Báo cáo khoa học: " Genetic improvement of oak KC Steiner in North America School of Forest Resources,Pennsylvania State University, University Park"

Chia sẻ: Nguyễn Minh Thắng | Ngày: | Loại File: PDF | Số trang:9

Thêm vào BST

Báo xấu

46
lượt xem 4
download

Download Vui lòng tải xuống để xem tài liệu đầy đủ

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Genetic improvement of oak KC Steiner in North America School of Forest Resources,Pennsylvania State University, University Park,...

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: Báo cáo khoa học: " Genetic improvement of oak KC Steiner in North America School of Forest Resources,Pennsylvania State University, University Park"

Review article Genetic improvement of oaks in North America KC Steiner School of Forest Resources, Pennsylvania State University, University Park, PA 16802, USA Summary —The resource and silvicultural contexts of oak tree improvement in North America are described briefly, and the methods, species, locations, and objectives of specific projects are sum- marized. Brief descriptions are provided of two projects that differ markedly in scope. Past experi- ence suggests that few of the existing projects will ultimately be successful unless project leaders take deliberate steps to transfer genetic gains from seed orchard to operational plantations. Quercus /genetic improvement / North america / review Résumé — Amélioration génétique des espèces nord-américaines. Le contexte de la ressource et de la sylviculture des chênes est tout d’abord brièvement décrit dans le cadre des programmes d’amélioration de ces espèces. Une revue des espèces concernées, des régions où ces pro- grammes sont menés, des objectifs affichés et des méthodes utilisées est ensuite faite. Deux pro- grammes, dont les ambitions sont différentes, sont plus particulièrement décrits. L’expérience pas- sée montre que peu de projets seront couronnés de succès, à moins que leurs responsables ne prennent des initiatives fermes pour transférer les gains génétiques obtenus dans les vergers à graines vers le reboisement. Quercus / amélioration génétique / Amérique du Nord / synthése in North America. The information regard- INTRODUCTION ing specific projects is based upon corre- spondence with approximately 60 forest There are many oak improvement pro- geneticists, andI think that it includes all grams in North America, and they are di- (or very nearly all) existing projects. rected at a rather large number of species. Naturally, the methods and objectives of these programs differ considerably, and a THE OAK RESOURCE comprehensive coverage of them would IN NORTH AMERICA involve excessive detail. Instead, this paper gives a general overview of oak im- provement with, in addition, some atten- statistical summary of the oak re- A rough in North America (exclusive of tion to peripheral matters thatI think are source will help us to circumscribe the important to those engaged in this activlty Mexico)
subject. Little (1979) accepts 58 native in mixtures with other species. ’Oak- cur species of tree-sized Quercus in the Unit- hickory’ is the most extensive (but not the ed States. Ten of these also occur in a only) forest type containing a large compo- small portion of Canada. Oaks are native nent of oak, and the area of this type is es- to 47 of the 48 contiguous states, but 62% timated to be 448,429 km (Anonymous, 2 of the species occur only east of about lon- To express this area in meaningful 1978). gitude 97° (or longitude 105° in the south, terms, it is very nearly equal to the com- Texas and Oklahoma). One important bined land areas of Germany, Denmark, northern species, Q macrocarpa, also ex- Belgium and the Netherlands. It is about tends west to 105°. Longitude 97°, which 10 times the area of all oak forest and lies roughly along the eastern edge of the woodlots in France (Anonymous, 1989). Great Plains region in figure 1, is approxi- mately the western limit of the eastern de- ciduous forest. This area, where most oak OAK PLANTING species are found, occupies only about IN THE UNITED STATES half of the US (exclusive of Alaska), but it contains 94% of all oak growing stock by Given the size of the oak resource in the volume (Waddell et al, 1989). US, the practice of planting to regenerate Of course, it is difficult to assign a land stands after harvesting is almost inconse- to the oak resource because oaks oc- quential. No one has compiled statistics on area
dance, and they produce finer timber than oak planting, but statistics for nursery ship- most other oaks. Q rubra is faster growing ments can provide an indirect measure of than Q alba, and that explains why it is planting activity. TableI shows 1990 ship- planted in larger numbers. In addition to ments of oak seedlings from forest tree those species listed, nurseries grew at nurseries (for reforestation only) in the least 18 other species for reforestation. eastern US *. The regions referred to in ta- Among these species not listed separately bleI are delineated in figure 1.I do not in table I, Q velutina and Q palustris were have similar figures for Canada, butI am grown in greatest quantity, each account- sure they would add only marginally to the ing for about 5% of total production. totals in table I. A surprising revelation of the nursery Shipments for 1990 totaled 13.8 million survey is a disparity between regions in seedlings. Q rubra was the most common- seedling production: the North Central re- ly grown species (39% of total), and Q alba gion was responsible for 64% of all US was the second most common (15%). production and the Northeast only 4%. These 2 species occur in great abun-
