Review of the Performance and Suitability of Pinus caribaea in Vietnam potx

Review of the Performance and Suitability of Pinus caribaea in Vietnam Mark J Dieters , Ha Huy Thinh2, Phan Thanh Huong , and Huynh Duc Nhan October 2006 Report prepared for CARD project 033/05VIE: Field evaluation and advanced vegetative mass-propagation technology for scaling up high-value plantations of Pinus caribaea and related hybrids in Vietnam (Project Output 1.1) Summary Pinus caribaea was first planted in Vietnam in 1963 Since that time, this species has been evaluated on potential sites throughout Vietnam As part of CARD project 033/05VIE, many of the trials involving P caribaea were inspected and relevant trials were remeasured in early 2006 This report summarizes the performance of P caribaea in trials established since 1976 by the Forest Research Centre in Phu Tho and the Research Centre for Forest Tree Improvement in Hanoi Summary data collated from various sources and newly collected data were analysed in a manner which would allow direct comparison to previous trial results Data up to 25 years after planting are presented from a total of 17 trials, planted on sites in the four major biogeographic regions of Vietnam that are most promising for the establishment pine plantations – northern, central, central highlands, and southern Vietnam These trial results clearly demonstrate the superior growth capacity of P caribaea over P kesiya, P merkusii and P massoniana P caribaea var hondurensis (PCH) demonstrated great adaptability to a wide range of sites from northern to southern Vietnam, with relatively little provenance variation observed amongst those provenances evaluated However, it appears that the provenances of var hondurensis tested in Vietnam are likely to have been selected based on results in international provenance trials; all tested provenances ranked well in the Oxford and/or CAMCORE series of provenance trials Only a limited sample of P caribaea derived from the Bahamas (i.e P caribaea var bahamensis, PCB) was evaluated; however, in trials located in northern Vietnam, growth of PCB was consistently good in comparison to PCH or other species Further, this variety is also likely to provide enhanced stem form and greater resistance to some insect pests than PCH Performance of the third variety (P caribaea var caribaea, PCC from Cuba) was poor compared to PCH and local pine species It is recommended that future breeding and tree improvement activities should focus on PCH and PCB for northern Vietnam, and PCH for central and southern Vietnam Development and testing of pine hybrids is likely to be difficult, and so should only form a secondary research priority School of Land and Food Sciences, The University of Queensland, St Lucia Queensland 4072, Australia Research Centre for Forest Tree Improvement, Forest Science Institute of Vietnam, Dong Ngac, Tu Liem, Hanoi Forest Research Centre, Phu Ninh, Phu Tho, Vietnam Background Pinus caribaea Morelet, especially P caribaea Morlet var hondurensis (Sénéclauze) W.H Barrett & Golfari (PCH) has demonstrated fast growth and adaptability to a wide range of sites across the tropics and sub-tropics (Gibson 1982, Birks and Barnes 1990, Dvorak et al 2000) The other two taxonomic varieties of P caribaea (i.e var bahamensis (PCB) and var caribaea (PCC)) have also shown potential in commercial plantations in some parts of the world with both of these varieties exhibiting greater tolerance to some insect pests (Baylis and Barnes 1989, Kha et al 1989) and greater resistance to wind-damage than the Central American (PCH) variety (Birks and Barnes 1990, Dieters and Nikles 2001) Further, PCB has demonstrated greater tolerance to cold temperatures than either PCC or PCH (Nikles 1966 p 103, Duncan et al 1996), which is rather surprising given its natural distribution at low elevation across the Bahama and Caicos Islands PCH has been used the most extensively for establishment of plantations with large areas planted in Venezuela and Queensland Australia, while significant areas have been planted with PCC in southern regions of China (Dieters & Nikles 1997) P caribaea was first planted in Vietnam at Da Lat in 1963 (Kha 2003, p.181) with a view to exploring the potential of this species in commercial plantations as an alternative to native conifers such as P merkusii and P kesiya The early plantings clearly demonstrated the excellent potential of P caribaea in Vietnam leading to the establishment of a network of trials from 1976 to the early 1980s in order to provide a more detailed evaluation of the performance of P caribaea, and to investigate provenance variation Of the Pinus species tested in Vietnam, Pinus caribaea has demonstrated superiority in both adaptability and growth rate, and having better stem form and branching characteristics than P kesiya, P massoniana or P merkusii (Le Dinh Kha pers comm.) and is regarded as one of the most promising Pinus species for forest planting in Vietnam (Kha et al 2002) Because of its adaptability, excellent growth and stem form, P caribaea is expected to provide a viable alternative plantation species to Acacia and Eucalyptus on the degraded hills and lowfertility sites of Vietnam, producing long-fibre pulp for paper manufacture as well as highquality sawn timber for construction and furniture production A more recent series of trials was established in the early part of this century to investigate impacts of intensive management on the productivity of P caribaea in an attempt to optimize its performance in plantations This report summarizes results from all relevant