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Báo cáo nghiên cứu khoa học " ACACIA PLANTATIONS FOR SAWLOG PRODUCTION: SOME SIVILCULTURAL MEASURES AND RECOMMENDED SUITABLE AND PROFITABLE ACACIA SPECIES "

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Nội dung Text: Báo cáo nghiên cứu khoa học " ACACIA PLANTATIONS FOR SAWLOG PRODUCTION: SOME SIVILCULTURAL MEASURES AND RECOMMENDED SUITABLE AND PROFITABLE ACACIA SPECIES "

  1. Collaboration for Agriculture and Rural Development (CARD) Program ACACIA PLANTATIONS FOR SAWLOG PRODUCTION: SOME SIVILCULTURAL MEASURES AND RECOMMENDED SUITABLE AND PROFITABLE ACACIA SPECIES Project title: Sustainable and profitable development of acacia plantations for sawlog production in Vietnam Project code: CARD 032/05 VIE Phi Hong Hai1*, Chris Harwood2, Chris Beadle2, Sadanandan Nambiar2, Khongsak Authors: Pinyopusarerk2, Vu Dinh Huong3, Dang Thinh Trieu4, Pham Xuan Dinh5, Trieu Thai Hung5 Project Implementing organisations: 1 Research Centre for Forest Tree Improvement - FSIV 2 CSIRO – Sustainable Ecosystems, Private Bag 12, Hobart 7001, Australia 3 Sub-Institute of Forestry Research in the South - FSIV 4 Silvicultural Technical Division - FSIV 5 Center for Forestry Science and production in Northern Central regions - FSIV * Responsible author (phi.hong.hai@fsiv.org.vn) SUMMARY Studies on thinning response to diameter growth, pruning response to log defects and response to phosphorus (P) of acacia hybrid growth in Quang Binh and Quang Tri showed that: (1) thinning method increased diameter growth of acacia hybrids; (2) pruning decreased log defects of acacia hybrids; (3) fertilisation of 10 g of elemental phosphorus (as 143 g superphosphate/tree) at planting time was sufficient for increasing of height grow of acacia hybrids at early stage in Quang Tri. In sawn timber plantations, Acacia mangium, A. auriculiformis, A. crassicarpa and Acacia hybrids (A. mangium x A. auriculiformis) were proved to be suitable species. A. crassicrapa was a promising species and performed well in inland sands in the central Vietnam. A. mangium was a suitable species in lowland in the northern Vietnam. While, A. auriculiformis was preferred planting in the southern Vietnam. Acacia hybrids could be planted in many sites from the North to the South. National clones, and technological advanced clones that approved by Ministry of Agriculture and Rural Development were suggested for using in commercial plantations of A. auriculiformis and acacia hybrids. For A. mangium and A. crassicarpa, seed sources from seed production areas and seed orchards were recommended to use. compesating source for this deficit. To meet 1. Introduction the demand of industrial wood and to increase forest coverage to 43%, the reforestation Needs on timber for processing industry in program has planned to plant 5 million Vietnam in 2010 is expected to be 9.35 million hectares of forest by 2010. Among them, more m3 (MARD, 1999). But now the natural than 2 million hectares are production forests, forests are limited for exploitation, so the this source can provide industrial wood. annual timber volume from this kind of timber Increasing forest productivity through sources will only provide less than 300,000 m3 improved seeds and silvicultural techniques per year (MARD, 1999). Timber from will play a crucial role to meet the demand for plantation forest and imports is expected as the 186
  2. CARD 032/05 – Acacia planation for sawlog production timber and and to reduce the volume of 2. Research materials and methods imported wood. 2.1 Thinning and pruning trial Acacia species have been imported into Vietnam since middle of 20th Century, mainly A mixed plantation forest of hybrid acacia from Papua New Guinea (PNG) and clones of 2.5 years old in Dong Hoi - Quang Queensland, Australia (Nguyen Hoang Nghia, Binh has been selected for thinning trial. 