Peter Ivanisevic, Savo Roncevic, Zoran Galic, and Sinisa Andrasev
Agricultural Faculty, Poplar Research Institute Novi Sad, Antona Cehova 13, P.O. Box 117, 21000 Novi Sad, Yugoslavia
The characteristics of soil used for poplar and willow growing in Yugoslavia have been analyzed. The largest complexes of poplar and willow are situated in inundations of the rivers Danube, Tisa, Sava, Morava, and Tamis, and in fragments along the smaller watercourses. Outside this region, poplars and willows grow in shelterbelts and windbreaks.
The floodplains of the above rivers have significantly different terrain configurations, mineralogical and mechanical compositions, hydrological regimes and forms of natural plant communities. The dominant process of floodplain genesis is fluvial sedimentation, which is functionally related to the transport competency of a river. The numerical analysis of this law shows that fluvial sedimentation of the average silt + clay content at the cross section of the floodplain profile has the form of the logarithm function: Y = 21.221 + 10.2769 lnX; r = 0.82; (X is the distance from the streambank). Depending on the transport competency of a river, three genetic portions of floodplains can be distinguished: along the bank, central, and terrace. Each has its evolution-genetic series of soil, specific hydrological regime, and characteristic forms of plant communities. According to these parameters, from a production-ecological aspect, floodplains are classified into several topographic-hydrological positions.
In the above floodplains, the soils belong to the hydromorphic order with the following soil classes: undeveloped hydromorphic soil, semigley, and gley. From the systematic aspect, at the level of soil type, the following soils are most often used for poplar and willow growing:
From the aspect of poplar and willow cultivation, the most significant property of these soils is the content of the fraction silt + clay (particles <0.02 mm). According to the quality assessment of the state of usable water content, the above soils are classified into the following categories of physiologically active water content: very poor, poor, medium, good, and very good. It can be generalised that the production potential of the above soils depends on the nature of the relief, soil mechanical composition, and naturally prevailing water-air regime. In the process of establishing poplar and willow plantations, the choice of the variety and planting technology is largely determined by the properties of the soil.
Jianjun Fang1, Yifan Han1, Sylvie Augustin2, Jun Zhao3, Rongling Wu4
1Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
2Station de Zoologie Forestiere, Ardon, 45160, Olivet,France.
3Forest Protection Research Center, Yinchuan 750004, China.
4Dept. of Statistics, North Carolina State University,Raleigh
Asian long-horned beetle (ALB) (Coleoptera Anoplophora glabripennis Motsch.) is the most harmful and widely dispersed pest to Chinese poplar trees. The chemical plant defence mechanism was studied in the experiment. The beetle can oviposit on many trees from different cultivars of Populus deltoides, but the hatch and survival rate often varied for different cultivars. From eggs to three-instar is the critical stage for the larvae survival, so something was suspected to pose adverse effects to the young larvae in the bark. The secondary metabolite of Populus species is dominated by phenolic glycosides, and it has been proved that phenolic glycosides have adverse effects on the growth of other insects. This study was conducted to test the hypothesis that the phenolic glycosides in the bark of poplar have similar effects on the beetle and account for the differences for larvae performance.
First, the natural composition of bark was studied, then the bioassay tests were designed according to the natural composition and level of phenolic glycosides compounds by artificial feeding. The bioassay result showed that all three kinds of phenolic glycosides could prolong duration of larval stadium. Salicortin especially at high levels (more than 2%), reduced the survival rate of neonate larvae, pupate rate and growth weight were decreased too. So the association between insect resistance and the chemical have been proved. The reason for varied performance of larvae can be partly explained by the varied concentration of phenolic glycosides for different trees.
Jiang Xiangning, Wang Tianhua, Chen Xuemei, and Gag Xiaoyi
The Experimental Center of Forest Biology, College of Plant Sciences
Beijing Forestry University, 100083, Beijing, China
An L-System-based: Fractal-generated : Turtle-interpreted : OOP techniques-implemented computer graphics model (LFT) has been encoded for theoretical plant growth and eco-physiology study. The model is divided into four function modules for parameter input, plant growth and forest stand modelling, results output, and virtual experiment design and conduct. Based on input parameters abstracted from field experiments and theoretical constants, the model preliminarily can graphically and dynamically simulate plant/tree growth and their stands, calculate leaf area index (LAI) of a stand, and determine optimal leaf density in a defined space and light interception ratio, etc. for plant growth, physiology, ecology, and theoretical biology study. Modelling results can be put out as a data table, line/bar chart, and/or graphics.
Surjit Johal, Ken Hunt, Bernard Yuen, Paul Watson
Pulp and Paper Institute of Canada, Vancouver, BC, Canada
Chemi-thermo-mechanical Pulping (CTMP) pulps were prepared and tested from nine selected "wild" aspen clones from north-east British Columbia. The results indicated that although the interclonal variability was low in eight of the nine clones, the specific refining energy required to reach a given freeness varied by up to 45% depending upon the clone selected. Similarly, the properties, i.e., tensile index, tear index, scattering coefficient, etc., for the pulps prepared from the clones also varied widely. Such variations are due to genetic differences between the clones. This can explain the variability of the aspen pulps produced by commercial pulp mills. More importantly, this highlights the opportunities that exist within Canada's native aspen populations to develop industrial plantations with superior, cold-climate clones.
Jon D. Johnson
Poplar Research Program, Washington State University-Puyallup, Puyallup, WA 98375, USA
The rapid growth of hybrid poplars makes them an ideal tree species to use in various environmental plantings for uptake of excess nutrients from municipal and industrial wastes and agricultural runoff, shading of streams to moderate water temperatures and competing undesirable vegetation, carbon sequestration, and other applications. Results from several studies will be presented to illustrate how hybrid poplars are used for these applications. Experience in the Pacific Northwest of the United States suggests that waste application can have a detrimental impact if a thorough assessment of site, clone, and type and quantity of waste is not done before these practices are implemented.
B. Jourez, A. Riboux, and A. Leclercq
Centre de Recherche de la Nature, des Forêts et du Bois - Ministère de la Région Wallonne Avenue Maréchal Juin, 23 B-5030 Gembloux, Belgium
In a greenhouse under controlled conditions, young shoots from poplar cuttings (P. euramericana cv. Ghoy) were artificially inclined to quantify the modifications induced by a gravitational stimulus. At the end of the growing season, basic density and longitudinal shrinkage were measured on very small samples taken from pure tension wood tissue observed on the upper face of the inclined axis and compared with opposite wood tissue, free of gelatinous fibres, developed on the opposite lower face.
Because of the very small sample dimensions (average volume 0.1 ml and 15 mm length in axial direction), the repeatability of measurement techniques for volume and shrinkage was established. The results indicated an accuracy up to 0.001 ml for the measurement of saturated volume needed for basic density calculation and up to 0.01 mm for the measurement of longitudinal shrinkage.
When young stems were inclined at 30o from the vertical, a difference of 5% was observed between basic density in opposite wood (384±18 kg/m3) and tension wood (402±17 kg/m3). On the same samples, longitudinal shrinkage reached 0.2% in opposite wood and was four times higher in tension wood. This difference is significant in whatever stems were considered. This ratio, in accordance with the literature, was obtained in our case with samples composed exclusively of gelatinous fibres or normal fibres.
When wood basic density increased, longitudinal shrinkage (R2 = 0.228) decreased in the opposite wood and increased in the tension wood (R2 = 0.225). This inverse behaviour between two opposite faces of an inclined stem could induce more and more important strains in samples following the increase of wood basic density.
When young stems were inclined at two levels (10oand 30o), basic density was different again considering the two types of wood. The shrinkage was systematically higher in tension wood and at 30o but without mutual interaction.
The experimental approach followed in this work allows the quantification of the impact of a gravitational stimulus, of controlled intensity, on physical properties of poplar tension wood tissue.
Davorin Kajba and Sasa Bogdan
Faculty of Forestry, University of Zagreb, 10000 Zagreb, Croatia
The first results of breeding the Chinese willow (Salix matsudana Koidz.) and the white willow (Salix alba L.) show that hybrids are obtained easily if S. matsudana is used as a female parent. There were difficulties in hybrid production when the hybrid of the F 1 or F 2 generation was used as a female parent in breeding by transgression, back crossing, selfing, and inbreeding. The hybrids of the F 1 generation exhibited vigorous growth at an early age compared to the Chinese willow (S. matsudana), and the same as the best clones of the white willow (Salix alba). Back crosses of F 1 generation hybrids were made on the Chinese willow, while for the production of F 2 generation hybrids, the genetically divergent (New Zealand, Croatia) hybrids Salix matsudana x Salix alba were used. In all produced hybrid families, a remarkable variability was established enabling the selection of the plus variants. The cloning of the plus variants realises a considerable genetic improvement in the short-rotation biomass production. The hybrid progenies bred by selfing have an extraordinary depression of growth, i.e., their vitality is poor. The purpose of producing plants of the divergent genetic constitution by selfing is the production of line hybrids. For now we have found that the majority of the plants bred by selfing are male and that the monoecious plants transform into the male sex.