trials involving P caribaea established since 1976 across the four major biogeographic regions of Vietnam (northern areas of Vietnam from Hanoi, extending to the border with China; low elevation sites in Central Vietnam; the Central Highlands of Vietnam; and low elevation regions of southern Vietnam in the vicinity of Ho Chi Minh City) on site-types believed to be suitable for pine plantations (Table 1; Figure 1) Summary data is presented from trials established by the Forestry Research Centre (FRC) at Phu Ninh and the Research Centre for Forest Tree Improvement (RCFTI) based in Hanoi This report aims to: summarize all available (relevant) information on the performance of P caribaea in Vietnam; make recommendations regarding the potential suitability of P caribaea varieties in each of the major bio-geographic regions of Vietnam; and identify potential hybrid combinations that may prove successful in Vietnam Trials planted on four sites in the northern region of Vietnam in 1976 Forest Science Institute of Vietnam (FSIV) in Hanoi, and partner organizations in other districts of Vietnam Table 1: Region and location details of P caribaea trials established in Vietnam Location Province Latitude Longitude Elevation (m) 60-90 Rainfall (mm) 1600 Region Thai Long Tuyen Quang 21° 45'N 105° 14'E Yen Kien Phu Tho 21° 35'N 105° 12'E 60-80 1600 North Son Nam Tuyen Quang 21° 33'N 105° 27'E 60-120 1600 North Den Hung Phu Tho 21° 22'N 105° 20'E 50 1600 North Dai Lai Vinh Phuc 21° 10'N 105° 17'E 50 1500 North Ba Vi Ha Tay 21° 07'N 105° 26'E 50 1680 North Dong Ha Quang Tri 16° 50'N 107° 05'E 50 2370 Central Pleiku Gia Lai 13° 59'N 108° 00'E 800 2270 Central Highlands Da Lat Lam Dong 11° 57'N 108° 26'E 1500 1730 Central Highlands Lang Hanh Lam Dong 11° 57'N 108° 26'E 960 1730 Central Highlands Song May Dong Nai 11° 15'N Note: Elevation figures are approximate 107° 06'E 40-60 1640 South-east (near HCM City) North Figure 1: Location of trials evaluating the performance of P caribaea in Vietnam Trials of Caribbean Pine in Vietnam Summary data (site means) are presented for a total of 17 trials established between 1976 and 2001 (Table 2) Summary data were collated from existing trials of P caribaea, many of the trials were inspected by project staff from both Queensland and Vietnam, and additional data were collected from: a) some of the older trials that were regarded as still being viable experiments in order to provide later-rotation data for this review; and, b) relevant species/provenance/management trials established since 2000 (Table 2) For consistency with previous analyses, all data collected in 2006 were analysed on a plot mean basis, and tree volumes were estimated using the following formulae: ⎛ dbh ⎞ Vol = π ⎜ ⎟ × ht × f , ⎝ ⎠ Where diameter at breast height (dbh) and total tree height (ht) are both in decimetres, and a form factor (f) was taken to be 0.5 Based on experience in Queensland, it is likely that use of this generic volume equation will over-estimate the true volume Consequently, volume data presented should be treated with caution However, as all previous analyses had used this form factor, 0.5 was retained to allow comparisons amongst trials Individual tree volumes were summed within each plot, and divided by plot area and age to estimate mean annual increments expressed in m3 ha-1 yr-1 The older trials (i.e those established before 1985) typically included other pine species such as P kesiya, P merkusii and P massoniana for comparison (Table 2) At that time these species had been used the most extensively for plantation establishment in Vietnam – P massoniana in northern Vietnam, and P kesiya and P merkusii in central and southern Vietnam Results of these species comparisons have been previously reported by a number of authors (e.g Ståhl 1988, Dien 1989 and Kha 2003, p 182) and the universal conclusion was that P caribaea is faster growing than alternative Pinus species across a range of sites in Vietnam For example, Dien (1989, p 64) concludes that “Pinus caribaea grew faster than other species on all sites” Consequently, data on the performance of other species in the early trials (1976) planted by FRC have not been included here – full details on the performance of all species in these trials are presented in Ståhl’s (1988) comprehensive report This report will focus on the relative performance of the three varieties of P caribaea and provenance variation within this species Table 2: Listing of all trials used to review the performance of P caribaea in Vietnam No Region Location Trial Type North Den Hung - Phu Tho Species/Provenance trial North Son Nam-Tuyen Quang Species/Provenance trial North Thai Long- Tuyen Quang Species/Provenance trial North Central Yen Kien - Phu Tho Dong Ha - Quang Tri Species/Provenance trial Species/Provenance trial 10 11 North North Central South-East North Central Central Highlands North Central Highlands Dai Lai - Vinh Phuc Dai Lai - Vinh Phuc Dong Ha - Quang Tri Song May - Dong Nai Dai Lai - Vinh Phuc Dong Ha - Quang Tri 12 13 14 15 16 Year Planted No Entries Trees per Plot No Reps Spacing (r×t, m) Last Measure Date Age (yrs) 1976 49 3×3 1984 1976 49 3×3 2002 25 1976 49 3×3 — — 1976 1980 49 3×3 1984 Mar-00 19.3 1981 1982 1984 1987 1987 1988 12 7 49 36 4 3×2 3×2 Mar-00 Jan-00 Mar-00 Apr-06 Jan-00 Mar-00 19.1 17.8 15.7 18.8 12.4 11.4 PCH, PCB, PCC PCH, PCB, PCC 1990 1990 11 10 49 49 3×2 3×2 May-06 Mar-00 16 9.5 PCH, PCC PCB, PCC, PCH, PEE, PEE × PCH F2 PCB, PCH × fertilizer 1991 25 3×2 Mar-00 8.7 Species/Provenance trial Species/Provenance trial Species trial Provenance trial Provenance trial Provenance