2003). In Vietnam, in 2005, the total area of Plantation model was built in December 2003, acacia plantation reached 400,000 hectares, with a mixture of the hybrid Acacia clones including 200,000 hectares of acacia hybrid BV10, BV16 and BV32. The trees in this (Ha Huy Thinh, 2005). Productivity and model are remarkably of good growth and sustainability of plantation of Acacia species good form. The plantation is well stocked are crucial to improving the country's (1000 trees/ha), healthy, average height of economy, the development of rural areas, and trees reached 8 meters, and crown lift is the creation of pulp and sawlog. minimal. With this growth rate, it is predicted that forest productivity is 20m3/ha/year for a The CARD project 032/05 VIE titled pulp production rotation. For all these reasons, “Sustainable and profitable development of this plantation already meets the criteria that acacia plantations for sawlog production in define an ideal site for managing an Acacia Vietnam" was implemented from 2006-2009 stand for solid wood. by a research collaboration between the Forestry Science Institute of Vietnam and the CSIRO, funded by the Collaboration for Agriculture and Rural Development (CARD) Program. The project applied a diversified approach, combining research to improve breeds, site and forest management, and economic evaluation. Assessment of improved varieties for Acacia has been made to identify the acacia species suitable for plantion for sawlog production, and other propagation techniques suitable for these varieties. Besides, silvicultural techniques for reforestation and forest management have also been evaluated by this project. In addition, two trials evaluating appropriate silvicultural techniques have been built at the Central region. The first Lift prunning in the Dong Hoi thinning trial is thinning trials to assess the impact of thinning technique on diameter growth, thus helping increase the diameter enough for Thinning response trial was established in June sawlog requirements. The second is 2006. Four thinning treatments, including the sustainable silvicultural trials to test the long- control (unthinning) has been used in the study term effects of different site management (Table 1). The basic design of the trial is techniques on sustainability of forest randomized complete block, with four productivity over several forest rotations. replications. All the trees in the experimental This paper summarises some key results from treatments were pruned to 2.3 m from the root. thinning and pruning trials and testing Pruning is carried out carefully so that the sustainable silviculture. Also, the evaluation of stems are cut close to the original branch and improved varieties for Acacia and silvicultural not harmful to the original branch. techniques for acacia plantation, as well as suitable Acacia species for sawlog production are also discussed and recommended. 187
  3. P.H. Hải, C. Harwood, C. Beadle, S. Nambiar, V. Đ. Hưởng, Đ. T. Triều, P.X. Đỉnh, T. T. Hưng Table 1. Thinning treatments and plot sizes at Dong Ha Thinning Trial Treatments (Stems/ha) Gross (Trees /plot) Net (Trees /plot) 1000 (unthinned, control) 63 35 600 38 21 450 28 16 300 19 11 Plot size (ha) 0.063 0.035 Dimensions (m × m) 28 × 22.5 20 × 17.5 2.2 Sustainable silviculture demonstration trial 2.3 Record keeping and statistical analysis A site for the silvicultural trial was chosen at Dong Ha - Quang Tri, managed by the Science Records on both thinning trial and sustainable Center and North Central production - Forestry silviculture experiment are kept and assessed Science Institute of Vietnam, to establish every six month beginning from thining sustainable silvicultural trials for long-term activity and plantation. Diameter at breast track . This site was planted with hybrid height (Dbh) and height (Ht) of all trees in Acacia, with the yield of 19 m3/ha/year at the each experimental plots were collected. The 9th year. After extraction, the area was fenced statistical analysis was processed on the off to avoid the effects of animal grazing. average value plots and using mathematical Leaves and twigs after the first pruning is kept fixed-effects model, where the replicate blocks on the site. Soil analysis results before planting and the experimental treatments are considered showed that the soil at this site is degraded, constant. with