Davorin Kajba1 and Pavle Vrataric2
1Faculty of Forestry, University of Zagreb, 10000 Zagreb, Croatia
2Forest District Osijek, 31000 Osijek, Croatia
Conservation of European black poplar (Populus nigra L.) genetic resources by the ex situ method began by the selection and autovegetative propagation of adult trees over the last 6 years. The selection was made not only in the area of the Drava, Sava, Mura, and Danube Rivers, but also on sites that until recently were inaccessible because of mines and that present the most valuable riparian forest areas in Europe. After the successful reproduction of European black poplar adult trees in spring 1995 a European black poplar clonal archive with 83 clones was established as part of a Salicetum in the Cakovec Forest District. In spring 1998, the second European black poplar clonal archive was established in the Darda Forest District. Presently, it contains 63 European black poplar clones, but it will be completed in the future depending on the old tree selection and reproduction program. In the nurseries another 37 clones are under reproduction, and they will be included in the clonal archives. Conservation of the European black poplar and its natural stands by means of the in situ method was included in the permanent protection either within nature parks and special forest vegetation reserves (the Danube River islands near Vukovar) or within the parts of riparian forests exempt from regular forest management (the Drava River forests near Slatina, and near Osijek). The Republic of Croatia has been a member of EUFORGEN Populus nigra Network since 1994, and it has participated in all six meetings held so far. Because of the extension of P. nigra. Network plan to white poplar (Populus alba), and considering the general condition of riparian forests in Europe, these areas are important for conserving the biological diversity of natural areas of Croatia.
D. Kajba1, B. Heinze2, P. Rotach3, S. de Vries4, and F. Lefèvre5
1University of Zagreb, Croatia
2Institute of Forest Genetics, FBVA, Vienna, Austria
3Swiss Federal Institute of Technology, Zurich, Switzerland
4ALTERRA, Wageningen, The Netherlands
5INRA, Avignon, France
Conservation of genetic resources has become a major objective in the management of forests. Much theoretical work has been devoted to the subject, and implementation has already started at local, national, and international scales.
Poplars are probably the most representative and threatened forest tree species of old natural floodplain forests in the temperate zone. It is a very didactic model for conservation genetics since various topics of interest are addressed: the integration of gene resource conservation and intensive breeding within a coherent frame of gene resource management; the co-evolution between wild and cultivated gene pools; and the necessary link between species conservation projects and preservation of habitats (in particular for a pioneer species in a dynamic ecosystem). These topics will be discussed and illustrated by the European experience for the conservation of Populus nigra. Different methods are developed that are considered complementary: ex situ, in situ, and restoration projects. Simultaneously, the conservation of riparian ecosystems is also a priority.
The question now is the evaluation of such an integrated strategy. Research in genetics and ecology can provide a priori guidelines to achieve the objectives faced within each conservation method, although exact threshold values are generally difficult to obtain. Vice versa, practical implementation can raise new questions for research, and in that particular case the in situ method appears to be quite complex: ecosystem modelling including the genetic dimension has to be enhanced. Criteria and indicators for the follow-up of gene resource management are being progressively developed, but still need to be tested on a real scale. In the field of gene resource management, also, the poplar model is almost unique even among other forest tree species. Breeders and environmentalists, geneticists and ecologists, forest managers and river managers are indeed actively collaborating for the same objective.
Almir Karacic
Department of Short Rotation Forestry, Swedish University of Agricultural Sciences, P.O. Box 7016, SE-750 07 Uppsala, Sweden
Little is known about growing poplars for energy purposes in Sweden. The few existing plantations are mostly restricted to locations in the southernmost provinces. Recent studies indicate though, that selected clones of both hybrid poplars (Populus trichocarpa Hook. x deltoides Bartr.) and hybrid aspen (Populus tremula L. x tremuloides Michx.) have a high biomass production on former agricultural land in the whole country. In the current phase of poplar studies in Sweden, before any larger trials or plantations are established, there is a need for developing accurate non-destructive biomass estimation methods. A variation in growth of different clonal material within a wide range of production systems and ecological conditions must be captured.
Biomass estimation procedures used in short-rotation poplar production were largely adopted from traditional forestry. They are based on allometric relations between tree dry weight and easily measured linear dimensions such as stem diameter and tree height. These relations were tested by regression analysis based on the data of a large number of destructively sampled trees from two trials and three plantations. In addition, sample trees from smaller trials in central and northern Sweden were included. The spacing was 1 x 2 m in both trials, and 3.3 x 3.3 m in the plantations. Dry weight (W) was related to stem diameter (D) at breast height using the general equation W = a + b Hupf Dc + d Hupf Dmc, where the variables a to f represent the parameters. By allocating Hup and Dm to each single entrance, the parameters were obtained in a single run for the whole data set. This function includes the upper height (Hup) and mean stem diameter (Dm) of the stand. These two variables describe the specific allometric relations affected by heritable characteristics of clone material, initial (and actual) spacing, and ecological conditions.
The regression analysis showed that the general equation used fit the data well. The obtained R2 was 0.99. The results of the production estimates indicate high production potentials of both hybrids in Sweden. Densely planted plots of hybrid aspen (spacing 1 x 2 m) near Uppsala, central Sweden, produced 60 t/ha over a period of 9 years. The two clones of hybrid poplar (Populus trichocarpa x deltoides C: OP5 and OP42, spacing 3.3 x 3.3 m) planted on soils of medium fertility produced between 60 and 70 t/ha over the same period. The last year increment was 15 t/ha.
The equation including the upper height and mean diameter of a stand could be used to estimate the biomass production in both hybrid poplars and hybrid aspen grown under different ecological conditions. It also facilitates the comparison between different production systems and clones. In general, the results indicate surprisingly high production potentials of both hybrid poplar and hybrid aspen on fertile agricultural land in Sweden.
Shams R. Khan
Pakistan Forest Institute, Peshawar, Pakistan
On account of higher demand for poplar wood mainly in match industries and in house construction on the one hand and slow growth in indigenous species on the other, there was no way left for foresters but to test exotics in Pakistan to meet the local requirements. Out of four indigenous poplars, Populus euphratica Oliv. is a lowland riverine species and the other three species, P. alba L., P. ciliata Wall, and P. nigra L., occur in temperate areas (1,600-3,000 m altitude) either as individual trees or in very small patches in northern Pakistan. The midland area, which is irrigated, has virtually no suitable poplars. Populus euramericana (CVI-214) has been found most suitable for farmlands and irrigated plantations since the mid-1950's. However, this species also has the problem of heartwood rotting as the tree reaches maturity, especially after age 10. Alternatively various clones of P. deltoides were tested in the 1960s but none on a commercial scale until now. Nevertheless, this proven germplasm could be used to develop cultivars for the different ecological zones of Pakistan.
To bring about further genetic improvement in P. deltoides, seeds of 181 open pollinated progenies were procured for the first time from Arkansas, Colorado, Kansas, Oklahoma, and Texas in 1982. The latitudinal, longitudinal, and altitudinal amplitude was 28 32° - 38 25° N, 94 00°- 103 45° W, and 08-1,268 m, respectively, in its native habitat. Seedlings of only 45 individual families were successfully raised and out planted in RCB design at six locations in Pakistan. Depending upon the available stock, number of half-sib families and replications varied from site to site. The latitude of planting sites ranged between 29 10° - 34 25°N, while the longitude and altitude varied between 69 00 - 733 20°E and 100-2,000 m, respectively.
The data collected on height growth revealed that ramets originating from Texas outperformed all others at six sites in spite of great geoclimatic intersite diversity, indicating the scope of large-scale planting of propagules from plus trees of the species from Texas. The seven Texas counties rated as best growth include Bosque, Brazos, Coke, Conzales, Haskell, Randall, and Young. Further strategies on the development of clonal forestry in collaboration with international agencies are also highlighted and discussed to develop suitable clones for wider adaptability and better growth over a range of sites in Pakistan.
