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Box 7626, College of Forest Resources, North Carolina State University, Raleigh, North Carolina 27695, USA |
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INTRODUCTION The forests of Mexico and Central America are some of the most genetically diverse in the world. Human population growth rates in the region of greater than 2% per year has placed tremendous pressure on these unique and valuable natural resources. Shifting agricultural farming, cattle grazing, wood cutting, and man-made fires have altered the size and the genetic structure of forest populations. Natural stands of some forest species have become so fragmented that the value of their allelic contributions to future gene pools is questionable. The Central America and Mexico Coniferous Resources Cooperative (CAMCORE) was formed in May, 1980, at the College of Forest Resources, North Carolina State University, to promote ex situ conservation of forest species native to Central America and Mexico. The cooperative's formation demonstrates the resolve of national forest seed banks, government agencies, universities, and the private industrial sector in the region to protect forest species and populations for future generations. Specifically, CAMCORE has three objectives: (i) to conserve, ex situ, threatened forest species and populations through mother tree seed collections, (ii) to test these species over a range of environments in the tropics and subtropics to find those with potential and (iii) to develop tree breeding programs for those that exhibit the most promise. In collaboration with national forestry seed banks, seed collections were initiated in Guatemala in 1980 and eventually expanded to include all Central American countries and Mexico by 1995. The program began with five members in four countries in 1980 and now has expanded to include 32 members in 16 countries (Table 1).
The ex situ conservation efforts have included some species that are severely endangered like Abies guatemalensis and Pinus maximartinezii. CAMCORE has sampled some species that have never been tested before at the provenance and family level like Pinus pringlei, P. teocote, P. herrerae, and P. cooperi, as well as some economically important species like P. caribaea var. hondurensis, P. tecunumanii, and P. patula (Dvorak, 1992; Dvorak and Donahue, 1992). In 1984, CAMCORE began working with important but threatened broadleaved species native to Middle America and/or northern South America like Bombacopsis quinata, Enterolobium cyclocarpum, and Albizia guachepele (Table 2). CONSERVATION STRATEGY The goal of the CAMCORE conservation program is to capture alleles at the mid-to-low frequencies (Dvorak, 1990). This is accomplished by locating as many populations of each target species in the various donor countries as possible through field explorations and obtaining seeds from approximately 30 mother trees per population. Seeds from the collections are then distributed by mother tree to national seed banks in donor countries, as well as cooperative members in South America, Africa and Asia for the establishment of field gene conservation banks and provenance/progeny trials. Table 1. 1996 CAMCORE Cooperative Membership
Table 2. CAMCORE Cooperative Conservation and Testing Program
All members use the same trial design when establishing field studies. For the conservation bank, each open-pollinated family is represented by at least 10 trees/per site on as many as 10 sites and established at 3 m x 5 m spacing to promote flower and seed production. The multiple site approach ensures the protection of the genetic material in case of a natural disaster at any one location. The provenance/progeny tests are established in a compact family design, with 6-tree family row plots and nine replications on as many as 20 sites. Data is collected from the field plantings at 1, 3, 5, and 8 years of age and is analyzed by CAMCORE at North Carolina State University. Pedigree information is maintained on all trees selected in natural populations and progeny tests on a data base in Raleigh. The establishment of multiple conservation banks and progeny tests across countries and continents allows local land races for each species to develop. For species that show economic potential, trees will be selected and genetic material will be exchanged among members and intensive tree breeding programs will be initiated. For species of only secondary interest, low cost open-pollinated seed orchards will be developed locally for a domestic source of seed. For species of high conservation value but of low economic potential, conservation banks will be maintained and protected. Therefore, the field management of the many provenances sampled by CAMCORE is somewhat analogous to the multiple breeding population strategy recommended by Namkoong et al. (1980).