Since the vast majority of oak seedlings ment is concentrated in the eastern half of produced by state-owned nurseries, the continent. In fact, there appear to be are which are not permitted to distribute no oak improvement programs west of across state boundaries, regional produc- Texas or the Dakotas. Only 2 Canadian tion figures are indicative of regional plant- projects emerged in my survey, but of ing activity. This disparity is not accounted course Canada lies north of most of the for by the relative importance of the oak oak range. resource. Oak timber is fully as abundant Nearly half of the 27 projects listed in ta- in the Northeast, Southeast and South as ble II are 5 years old or younger. This may it is in the North Central region (Waddell et partly reflect the increasingly shorter ’half- al, 1989). Ownership patterns, topography, life’ of forestry research projects in gener- silvicultural traditions, and (in the southern al. However,I tend to think it is indicative states) a preference for planting pine in of a response by forest geneticists to in- place of oak may all contribute to these re- creasing interest in the oak resource and, gional differences. However, the disparity especially, in planting oak. Although no cannot be understood as a simple conse- concrete data are available, the production quence of resource economics. of oak nursery stock appears to be in- Even with liberal assumptions, 13,8 mil- creasing annually at a fairly rapid rate. lion seedlings could be used to regenerate Oak improvement in the United States no more than a few percent of the annual and Canada is performed mainly by public harvest of oak stands. This underutilization agencies and institutions. Only 3 of the of artificial regeneration suggests little op- projects in table II are run by industry or portunity for real achievements in oak tree with full financial support from industry improvement, since planting is the means (North Carolina State University’s coopera- by which genetic gains are realized. It is il- tive). Some other university projects may luminating to contrast oaks with the south- be supplemented with funds from the pri- ern pines (primarily Pinus taeda), for which vate sector. Most (17) of the projects are tree improvement programs are well- state-level projects, run either by state advanced. The US has only about half the agencies or by universities that house area of southern pine forest as it does state agricultural experiment stations. oak-hickory forest, but we plant over 100 Europeans may wonder about the redun- times as many southern pines as oaks dancy of 19 projects on the genetic im- (McDonald and Krugman, 1986). As we provement of Q rubra (of which only 5.4 shall see, the somewhat dismal figures for million seedlings were planted in 1990). oak planting are not mirrored by a similarly This is a consequence of our federal sys- low level of tree improvement.I shall re- tem of government. Theoretically, Wash- turn to the implications of this paradox. ington could play the role of coordinator, since most of these state-level programs are funded in part with federal tax monies. LOCATION AND ADMINISTRATION However, recalling that the United States OF OAK IMPROVEMENT PROJECTS began as a federation, it is still true that states behave semi-autonomously. Table II shows the geographic distribution This is not to say that there is no coop- of tree improvement projects and the spe- eration among projects, because material cies at which they are directed. For rea- and information are freely exchanged. For sons already made clear, oak improve- example, several projects in table II have
plantations of the provenance tests put to- proved juvenile growth to enhance planta- gether by Howard Kriebel at Ohio State tion success. Improvement activities in the University (see Kriebel et al, 1988) and Southern and Southeastern regions are Robert Farmer, formerly of Tennessee concentrated most heavily on Q nigra. In Valley Authority (see Farmer et al, 1981). some projects, Q phellos is treated along Also, 7 of the state agencies listed in table with Q nigra and their hybrid as a single II participate in a cooperative tree improve- species complex. Improvement objectives ment program for fine hardwoods. None- with these species are either timber or pulp theless, the projects are autonomous pro- production, depending upon the project. jects. Improvement programs in the Great Plains are focused exclusively on Q macrocarpa for in shelterbelts. use IMPROVEMENT OBJECTIVES As part of the overall improvement strat- AND METHODS egy, provenance tests or progeny tests of unselected wild trees are each