Progress and strategies in cross breeding of poplars in China

The advance in intrasection and intersection cross breeding of poplars in China over the past 50 years is reviewed. Great progress has been made in Sections Leuce and Aigeiros, and satisfactory results of intersection hybridization have been achieved in the crossing between Sections Tacamahaca and Aigeiros. The modes of hybridization include single cross, double cross, triple cross, backcross, etc. It is known that using hybrids as parents to cross with other species or hybrids is an effective and easy way to obtain heterosis. Fast growth, cold and drought tolerance, pest and disease resistance, narrow crowns and rootage, etc. are breeding goals. The conventional artificial crossing is still a major breeding method, and a combination of the conventional artificial crossing with physical radiation and chemical induction can create new triploid individuals that possess higher yield potential. The super clones cultivated have already displayed enormous socioeconomic and ecological benefits in practice. Finally, the problems that investigators have to face at present are discussed as well as some strategies in poplar cross breeding in China.     

Important insect pests of poplars in agroforestry and strategies for their management in northwestern India

Today, more than 143 species of insects infest both indigenous as well as exotic species of poplars in northwestern India, with about 65 species infesting Populus deltoides alone. Random sampling surveys (1984-2002) were undertaken in lower hills and plains of six states (Uttar Pradesh, Uttaranchal, Haryana, Punjab, Himachal Pradesh, and Jammu and Kashmir) in this region. The survey included 36 nurseries, 84 large ( ≥ 3 ha) and 255 small (< 3 ha) block and bund plantations and recorded seven species causing outbreaks. However, eight insects having wide spread distribution in this region were identified as posing a threat to agroforestry with P. deltoides and need to be managed. Amongst these, three species (Clostera cupreata, C. fulgurita and Apriona cinerea) were ranked as 'major pests' as they had relatively higher incidence (> 50% of attack) and caused extensive economic loss during outbreaks, coupled with tree mortality which persisted for several years in succession over large areas. Five insects were identified as 'potential pests', as they also caused heavy infestation and economic loss, but only in some years, on a localized scale and with no large scale plant mortality, but need to be checked to improve productivity. The 'potential pests' were: one species in plantations (Ascotis selenaria) and four insects in nurseries [(Eucosma glaciata , Phalantha phalantha, Nodostoma waterhousie and white grubs) with >50% incidence]. Integrated pest management practices, comprising cultural methods, use of bio-pesticides, tolerant poplar varieties/clones, natural enemies, recommended safe insecticides and avoiding alternate host plants of the pest, are discussed for important pests.     

Establishment strategies for poplars,including mulch and plant types,on agricultural land in Sweden

Biomass from forestry is one of the largest components of Sweden’s renewable resources. Poplars are currently the highest producing tree species available and are therefore natural choices for biomass-oriented production. Growing poplars has been of most interest on agricultural land, but the knowledge and experience about their cultivation is still limited. Factors that have a large impact on the regeneration results are plant material, competing vegetation, browsing and damage caused by voles or climatic factors. Due to large establishment costs, there is a need to find methods to secure the establishment both biologically and economically. In this study the effect of plastic mulch in combination with three different plant types (short cuttings, long cuttings and rooted plants) were tested at three different sites. Five years after planting, the overall effect of mulch was an improved plant survival and growth. In most cases, long cuttings outperformed short cuttings and rooted plants. Clonal differences were present, indicating the importance of using plant material adapted to site conditions. All sites were heavily affected by browsing and during the experimental period 100% of the plants were damaged at some point. Planting poplars without fencing is therefore doubtful. Results from this study conclude that poplars can be established with success on agricultural land if proper measures are used depending on the site to be planted.     

Planted forests: poplars

Poplars (Populus spp.) have been planted in Europe and Asia since very early times. Known in the Near East as the blessed tree, poplars have been the primary timber producer in regions lacking natural forests in the northern hemisphere. Now, though, we are seeing poplar plantations becoming part of the forest resources even in the abundantly forested Pacific Northwest. Though still a minor contributor to the world's timber supply, the area of land planted to poplars is, nevertheless, increasing rapidly, particularly in China, South Korea, and the United States. The 1992 report from the International Poplar Commission listed nineteen countries with at least 10,000 ha of planted poplars and seven with more than 100,000 ha. Much of the success of poplar plantations results from the breeding of fast-growing and disease-resistant poplar hybrids. Accordingly, at least eleven countries support poplar breeding programs. Uses of poplar wood range from peeled poles for rafters and other elements of construction in agrarian economies to the manufacture of paper, plywood, oriented strand board, and engineered lumber in industrial nations. Interest has also developed in poplar plantations as a renewable source of energy.     