D. Khasa1, P. Chakravarty1, B. Thomas1, A. Robertson2, and B. Dancik1
1Department of Renewable Resources, University of Alberta, Edmonton, AB, T0A 0M0, Canada
2Alberta-Pacific Forest Industries, Inc., P.O. Box 8000, Boyle, AB, T0A 0M0, Canada
Use of selected microbial strains in intensive culture of Populus trees (populiculture) may improve the establishment of introduced Populus trees on previously cleared agricultural or disturbed sites in the Canadian prairie provinces. Container-grown aspen (Populus tremuloides Michx.) and balsam poplar (P. balsamifera L.) seedlings and hybrid poplar cuttings (Walker, Assiniboine, Manitou, and Northwest) were treated with six species of ectomycorrhizal fungi (Hebeloma longicaudum Pers.: Fr., Laccaria bicolor [R. Mre.], Paxillus involutus [Batsch: Fr.], Pisolithus tinctorius ([Mich.: Pers.] Coker and Couch), Rhizopogon vinicolor A.H. Smith, and Suillus tomentosus Kauffman), an arbuscular mycor-rhizal fungus (Glomus intraradices Schenck and Smith), two species of bacteria (Agrobacterium sp. and Burkholderia cepacia Burkholder), and a growth hormone (Stimroot No. 3, containing 0.8% IBA rooting powder). Seedlings and cuttings were grown for 10 weeks under three levels of fertiliser (33%, 67%, and 100% of the fertiliser regime used in the nursery). Both treated and non-treated seedlings and cuttings showed enhanced growth with high levels of fertiliser. Aspen and balsam poplar seedlings showed higher growth and nutrient uptake (N, P, and K) when seedlings were co-inoculated with P. involutus and B. cepacia as compared to other treatments. The amount of calcium and magnesium did not differ significantly between treatments. Ectomycorrhizal and endomycorrhizal colonizations were not affected regardless of fertiliser treatment. For hybrid poplar cuttings, higher seedling growth and micorrhizal colonization, and lower shoot-root ratio were observed when inoculated with G. intraradices, L. bicolor, P. involutus, P. tinctorius, and P. involutus + B. cepacia at all fertilizer levels. While N, P, and K contents did not differ between treatments, Cu was higher when inoculated with P. involutus + B. cepacia. This study provides candidate beneficial microbial inoculants that offer promise for development of commercial inoculants for populiculture.
D.K. Khurana
Dept. of Tree Improvement, College of Forestry, Y.S. Parmar University of Horticulture & Forestry, Nauni (Solan) - 173230, India
Hybrids in poplars are increasingly being used for various reasons that could relate to either planting on harsh sites, disease or pest resistance, and sometimes for accelerated growth. Hybrids of Populus ciliata x maximowiczii were raised for sites not suitable for either P. ciliata or falling outside its zone and where P. deltoides clones were found unsuitable. Initial growth differences in the nursery (32.60 N, 77.30 E) were reported to be greater by the parent at one site. Subsequently these were planted at three sites: i) Katrain (31.45 N, 77.30 E) representing river floodplain deposits, ii) Palampur (32.60 N, 77.30 E) representing a tea garden with no irrigation, and iii) Nauni (31.10 N, 77.20 E) representing a) seasonal water source, and b) dry fallow land. Growth differences were site specific, and poor performance with diameter growth of less than 10 cm in 4 years was observed at site ii and iii-b where water availability was seasonal. The growth at site i varied between 15 and 20 cm at age 4, and the growth at site iii-a ranged between 20 and 25 cm with a good height growth of about 20 m. The rooting was profuse in these hybrids in comparison to P. ciliata; the leaf size was double that of P. ciliata and four times than that of P. maximowiczii. Siblings showed a range of variation in branching pattern from the rosette shape of branching in P. maximowiczii to the simple alternate type in P. ciliata.
D.K. Khurana, S. Narljede, and M.B. Chandrashekhar
Dept. of Tree Improvement, College of Forestry, Y.S. Parmar University of Horticulture & Forestry, Nauni (Solan) - 173230, India
Whereas the post-war 20th century belonged to eucalypts, tropical pines, poplars, and Casuarina species, it seems that the first quarter of the 21st century is going to belong to poplars. The impatience for quicker production of wood today has raised our expectations for harvest at 6-10 years, and this has been made possible by poplars in manmade plantations. These plantations are being raised in all kinds of edaphic conditions, but their survival, growth, and development depend on the root system these plants support. Poplars are reported to have a variable type of root system made up of strong horizontal surface roots from which develop vertical plunging roots. The development of the plunging roots, which were earlier considered to be limited by the level of water table or by the soil conditions, has been found to be under strong genetic control and clone specific. Different clones derived from the progeny of a single family can show different rooting behaviour that is mainly categorised into five different types (Category A, B, C, D, and E) depending mainly on the frequency and type of vertical plunging root system and the strength and volume of the horizontal anchor root system. The root behaviour, which can be identified and establishes itself by the 4th month (120 days after planting), remains consistent till the end of the planting season in the nursery and continues into the plantation. Plantation success depends on the root pattern and behaviour. Many clones fail to establish in the field due to poor rooting behaviour. During establishment of plantations, the white roots appear first on the submerged portion of the stem up to the collar zone and then on the cut root ends of the ETPs or barbatelles. However, the basic plunging and anchor root system specific to the clone soon appears and is the cause for rapid growth and development of plants in plantations. Genetic differences between different clones in rooting behaviour can account for double the growth differences between the different clones.
Bojana Klasnja, Spiro Kopitovic, and Sinisa Andrasev
Agricultural Faculty Poplar Research Institute Novi Sad, Antona Cehova 13, P.O. Box 117, 21000 Novi Sad, Yugoslavia
The trend of modern mechanical conversion of wood is to utilise the raw material as completely as possible. In this sense, primary sawmilling is oriented to target manufacture with a suitable degree of finishing. The manufacture of peeled veneer has similar tendencies. Also, the quality characteristics of produced semi-finished and finished products should not be disregarded.
This paper presents the structural, physical, and mechanical properties, as well as the chemical composition of wood of poplar clones Populus euramericana clone I-214, cv. Robusta, and eastern cottonwood P. deltoides clones 457, 618, and 725. Sawmilling of poplar roundwood with a certain degree of finishing (production of pallet components) was also studied. The sawing of poplar (I-214 and cv. Robusta) round wood was monitored in a sawmill plant for unedged sawnwood and partial conversion into packing stock (pallets). The manufacture of peeled veneer from the logs of several poplar clones (I-214, 457, 618, and 725) was studied in parallel, with the assessment of the utilisation percentage and the share of full veneer sheets. The first logs 4-6 m long were peeled in the factory manufacturing peeled (construction) veneer. The logs were cut into lengths immediately before peeling, depending on the expected assortment and potential sizes of veneer sheets.
The study of sawmill processing of wood of the above poplar clones indicates a primary sawing plan must be considered. Meeting this goal depends mainly on the right choice of the production program and its consistent realisation. It is also necessary to respect the flexibility of the production program and to adapt to market conditions. This means that uniform solutions are not always present in the balance of different components of poplar wood sawmilling. The study of peeled veneer shows that the clone does not affect the utilisation percentage; log diameter has the primary effect. The effect of the species has some significance in the interaction with log diameter. The diameter of logs has a significant influence on the percentage of full veneer sheets, as well as on veneer quality characteristics, while the interaction of clone and diameter is not significant. A stochastic correlation was also established between the utilisation percentage in peeling and the percentage of full veneer sheets.
Sacit Kocar
Poplar and Fast Growing Forest Trees Research Institute, Izmit, Turkey
In this study, comparisons were made between periods of rotation based on the plantation age of maximum financial output and on the maximum of the current and mean annual wood increment from I-214 poplar plantations established on three different sites and at seven various spacing. Internal rate of return (IRR), net present value (NPV), and net benefit/cost ratio (NBCR) were used in estimating the periods of financial rotation.
The analyses showed that the periods of rotation based on the ages of maximum IRR and current annual wood increment have promise, whereas periods of rotation based on the ages of maximum NPV, NBCR and mean annual wood increment have promise at a later plantation age class. Since the periods of rotation based on NPV and NBCR varied depending on the interest rates, adoption of IRR in evaluating plantation investments is regarded as more suitable.
Sacit Kocar and Ahmet Diner
Poplar and Fast Growing Forest Trees Research Institute, Izmit, Turkey
In this study, financial analyses were made comparing conventional and innovative techniques of operations conducted in poplar plantations. The methods of calculating net present value (NPV), net benefit/cost ratio (NBCR), and internal rate of return (IRR) were adopted for the financial analyses. Due to the higher cost of machinery and equipment required for newly introduced technologies of operations conducted in poplar cultivation, comparative analyses resulted in favour of the conventional technologies. Compared with hybrid poplars (Populus x euramericana cv. I-214 Dode-Guinier), black poplar (P. usbekistanica cv. Afghanica) plantations are established in much closer spacing, which significantly increases operating standard times and plantation costs without plantation benefits. Therefore, financial analyses gave higher values of NPV, NBCR, and IRR for plantations with I-214 poplars.