low total nitrogen, phosphorus and pH. Six hybrid acacia clones (BV10, BV16, BV32, BV71, BV73 and BV75), being the national seed and technical advance, have been used to establish the sustainable silvicultural trials. The experiment was designed in randomized complete block (5 experimental treatments and 4 replicates). The experimental plot size is 21.5 x 20 m (6 rows x 10 trees/row). Experimental plots are separate from one another by three rows of trees in both dimensions. The experimental treatments are as shown in Table 2 to examine the impact of the increase in the amount of phosphate fertilizer to the increase in stem diameter, and the effectiveness of different weeding methods (method of using herbicides Roundup and manual weeding two times per year). The amount of phosphate fertilizer for each plant was determined from analysis of soil and leaf nutrient testing before establishment of the siviculture experiment. Measuring stem taper in the Dong Hoi thinning trial 188
  4. CARD 032/05 – Acacia planation for sawlog production Table 2. Experimental treatments applied for siviculture trial in Dong Ha Treatment ID Nutrition treatment Vegetation management T1 Control – no fertilizer Pre-planting herbicide spray and two sprays per year to give complete weed T2 P1 10 g elemental P applied as control, with a rate of 4l ha-1 Roundup superphosphate herbicide per application T3 P2 20 g elemental P applied as superphosphate T4 P3 (=P2 + 10 g K per tree applied as potassium sulphate) T5 Control – no fertilizer No herbicide application. Two hand weeding per year as per standard practice at Dong ha Station the trees in control plots (no thinning) has the 3. Research results and discussions diameter of 14.5 cm (Table 3). The individual 3. 1 Impact of thinning on individual tree tree diameter and wood volume in the diameter treatment plots of thinning down to 300 stems/ha and 450 stems/ha are larger than that Results of demonstration pruning trial in Dong in the plot of 600 stems/ha, but the Hoi, Quang Binh have confirmed that pruning phenomenon of tree top fracture and early can improve growth in diameter of the Acacia separation of stems is quite common. hybrid in the trial. After 2 years of thinning, Therefore, thinning down to the density of 300 the trees in the trial plot reached an average stems/ha and 450 stems/ha is not suitable for diameter at breast height of over 16cm, while sawlog plantation. Table 2. Individual tree growth and stand basal area 24 months after thinning treatments imposed, i.e. stand age 4.5 years, in the trial at Dong Hoi, Quang Binh Tree height (m) Diameter at Basal area Thinning treatment % wood (m2/ha) breast height (stems/ha) volume (cm) 300 16.8 17.1 7.4 28 450 17.2 16.3 9.6 23 600 17.3 15.9 11.9 19 1000 17.2 14.5 14.1 7 Statistical error none P
  5. P.H. Hải, C. Harwood, C. Beadle, S. Nambiar, V. Đ. Hưởng, Đ. T. Triều, P.X. Đỉnh, T. T. Hưng& P.Khongsak Most of Acacia forests in Vietnam were enough for sawing (dbh over bark range from planted with initial density from 1000 to 1600 20 cm upwards. Butt logs of 2 m in length stems/ha (i.e. planting distances 4 x 2m, 3 x were sawn on a bandsaw to produce from 4 to 3m, 3 x 2.5 m and 3 x 2 m) (Nguyen Thi Lieu, 6 boards per log, of about 30 mm in thickness. 2004; Pham The Dung, et.al, 2005; Vu Dinh Defects (mostly associated with branches and Huong et. al, 2006; Nguyen Huy Son et. al, associated dead and discoloured wood) were 2006; Nguyen Duc Minh et. al, 2004). The marked on each board. All boards were thicker density, the stronger competition photographed. The numbers of defects in the between the trees in the forest. Therefore, early outer wood, laid down after pruning, and the pruning is very important to promote growth in inner wood laid down before pruning were diameter of the trees in the forest. On the well- scored (Table 4). established forest site, if the good seeds are As expected, the average number of defects on planted with appropriate silvicultural the inner part of the game is similar between management, including weeding and the trees is not pruning and pruning trees (4.9 fertilizing, the by-product from pruning at the and 5.0, respectively). Because the inner age of 2.5 to 3 years old can be sold as pulp timber boards were formed before pruning is wood, and the remaining trees can provide done. In contrast, the planks are sawn from the sawlog after a short-rotation of 5-6 years. tree pruning is 0.5 defects / Snowboarding at the outer boards, while boards from tree 3. 