Establishment-year height growth in hybrid poplars; relations with longer-term growth

We examined the potential for using components of establishment-year height growth in predicting longer-term growth rankings of six hybrids of Populus deltoides × nigra and one of P. nigra × maximowiczii. Height rankings at the end of the establishment year were correlated (P 0.10) amongst the four field trials and were generally stable from 38 days after planting onward. End-of-season height rankings from field trials and a controlled environment trial were weakly correlated. Height rankings at the end of the first year did not correlate with rankings at the end of the fifth year, correlations with fifth-year ranks did improve in the second and third years. Shifts in clonal rankings after the establishment year may have been associated with (1) a decreased influence of the planted cutting on growth after the establishment year (2) clonal differences in the time of budburst which were minimized at the time of planting (3) clonal differences in late-season photosynthate allocation to roots (4) clonal differences in branching patterns and canopy development after the establishment year.     

感、抗病杨树种类接种溃疡病菌后酚类物质的变化

为探讨杨树对溃疡病的抗病机制,用溃疡病菌Botryosphaeria dothidea接种抗病毛白杨Populus tomentosa和感病北京杨P.beijingensis,测定2种杨树感染后酚类物质含量的变化。结果表明,两树种间及同树种内接种溃疡病菌前后酚类物质含量变化存在很大差异。抗病毛白杨接种后没食子酸、儿茶酸、对羟基苯甲酸、阿魏酸含量迅速积累达到高峰值,苯酚、邻苯二酚和香豆酸的含量积累相对较慢,苯甲酸含量变化不明显;感病北京杨与之相反,邻苯二酚、阿魏酸、苯甲酸变化幅度相对较大。经方差分析,两树种间8种物质差异分别达到显著或极显著水平;同树种内,毛白杨接种溃疡病菌后苯酚、香豆酸、阿魏酸含量显著或极显著高于对照;北京杨接种后香豆酸、阿魏酸的含量显著低于对照。根据这些含量变化及差异性分析,认为没食子酸、儿茶酸、苯酚与杨树对溃疡病的抗性密切相关,香豆酸、对羟基苯甲酸、邻苯二酚、阿魏酸次之,苯甲酸关系不大。     

杨树食叶害虫防治技术

结合杨树食叶害虫综合防治技术组装配套技术研究，总结了杨树食叶害虫防治的人工物理防治，地面喷雾、喷粉、喷烟或放烟防治，飞机防治，毒环和毒绳防治，干基打孔注药防治，生物防治，营林措施防治7项技术和综合控制技术。     

Management of diseases of poplars

Resistance is the cornerstone of management of diseases of poplar. Maximization of its effectiveness requires the concerted employment of proper site, selection, silvicultural practices and sometimes direct or chemical control.     

地膜覆盖杨树扦插育苗技术

在杨树扦插育苗时，采取地膜覆盖、苗圃整地、种穗选取与假植处理等技术措施，能较好地提高苗木的出穗率和质量。     

杨树伐根嫁接技术

魏淑霞,吕金才(洮南机械林场,吉林白城　137100)　　2000年春,我们对洮南林场1958年营造的2 47ｈｍ2、937株小青杨过熟林进行伐根插皮枝接小黑杨更新,接穗成活率为91 3%,伐根嫁接成活率为99 4%,2ａ生平均树高为5 97ｍ,平均胸径6 8ｃｍ。每公顷工料费524元,仅为机械整地造林成本的38 8%。伐根嫁接更新成活率高,生长快,成本低,是本地区成过熟林更新的有效途径。1嫁接时间应在接穗萌动以前,砧木离皮以后,过早伐根皮层硬,韧性差,插接时易伤及接穗,韧皮接合不紧密,过晚接穗萌动不易成活,吉林省中西部在4月中、下旬为好。如接穗低温保存,可接至5月…     

我国转基因杨树的研究及应用现状

综述了我国转基因杨树研究的主要进展,以及在我国人工林建设中的应用现状和潜力。指出我国抗虫转基因杨树的培育已经取得重大突破并处于世界领先地位,将为人工林建设不断提供抗虫新品种;耐盐碱、纸浆材的转基因研究取得了较大进展,经过进一步田间试验,将进入商品化应用;杨树基因组全序列的完成,将促进木材形成过程的认识,为杨树木材品质的基因工程改良及商品林的定向培育奠定基础。     

杨树苗期施肥试验

对长林1号、中黑防、小黑无絮速生杨进行施肥试验,结果表明：最佳施肥方案为速生前期施1/2,速生后期施1/2,施肥量（N：P：K=2.01.00.5）1 500 kg.hm^-2;施肥苗木与对照相比较提前3～7 d封顶,而且木质化程度好,苗木合格率比对照提高11.6%。     

Bacteria associated with tarnished plant bug stem lesions on hybrid poplars in Ontario

Bacteria were always recovered from degraded tissue of large and mid-sized tarnished plant bug (Lygus lineolaris) lesions, less frequently from small lesions and bumps, and rarely from healthy tissues of current year shoots of hybrid poplar in southern Ontario, Canada. All 209 isolates obtained were gram-negative rods; 61 were members of the Enterobacteriaceae. Compartmentalized disrupted areas in the xylem were associated with bumps and large insect incited lesions. Large numbers of bacteria were associated with pockets of thick-walled fibers in the disrupted tissues. Microscopic observations suggest that bacteria contribute to degradation of disrupted tissues through breakdown of the fibers. The role of bacteria in TPB lesion formation, however, is still not clear.     