trial Species/Taxa PCH, PMERK, POOC, PKES PCH, PMERK, POOC, PKES PCH, PMERK, POOC, PKES PCH, PMERK, POOC, PKES PMERK, PCC, PEE PCH, PCC, PMASS, PMERK, POOC, PEE PCH, PCC, POOC, PEE PCH, PMERK PCH PCH PCH Pleiku - Gia Lai Xuan Khanh - Ha Tay Provenance trial Provenance trial Lang Hanh - Lam Dong Provenance trial 49 36 3×2 3×2 North Cam Quy - Ha Tay Taxa comparison trial 1996 36 3×3 Sept-06 2000 15 3×3 Apr-06 North Cam Quy - Ha Tay Intensive management Central 17 Lang Hanh – Lam Dong Species/Provenance trial PCC, PCH, PEE 2001 30 3×2 May-06 Highlands Central 18 Lang Hanh, - Lam Dong) Intensive management PCC, PCH × fertilizer 2001 30 3×2 May-06 Highlands Species/Taxa: PCB = P caribaea var bahamensis, PCC = P caribaea var caribaea, PCH = P caribaea var hondurensis, PEE = P elliottii, PKES = P kesiya, PMASS P massoniana, PMERK = P merkusii, POOC = P oocarpa 10.4 5.8 4.8 4.8 = Growth and Survival The results presented here are a compilation of summary data from trials established over a 25 year period across the length of Vietnam, established for a range of purposes The earlier trials aimed to evaluate the performance of P caribaea in comparison to the local pine species (P kesiya, P merkusii, and P massoniana) The focus of the trials then moved to evaluation of provenance variation within P caribaea, and finally investigation of the growth potential of P caribaea through fertilizer application Due to the long period over which the trials were established, the results are potentially confounded by the low survival (often less than 50%) in many trials that resulted from a combination of effects including: illegal harvesting, fire damage, and possibly inadequate establishment silviculture The differential stocking levels both within and between trials are likely to bias evaluations of diameter and volume production of the taxa at later ages, consequently height data may be the most reliable trait for taxa comparisons Further, no reliable volume equations are available to compare volume differences between species, or between varieties of P caribaea in Vietnam, therefore differences in stem taper and bark thickness will alter rankings of species and taxa In the absence of a reliable volume equation for P caribaea in Vietnam, productivity estimates should only be regarded as approximate Forest Research Centre (FRC, Phu Ninh) Trials Established 1976: Four trials were established by FRC in 1976 in northern Vietnam (Table 2, Trials – 4) to assess species differences and provenance variation within species The trials included all three varieties of P caribaea (4 provenances of PCH, and each of both PCB and PCC, Table 3; however, a fifth provenance of PCH (Alimicamba) was also included at one site but no data are presented for this provenance) The trial planted at Thai Long was damaged by fire in 1977 when the trial was less than years of age, resulting in significant mortality, therefore no results are presented for this site Summary data are presented for the three remaining sites at years of age (Table 4), and the Son Nam site at 25 years of age (Table 5) Table 3: Provenances of P caribaea tested in Forest Research Centre trials Code 202 203 204 205 206 207 Provenance Poptún, Penten, Guatemala (var hondurensis) Guanaja Island, Honduras (var hondurensis) Andros Island, Bahamas (var bahamensis) Cajalbana, Cuba (var caribaea) Mountain Pine Ridge, Belize (var hondurensis) Poptún, Penten, Guatemala (var hondurensis) Longitude 16°22' N Latitude 89°25' W Altitude (m) 500 16°27' N 85°54' W 75 24°30' N 78°20' W 20°30' N 81°31' W 150 17°00' N 88°55' W 400 16°15' N 89°30' W 250 The results indicate that as a species, P caribaea is capable of reasonable growth rates in the northern region of Vietnam, with the best provenance (Mountain Pine Ridge, 206) averaging nearly 20m in height at 25 years of age on the Son Nam site Results observed here indicate relatively little variation in growth rates between the provenances of PCH, but PCC (205) grew rather slowly compared to either PCB or PCH, and does not appear suited to sites in northern Vietnam By contrast PCB had the fastest height growth to years of age (Table 4) and was second only to the Mountain Pine Ridge provenance of PCH at 25 years of age (Table 5) Of the PCH provenances tested, the upland sources from Poptún and Mountain Pine Ridge appear to be better than the Guanaja source Table 4: Mean height and tree volume of P caribaea at years (1984) of age in FRC trials (Trials – 4, refer Table 2) Code 202 Den Hung Volume Height (m) (dm3/tree) 6.1 66 Son Nam Volume Height (m) (dm3/tree) 8.6 207 Yen Kien Volume Height (m) (dm3/tree) 8.9 201 203 5.4 56 8.2 188 9.1 164 204 6.9 65 9.4 184 9.6 213 205 6.5 65 6.4 112 9.0 173 206 5.9 56 8.7 216 9.2 200 207 6.1 68 8.5 206 9.0 193 LSD — — 1.16 47.6 0.75 41.7 Note: Entry 204 = PCB, 205 = PCC, all other entries are PCH Table 5: Mean growth and survival of P caribaea at 25 years of age (2002) at Son Nam site in FRC trials (Trial 2, refer Table 2) Diameter (cm) 26.5 Height (m) 18.3 Volume (dm3/tree) 505 Volume (m3/ha) 382 Survival (tree/ha) 755 203 27.5 17.8 489 245 489 204 24.7 18.5 511 216 511 205 25.5 15.8 422 163 422 206 28.7 19.7 522 323 522 207 27.3 19.5 455 258 455 Code 202 Note: Entry 204 = PCB, 205 = PCC, all other entries are PCH In Ståhl’s (1988) report, he highlights a further complication that is not reflected in the data presented above – “a large difference in the form and tapering between mainly the Bahamas and the var hondurensis provenances The Cuban variety is intermediate.” Generally PCB is much straighter with less taper than PCH both in these