Spiro Kopitovic, Bojana Klasnja, and Jovan Markovic
Agricultural Faculty, Poplar Research Institute Novi Sad, Antona Cehova 13, P.O. Box 117, 21000 Novi Sad, Yugoslavia
The raw material base in FR Yugoslavia, especially in Serbia, is dominated by deciduous tree species, so the supply of coniferous wood for fibre production is limited. In this case, the lack coniferous wood is mainly compensated for by using poplar and willow wood.
As wood used for energy purposes, beech holds the top position, followed by wood of other hard broadleaved trees. However, in lowland regions, willow and poplar wood is also used for energy. The properties (structural, physical, mechanical properties, and chemical composition) of poplar and willow wood were researched at the Poplar Research Institute in Novi Sad to assess the parameters in the technological procedures of groundwood, semichemical, and sulphate pulp production. The experimental material was poplar wood Populus x euramericana (I-214, cv. Robusta), P. deltoides (457 and 618) and willow wood Salix alba (107/65//7). The analyses referring to semichemical and sulphate pulp production were performed in laboratory conditions, while the analyses pertaining to groundwood were carried out in industrial conditions. The yield, chemical properties, and physical-mechanical characteristics of fibres intended for papermaking were determined.
During the research of poplar and willow wood utilisation for energy, we determined the calorific value of wood of P. x euramericana (I-214), P. deltoides (PE 19/66), and willow Salix alba (378). The experimental materials were 1- and 2-year-old seedlings, as well as 12-year-(I-214), 8-year-(PE 19/66), and 14- year-(378) old wood. In addition to higher heating value, the fuel value index (FVI) was also determined.
Richard F. Kopp1, Lawrence B. Smart1, Lawrence P. Abrahamson1, 2, Charles A. Maynard2, and J.G. Isebrands3
1Faculty of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
2Faculty of Forestry, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
3North Central Research Station, Rhinelander, WI, USA
Willow is rapidly coming to the forefront as a biomass crop when grown under short-rotation intensive culture, and the State University of New York College of Environmental Science and Forestry (SUNY-ESF) has been a leader in North America in research aimed at dedicated willow crop systems. SUNY-ESF has assembled a diverse collection of willow germplasm from across the north-east United States and south-east Canada and is currently testing the material in replicated clone-site trials. Significant increases in yield and wood qualities are likely to be attained through the development of genetically superior clones by traditional breeding. Willow breeding began at SUNY-ESF during 1998 with the goal of producing progeny that are well adapted to a wide variety of site conditions. Breeding efforts during 1998 focused on producing F 1 Salix eriocephala progeny and identifying combinations of willow species that can be successfully mated. During 1999, breeding focused on producing interspecific hybrid progeny. Controlled crosses to produce F 2 full-sib progeny were completed during February 2000. The SUNY-ESF willow germplasm collection will be expanded during 2000 in co-operation with the USDA Forest Service, North Central Research Station in Rhinelander, WI, to provide new germplasm for breeding and to develop new willow clones that are well adapted to the north-east and north-central United States. The breeding strategy with the new germplasm will be to test as many clone combinations as possible, including intraspecific and interspecific matings, with the objective of identifying favourable combinations of parent clones and maximising the possibility of producing progeny exhibiting heterosis. Large genetic diversity will be maintained in the breeding population to maximise breeding options in anticipation of changing pest populations and wood quality demands.
K.R. Kosola and D.I. Dickmann
Department of Forestry, Michigan State University, East Lansing, MI 48824-1222, USA
What are we missing by ignoring root traits in breeding Populus for biomass production? Trees with higher growth rates often have lower contents of phenolic glycosides and condensed tannins, which have been linked to leaf defence. Little attention, however, has been paid to root defence. Is the same trade-off seen between growth and root defence? Is genetic variation in growth rate correlated with allocation of leaf and root defensive compounds in P. deltoides? We examined these questions in a preliminary study of 12 eastern cottonwood (P. deltoides) clones with a wide range of growth rates determined after 5 years. For each clone, we measured concentrations of phenolic compounds and condensed tannins in both roots and leaves. We found little correlation between tree growth and leaf phenolic compounds or tannins, indicating that there may be significant species or environmental factors influencing the expected trade off between growth and leaf defence. Contrary to our expectations, there was a close positive correlation between tree growth and root condensed tannin concentration (Root % tannins = 0.98 (dbh (cm)) = 0.03, r2 = 0.74). Whether a root tannin concentration plays a role in determining tree growth potential is unknown. If root turnover declines with increasing root tannin content, the reduced root loss might lead to increased carbon availability for allocation to tree growth or more effective soil resource acquisition. During spring and summer 2000, we will sample the same 12 P. deltoides clones in four sites of a regional Populus trial (Westport, MN; Ames, IA; Arlington, WI; and East Lansing, MI) to test for GxE interactions affecting concentrations of phenolic compounds and condensed tannins in leaves and roots. We expect that tree growth and root tannin concentration will be positively correlated in trees growing at all four sites, and that any GxE effects on growth will also affect root tannin concentration.
David E. Kretschmann1, J.G. Isebrands2 , and Glen Stanosz3
1USDA Forest Service, Forest Products Laboratory, Madison, WI 53705-2398, USA
2USDA Forest Service, North Central Research Station, Rhinelander, WI 54501, USA
3Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706-1598, USA
Aspen (Populus tremuloides) is an important component of the resource of the Lake States of Michigan, Minnesota, and Wisconsin. In recent years, concern has surfaced that the aspen cut will exceed its growth. This concern arises from the increased demand placed on the aspen resource by paper, composite, and solid wood industries. To satisfy this demand for forest products, it is expected that much of the future timber will be from improved trees grown on managed plantations. It is critical that the mechanical properties of this resource are clearly understood so that alternative uses of this material can be evaluated. My talk today will give an example of the kind of study that should be conducted to assess the mechanical properties of particular hybrids. This study examined the drying behaviour and mechanical properties of Wisconsin-5 hybrid. Results suggest that this poplar clone would produce visually graded material that is similar in properties and characteristics to aspen and cottonwood. Close to 65% of the material produced made grades of either standard or No. 2. The Machine Stress Rating grade most likely to be produced from this material would be 1450f-1.3E. To avoid excessive drying, this material should be dried in flitch form.
Gary A. Kuhn1 and Scott J. Josiah2
1Natural Resources Conservation Service Agroforester, USDA National Agroforestry Center, Western Office, Spokane, WA, USA
2University of Nebraska, Lincoln, NE, USA
Windbreaks have historically provided valuable protection to soils and crops in many areas of the United States. They are a modern conservation practice still needed in today's agriculture. Field windbreaks can protect livestock and a variety of wind-sensitive crops, improve crop yields, and control wind erosion. However, many field windbreaks are removed or not planted because of the perception that they take too much land out of production and compete with adjacent crops.
An exciting new concept called a "timberbelt" can protect crops and soil from the wind, while at the same time produce wood products. Timberbelts are multiple-row windbreaks that are planted with commercially valuable, fast-growing trees, such as hybrid poplar. Producing a direct income from these windbreaks also would diversify sources of farm income and reduce overall financial risk.
The technology of growing hybrid poplars for wood and fibre products is rapidly advancing throughout many regions of the country. Because of their rapid growth and marketable products, hybrid poplars fit well into the timberbelt concept. New hybrid poplar clones have been developed that can produce saleable wood products in short rotations-commonly 7-12 years. Poplar markets currently exist for pulp and oriented strand board, and are emerging for veneer and solid wood products.
Timberbelts potentially provide all the benefits of windbreaks and if planted to hybrid poplar would produce 3-8 cords/tons of wood per acre per year depending on the region (irrigated poplar producing at the higher end). Carbon sequestration credits from the carbon stored in the timberbelt could help offset planting and establishment costs. Hybrid poplar timberbelts could store 30-80 metric tons of carbon per acre in 7- to 12-year rotations.
A timberbelt demonstration was planted in co-operation with the USDA National Agroforestry Center; University of Minnesota's Center for Integrated Natural Resources and Agricultural Management; a land-owner in Chippewa County, Minnesota; the WesMIN and Prairie County RC&Ds; and CENTROL, a crop consulting company.
Ten 9- to 14-row timberbelts were planted in the spring of 1998. Seven hybrid poplar clones and clones of eastern cottonwood were used. They were designed to protect adjacent crops (corn, beans, and sugar beets) and to produce wood products in 10- to 12-year rotations. Current data will be presented in the paper on timberbelt design, clone suitability and growth, adjacent crop yields, and estimated financial returns.