2 Impact of thinning on tree defect pruning is 1.2 defects / boards. Such pruning trees have fewer defects than. Handling A sawing study was conducted on logs to changes to test the effects of pruning to defects study the effects of pruning on tree defect. 15 in the outer wood planks showed clear thinned trees from thinning treatment plots and differences (P
  6. CARD 032/05 – Acacia planation for sawlog production causing death knotty core on the surface of Clear impact of phosphate to the growth of sawn boards. (2) First pruning should be done hybrid acacia in the age of 2 years has been earlier, when the lower branches of a tree are demonstrated. The average height of hybrid alive. Such pruning associated with pruning acacia in the second rotation is approximately dead branches will avoid the small defects on 7 m at 2 years old and is considered quite the sawn boards. However, the good promising in the treatment of supporting combination between early pruning to remove phosphate fertilizer at Dong Ha, Quang Tri. the defects and the risk of limited growth rate The difference between the control treatment due to pruning activity should be noted. If the and phosphate fertilizer application is clear and tree diameter at breast height is 7 cm and its the differences at 1% (P
  7. P.H. Hải, C. Harwood, C. Beadle, S. Nambiar, V. Đ. Hưởng, Đ. T. Triều, P.X. Đỉnh, T. T. Hưng& P.Khongsak Table 5. Survival rate, Diameter at breast height (Dbh) and Height (Ht) of Acacia hybrid in sustainable sivilcuture experiment in Dong Ha after 2 years of age Treatments Ht (m) Dbh (cm) Survival (%) Control – no fertilizer 6.16 7.47 80.0 P1 10 g elemental P applied as superphosphate 6.98 8.57 80.4 P2 20 g elemental P applied as superphosphate 6.95 8.53 76.3 P3 (=P2 + 10 g K per tree applied as potassium sulphate) 6.89 8.70 82.1 Control – no fertilizer 6.41 7.88 80.0 Statistical significance P
  8. CARD 032/05 – Acacia planation for sawlog production approved by MARD as National Germplasms of Acacia auriculiformis clones in Vietnam and Technological-Advanced Germplasms. (Phi Hong Hai, 2009). This means that when These clones have fast growth and good using the 20 above clones of Acacia quality stems. For example, the clones BVlt25, auriculiformis it is necessary to pay special BVlt81, BVlt 83, and BVlt 85, selected from attention to ecological zones suitable for each Coen River provenance planted in Ha Noi that clone. have achieved average productivity (MAI) 3.4.2 Acacia hybrid clones from 10.5 to 13.1 m3/ha/year in Ha Tay and Currently, the clones of hybrid acacia (A. Quang Tri (Le Dinh Kha, 2006). However, 11 Mangium x A. auriculiformis) have been other superior clones were selected from widely grown in Vietnam. Hybrid acacia wood Acacia auriculiformis nurseries in Binh Phuoc can be used for sawlog, because they have an (as Clt7, Clt18, Clt19, Clt26, Clt43, Clt57, average wood density (0.45 g/cm3), and Clt64, Clt98, Clt133, Clt1F, and Clt171) have higher productivity (MAI : 15-30m3/ha/year in bending properties is 90 - 103 kg/m2. The best clone of acacia hybrids shows superiority in Quang Binh and Binh Duong) (Fees Red Sea, growth than its two parent species in all trials 2009a). In addition, the AA1, AA9, and AA15 in the lowlands in Northern, Central and South have both good disease resistance and high Vietnam (Le Dinh Kha, 2001). In most suitable growth, the productivity is from 25-33.6 m3/ha/year in Dong Nai and Binh Phuoc sites in the southern and central regions, the acacia hybrid clones can achieve productivity (Nguyen Hoang Nghia, 2007). of 35-40 m3/ha/year after the rotation of 5-7 years (Le Dinh Kha, 2001). Even on the infertile and thin topsoils sites in Ba Vi - Ha Noi, the productivity of Acacia hybrid