trials (as reported by Ståhl, 1988), in Queensland and in other parts of the world It is also likely that PCB has thinner bark than PCH When taken together (better stem form, less taper and thinner bark) it is likely that PCB may produce greater utilizable volume than PCH when grown in the northern region of Vietnam Further, the known superior insect and frost tolerance of PCB may also provide additional benefits over PCH on some sites in the northern region of Vietnam Species and Provenance within Species Trials Established 1980 – 1984: In the early 1980s four species trials and provenance within species trials were established by RCFTI and its partners – two trials in northern Vietnam at Dai Lai and two in central Vietnam at Dong Ha (Table 2, Trials – 8) In the two trials established at Dong Ha in central Vietnam, even though the first trial was unreplicated, P elliottii growth rates were approximately half that of P merkusii (Table 6) at 19 years of age In central Vietnam P elliottii is well south of its natural latitudinal range, and appears to be poorly adapted to sites in central Vietnam This unreplicated trial at Dong Ha only includes the slower growing Cuban variety (PCC) of P caribaea, which did not perform as well as the best provenances of P merkusii on this site In the second trial at Dong Ha (Table 7) only PCH and P merkusii are included, with PCH showing greater height and volume than P merkusii but smaller diameter to 15 years of age A similar trend was also observed in the earlier unreplicated trial (Table 6) where PCC was taller than the best provenance of P merkusii but with reduced diameter Table 6: Mean growth at 19 years of age, in species/provenance trial established at Dong Ha in 1980 (Trial 5, refer Table 2) Diameter (cm) 20.8 Height (m) 9.9 Volume/tree (dm3) 167.4 Bo Trạch – Quang Binh 20.3 9.3 149.6 P merkusii Bac Thai 19.9 8.9 138.0 P caribaea var caribaea Cuba 17.7 11.4 139.6 P merkusii Da Lat – Lam Dong 14.5 6.8 64.5 P merkusii Ha Trung - Thanh Hoa 15.1 9.3 83.2 P elliottii USA 9.5 5.6 19.8 Species P merkusii Provenance/Source Thua Thien Hue P merkusii Note: This trial only contained a single replicate of each species/provenance In the first of the two trials established at Dai Lai in northern Vietnam, the Honduras provenance of PCH was clearly superior in height to all other species; however, overall survival is poor (Table 8) P massonianna was generally second to PCH, followed by P oocarpa and PCC Here P elliottii performs better than at Dong Ha (Table 6), but is still clearly inferior to PCH, PCC and P massoniana The native conifer (P merkusii) did not perform well in comparison to P caribaea or P massoniana at Dai Lai, with substantially less height growth (Table 8) The final trial of this set of four experiments does not include any of the local pine species – only species from the Americas (Table 9) Again the Honduras source of PCH is superior in height growth to the other provenances of PCH, and PCH is similar to P oocarpa in growth rates, but clearly superior to both PCC and P elliottii These results suggest that PCH is likely to be superior in both height and diameter growth to both P merkusii and P massoniana in northern Vietnam, and superior in height growth to P merkusii in central Vietnam PCC was inferior in growth rates to the local pine species and PCH on sites in both central and northern Vietnam P elliottii was poorly adapted to sites in central Vietnam Possibly P tecunumanii – P tecunumanii was not separated taxonomically from P oocarpa until after this trial was established Table 7: Mean growth at 15.6 years of age, in species trial established at Dong Ha in 1984 (Trial 8, refer Table 2) P merkusii Diameter (cm) 19.1 Height (m) 14.1 Volume/tree (dm3) 201.7 21.3 Species P caribaea var hondurensis 10.1 180.0 Table 8: Mean growth and survival at 19 years of age, in species/provenance trial established at Dai Lai in 1981 (Trial 6, refer Table 2) Diameter (cm) 26.5 Height (m) 18.2 Volume/tree (dm3) 516.5 Survival (%) 29 Tam Dao 25.6 16.4 436.5 20 P oocarpa Mexico 25.5 16.6 431.5 24 P massoniana China 23.9 16.2 368.5 21 P massoniana P caribaea var caribaea Yen Lap Quang Ninh Cuba 22.8 22.4 16.3 16.5 344.5 350.5 29 24 22.2 16.7 342.0 27 21.3 20.5 11.0 10.9 205.0 189.5 31 23 Species P caribaea var hondurensis Source/Origin Honduras P massoniana P merkusii P merkusii Loc Binh Lang Son Ha Trung – Thanh Hoa Hue P elliottii USA 20.2 14.4 252.0 22 P merkusii Da Lat 18.4 9.7 148.0 14 22.7 14.8 P massoniana Grand Means 23.8 Note: Results previously reported by Kha (2003, Table 7.6, p 182) Table 9: Mean growth and survival at 17.8 years of age, in species/provenance trial established at Dai Lai in 1982 (Trial 7, refer Table 2) Diameter (cm) 23.2 Height (m) 17.1 Volume/tree (dm3) 392 Survival (%) 15 Poptun 23.7 15.4 385 22 P oocarpa Guatemala 14781 23.7 15.4 354 22 P caribaea var hondurensis Krâ 22.2 15.8 325 19 P oocarpa Mexico 22.1 15.2 313 17 P caribaea var caribaea Cuba 20.3 14.9 247 25 P caribaea var caribaea Krâ 157619 19.9 14.6 233 26 P elliottii PAM 19.8 14 202 17 P elliottii USA16519 18.9 13.6 227 16 21.6 15.1 Species P caribaea var hondurensis Provenance/Source Honduras 16545 P caribaea var hondurensis Grand Means 20.0 Provenance Trials of P caribaea Established Between 1987 and 1991: In the five year period from 1987 to 1991 RCFTI and its partners established six provenance trials of P caribaea: two in northern, one in central, one in south and two in the Central Highlands region of Vietnam (Trials – 14, Table 2) These trials differ from the earlier trials by not testing any local pine species