Stig Larsson
Svalöf Weibull AB, SE-268 81 Svalöv, Sweden
Short-rotation willow (Salix) coppice has been marketed for 10 years in Sweden, and so far 18,000 ha have been planted. During five winters from 1996 to 2000 about 5,000 ha were harvested. The yields varied from 1 to 15 tonnes dry matter (odt) per hectare per year, and the average yield was 4.5 odt per hectare. Most plantations were harvested for the first time, which partly explains the relatively low yield figures. The yield will rise when the plantations are well established. Willow has until now been a low priority crop on the farms as the main part of willow coppice in Sweden is an alternative crop on "set- aside" land. That explains why fewer than 25% of the plantations have ever been fertilised. Fertilisation and better weed control would certainly improve the yield figures a lot. Another important factor for achieving higher yields in the future is the improvement of the planting material through plant breeding. Very few plantations of new varieties have been harvested yet. Some of the commercial varieties now available for planting have a yield more than 50% higher than that of material used earlier.
Table I: Relative yields and the leaf rust scores of commercial varieties of willow from Svalöf Weibull AB compared to the most widely used old variety, L 78183. No. of trials within brackets.
Varieties |
Rel. yield(%) |
Rel. rust score(%) |
Marketing year |
L 78183 |
100 |
100 |
1990 |
SW Rapp |
113 (30) |
43 |
1993 |
SW Jorr |
119 (37) |
35 |
1995 |
SW Björn |
133 (18) |
1 |
1997 |
SW Tora |
149 (23) |
1 |
1997 |
SW Sven |
151 (6) |
1 |
2000 |
SW Torhild |
155 (6) |
6 |
2000 |
SW Olof |
209 (6) |
15 |
2001 |
Willow is a crop that has not been bred for biomass production, which means that there are possibilities to make rapid improvements both in yield and in pest and disease resistance. A breeding program was set up in 1987 at the plant breeding company Svalöf Weibull AB. Breeding of willow at Svalöf Weibull AB aims at producing new varieties with higher dry matter yield, improved resistance to pests and diseases, better frost and drought tolerance for certain areas, and a plant shape suited for mechanised harvesting. Through plant breeding, the relative yields of willow have been increased dramatically compared with earlier grown varieties, and levels of leaf rust have been reduced to almost nil. Fifteen varieties of willow are now protected for plant breeders in the European Union and marketed in a number of European countries. Plantations of willow for biomass production have been established in Denmark, France, The Netherlands, Poland, Sweden and the United Kingdom.
Scott Leavengood1 and Mike Reichenbach1
1Oregon State University, Corvallis, OR, USA
2University of Minnesota, St. Paul, MN, USA
Faculty members at Oregon State University (OSU) have developed a unique mechanism for communicating technical information on hybrid poplar culture and utilisation. The website, known as the "OSU Hybrid Poplar Working Group Home Page", was developed by Forestry Extension Agent Mike Reichenbach (now with the University of Minnesota). The website was created in response to a need to improve internal communication. Numerous OSU faculty members conduct research on hybrid poplar. They represent several colleges and are located all around the state - at OSU's central campus in Corvallis, at county extension offices, and at regional agricultural experiment stations. Lacking a mechanism for internal communication, it was nearly impossible for faculty members to ask one another questions and to simply know "who was doing what, where, and what they learned" about growing and utilising hybrid poplar. A unique feature of the website is that it is a "dynamic web page." The term "dynamic" is appropriate in that selected users (the "Working Group"), as opposed to a single webmaster, may change the content of the website. The information on the page is available to the general public, but a username and password are needed to post or remove information from the site.
The OSU Working Group Home Page includes several topic areas, including:
Each topic area is a separate page to which Working Group members may post information. Information may be posted by simply entering text into a web-based form, by entering HTML code, or by creating a link to an existing web page. The website also contains an interactive calendar that allows Working Group members to post and view educational events as well as links to allow visitors to contact members of the Working Group or post a question via e-mail to the entire Working Group. The website is currently not living up to its potential. Many of the topic pages are still blank and the interactive calendar is also largely empty. This underutilisation is likely due to a combination of factors. One factor is certainly that faculty staff are busy, and converting reports to HTML format can take a good deal of time. Another likely factor is lack of familiarity with dynamic web page technology. Dynamic web pages are relatively new to the staff involved (including the webmaster) and therefore folks who are not experienced web programmers may be somewhat reluctant to try posting information to the site. It is unclear at this time how to overcome these limitations. A training program for the Working Group is a likely solution, but convening this widely dispersed group of people will certainly be a challenge. An interactive website has excellent potential for fostering communication and dissemination of information about a multidisciplinary topic such as hybrid poplar. The practical utility of such a site, however, will depend on a dedicated staff member to collect and convert information to HTML format, keep the site up-to-date, and promote the site.
Li Jingyi, Zhang Zhiyi
Department of Forest Genetics and Tree Breeding, Beijing Forestry University, Beijing 100083, P. R. China
Growth, photosynthetic indices, and morphological and phenological traits were studied on 1-year old Populus tomentosa Can. clones growing in container, including 15 triploid clones and 6 diploid clones. Considerable variation in growth, photosynthetic indices, and morphological and phenological traits were found. Most triploid clones showed obvious superiority over diploid clones both on stem height and basal diameter growth, with a longer period of rapid growth and a higher growth rate. The repeatability of stem height and basal diameter measured on different dates ranged from 0.8476 to 0.9461 and 0.8468 to 0.9025 respectively. Similarity of within-tree photosynthesis patterns was found for 3 triploid clones B330, B301, and B304, and 2 diploid clones BM33 and BM86, but higher photosynthetic rates in old leaves for clones B330 and B30 1. Net photosynthetic rate, single leaf photosynthesis (net photosynthetic rate*single leaf area) whole tree photosynthesis (net photosynthetic rate*total leaf area per tree) and total leaf area per tree were significantly correlated with growth. Whole tree photosynthesis and total leaf area per tree showed a more significant correlation with growth(r = 0.806 - 0.836). For leaf, branch, and internodes traits, repeatability ranged from 0.33 to 0.95. The degree of genetic control was stronger for leaf and internodes traits than for branch traits, the highest for internodes length (R = 0.95). Single leaf area, leaf blade length, leaf width and internode length showed high genetic correlation with stem height and basal diameter(r>0.72). Time of leaf flush, bud set, and leaf fall was also under strong genetic control, but only showed weak correlation with growth. Several morphological and physiological traits such as leaf size, internodes length, total leaf area per tree, net photosynthetic rate and whole tree photosynthesis might be responsible for good performance of the triploid clones in growth. The results suggested that such traits could be useful for the early selection of rapid-growing clones of Populus tomentosa Can.
Li Kaitong
Heilongjiang Forestry Research Institute, Harbin, 150040, China
In this paper a general introduction is given to research advances in genetics improvement and breeding of Chinese aspen (Populus davidiana Dode) in China. This introduction includes natural distribution and collection, conservation, gene diversity, provenance trial, crossing breeding, vegetative propagation and disease resistance etc. Based on the current situation of forest tree breeding in China, some strategic suggestions concerning the future development of Chinese aspen genetics improvement in China are presented, taking into consideration the existing domestic demands of forestry production and international trends in forest tree breeding.
Louis Licht
Ecolotree, Iowa City, IA, USA
Poplar trees now grow within 30 miles of Portland, Oregon, to both cover landfills and treat wastewater. It is the tenth anniversary of the 1990 planting of the Lakeside, OR, Landfill. We will look specifically at poplar's role as the transition crop between a newly completed landfill with an unplanted soil cap to a densely forested ecosystem. This Oregon landfill was the launching point for other installations worldwide. Poplar provides one way to filter pollutants from the soil gases and groundwater with deep root systems while growing a marketable, perennial wood fibre crop. Ecolotree® installed Lakeside and many other landfills with important technical collaboration by CH2M Hill, Inc.
Liu Xiaodong1, Yin Weilun1, Zhu Chunquan2, Lei Jingpin2, Cheng Guizheng3, and Li Wenshu3
1Beijing Forestry University Beijing 100083, China
2The Chinese Academy of Forestry, Beijing 100091, China
3Heishui Forest Farm, Jianping County, Liaoning province Jianping 122411, China
Crown architecture (including vertical distribution of primary branches, leaf area, and cumulative leaf area index; crown form, vertical changes of branch inclinations) of intensive and extensive cultivated poplar (Populus simonii x P. pyramidalis cv. Chifengensis 36) plantations were studied in Liaoning province, China. The results showed that the layer with maximum branch length in intensive culture trees is relatively lower than that of extensive ones. Most trees in intensive culture plantations have conical crowns. But in extensive culture plantations, trees have parabolic cylinder crowns. The distribution pattern of the primary branch of trees in intensive culture benefits light interception. Branch inclination angle also varied significantly with crown length. The estimated leaf area index (LAI) by destructive method was 3.0362 m2m-2 for the intensive culture plantation, and 2.1786 m2m-2 for extensive one. The cumulative leaf area index (CLAI) for intensive and extensive culture plantations can be simulated by the following models, respectively: ICLAI = 0.2607*Z 1.8030 e -0.1643Z (R2 = 0.9919) and ECLAI = 0.0639*Z 2.6480 e -0.2530 (R2 = 0.9960), where Z is the length of crown. If simulated by the crown length of standard trees in two plantations, the CLAI was 3.1221 m2m-2 and 2.2619 m2m-2 for intensive and extensive culture plantations, which differed by about 2.8% and 3.8% from results found in destructive method estimations, respectively. In conclusion, there is a high linear correlation relationship between the standard tree and simulated model for both plantations. The cultivation measures have significant effects on the crown architecture. The conical-shaped crown, large branch inclination angle, and higher CLAI contribute to the higher productivity of intensive culture poplar plantations.