used in The 27 oak improvement projects are di- about half of the projects, and two-thirds rected at a total of 9 species (table II). employ one or the other (table III). Such Some projects claim effort on as many as are planned in the other projects, or tests 4 or 5 species, but the focus of such pro- alternatively, the project leaders are using jects is usually a single species. plus-tree selection to produce a base pop- Not surprisingly, Q rubra is receiving ulation for improvement. Actually, plus-tree much more attention than any other spe- selection (in wild stands, because we have cies, especially in the Northeastern and very few older plantations) is used or con- North Central regions. The ultimate im- templated for use in about half of all pro- provement objective with this species is jects. This is somewhat surprising since timber and veneer production, though the there is little evidence that plus-tree selec- near-term objective in one project is im- is tion indeed effective hardwood in
stands, but of 1) delineate breeding zones within the re- course some programs may be gion; 2) make careful plus-tree selections practicing low-intensity, inexpensive a form of selection. in wild stands; 3) graft ramets into multiple breeding populations (distinct sublines); About half of the projects have pro- and 4) conduct half-sib progeny tests to gressed to seed orchards (seedling, clonal identify: a) the 2 best clones in each sub- or both) (table III). Clonal seed orchards of line for regrafting into a production or- oak in North America are largely a recent chard, and b) the best progenies within development, and this is reflected in the sublines for creating the next generation of fact that progeny tests have not yet been breeding populations. The overall strategy initiated on most of the orchards. No full- taken from McKeand and Beineke is sib progeny tests have been implemented (1980). Each breeding zone is planned to in any project and they are being contem- have 10-12 sublines, each containing 25- plated in only 3 projects. This of course is 30 clones from (in the first iteration) plus- partly a reflection of the high cost of polli- tree selections. The cooperative has made nating oaks artificially. over 300 plus-tree selections and has be- gun to graft them into subline breeding populations. Among cooperative members, Two examples Indiana has made the most progress with Q rubra, and Mark Coggeshall has a sep- The arate report on this project in these pro- complexity and, one might say, so- phistication of the improvement plan varies ceedings. considerably among projects. To a degree, The second example is a plan ad- this is a function of the emphasis given to vanced by Steiner (1986) for the purpose oak improvement, relative to other respon- of achieving gains in planting success as sibilities, by the various project leaders. inexpensively as possible. The strategic However, it is also a function of legitimate goal is to utilize genetic improvement, di- differences in opinion over the justification rected at juvenile growth rate, to further the for investments in oak improvement. The use of artificial regeneration of oaks, and full spectrum can be illustrated with 2 ex- thereby open avenues for more compre- amples — one using elaborate and rela- hensive approaches to tree improvement. tively expensive designs and methods, the The underlying philosophy is that the value other simple and inexpensive in design of any realistic gain in yield, as sought in and execution. conventional improvement schemes, is The first example is taken from a con- small compared to the economic advantag- sortium of independent projects being car- es of enhancing the regeneration of valu- ried out by 7 state agencies in the North able oaks in mixed stands. This can be done by making planting a practical silvi- Central region *. Considering all oak im- cultural alternative. Overall survival in provement work in North America, this hardwood plantations in the US is appall- cooperative is unsurpassed for its careful ingly low, 9% in one survey (Hill, 1986), planning and coordination among individu- and it is widely considered that success al projects. Briefly, this program intends to: * The state agencies are those of Illinois, Indiana, Michigan, Minnesota, Missouri, Ohio and Wisconsin (table II). This description is taken from a 7-page unpublished document entitled: North Central Fine Hardwood Tree Improvement Cooperative: Ten-Year Plan (dated 1989), and from the cooperative’s 1991 annual report.
