeStzoneandsteppezone,eventundrazonefromthenorthernpartofNorthAmericatothenorthernpartof…     

Linking wolves to willows via risk-sensitive foraging by ungulates in the northern Yellowstone ecosystem

After an absence of approximately 70 years, gray wolves (Canis lupus) were re-introduced into Yellowstone National Park in the mid-1990s. We studied the potential influence of wolf/ungulate interactions upon willow (Salix spp.) growth in the valleys of the Gallatin and Lamar Rivers, as well as Slough and Soda Butte Creeks, in the northern Yellowstone ecosystem. When we compared willow heights from photographs taken prior to 1998 (willows <2 m tall) with those taken in 2004, we found an increase in willow height for 22 of 42 sites within the study area. Based on comparisons of the chronosequence photos, since wolf introduction none of the 16 upland riparian sites showed an increase in willow height, while 22 of 26 of the valley-bottom riparian sites had willow height increases. In 2004, willow height exhibited a strong inverse relationship with the percentage of browsed stems (r = −0.81, p < 0.01, n = 42). Results of regressions for valley-bottom sites indicated that view distance, impediment distance, and the number of bison (Bison bison) flops were inversely related to willow height (p ≤ 0.02). Increased willow heights were not significantly (p = 0.18) related to patterns of moisture availability. Willow height increases documented in this study appear to have been at least partially due to behaviorally mediated trophic cascades involving wolves and ungulates, via a mechanism of predation risk. While willow release (i.e., increased height growth) within the study area is in a very early stage, results suggest potentially important indirect effects of a top carnivore in a terrestrial food chain that may aid in the restoration of riparian species and the preservation of biodiversity.     

The role of competitors for <Emphasis Type="Italic">Chrysomela lapponica</Emphasis>, a north Eurasian willow pest,in pioneering a new host plant

The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern region of its occurrence. However, in Central Europe, some populations are known that have specialised on birch. In this study, we investigated the significance of other herbivores occurring together on the same host plants as possible exploitative competitors of C. lapponica. Two populations were studied: a population from Finland specialised on the willow Salix borealis, and a population from the Czech Republic, specialised on the birch Betula pubescens. Abundances of folivorous and suctivorous insects on both host plants were recorded at both population sites. The willow leaf beetle Phratora vitellinae was the most abundant herbivorous insect at both study sites on willow. A field study was conducted to examine the effects of P. vitellinae on the performance of C. lapponica. The presence of P. vitellinae larvae on the same twig upon which C. lapponica larvae were feeding did not affect increase of body weight in C. lapponica larvae. Thus, the high resource availability of both willows and birches suggest that interspecific competition is unlikely to be a selection factor driving the evolution of host shift in C. lapponica.     

论柳树家族及其在园林绿化上的应用

柳树资源丰富,适应性广,观赏价值较高,耐水湿,在中国城乡绿化中具有悠久的利用历史。它不仅在农业、园林等方面有着广泛的应用,而且在中国古代还形成了独特的“柳文化”。笔者依据相关文献,概述了具有较高应用价值的柳树家族种类的生物学特性、生态习性及主要观赏特性,总结了柳树的文化内涵,阐述了柳树的综合价值以及园林绿化应用形式,指出了柳树树种资源在园林应用方面存在的问题,并提出了对策。     

柳树的重剪技术

通过对种植在公园岸边的柳树进行重度修剪试验,结果表明柳树可以通过重剪,对树体的高度、形状进行调控,达到矮化树冠、促发新枝、丰满树冠、提高观赏价值和抗倒伏的目的.     

NON-DESTRUCTIVE SAMPLING FOR YIELD ESTIMATION

AIMThemostcommonmethodforas-sessingtotalbiomassisbydestructive1ysampling,i.e.cuttingdownrandomsam-ples,weighingthem,andextrapo1atingtheresultsfortheentirep1antation.Theesti-matewi1lgenerallybemoreaccuratewithalargersample,butenteringa3-5yearo1dplantationtocutdownshootsanddragthemouttobeweighed,isatime-con-sumingbusiness.Itisthereforenecessarytofindsomereliab1emeansofestimatingbiomassfromparameterswhichcanbeeas-ilymeasuredwhi1etheshootsarestillstanding.Amodelneedstobecreatedtoassessbiomassfirs…     

苏柳932等5个柳树优良无性系幼林生长及干形的初步研究

为进一步了解柳树优良无性系的生长特点,为无性系的合理利用提供依据,对苏柳932,799,795,797和172等5个柳树优良无性系2年生幼林的树高、胸径、材积等生长指标以及生物量和形率进行了测定分析。结果表明,苏柳5个无性系的胸径平均值为4．28cm,其中苏柳172的平均胸径最大（4．71cm）;树高平均值为6．97m,其中苏柳795平均树高最高（7．75m）。苏柳795的形率qo．5、q0．7值分别为0．68,0．44,是各无性系中形率的最高值,主干生物量占单株地上部分总生物量的比例最高（76．02％）,出材率高,是优良的用材林树种;而苏柳932的总生物量最高,为12．35kg／株,枝量、叶量占总生物量的比例最大,为42．0％,14．4％,属于防风防浪和生物能源林的造林良种。     

川东北地区杨树与柳树锈病发生与病理学观察

杨树和柳树均属于杨柳科植物,两者在经济林及绿化行道树上的运用越来越广泛。锈病在杨树和柳树高栽植密度苗圃地和成片用材林的发生极为严重。本研究比较杨树和柳树锈病的发病症状、流行特点及病原菌特征,为该病的防治提供理论和实际指导依据。以川东北地区4区(县)(南充市高坪区和西充县,广安市前锋区和武胜县)患发锈病的杨树和柳树为研究对象,采用流行病学调查和显微观察技术等方法。杨树锈病和柳树锈病大都侵害叶和幼苗,引起树叶早期脱落,幼苗枯萎。但杨树锈病的病原菌为锈菌科栅锈菌属松杨栅锈菌(Melampsora larici-populins),柳树锈病的病原菌为锈菌科栅锈菌属拟鞘锈栅锈菌(Melampsora coleosporioides Diet.)。杨树锈病和柳树锈病虽有共同的发病特征,但在为害症状、病原类型和发生规律方面均有很大的不同。建议在防治时根据寄主的不同选择针对性强的防治方法。     

Short rotation willow coppice biomass as an industrial and energy feedstock

In order to increase the yield of short rotation willow coppice cultivated on agricultural land and to improve the biomass quality as an industrial and energy feedstock, particular consideration should be devoted to proper location and to the cultivation of woody plants. This paper presents the yield of five new cultivars of willow coppice and the relationship between the chemical composition of biomass and the plant harvest cycle. The Tur cultivar has been shown to have the highest mean productivity of 21.5 t of d.m. ha⁻¹ year⁻¹. In a three-year harvest cycle, the cultivar also gave biomass with the highest cellulose:lignin ratio (2.14). The significantly highest yield of dry biomass from the cultivars under study (20.5 t of d.m. ha⁻¹ year⁻¹) was achieved in a three-year harvest cycle. It was lower by 3.4% on average in a two-year harvest cycle and lower by 17.2% in a one-year harvest cycle as compared to a three-year cycle. As the harvest cycle was extended, the biomass quality in terms of its chemical composition improved. The biomass obtained in a three-year cycle contained the highest amount of cellulose (44.6% of d.m.) and the lowest amount of lignin (21.8% of d.m.). The results indicate that the agrotechnical factors, including the cultivar and the harvest cycle, affect not only the yield, but also the qualitative features of short rotation coppice willow biomass.