Liu Xiaodong1, Yin Weilun1, Zhu Chunquan2, Lei Jingpin2, Song Xianlin3 and Li Xuemin4
1Beijing Forestry University, Beijing, 100083, China
2The Chinese Academy of Forestry, Beijing, 100091, China
3Heishui Forest Farm, Jianping County, Jianping, 122411, China
4Jianping Forest Bureau, Jianping, 122411, China
Combining the results obtained on the leaf area dynamic and light distribution in the canopy, photosynthetic productivity was studied in intensive and extensive cultured poplar (Populus simonii x P. pyramidalis cv. Chifengensis 36) plantations in Liaoning province, China. During the growing season, the relation between CO2 exchange and the intensity of photosynthetically active radiation (PAR) was studied in the two plantations. The daily change of PAR in different types of weather (sunny, cloudy, and rainy days) was also studied. The photosynthesis model was established, and the photosynthetic productivity of the two plantations in different types of weather was calculated. Comparing the results in the two plantations, it was found that the mean light saturated assimilation rate (Amax ) in the upper and lower crown in July, August, and September in the intensive culture plantation was 1.74 and 1.40 times that of the values of extensive culture one, respectively, which means the photosynthetic capacity of leaves was higher in the intensive culture plantation. The photosynthetic productivity in the intensive culture trees was higher than that in extensive ones, especially later in the growing season. In conclusion, management measures have obvious effects on photosynthetic productivity.
Liu Xiaodong1, Yin Weilun1, Zhu Chunquan2, Lei Jingpin2, Song Xianlin3, and Li Xuemin4
1Beijing Forestry University, Beijing 100083, China
2The Chinese Academy of Forestry, Beijing 100091, China
3Heishui Forest Farm, Jianping County, Jianping 122411, China
4Jianping Forest Bureau, Jianping 122411, China
In this paper, light distribution and transmittance in the canopy of intensive and extensive cultured poplar (Populus simonii x P. pyramidalis cv. `Chifengensis 36') plantations were studied. The experiment site was in Heishui Forest Farm, Liaoning Province, China. Based on data on total solar radiation and Photosynthetically Active Radiation (PAR) in the two plantations, equations transforming from total radiation to ground PAR were established. Combined with the leaf area index (LAI), and its vertical distribution in the canopy, the extinction coefficient (K) and the vertical distribution of PAR in two stands were calculated, respectively. The daily and seasonal change of K and PAR transmittance were also studied in the intensive plantation. The results showed that the maximum K value and the minimum PAR transmittance appeared in July, because the trees had the maximum seasonal leaf area and they absorbed more PAR. The relationship between PAR transmittance and cumulative LAI within the canopy was established; the result showed it was a linear model. We compared the absorption of PAR in the two stands, because the intensive culture plantation had a higher leaf area in different canopy layers. The interception of PAR in the intensive culture stand was higher than that in the extensive culture plantation; this interception resulted in higher productivity in the former. These results can be used for further studies of photosynthetic productivity.
Lu Hai, Li Jin, Wang Shasheng, Li Yi, Jiang Xiangning1, and Li Fenglan
1Experimental Center of Forest Biology, College of Plant Sciences, Beijing Forestry University, Beijing, 100083, China
The Laboratory of Ornamental Plants and Forest Tree Breeding and Biotechnology, Forestry Administration, 100083, China
The Xylem-Specific-Expression Promoter of the Glycine-Rich-Protein (GRP1.8) gene was amplified by the PCR method from total DNA extracted from Populus tomentosa and bean, and cloning into pUC18-T vector. The PCR products were sequenced. Compared with the sequence of French bean, an extremely high cogenetic level (about 98%) was found. The expression vector pBI was constructed by inserting the promoter sequence upstream of the GUS gene in pBI121, resulting in the replacement of the original CaMV35S promoter by the GRP1.8 promoter. Adding X-GLUC (5-Bromo-4-Chloro-3-Indolyl-D-glucuronide) as a substrate and induced by a specific inducing factor, the blue stain of Escherichia coli indicated that the GUS gene in Escherichia coli was activated by the GRP1.8 gene promoter, which was induced by a specific inducing factor.
Lu Mengzhu, Xie Hongli, Zhang Hui, Tang Qian, Liu Yarong, and Wang Shiji
Chinese Academy of Forestry, Beijing, China
The intergenic region of trnL and trnF was amplified by polymerase chain reaction (PCR) for seven samples (varieties) of Populus euphratica Oliv., and one sample of P. cathayama Rehd. The PCR products were cloned into the pGEM-T vector and their sequences were further determined. The phylogenetic analysis of the poplars based on the genetic distances among the above sequences was performed using the Neighbour-Joining method. Three samples collected from Pakistan, Iran, and Kenya are closely related and form a separate group. The variety of P. euphratica called P. pruinosa from Xinjiang (China) represents a separate branch in the phylogenetic tree, while the three samples from Xinjiang, Gansu (China), and Turkey are grouped in an additional major branch. These results indicate that the major branches represent three different species, given their early divergence as indicated by the phylogenetic tree. Because P. pruinosa is far from any other samples, a separate subsection under the section Turanga could be considered. The present study supports the use of the intergenic sequence of the chloroplast genome for the reconstruction of phylogeny of this section.
Lu Wen, Zhang Weidong, and Bao Jun
Tongliao Forestry Bureau, Inner Mongolia, China
At present, forest pests and diseases severely threaten poplar resources in the Three-North Region of China. As a result, people are getting worried about poplar development and starting to have doubts about poplar's future and position. Some people even have negative attitudes towards poplar development. By introducing years of research experiences and results, in combination with the increasing social and economic demands for forestry in the region and the development of some major national forestry ecological programs, this article will try to prove that poplar has always played a very critical role and its function is irreplaceable. From the strategic point of view, it is quite practical to identify poplar as the dominant planting species in the Three-North Region. Our challenges now are to tackle the existing problems, try to improve management, and make use of the unique advantages of poplar to better serve the Three-North Shelterbelt Program so that it can play a more important function in the process of greening and developing the Three-North Region of China.
Lu Wen1, Zhang Weidong1 , Bao Jun1, Jos Van Slijcken2, and Pierre Sigaud2
1Tongliao Forestry Bureau, Inner Mongolia, China
2Institute of Forestry and Game Management, Geraardsbergan, Belgium
Reviewing the scientific documentation on Populus simonii from both national and international sources is an important part of scientific research on the species. Through reviewing and sorting 195 articles from the CAB and 200 articles from CTC and CFA on the research of the species, the present status of distribution of the scientific documentation in terms of times, countries, and subjects resulted in knowledge of the scope and present status of the research on the species in and outside of China. Research on the species involves 23 aspects of 14 subjects, such as forest biology, tree breeding, and forest protection. Among the research aspects, the study of breeding and resistance physiology through bio-engineering techniques has become popular nation-wide.
Lu Wen, Zhang Weidong, Feng Zhengfu, Bao Jun, Song Baoming, Gao Zhihua, and Han Yusheng
Tongliao Forestry Bureau, Inner Mongolia, China
The primary research of the project is one of poplar clone introduction and selection to evaluate clone quality based on integrated appraisal at the seedling stage. In 10 years of trials, 28 clones have been selected through the appraisal of and integrated appraisal of seven indexes. It was found that in Jian10# (P. x euramericana cv. ND182), Xiaohei 8401 (P. simonii-Baicheng x P. nigra-Aertai 8401), Bailin 2# (P. nigra x P. pyramidalis), Euro-America 1-M (P. euramericana cl. I-M ), Zhonglin 86-22 (P. Zhonglin 86-22 ), Heilin 1# (P. xiaohei x P. p15A cl.), Liaoza2# ( P. simonii x Xiaozhuannica cl. Liaoza-2), Niqing x Shanhaiguan (P. nigra x Populus deltoides cv. Shanhaiguan), Zhongchi Heixiao (P. nigra x P. simonii cv. Zhongchi), Faku1# (P. simonii x Xiaozhuannica cl. 'Faku-1), etc., the growth increment is higher than that of Baicheng 41# (P. simonii x Xiaozhuannica cl 'Baicheng-41) and Baicheng 2# (P. simonii x Xiaozhuannica cl. 'Baicheng-2) as local main tree species. Meanwhile, cold resistance, disease and pest resistance, and stem form are also adequate. So the above clones are very suitable for planting and expansion in Korqin Sandy Land.