can achieve 15 m3/ha/year, while Acacia mangium reaches only 9 m3/ha/year (Doan Ngoc Dao, 2003). Acacia hybrid clones have very high uniformity of growth. Seventeen clones of hybrid acacia (BV10, BV16, BV29, BV32, BV33, BV71, BV73, BV75, M8, MA1, AM3, AM2, AH1, AH7, TB1, TB7 and TB11) has been approved for mass production. New clones of hybrid acacia also continue to be selected to provide extra diversity to seed collection and to limit pests and diseases for planted forests. Many clones of the Acacia hybrid will be recognized in the future. Clone trial of A. auriculiformis clones at Bau Bang, age 4.5 years after planting 3.4.3 Propagation for suitables Acacia species In addition to increasing productivity of Selection and use of outstanding individual Acacia auriculiformis forest, improvement of genotypes in clonal plantations enables the shrinkage of Acacia auriculiformis wood exploitation of both additive and non-additive has been studied and contributed to increase genetic variation and thus maximises genetic usable proportion of wood for processing (Phi gain in the production plantations (Eldridge et Hong Hai, 2009). Some clones like Clt7, al. 1993). This makes clonal forestry the most Clt12, Clt18 and Clt25 have both fast growth attractive propagation option where it is and low degree of shrinkage, therefore, these feasible. However, clonal forestry is not clones are recommended for use in sawlogs considered feasible for A. crassicarpa and A. plantation (Phi Hong Hai, 2009). However, mangium. Although a majority of individuals genetic interactions - the situation of growth of A. crassicarpa and A. mangium a can be and stem quality is meaningful for plantation clonally propagated from basal coppice, and 193
  9. P.H. Hải, C. Harwood, C. Beadle, S. Nambiar, V. Đ. Hưởng, Đ. T. Triều, P.X. Đỉnh, T. T. Hưng& P.Khongsak hedge plants can be established, hedge plant suitable for sawlog plantation. A. Crassicarpa maturation appears to be more rapid than for A. is promising species, particularly on the auriculiformis and acacia hybrid. Experience problem land areas such as sandy field in the from Indonesia shows that poor rooting vigour central region. Acacia mangium and Acacia of cuttings and slow growth of cuttings in the hybrid are suitable with sawlog plantations in field is typically found in these species (Yang the lowlands in the north. While, A. et. Al, 2006). Thus, by planting high quality Auriculiformis and Acacia hybrid are most seeds (from nurseries and seed production) is favorite species in the South. The seeds recommended for Acacia mangium and A. supplied for mass production are national crassicarpa. Family Clonal Forestry can also germplasms or technological advanced be an option for plantation of these two Acacia germplasms for A. Auriculiformis and Acacia hybrid, and the seeds from seed orchards and species. seed production for A. Mangium and A. A. auriculiformis and Acacia hybrid can be Crassicarpa. propagated easily from basal coppice and can be preserved for long-term rejuvenation in the Reference tissue culture room. Then, the plant tissue is used as hedge plant for mass propagation for 1. Arnold, R. J.; Cuevas, E. (2003). Genetic production. The steps of propagation of Acacia variation in early growth, stem straightness hybrid cuttings were described in detail (Le and survival in Acacia crassicarpa, A. Dinh Kha, 2001) and can be applied to A. mangium and Eucalyptus urophylla in auriculiformis. But in almost remote and Bukidnon province, Philippines. Journal of Tropical Forest Science 15 (2): 332-351 isolated areas, where vegetative propagation 2. Đoàn Ngọc Dao (2003). Tiếp tục so sánh sinh system has not really been developed, seeds trưởng và khả năng cải tạo đất của Keo lai với from seedling seed orchards of Acacia hai loài bố mẹ sau 5 tuổi. Luận văn thạc sĩ. auriculiformis should be used. Seed collected Trường đại học lâm nghiệp. 