and including Queensland (Australia) and local sources of P caribaea as well as sources from the species natural range Results from these trials between 8.7 and 18.8 years of age (Tables 10 – 15, Figures and 3) indicate that there was relatively little variation between provenances of PCH There is certainly no pattern to the observed growth performance of provenances in these trials – lowelevation sources such as Alamicamba and Guanaja not appear to perform consistently better or worse that higher-elevation sources such and Poptun or Mountain Pine Ridge (MPR) Nor does provenance origin appear to reflect adaptation to site types in Vietnam (particularly low-elevation versus high elevation) with low-elevation sources of PCH performing well on high-elevation sites in the Central Highlands, and higher-elevation sources performing well on low-elevation sites in northern and central regions of Vietnam Two of the trials (Tables 11 and 13) include all three varieties of P caribaea Relative performance of these varieties differed in these two trials – the first in northern Vietnam at Ha Tay, and the second in the Central Highlands at Pleiku In northern Vietnam the mean diameter of PCB was similar to that of PCH but the best PCB provenances had much greater height than the best PCH provenances (Table 11) However, PCC performed poorly compared to both PCB and PCH on this site in northern Vietnam In contrast, in the trial located at Pleiku in the Central Highlands, PCC was the fastest growing of all varieties tested (Table 13) with the largest mean diameter, while PCB generally had the smallest mean diameter and volume This difference between the Ha Tay and Pleiku sites may reflect the differences in age between the trials and differences in the growth curves of these varieties, or differences in stocking Alternatively, the observed differences may reflect true differences in the adaptation of P caribaea varieties to sites in Vietnam – suggesting that the bahamensis variety is better adapted to northern regions, while the caribaea variety from Cuba is better adapted to the Central Highlands By contrast the hondurensis variety appeared to show much greater adaptability than either PCB or PCC, growing well across a wide latitudinal range in Vietnam The improved sources of P caribaea imported from Queensland that were included in these trials have performed equal to or better than the natural sources of PCH tested (Figures and 3) The Queensland seedlots tested are probably derived from first generation clonal seed orchards, largely composed of trees selected in the Mountain Pine Ridge (MPR) provenance from Belize In the first cycle of genetic improvement in Queensland most emphasis was placed on improving the stem form of P caribaea, and comparatively small gains were made in growth rates (Nikles 1996) The results presented in these tables and graphs not reflect improvements in stem form, which were clearly evident when the trials at Pleiku and Song May were remeasured for this report in early 2006 Nevertheless, it is clear that material selected in Queensland, can and does perform well when planted across all sitetypes in (northern, central, central highlands and southern) Vietnam The general performance of the three varieties of P caribaea observed in these trials is entirely consistent with results reported for international provenance trials, where PCH demonstrated much faster growth rates across a wide range of sites than either PCB or PCC, but PCH had inferior stem straightness and generally less resistance to wind-damage (Birks and Barnes 1990) However, the relatively small amount of provenance variation in P 10 caribaea var hondurensis found in this and the earlier series of trials contrasts with that found in previous studies (e.g Birks and Barnes 1990, Dvorak et al 1993, Dvorak et al 2000, Hodge and Dvorak 2001), where large differences were observed between provenances of PCH The limited provenance variation observed in these Vietnamese trials of PCH, may result from the fact that these trials generally included only the faster growing provenances – for example Birks and Barnes (1990) list Guanaja, Alamicamba and Queensland as three of the top five provenances; Crockford et al (1990) report Queensland, Guanaja, Mountain Pine Ridge and Alamicamba as four of the top five provenances; and, Dvorak et al (2000, p 28) list Limón, Queensland, Guanaja, Poptún and Alamicamba amongst the fastest growing provenances By contrast provenances which have previously been reported as having very poor growth potential in international provenance trials (e.g Los Limones, Dvorak et al 2000) were not included in provenance trials in Vietnam Table 10: Mean growth and survival at 12.4 years in P caribaea provenance trial established at Dai Lai (Vinh Phuc, northern VN) in 1987 (Trial 10, refer Table 2) Provenance Guanaja Location Honduras Diameter (cm) 19.3 Height (m) 13.4 Volume/tree (dm3) 224.5 Survival (%) 23 Alamicamba Nicaragua 19.3 13.0 202.5 31 Poptún Guatemala 18.6 13.0 186.5 31 Poptún Guatemala 19.8 12.9 193.0 41 Poptún Guatemala 19.9 13.6 248.0 32 Queensland (M.P.R) Belize 19.5 13.5 214.0 33 M.P.R Belize 19.3 13.1 197.5 47 19.28 13.2 Grand Means 23.8 Note: M.P.R = Mountain Pine Ridge Table 11: Mean growth and survival at 9.5 years of P caribaea provenance trial established in 1990 at Xuan Khanh (Ha Tay, northern VN – Trial 13, refer Table 2) Provenance Abaco CH Diameter (cm) 14.1 Height (m) 10.6 Volume/tree (dm3) 93.3 Survival (%) 29 Abaco NC 13.3 10.5 76.7 41 Andros 13.4 9.1 70.1 40 PCC Cuba 12.7 9.7 64.2 19 PCH Limon, Honduras 14.5 8.8 79.5 11 