Hester Lyons
ADAS Wolverhampton, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK
The PAMUCEAF project aims to assess the potential for diversification of arable agriculture into commercial poplar production across Europe. As part of the first stage of the project, a pan-European analysis was required to assess the physical scope for poplar production across the region. The potential for commercial poplar production is defined by limits to the rate of growth, as defined by soil characteristics, water resources, and temperatures. This poster describes a methodology for analysing the spatial distribution of the potential for poplar growth in Europe, using data available at both European and regional scales.
The analysis was carried out on a regular grid of 0.5o latitude/longitude, using available pan-European data. Physical suitability of areas was assessed using an interpretation of soil types. Water resource use was investigated using modelled evapotranspiration figures. A calibrated stochastic weather generator was used to assess the occurrence and frequency of damaging frost early and late in the growing season. The same simulated daily weather data were used to model the start of the growing season across Europe. Characteristics representative of an intermediate poplar clone were used to assess these factors across Europe.
The results give an overview of the areas in the EU15 and Poland where poplar is likely to grow well, along with indications of where additional water resources would be required for maximum growth, and where a risk of frost damage during the growing season exists. The results should be interpreted in the light of current developments in poplar breeding, which may be able to overcome some of the limits encountered through the development of regionally better adapted clones. The methodology developed during this part of the study will be used with regional scale data in the future to identify key areas for poplar growth in the five partner countries involved in the PAMUCEAF project.
Jovan Markovic, Savo Roncevic, and Sinisa Andrasev
Agricultural Faculty, Poplar Research Institute Novi Sad, Antona Cehova 13, P.O. Box 117, 21000 Novi Sad, Yugoslavia
The results of a study performed in 27 test plantations located on different types and forms of alluvial soil along the rivers Danube, Sava, Drava, and Tisza refer to poplar biomass production in short rotations. Test plantations were established during 1960-1985, with different densities varying between 1,111 and 16,666 trees/ha and different spacing systems, using cuttings, roots, and 1- and 2-year-old rooted cuttings. The study includes about 50 varieties-clones of Euroamerican poplar and eastern cottonwood. In some denser test plantations, reproduced by stump re-sprouting, there were several rotations (2-4) with 2- or 4-year felling cycles.
The results indicate that, depending on soil fertility, planting density, and clone type in dense plantations with more than 5,000 trees/ ha, in 3 to 6 growing seasons, the amount of produced biomass was 70-150 m3/ha(wood and bark), with average diameter at breast height d1,3 = 5-10 cm and height of 6-11 m. In dense test plantations with 8,333-6,666 trees/ha, reproduced by stump sprouting, in four 2-year rotations (8 years) or in 2- to 3-year rotations (6-9 years), the amount of produced biomass was 170 to 205 m3/ha with diameter at breast height of 4-7 cm, and height of 5-9 m.
In test plantations with 2,000-4,000 trees/ha, in 5 to 9 growing seasons, depending on density, age, soil properties, and clone type, the amount of produced biomass was 95-275 m3/ha, diameter at breast height 13-17 cm, and height 14-18 m.
In test plantations with 1,000-2,000 trees/ha, in 6 to 9 growing seasons, the amount of biomass produced was 51-263 m3/ha, average dbh (d1,3) was 11-19 cm, and height was 12-19 m. In the same test plantations, at ages between 10 and 14 years, biomass production was 225-414 m3/ha, average dbh was 16-28 cm, and height was 18-25 m. At ages between 18 and 23 years, there was a significant natural decline of trees (30-60%); biomass production was 446-778 m3/ha, average dbh (d1,3) was 22-29 cm, and height was 27-33 m.
By adequate selection of soil, planting density, poplar variety, and planting stock, significant quantities of biomass can be produced in short rotations. Biomass produced in dense plantations in 2- to 4-year rotations, i.e., small trees with a high percentage of bark, can nowadays be evaluated for energy. Test plantations with somewhat lower densities (2,000-4,000 trees), in 5- to 9-year rotations, produce poplar biomass that is partly used in fibre manufacture and partly for energy. Test plantations with 1,000-2,000 trees/ha produce significant quantities of biomass that is used predominantly for fibre.
L.L. May De Mio1, L. Amorim2, and Filho Bergamin2
1Departmento de Fitotecnia e Fitossanitarisomo, SCA-UFPR, Rua dos Funcionarios, 1540, CEP. 80.035-050, Curitiba, PR, Brazil
2Departmento de Entomologia, Fitpatologia e Zoologia Agricola, ESALQ-USP, C.P.09, 13.418-900, Piracicaba, SP, Brazil
Poplar rust is the most important disease in nurseries and in the field in Brazil. Most clones are susceptible and the epidemic is more severe year after year. The objective of this study was to quantify the influence of temperature and leaf wetness duration on the infection of Melampsora medusae on three poplar clones: Latorre - highly susceptible; SM - moderately susceptible; SJ - resistant. In a first trial, potted plants were inoculated with a uredospores suspension (104 spores/ml) and subjected to different temperatures (8, 11, 12, 16, 21, 26, and 31°C). The same suspension was distributed into Petri dishes with water agar medium for assessment of spore germination after incubation for 24 hours in the following temperatures: 6, 11, 12, 16, 21, 26, and 31°C. In a second trial, potted plants were inoculated with a uredospores suspension (104 spores/ml) and subjected to different leaf wetness periods (0, 3, 6, 12, and 24 hours). In this trial all plants were kept at 21°C. The estimated latent period was 7 days for clone Latorre and 8 days for SJ (both at 21°C). The range of optimum temperature for infection was between 16 and 21°C. No symptoms of the disease were observed at 31°C and 8°C. The optimum range of temperature for uredospore germination was between 11 and 21°C (around 80%), although germination was also observed at 6 and 26°C (around 40%). At 31°C, only 10% of the spores germinated. The number of pustules increased with the increase in the leaf wetness duration. The minimum wetness period necessary for infection was 3 hours. There was no difference in the number of pustules in plants subjected to 12 or 24 hours of leaf wetness.
H.S. McNabb, Jr. 1,3, Richard B. Hall1, Thomas C. Harrington1,3, Elwood R. Hart1,2 and A. Assibi Mahama1
1Department of Forestry, 2Department of Entomology, 3Department of Plant Pathology,
Iowa State University, Ames, IA 50011, USA
In 1988, a project was begun to develop new Populus clones for use in biomass energy production in the north central region of the United States. Emphasis is being placed on improving breeding and selection techniques, selection and breeding for pest resistance, dry weight yield potential, and ease of propagation. In 1999, we completed 56 new crosses and planted over 11,000 seedlings at three progeny test sites. We produced planting stock for 20 promising new clones for a new regional test. We scaled-up 12 new clones to be distributed for commercial-scale testing plantations.
We found that 1999 was an abnormal year for Melampsora leaf rust development with the infections starting earlier, but not expanding significantly until very late. As in 1998, the 1999 epidemic started earlier in Ames than in the Minnesota population with larch, the alternate host from which the initial inoculum purportedly originates. We found the canker pathogen Cryptosphaeria populina attacking and killing DN hybrids in some additional plantings, and Agrilus borers were strongly associated with the canker fungus. So far, we have found only six P. deltoides x P. maximowiczii clones that may have sufficient resistance for Septoria canker to allow commercial use.
Field experiments to determine the feeding performance of larval cottonwood leaf beetle (CLB) on eight Populus selections were completed. Overall, performance declined throughout the season. Larval performance was generally lower on clones with higher Tacamahaca parentage. Long-chain fatty alcohols and alpha-tocopherylquinone (-TQ) were monitored on these eight clones with and without larval C. scripta defoliation. Total alcohol amount, _-TQ amount, and total alcohol : _-TQ ratio varied greatly among generations. The long-term study of the effect of CLB on growth and biomass accumulation in the 1998 replicated plantings of four select Populus clones was continued using Novodor® and Raven®, both commercially available Bt products. These treatments were quite effective in managing the beetle during the first two generations. After two growing seasons, volume reduction in the unprotected clones was highly significant. CLB pupae from the laboratory colony were evaluated to determine if correlations existed between various pupal or adult parameters and fecundity or longevity. Pupal or adult weight was not a good indicator of fecundity, total oviposition events, number of eggs/beetle/day, or adult longevity.