RESULTS OF THE CONSERVATION EFFORTS Since initiating the program in 1980, CAMCORE has sampled 30 forest species and 8100 mother trees in 285 different locations in Mexico and Central America (Table 2). For some species, a genetic base of 1500 open-pollinated families has been assembled. More than 1000 hectares of field conservation banks and provenance/progeny tests are being maintained by cooperative members in South America, Africa and Asia. The average survival rate of trees in CAMCORE field studies across all locations is now approximately 87%. Of the approximately 8000 trees selected by CAMCORE in natural stands in Mexico and Central America since 1980, it is estimated that only 3000 of these still exist, the rest being harvested or destroyed by man. Therefore, as a result of the foresight and commitment of organizations involved in the CAMCORE program, these valuable genetic resources have been conserved for future use by the international forestry community. In addition, the exploration activities in Mexico and Central America by CAMCORE field crews and government foresters, as well as related research activities, have yielded much important information to further gene conservation activities. 1. The geographic ranges of Pinus tecunumanii, P. chiapensis, and P. greggii have been enlarged as new populations have been discovered (Dvorak et al. 1996b; Dvorak and Shaw 1992; Donahue et al. 1991; Lopez-Upton and Donahue 1996). 2. Exploration and seed collection trips have produced better information on the taxonomy of several of the pine species, including Pinus greggii and P. tecunumanii (Donahue et al. 1996; Dvorak and Raymond 1991). These classical taxonomic studies have been followed by molecular studies to generate (RAPD) phylogeny diagrams of the Mexican and Central American closed-cone pines using the wide array of CAMCORE material available. Results suggest a distinctly separate relationship between P. patula and P. tecunumanii and intraspecific differences between northern and central populations of P. greggii and high and low elevations populations of P. tecunumanii (Grattapaglia et al. 1992). Such information will be used to better understand the role of hybridization and introgression and the maintenance of genetic diversity in pine populations in Central America and Mexico. 3. Information on flowering times in natural stands have been observed to give us a better understanding of how to promote flowering and seed production in exotic environments. For example, work by CAMCORE indicated that the reproductive cycle for the endangered piñon pine, P. maximartinezii probably has a three year reproductive cycle rather than, as assumed earlier, a two year cycle (Donahue and Mar 1995). Furthermore, a comprehensive survey has been conducted for P. tecunumanii to determine the best locations for seed orchards and seed productions areas (Dvorak and Lambeth 1992). Additional surveys for P. maximinoi and P. chiapensis are planned for 1996-1997. 4. To better understand how genetic diversity is structured in natural populations in Mexico and Central America, CAMCORE has initiated allozyme and molecular marker studies to complement information from provenance/progeny tests. Preliminary information from both fragmented and non-fragmented populations of P. tecunumanii in Guatemala suggest that CAMCORE collections not only sample alleles at the mid-and low frequencies but also include many alleles with frequencies of 1% or less (Hamrick and Dvorak, 1996). Alleles considered rare in fragmented populations were often times found at higher frequencies in other populations. Results suggest that for gene conservation purposes of P. tecunumanii a sample size of less than 30 trees per population would be adequate to sample the genetic variation present. 5. A computer generated model is being developed at CAMCORE that uses variables from natural stands, genetic tests, and plantations to prioritize threatened populations. 6. Preliminary assessments are also being made using allozyme data from genetic tests to determine the optimum way to manage and maintain genetic diversity in field trials over multiple generations. Applied questions like how to thin ex situ field plantings to maximize genetic diversity will be addressed. The provenance/progeny tests have also produced useful information to further gene conservation efforts. The better provenances have been identified for a number of species and local government organizations can use this information to develop seed stands and seed orchards to produce seeds for local use (Dvorak and Shaw 1992; Dvorak and Ross 1994; Wright et al. 1995). Requests for commercial amounts of seeds based on the research results from CAMCORE tests have been funneled back to seed banks in Mexico, Guatemala, Honduras and Nicaragua for species like Pinus greggii, P. tecunumanii, P. chiapensis and P. caribaea var. hondurensis. The field plantings have given us a better understanding about the genetics and silviculture of the species to improve survival and growth for long term conservation and utilization. For example, reproductive biology studies on the native broadleaved species Bombacopsis quinata by CAMCORE member Monterrey Forestal has improved seed production five fold (Urueña 1992). Great advances have also been made with P. tecunumanii. The species is very sensitive to container size in the nursery and if not monitored, J-rooting and subsequent wind throw becomes a problem. Changes in nursery protocol (container size, seedling outplanting height etc.) have improved survival and subsequent development. Stem breakage problems in P. tecunumanii are under at least partial genetic control and efforts are underway by CAMCORE members to breed populations that do not carry this defect (Dvorak et al. 1993). Pinus chiapensis has a propensity to fork at the base but results from CAMCORE studies indicate that this problem can be easily managed by corrective pruning at an early age (Wright et al. 1996; Dvorak et al. 1996a). Results from Pinus pringlei studies indicate that the species has no resistance to frosts and must be planted in warm areas to ensure its long term survival. However, when