Alamicamba, Honduras 12.4 8.8 57.9 49 Guanaja Is., Honduras 13.8 8.9 76.1 36 Poptun 2, Honduras 13.3 8.8 65.7 33 Cardwell (T473'O'), Queensland 13.7 8.8 71.4 29 Byfield (R482'CP'), Queensland 13.4 9.4 78.1 39 Grand Means 13.5 9.33 Variety PCB 32 11 Table 12: Mean growth and survival at 12.5 years in P caribaea provenance trial established in 1988 at Dong Ha (Quang Tri, central VN – Trial 11, refer Table 2) Provenance Poptun 1, Guatemala Diameter (cm) 17.7 Height (m) 7.4 Volume/tree (dm3) 98 Survival (%) 61 Poptun 2, Guatemala 19.3 8.4 128 52 Alamicamba, Nicaragua 17.8 7.8 103 645 Guanaja Is., Honduras 16.9 7.5 95 53 M.P.R., Belize 18.5 8.2 117 70 Queensland, Australia 18.3 7.9 110 71 Grand Mean 18.1 7.8 62 Table 13: Mean growth and survival at 16.0 years in P caribaea provenance trial established in 1990 at Pleiku (Gia Lai, Central Highlands – Trial 12, refer Table 2) Diameter Height Volume/tree Volume Survival (m3 ha-1 yr-1) (cm) (m) (dm3) (%) Provenance Code PCB, Abaco PCB 21.8 19.5 386.1 25.8 50 PCB, Andros PCB 20.4 17.7 304.5 24.1 56 23.5 18.7 435.3 25.7 42 PCC, Cuba PCC Alamicamba, Nicaragua ALA 22.2 18.7 381.9 29.3 56 Limon, Honduras LIM 21.4 17.7 345.1 21.8 46 Poptun, Guatemala POP 20.8 18.9 333.4 25.8 56 Byfield R482, Australia BYF 22.2 19.5 403.2 25.0 48 Cardwell T473, Australia CWD 21.3 19.0 359.3 26.4 56 Guanaja, Honduras GUA 22.6 16.7 359.7 18.9 37 Grand Means 21.8 18.5 367.6 24.7 50 SE of Means 1.2 0.6 49.9 3.2 Note: ALA, LIM, POP, BYF, CWD, and GUA are all P caribaea var hondurensis BYF and CWD being improved sources from Queensland, while all other sources originate from the natural range of the species 500 Mean Volume (dm3/tree) MAI (m3 ha-1 yr-1 x 10) Volume 400 300 200 100 P PO PC C An Ab dr os ac o PC B_ M PC B_ LI A G U D C W BY F AL A Figure 2: Performance of P caribaea provenances at 16.0 years established at Pleiku (Gai Lai, Central Highlands) Provenance codes as described in Table 13 12 Table 14: Mean growth and survival at 8.7 years of a P caribaea provenance trial established in 1991 at Lang Hanh (Lam Dong, Central Highlands – Trial 14, refer Table 2) Diameter (cm) 16.4 Ht (m) 11.9 Volume/tree (dm3) 147 Survival (%) 71 Alamicamba, Nicaragua 15.7 10.9 118 66 Limone, Honduras 16.6 11.0 135 61 Poptun, Guatemala 16.6 12.1 144 81 Guanaja Is., Honduras 15.0 9.8 113 Byfield (R482), Australia 20.8 13.3 232 25 Cardwell (T473), Australia 19.8 13.1 209 74 Grand Means 17.4 11.7 Provenance Cuba (PCC) 55.3 Table 15: Mean growth and survival at 18.8 years of P caribaea provenances, established in 1987 at Song Mai (Dong Nai, south-east VN – Trial 9, refer Table 2) Provenance Alamicamba, Nicaragua Code ALA Diameter (cm) 26.5 Height (m) 21.5 Volume/tree (dm3) 646.2 Volume (m3 ha-1 yr-1) 30.4 Survival (%) 43 Guanaja Is Honduras GUA 28.3 21.0 713.4 27.8 30 Poptun 1, Guatemala POP1 28.6 19.5 712.1 22.7 27 Poptun 2, Guatemala POP2 27.1 20.4 647.6 27.6 37 Poptun 3, Guatemala POP3 28.5 19.8 688.5 21.0 26 M.P.R., Belize MPR 26.7 20.1 607.2 19.6 28 Queensland QLD 29.0 21.1 765.7 27.4 31 Grand Means 27.8 20.5 681.7 25.0 32 SE of LS Means 1.1 0.7 62.1 2.7 1000 Mean Volume (dm3/tree) MAI (m3 ha-1 yr-1 x 10) Volume 800 600 400 200 ALA GUA MPR POP1 POP2 POP3 QLD Pinus caribaea var hondurensis Provenance Figure 3: Performance of P caribaea provenances at 18.8 years established at Song May (Dong Nai, south-east Vietnam) Provenance codes as described in Table 15 13 Trials of P caribaea established in Vietnam from 1996 to present: Over the last 10 years a number of trials of P caribaea have been established by RCFTI in Vietnam – including taxa comparison, intensive management, and progeny trials However, for the purposes of this review, we have chosen only those trials that include P caribaea var hondurensis and at least one other species or taxa Trials established during this period focused more strongly on P caribaea var hondurensis than earlier trials, included Vietnamese sources of P caribaea and examined the potential of some hybrid combinations involving PCH The first of these trials was planted in 1996 at Ha Tay in northern Vietnam primarily to evaluate the performance of the Queensland-bred F2 hybrid between PCH and P elliottii This hybrid has performed well compared to both parental species in many parts of the sub-tropics world-wide, including southern China Ten-year data (Table 16) suggests that this hybrid was superior to PEE, similar to PCH, but inferior to PCB in both height, diameter and volume development However, in this test, taxa differences were only significant for height and mean annual increment The good performance of PCB compared to both PCH, PCC and P elliottii on this site in northern Vietnam, is similar to that previously observed in other trials located in this region of Vietnam (Tables 4, and 11) The excellent potential of the Bahamas variety (PCB) is further demonstrated by excellent early growth of this variety compared to both local Vietmanese (Dai Lai) and Queensland sources of PCH, in an intensive management trial planted at Cam Quy (Table 17) This trial investigated the effects of different rates of phosphorus fertilizer (with/without additional NPK) The analysis of variance indicated significant interactions between the fertilizer treatments and the three taxa evaluated in this trial; growth rates were maximized for each taxa under a different fertilizer regime (indicated in bold italics in Table 17) Nevertheless, PCB had the highest maximum growth rates (Figure 4), and the highest average growth rates across all fertilizer treatments Further, growth of PCB maximized at lower fertilizer application rates than