Rick Meilan1, Caiping Ma1, Steve DiFazio1, Jake Eaton2, Larry Miller3, Ron Crockett4, and Steve Strauss1
1Department of Forest Science, Oregon State University, Corvallis, OR 97331-5752, USA
2Hybrid Poplar Program, Potlatch Corporation, P.O. Box 38, Boardman, OR 97878, USA
3Cottonwood Fiber Farm, Boise Cascade Corporation, P.O. Box 500, Wallula, WA 99363, USA
4Monsanto Agricultural Company, 17004 N.E. 37th Circle, Vancouver, WA 98682, USA
Weed and insect pests often have significant impacts on survival and growth of poplar plantations. We tested herbicide and insect resistance genes that are widely used in agricultural crops and are expected to improve the efficiency of pest control and reduce management costs. We screened over 110 transgenic lines (i.e., products of asexual gene transfer) of hybrid cottonwood for resistance to glyphosate (active ingredient in Roundup herbicide) during several years of field trials. The lines were produced with a construct provided by Monsanto that encoded two resistance genes - one for glyphosate degradation and one that imparted glyphosate insensitivity. The studies included 40 triploid hybrid lines (Populus trichocarpa x P. deltoides) that were grown at two field sites (east and west of the Cascade Mountains) and 73 diploid hybrid lines (P. trichocarpa x P. deltoides and P. trichocarpa x P. nigra) that were grown at a single site (eastern Oregon). Most of the clones used for gene transfer are employed in commercial production. In each trial, a number of transgenic lines were discovered that showed no foliar damage or reduction in growth after spraying at or above herbicide concentrations used commercially.
For insect resistance, we field-tested 53 hybrid lines (P. trichocarpa x P. deltoides and P. deltoides x P. nigra) that were transformed with a rebuilt Cry3A Bacillus thuringiensis toxin gene provided by Mycogen. This gene was intended to impart resistance to the primary insect pest of poplars in Oregon, the cottonwood leaf beetle (Chrysomela scripta). Nearly all of the transgenic lines were virtually free of feeding damage under natural infestation in eastern Oregon, whereas the non-transgenic lines sustained significant levels of defoliation. As a consequence, the non-transgenic plants grew an average of 13% less in a single year than did the transgenic lines. Both kinds of genes appear to hold considerable promise for use in short-rotation plantations after a method for reducing gene flow has been developed and studies of environmentally prudent management strategies have been completed.
L. Meiresonne1, N. Nadezhdina2, J. Cermak2, J. Van Slycken1, and R. Ceulemans3
1Institute for Forestry and Game Management (IBW), Ministry of the Flemish Community, Gaverstraat 4 B-9500 Geraardsbergen, Belgium
2Institute of Forest Ecology, Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Zemedelska 3, CS-61300 Brno, Czech Republic
3Department of Biology, University of Antwerpen (UIA), Universiteitsplein 1 B-2610 Wilrijk, Belgium
The knowledge of water use from a poplar stand is important for the better understanding of its impact on the hydrological cycle and for regional water balance studies. Poplars prefer moist to wet soils for optimal growth and production levels. In this research, it was the aim (1) to calibrate and validate a water balance model using two different approaches: comparison between measured and simulated soil water content and comparison between the simulated stand transpiration and values scaled-up from sap flow measurements on individual representative trees, (2) to quantify the transpiration of a fast-growing monoclonal poplar (Populus trichocarpa x P. deltoides cv. Beaupré) stand in East Flanders (Belgium) for 5 consecutive years.
To quantify the transpiration of the stand, we simulated the terms of the water balance by the water module of the model WAVE (Water and Agrochemicals in soil, crop and Vadose Environment) model. It describes the one-dimensional water transport in the soil using the Richards (1931) equation, based on soil hydraulic properties. The model was calibrated by comparing the soil moisture content measured by TDR sensors and simulated by the model. The model gave a very good agreement between measured and simulated soil water content, even at shallow depths of 10 and 25 cm. During August 1997, sap flow was measured to quantify the transpiration, using the heat field deformation method with linear radial heating and a combined sensor. The model was validated by comparing the measured (sap flow technique) and the modelled transpiration data. The totals over the whole period from August 9 to September 3, 1997 showed good agreement between the modelled and measured transpiration, i.e., 141 and 149 mm, respectively. Simulation by the model yielded for the growing season (April 1 until October 31) a transpiration of 325 mm (average 1.5 mm/day and 5.3 mm/day maximum) for 1995, 195 mm for 1996 (0.9 mm and 5.2 mm), 311 mm for 1997 (1.5 mm and 5.1 mm), and 288 mm for 1998 (1.4 mm and 4.9 mm).
P. Mertens
Research Center on Nature, Woods, and Timber, Gembloux, Belgium
The total production of timber and the dominating height of forest trees are weakly linked. This relationship is fundamental in calculating tables or production models since it is independent of the quality of the site. Verification of this dendrometric principle for the three poplar cultivars P. x Ghoy, P. x Beaupré, and P. x Boelare is considered here. In the 111 plots of 20 to 25 trees sampled (2,319 circumferences measured), the total production was estimated using the basal area. The total height of trees was measured using the `Vertex' dendrometer on 392 trees. The 31 plots of P. x Ghoy, 4 plots of P. x Boelare, and 39 plots of P. x Beaupré sampled are located in the Mosan basin, and in the whole potential area of the P. x euramericana and P. x interamericana (Hesbaye, Condroz, Famenne, and Gaume) poplar cultures. The localisation, spacing between trees, pH at 20-30 cm depth, groundwater level, and soil type represent parameters with which each plot can be identified. The result obtained can be expressed in an equation relating the mean height and mean circumference of the poplar stands, with a mean spacing between trees of 8 m. After comparing the coefficient values, it was noticed that the use of this relationship can be extended to individual tree cases. In other words, the variability within the plots has not affected the precision of the curves obtained. In addition, the similarity of the curves obtained for P. x Boelare and P. x Beaupré enable the data to be grouped and thus generate one equation for the two cultivars.
For the P. x Ghoy: ln(height) = 0.1538 (ln(mean circumference))2 -1.2153 ln(mean circumference) + 6.5087. For the P. x Boelare, P. x Beaupré: ln(height) = 0.0729 (ln(mean circumference)) 2 - 0.2032 ln(mean circumference) + 3.4626. The use of the circumference in these equations is sufficient to express the relationship of productivit y sought, since the plantation density is constant. The influence of available site parameters was tested for the two models obtained. No systematic error was detected. The difference between the above two models is minimal, but they show that P. x Boelare and P. x Beaupré are slightly longer (less stocky) than P. x Ghoy, especially for trees with a circumference exceeding 150 cm. The limits of heights correspond to a total variation of 2 m in relation to the mean value for P. x Ghoy, and of 3 m for P. x Boelare and P. x Beaupré. The relationship between mean circumference and total height simplifies life for the practitioner. Starting from the mean circumference of a stand with a spacing of 8 m, the practitioner may estimate the probable limits of the total height variation without having to measure them. This value for a given age enables the productivity of poplar stands to be compared. Extrapolation to spacings of 7 to 9 m does not change these results much, but additional data should confirm this hypothesis. In addition, estimation of the total volume (of the trunk) per tree or per stand becomes more precise using the circumference-height relationship discussed.
P. Mertens1 and F. Etienne2
1Research Center on Nature, Woods and Timber
2I.S.I. de Huy, Gembloux, Belgium
Phenolics are the only class of secondary compounds in the Salicaceae. These carbon-based compounds include phenolic glycosides, flavanoids, and tannins. No nitrogen-based compounds are known to exist in Populus. Bud exudates of almost every species of Populus have high concentrations of flavanoids. Their abundance and diversity have made them helpful in chemical taxonomy where they have been used to discriminate between poplar species, hybrids, and even clones. Foreseeing the interest in such a tool, research was carried out to improve the methods for identifying reproductive material of Populus.
The main objective of the study is to propose an aromatic fingerprint tool. It must be able to distinguish hybrids and clones and be related to genetically important economic traits. This first investigation shows the discrimination level of aromatic profiles. It also examines the efficiency of the method, seeking reproducible, low-cost results on the basis of neither random nor restricted markers. The aromatic technology obtained with gas chromatography gives a stable fingerprint of species, hybrids, and clones. The clone discrimination and identification is one of the main results of this aromatic fingerprinting with the method used. From the aspect of methodology, the aromatic fingerprint method is located between the RAPD and the AFLP technologies.
The knowledge of specific phenol composition of poplar species has practical issues. Indeed, for reproductive material for which nothing is known, the aromatic fingerprint can identify the probable species or hybrid compounds. After this first step in the investigation, P. trichocarpa, P. nigra, P. deltoides, P. x interamericana, and P. x euramericana can be distinguished.