planted on the correct site, it produces wood of excellent quality. FUTURE PLANS Explorations for new populations of forest trees in Central America and Mexico will continue in the future. Studies using the latest molecular marker tools are planned to develop more efficient gene conservation strategies. Intensive selections are underway in CAMCORE progeny tests to develop second generation material with across site analyses of CAMCORE trials being conducted using best linear prediction methodology. Once seed orchards are in production, efforts will be initiated with host government organizations to re-introduce material into native environments where this is feasible and warranted. The oldest seed orchards in the CAMCORE cooperative have just turned four years of age. CONCLUSION The CAMCORE initiative is an excellent example of how collaboration by the international forestry community can result in the successful conservation of species and populations. Furthermore, it demonstrates the very prominent and positive role that the private forestry sector is willing to accept in order to promote gene conservation and facilitate technology transfer in the tropics and subtropics. The CAMCORE ex situ conservation efforts are meant to complement in situ forestry conservation programs developed at the national and regional level in Mexico and Central America. The continued participation, interest, and good will of both local and international agencies in forest gene conservation activities are essential for the long term protection of these valuable species. CAMCORE is a non-profit organization and its continued existence will depend primarily on financial contributions from the private sector. Its strongest financial supporters over the years have been private forest industry, mainly from developing countries. Membership in CAMCORE is open to any organization willing to share in the costs of the program and the establishment of field conservation plantings and genetic tests. CAMCORE actively participates in and supports IUFRO working groups and has strong working relations with many national and international forestry agencies. The cooperative produces technical reports, technical bulletins and annual reports which are available by writing to: The CAMCORE Cooperative LITERATURE CITED Donahue, J. K, J. P. Perry, A. E. Squillace and S. Liu. 1996. Geographic variation in stem-xylem terpene chemistry in native populations of Pinus greggii Engelm. Forest Genetics (in press). Donahue, J. K and C. M. Lopez. 1995. Observations of Pinus maximartinezii Rzed. Madroño. Vol. 42,No. 1. pp.19-26. Donahue, J. K., E. A. Gutierrez, and W. S. Dvorak. 1991. The distribution, ecology and gene conservation of Pinus ayacahuite and P. chiapensis in Mexico and Central America. CAMCORE Bulletin on Tropical Forestry, No. 8. College of Forest Resources, North Carolina State University. 28 p. Dvorak, W. S., J. K. Donahue and J. A. Vasquez. 1996a. Provenance and progeny results for the tropical white pine, Pinus chiapensis, at five and eight years of age. New Forests (in press). Dvorak, W. S., J. E. Kietzka, and J. K. Donahue. 1996b. Three-year survival and growth of provenances of Pinus greggii in the tropics and subtropics. For. Ecol. & Mgmt. (in press). Dvorak, W. S. and K. D. Ross. 1994. Three-year growth and stability of Honduran provenances and families of Pinus tecunumanii. For. Ecol. & Mgmt. 63. pp. 1-11. Dvorak, W. S., C. C. Lambeth, and B. Li. 1993. Genetic and site effects on stem breakage in Pinus tecunumanii. New Forests 7: 237-253. Dvorak, W. S. 1992. Recent advances in the testing and development of tropical and subtropical pine provenances from Mexico and Central America. IN: Proc. IUFRO. Breeding Tropical Trees. (C. C. Lambeth and W. S. Dvorak, eds.). Cartegena and Cali, Colombia. Oct. pp. 385-394. Dvorak, W. S and J. K. Donahue. 1992. Twelve year review of the CAMCORE Cooperative: 1980-1992. College of Forest Resources, North Carolina State University. 93 p. Dvorak, W. S. and C. C. Lambeth. 1992. Results of a survey to determine the cone and seed production of Pinus tecunumanii in the tropics and subtropics. IN: Proc. IUFRO. Breeding Tropical Trees. (C. C. Lambeth and W. S. Dvorak, eds.). Cartegena and Cali, Colombia. Oct. pp. 38-42. Dvorak, W. S. and E. A. Shaw. 1992. Five year results for growth and stem form of Pinus tecunumanii in Brazil, Colombia and South Africa. CAMCORE Bulletin on Tropical Forestry, No. 10. College of Forest Resources, North Carolina State University. 22 p. Dvorak, W. S. and R. H. Raymond. 1991. The taxonomic status of closely related closed cone pines in Mexico and Central America. New Forests 4:291-307 Dvorak, W. S. 1990. CAMCORE: Industry and government's efforts to conserve threatened forest species in Guatemala, Honduras and Mexico. For. Ecol. & Mgmt. 35:151-157. Grattapaglia, D., D. O'Malley and W. S. Dvorak. 1992. Phylogenetic analysis of Central American and Mexican pines using RAPD markers on bulked DNA samples. IN: Proc. IUFRO. Breeding Tropical Trees. (C. C. Lambeth and W. S. Dvorak, eds.). Cartegena and Cali, Colombia. Oct. pp. 132-141. Hamrick, J. L. and W. S. Dvorak. 1996. Assessing sampling efficiency for ex situ conservation of pines in Central America (in preparation). Lopez-Upton, J. and J. K. Donahue. 1996. Seed production of Pinus greggii Engelm. in natural stands in Mexico. Tree Planter's Notes, No. 3. (in press). Namkoong, G, R. Barnes and J. Burley. 1980. A philosophy of breeding strategy for tropical trees.Tropical Forestry Papers No. 16. Oxford Forestry Institute, University of Oxford. UK. 67 p. Urueña L., H. 1992. Production and management of Bombacopsis quinata (red ceiba) seed. IN: Proc.IUFRO. Breeding Tropical Trees. (C. C. Lambeth and W. S. Dvorak, eds.). Cartegena and Cali, Colombia. Oct. pp. 43-47. Wright, J. A., A. M. Marin V. and W. S. Dvorak. 1996. Conservation and use of Pinus chiapensis genetic resource in Colombia. Forest Ecol. & Mgmt. (in press). Wright, J. A., L. F. Osorio and W. S. Dvorak. 1995. Recent developments in a tree breeding program with Pinus patula in Colombia. For. Ecol. & Mgmt. 72: 229-234. |
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