69 trang from acacia hybrid trees must never be used 3. Hà Huy Thịnh (2005). Nghiên cứu chọn, tạo because the performance of the resulting giống có năng suất và chất lượng cao cho một advanced generation interspecific hybrids has số loài cây trồng rừng chủ lực. Viện Khoa học been shown to be very variable from tree to lâm nghiệp Việt Nam. 161 trang tree and much poorer than that of the selected 4. Harwood, C.E. and Williams, E.R. (1992). A F1 hybrid clones (Le Dinh Kha, 2001). review of provenance variation in the growth of Acacia mangium. pp. 22-30 in Carron, L.T. 4. Conclusions and recommendations and Aken, K. eds. Breeding Technologies for Tropical Acacias. ACIAR Proceedings No. Appropriate density in the common acacia 37. Australian Centre for International plantations is 1000 - 1600 stems / ha. Thinning Agricultural Research, Canberra. increases in the diameter of the tree. Thinning 5. Le Dinh Kha (2001). Studies on the use of to 600 stems / ha in Acacia hybrid plantation in natural hybrids between Acacia auriculiformis Quang Binh is most appropriate. Pruning also and Acacia mangium in Vietnam. Agriculture remarkably reduces defects in the wood. Publishing House, Hanoi. 171 trang Therefore, thinning and pruning are important 6. Lê Đình Khả (2003). Chọn tạo giống và nhân silvicultural measures for sawlog plantation to giống cho một số loài cây trồng rừng chủ yếu make sufficiently large diameter and defect- ở Việt Nam. Nhà xuất bản Nông nghiệp, Hà Nội. 171 trang free wood. Elemental phosphate fertilizer application of 10g / tree (equivalent to 143 g 7. Lê Đình Khả (2006). Báo cáo công nhận giống một số dòng Keo lá tràm. Viện Khoa superphosphate per tree) is sufficient to create học Lâm nghiệp Việt Nam, Hà Nội. 17 trang. differences in height growth of hybrid acacia in the first stage in Quang Tri and actually 8. Nambiar S. (1999). New forests: wood ensure sustainability throughout the rotation. production and environmental services. CSIRO publishing. 256 trang. A. Mangium, A. Auriculiformis, A. Crassicarpa 9. Nguyễn Đức Minh, Nguyễn Thị Thu Hương, and Acacia hybrid are the Acacia species và Đoàn Đình Tam (2004). Nghiên cứu nhu 194
  10. CARD 032/05 – Acacia planation for sawlog production cầu dinh dưỡng khoáng (N,P,K) và chế độ 15. Phi Hong Hai (2009). Genetic improvement of nước của một số dòng keo lai (acacia hybrid) plantation-grown Acacia auriculiformis for và bạch đàn (Eucalyptus urophylla) trong giai sawn timber production. Doctoral thesis đoạn vườn ươm và rừng non. Báo cáo tổng kết No.2009:56. Swedish University of đề tài. Viện Khoa học lâm nghiệp Việt Nam. Agricultural Science. 10. Nguyễn Hoàng Nghĩa (2003). Phát triển các 16. Phí Hồng Hải, Hà Huy Thịnh và Đỗ Hữu Sơn loài Keo Acacia ở Việt Nam. Nhà xuất bản (2009a). Triển vọng phát triển của một số Nông nghiệp, hà Nội. 121 trang dòng Keo lá tràm trong trồng rừng gỗ xẻ. Tạp chí Nông nghiệp và phát triển nông thôn (12): 11. Nguyễn Hoàng Nghĩa (2007). Báo cáo công 173-179. nhận một số dòng Keo lá tràm. Viện Khoa học Lâm nghiệp Việt Nam, Hà Nội. 20 trang 17. Pinyopusarerk, K. (1990). Acacia auriculiformis: an annotated bibliography. 12. Nguyễn Huy Sơn, Nguyễn Xuân Quát và Bangkok, Thailand: Winrock International- Đoàn Hoài Nam (2006). Kỹ thuật trồng rừng F/FRED and ACIAR, 154 p. thâm canh một số loài cây gỗ nguyên liệu. Nhà xuất bản thống kê, 128 trang 18. Vance C. P., Graham P. H. và Allan D.L. (2002). Biological Nitrogen Fixation: 13. Nguyễn Thị Liệu (2004). Điều tra tập đoàn Phosphorus - A Critical Future Need? . cây trồng và xây dựng mô hình trồng rừng keo Current Plant Science and Biotechnology in lưỡi liềm Acacia crassicarpar trên cát nội đồng Agriculture (Ed. Pedrosa F.O., Hungria M., vùng Bắc Trung Bộ. Viện Khoa học Lâm Yates G.and Newton W.E.). Springer nghiệp Việt Nam. Netherlands : 509-514. 14. Phạm thế Dũng, Ngô Văn Ngọc, Hồ Văn 19. Phúc, Nguyễn Thị Lề, Nguyễn Thị Nhuần, Yang M., Xie X., He X. and Zhang F. Phạm Viết Tùng và Nguyễn Thanh Bình (2006). Plant regeneration from phyllode (2005). Nghiên cứu một số biện pháp kỹ thuật explants of Acacia crassicarpa via thâm canh rừng cho các dòng keo lai được organogenesis. Plant Cell, Tissue and Organ tuyển chọn trên đất phù sa cổ tại tỉnh Bình Culture (85): 241-245. Phước làm nguyên liệu giấy. Viện Khoa học Lâm nghiệp Việt Nam. 195
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