with oak would be better if the plantings are projects with new personnel, em- these could be made to grow faster. seedlings ployed by different agencies or institutions and probably with different plans for the Procedures in this example are simple material than those of the original project and can be integrated into the normal nur- leaders. This is a clear example of the sery production routine with relatively little problem of ’administrative fatigue’ in forest additional cost. Acorns are obtained from tree improvement, as described by Wright seed collectors in the usual manner, ex- (1962): success precluded by the inevita- cept that collectors maintain detailed origin bility of personnel turnover. record by seed parent. A portion of seed from each open-pollinated family is sown It seems likely that many, perhaps most, separately by replicated plots within the of the current projects on oak improvement nursery bed. Seedlots with the highest per- will not survive the next 20 years, unless centage of first-quality nursery stock are steps are taken to avoid the pitfalls en- identified and transplanted for short-term countered by earlier projects. Indeed, in (3-5-yr) progeny tests. After testing, par- the several months since the original sur- ents of the best lots are identified as ’seed vey, at least 2 of the projects in table II production plus trees’ (SPPTs), steps are have become endangered because of bud- taken to protect these trees and seed col- get cuts and personnel departures. Given lectors are required to collect from them in the rather low (but increasing) level of oak subsequent years. The process is repeat- planting in North America, the current num- ed annually until enough SPPTs are identi- ber of improvement projects may be ex- fied to supply annual seed requirements, cessive. However, I feel certain that there at which point the entire oak production of is an opportunity to greatly expand the use the nursery would consist of stock with su- of planting through education and training. perior potential for producing successful Tree breeders should play a role in this plantations. If resources are available, ge- if they wish to ensure a market for the netic gains in performance can be in- fruits of their labors. Historically, tree im- creased further by grafting SPPTs into clo- provement gains have not been adopted nal orchards. This plan is in its third year by practioners in the US unless there has of implementation by the Pennsylvania Bu- been a pre-existing demand. A linkage reau of Forestry. with planting practice is part of the ’opera- tional’ component of tree improvement, which Zobel and Talbert (1984) considered Analysis to be crucial to the success of tree im- provement projects. Although their finan- Every project leader hopes that his efforts cial support tends to be low and uncertain, will be fruitful and continued after his inevi- state agency programs are the most promi- table departure. Experience suggests oth- sing of success because the operational erwise. Of the 7 oak improvement projects component of these projects is usually en- mentioned by Cech (1971),only 1 seems hanced by close organizational ties with to have survived the last 20 years of state-owned nursery systems. University ’progress’. Furthermore, it is difficult to de- and Forest Service experiment station pro- tect any evidence that those defunct pro- jects may be less successful because ap- jects have had a measurable impact on plied tree improvement tends to lie slightly oak siviculture and management. In many outside their organizational missions, cases, the abandoned tests and orchards which emphasize research. On the bal- have been rescued by other projects, but ance, North American progress in oak tree
Kriebel HG, Merritt C, Stadt T (1988) Genetics in silvicul- improvement and its application of growth rate in Quercus rubra: provenance ture will continue to be slow. and family effects by the early third decade in the North Central USA. Silvae Genet 37, 193-198 REFERENCES Little EL Jr (1979) Checklist of United States Trees (Native and Naturalized). US Dep Ag- ric, Agriculture Handbook No 541, Washing- Anonymous (1978) Forest Statistics of the US, ton, DC, 375 pp 1977 (Review Draft). USDA Forest Service, Washington, DC, 133 pp McDonald SE, Krugman SL (1986) Worldwide planting of southern pines.J For84, 21-24 Anonymous (1981) Directory of Forest Tree Nur- series in the United States. Joint Publ Ameri- McKeand S, Beineke WF (1980) Sublining for Association of Nurserymen and USDA can half-sib breeding populations of forest trees. Forest Service, 35 pp Silvae Genet 29, 14-17 Memento. AFOCEL- (1989) Anonymous Steiner KC (1986) Integrating tree improvement ARMEF, Direction Generale, Paris, 16 pp with hardwood seedling production. In: Pro- ceedings of the Northeastern Area Nursery- Cech FC (1971) Tree improvement research in men’s Conference (State College, Pennsyl- the oak species. In: Oak Symposium Pro- vania), 24-30 ceedings. USDA Forest Service, Northeast- ern Forest Experiment Station, 55-59 Waddell KL, Oswald DD, Powell DS (1989) For- est Statistics of the United States, 1987. US Farmer RE Jr, Barnhill MA, Rennie JC (1981) Dep Agric For Serv, Resource Bulletin PNW- Variation in 10-year growth of northern red RB-168, 106 pp oak from provenances in the Tennessee Val- ley. In: Proceedings of the North Central Tree JW (1962) Genetics of Forest Tree Im- Wright Improvement Conference 2, 100-105 provement. FAO For For Prod Stud 16, 399 pp Hill JA (1986) Survival of Pennsylvania State Nur- sery seedlings, 1971-1981. In: Proceedings of Zobel BJ, Talbert JT (1984) Applied Forest Tree the Northeastern Area Nurserymen’s Confer- Improvement. John Wiley and Sons, New (State College, Pennsylvania), 1-4 York, 505 pp ence