did PCH – 150g P205 per tree, compared 450g/tree in case of Dai Lai PCH, and 200g/tree of P205 + 200g/tree of NPK for Queensland PCH This suggests that PCB is able to obtain higher growth rates than PCH in northern Vietnam with lower fertilizer inputs Table 16: Mean growth and survival at 10.3 years in taxa comparison trial established in 1996 at Cam Quy (Ha Tay, northern Vietnam – Trial 15, refer Table 2) Seeds of all taxa were obtained from Queensland (Table 7.8 from Kha 2003) Height (m) 8.70 Diameter (cm) 14.68 Volume/tree (dm3) 82.37 Volume (m3 ha-1 yr-1) 7.63 Survival (%) 86 P caribaea var bahamensis (PCB) 9.24 15.21 89.79 8.41 87 P caribaea var caribaea (PCC) 8.10 13.34 62.63 6.00 89 P caribaea var hondurensis (PCH) 8.62 14.83 82.13 5.54 71 P elliottii (PEE) 8.25 14.58 74.96 6.03 79 SE of LS Means 0.25 0.76 9.41 0.77 09 Grand Means 8.58 14.52 78.38 6.76 82 Species / Taxa PEE × PCH F2 Hyrbrid 14 Table 17: Mean growth and survival at 5.8 years of age in P caribaea fertilizer trial planted in 2000 at Cam Quy, Ha Tay (northern Vietnam; Trial 16 – refer Table 2) Height Diameter Volume/tree Volume Survival (m3 ha-1 yr-1) (m) (cm) (dm3) (%) 4.7 6.9 12.5 2.1 83 P caribaea var 6.5 10.1 27.5 4.5 85 bahamensis (ex 6.2 9.7 24.6 3.9 82 Queensland) 5.8 9.0 19.5 3.1 80 6.0 8.8 21.1 3.9 97 6.3 9.4 24.8 4.6 97 6.3 9.4 23.6 4.2 92 6.2 9.2 23.8 4.2 92 Means 6.0 9.0 22.2 3.8 88 5.1 8.8 17.5 2.2 67 P.caribaea var 4.8 7.2 12.7 1.8 65 hondurensis (ex Dai 5.0 8.5 17.6 2.8 85 Lai) 5.4 8.7 20.8 2.8 68 4.6 7.9 13.5 1.4 42 4.7 8.2 14.4 2.1 77 4.9 8.1 15.3 2.3 75 4.3 6.8 10.5 1.4 70 Means 4.8 8.0 15.3 2.1 69 4.6 6.9 12.4 1.5 62 P caribaea var 4.8 8.1 16.1 1.8 60 hondurensis (ex 4.8 8.5 15.8 2.2 73 Queensland) 4.6 7.6 13.3 1.7 68 4.9 9.0 19.7 2.0 53 4.9 7.5 14.5 1.6 52 5.4 9.0 20.5 2.4 60 5.4 8.7 19.2 1.8 53 Means 4.9 8.2 16.4 1.9 60 Grand Means 5.3 8.4 18.0 2.6 72 SE of LS Means 0.3 0.5 2.5 0.4 Note: Fertilizer × taxa interactions significant (p < 0.05) for diameter, height and volume/tree Fertilizer treatments: nil, P2O5 150g, P2O5 300g, P2O5450g, P2O5 200g + NPK, P2O5 200g +50g NPK, P2O5 200g +100g NPK, P2O5 200g +150g NPK for treatments 1, 2, … , respectively Fert Tmt 30 28 26 Mean Volume (dm3/tree) Taxa 24 22 20 18 16 14 12 10 8 10 Fertilizer Treatment PCB PCH 1160 PCH Dai Lai Figure 4: Mean growth at 5.8 years of age in P caribaea fertilizer trial at Cam Quy (refer Table 17) 15 The final two trials to be considered were planted adjacent to one another on a site at Lang Hanh, Lam Dong Province The first trial compared PCH, PCC, the F2 hybrid between P elliottii (PEE) and PCH, and P elliottii The second trial compared the performance of PCC and PCH under three different fertilizer regimes Considered together, these two trials clearly demonstrate the superiority of PCH over PCC on sites in the Central Highlands of Vietnam – to years of age PCC performed very poorly compared to PCH (Tables 18 and 19) Again P elliottii is showing poor adaptation to sites in the Central Highlands The hybrid between P elliottii and PCH grew poorly compared to PCH on this high elevation site in Central Vietnam It appears that like P elliottii this hybrid combination with P elliottii is poorly adapted to low latitudes of central Vietnam There were only relatively small differences in the growth of the Vietnam and Queensland sources of PCC and PCH evaluated in the Cam Quy (Table 17) and Lang Hanh (Tables 18 and 19) trials Probably of most interest in this result is not the small difference observed between material of Queensland and Vietnam origin, but rather that material selected in two different countries performed similarly when tested in diverse environments in Vietnam Application of phosphate fertilizer to the Lang Hanh trial markedly increased the growth rates of both PCC and PCH; only with the addition of NPK fertilizer did the growth of PCC begin to approach that of PCH Addition of fertilizer almost doubled volume increments to years of age; however addition of NPK appeared to have an adverse impact on survival in both varieties and growth in PCH (Table 19) This suggests substantial benefits from the application of phosphorus fertilizer to enhance growth rates of P caribaea, as previously reported for a similar trial located in northern Vietnam (Table 17) Table 18: Mean growth and survival at 4.8 years of age in P caribaea variety/provenance trial planted in 2001 at Lang Hanh (Lam Dong, Central Highlands; Trial 17 – refer Table 2) Height (m) 3.1 Diameter (cm) 4.7 P caribaea var caribaea (ex Vietnam, Dong Ha) PEE × PCH F2 Hybrid (ex Queensland) 3.5 5.6 4.8 1.1 64 3.4 5.4 4.7 1.1 68 P caribaea var hondurensis (ex Queensland) P caribaea var hondurensis (ex Vietnam, Dai Lai) P elliottii 4.5 7.2 10.8 2.6 71 4.2 6.9 9.2 1.7 53 2.6 4.1 2.2 0.4 36 Grand Means 3.5 4.6 5.8 1.3 58 SE of LS Means 0.2 0.3 0.6 0.2 Taxa P caribaea var caribaea (ex Cuba) Volume/tree Volume (m3 ha-1 yr-1) (dm3) 3.2 0.7 Survival (%) 58 16 Table 19: Mean growth and survival at 4.8 years of age in P caribaea fertilizer trial planted in 2001 (Trial 18 located adjacent to Trial 17 – refer Table 2) Taxa Height (m) 3.2 Diameter (cm) 5.8 Volume/tree (dm3) 4.7 Volume (m3 ha-1 yr-1) 0.9 Survival (%) 57 4.0 6.7 8.5 1.7 57 4.0 7.4 9.9 0.7 23 4.3 7.5 11.0 1.8 49 5.1 8.6 16.6 3.1 56 4.4 7.3 10.9 1.5 39 4.0 7.0 9.1 1.7 50 4.9 8.2 14.9 2.7 48 P caribaea var caribaea (PCC, ex central Vietnam) Fert Tmt 4.2 7.0 13.3 1.5 30 0.4 0.7 2.7 0.6 11 P caribaea var hondurensis (PCH, ex Queensland) P caribaea var hondurensis (PCH ex northern Vietnam) SE of LS Means 4.2 7.3 11.0 1.7 45 Grand Means Note: Fertilizer × taxa interactions