红花串核桃种类型(品种)特性及育种策略

为开发利用红花串核桃这一优良种质资源,对形态学特征和主要生物学特性等品种特性进行了观测,制定了育种策略并探讨了品种选育技术。红花串核桃属于早实晚熟丰产耐晚霜品种,为薄麻壳泡核桃,具有二次开花结实特性;第一次果的生产利用价值和商品性能高,8年生单株产坚果15kg以上,坚果椭圆形、整齐端正、缝合线高,种仁浅黄色,取仁易、取整仁,平均单果重14.28g,种壳厚1.3mm,出仁率54%;第2次果是核桃遗传育种的新型试材,目前的生产利用价值和商品性能较低。     

杨树日本龟蜡蚧发生规律及危害特点

日本龟蜡蚧Ceroplastes japonica Green在连云港地区1 a发生1代,11月上中旬以受精雌成虫聚集在1～2 a生小枝的背面越冬,翌年5月中旬开始产卵,6月下旬为若虫孵化、涌散高峰期.文章报道了日本龟蜡蚧在杨树上的发生规律和危害特点并对其发生与环境的相关性及扩散规律、天敌进行了初步研究.     

Hybrid poplars: present status and potential in Britain

Past and potential future use of hybrid poplars for wood productionin Britain is considered, and preliminary results of trialswith new clones imported from Belgium in 1985 are given. A seriesof nine field experiments established in 1991, to a common protocol,was analysed using stepwise multiple regression. The superiorvigour of ‘Beaupré’ compared with ‘Ghoy’,‘Robusta’ and ‘Trichobel’ was clearin almost every case. For ‘Beaupré’ (Populustrichocarpa x P. deltoides) altitude emerged as the variableexplaining most variation in tree height after six growing seasons,height declining with increasing altitude. The four best siteswere characterized by low elevation and low rainfall. At the two older sites planted in 1987, at Ampthill and Bedgebury,the ‘interamerican’ hybrids (P. trichocarpa x P.deltoides) were the most vigorous, and the clones ‘Unal’and ‘Raspalje’, which were thought to be too rustsusceptible to release for commercial use in 1990, achievedsimilar stem sizes to those of ‘Beaupré’and ‘Bolelare’. The General Yield Class (based ona reference spacing of 8 x 8 m) calculated for ‘Beaupré’was 8 at Ampthill and 24 at Bedgebury. Future prospects for poplar planting are considered in relationto possible reform of the Common Agricultural Policy.     

意杨纸浆材材性变异的研究

本文报道了意杨三个无性系纸浆材材性变异规律。纤维长度、长宽比径向表现为递增，８～１０年后纤维长度趋于稳定，８年后长宽比趋于稳定；纤维长度在纵向上呈递减的模式。基本密度径向上呈递增的模式，８年后趋于稳定，纵向上表现出递增的趋势。纤维素含量径向呈递增模式，１０～１２年后递增速度减慢；木素、多缩戊糖含量在径向呈递减趋势，１０年后趋于稳定，而多缩戊糖含量１０～１２年后趋于稳定。意杨木材幼龄期约为８年。从意杨纸浆材材性工艺指标，确定意杨纸浆林８～９年时主伐利用较佳。     

Comparative analysis on the communication strategies of the forest owners' associations in Europe

This research reports a comparative analysis of the communication strategy that forest owners' associations across Europe use to influence society on one side and the decision-makers on the other, in order to fulfill forest owners' interests. 60% of Europe's forests are privately owned by an estimated number of 16 million forest owners, who are represented by forest owners' associations. One of its main functions is to influence the public perceptions on forests and forestry. In this article it is analyzed how a specific forestry stakeholder fixes its strategies to communicate with and lobby society in order to get acceptability for their proposals/demands. Open-end surveys have been used as a source of information in 2006 and repeated in 2012. Besides of the comparison among countries, a comparison along the time has been also performed. The whole communication frame is analyzed, considering the objectives, the structure, the messages, the channels, and the evaluation. The main conclusions that arise are: first, the temporary comparison (2006–2012) results into an improvement in several issues; second, there is room for improvement of professionalization of communication in forest owners' associations in Europe; third, social research into public perception of forestry might help to define communication strategies.     

Volume equations for poplars growing on farmland in Sweden

Abstract

Volume equations for poplars growing on farmland in Sweden. The aim of the study was to construct a simple volume equation for poplar and to evaluate the equation together with seven published equations. Data from 72 poplars were collected from 37 stands in central and southern Sweden (lat. 55–60°N). The stands’ mean age and density was 21 years and 940 stems ha^?1, respectively and the trees’ mean diameter at breast height (DBH) was 25 cm. One simple volume equation with three parameters to be estimated for poplar was constructed with DBH and total height (H) as independent variables. This equation was analyzed and compared to seven published simple equations. The best performance, in terms of low values of Root Mean Square Error (RMSE) and Absolute Bias, was achieved by the equations developed by Eriksson and by Scott. However, due to these equations high level of multicollinearity an alternative recommendation was made where the constructed equation is recommended.