not significant Fertilizer Treatments: = Nil Control; = 300g phosphate/tree; = 200g phosphate plus 100g NPK per tree Key Findings & Proposed Future Directions Species/Taxa Performance The results presented from the older trials of P caribaea indicate the excellent potential of P caribaea for commercial plantation forestry in Vietnam Estimated volume production may be imprecise due to a number of factors (e.g lack of reliable volume equations, illegal thinning, and low survival rates in some trials); nevertheless, it is clear that P caribaea var hondurensis (PCH) and/or P caribaea var bahamensis (PCB) were superior to alternative pine species on test sites in northern Vietnam, while PCH was clearly superior to other pines on both low- and high-elevation sites of central Vietnam and low-elevation sites in southern Vietnam PCH demonstrated wide adaptability, but appeared to be particularly well adapted to sites in the central and southern regions of Vietnam PCB performed well compared to PCH in the north, but on the basis of the trial results presented P caribaea var caribaea (PCC) does not appear to offer any advantages over either PCH or PCB for plantations in Vietnam In northern Vietnam PCB may be superior to PCH, because: Trial results from northern Vietnam suggest that PCB has the potential to equal or exceed the growth rates of PCH in the north; Higher growth potential with lower fertilizer inputs; Excellent stem form as noted by Ståhl (1988); Resistance to damage from both tip moth and frost, which may be contributing to good growth of PCB on sites in northern Vietnam Hybrids between PCB and PCH may prove very useful in northern Vietnam – this hybrid has performed well on some sites in Queensland, combining the faster growth rate of PCH with the superior stem form of PCB However Asian pines such as P merkusii and P massoniana are highly valued for resin production Although P caribaea consistently demonstrated substantially greater growth potential than P merkusii, P massoniana and P kesiya, the suitability of P caribaea for resin production needs to be evaluated Hybrids between local species and PCH (e.g PCH × P 17 merkusii, × P kesiya or × P massoniana) may potentially combine superior growth of P caribaea with the high quality resin production of the local species; however, initial attempts to produce these hybrids have been largely unsuccessful Based on experience in Queensland, P tecunumanii and hybrids between P caribaea and P tecunumanii are likely to perform well in tropical regions of central and southern Vietnam (Gwaze et al 1999, Brawner et al 2005) The hybrid between P caribaea and P elliottii has not demonstrated any clear advantage over PCH and/or PCB in early results from a single trial at Cam Quy, in northern Vietnam However this hybrid has performed well compared to P massoniana on sites in Guangxi near the border between China and Vietnam Therefore, further evaluation of the potential of the PEE × PCH hybrid compared to PCH, PCB and PCH × PCB is required to clarify its suitability in northern Vietnam It is unlikely that any hybrid involving P elliottii will perform well on sites in either central or southern Vietnam given the very poor performance of P elliottii in trials in these regions Breeding and Tree Improvement Activities Future breeding efforts should focus on PCH and PCB (and possibly the hybrid between these two varieties) for northern Vietnam, and PCH for deployment in central (including Central Highlands) and southern Vietnam Development and testing of other hybrid combinations is likely to be difficult and potentially beyond the capacity of local resources, and so should only form a minor component of future breeding and tree improvement activities in Vietnam Relatively little variation was observed between the provenances of PCH tested in Vietnam, and sources derived from Queensland were equal to, or slightly better than, either the best natural provenances or local sources of PCH However, the set of PCH provenances that were tested are amongst the best provenances of PCH in both the Oxford and CAMCORE series of international provenance trials This suggests that a genetic improvement program for P caribaea in Vietnam would benefit from: Local phenotypic selection of the best PCH individual trees regardless of provenance origin All PCH provenances represented in trials are likely to contribute valuable genes to the future genetic improvement of this species in Vietnam Inter-provenance hybrids may also provide additional vigour compared to within provenance crosses (Johnston et al 2003) Importation of genetically improved material of PCH that has been selected and bred in Queensland – this material is genetically diverse, originates largely from a different provenance to many of the PCH plus-trees selected in Vietnam (i.e Mountain Pine Ridge vs Poptun provenances), and has been intensively selected for stem-straightness as well as resistance to wind-damage Importation of genetic material of PCB from Queensland (or southern China) to increase the genetic diversity of this variety in Vietnam Both Queensland and Guangxi received seedlots collected by the Oxford Forestry Institute across the range of PCB in the Bahamas Establishment of commercial plantations of P caribaea in Vietnam is limited by the availability of high-quality seed To support an expanded plantation program with P caribaea in Vietnam a reliable source of genetically improved planting stock is required Results presented here demonstrate that genetically improved material from Queensland has excellent potential across a wide range of sites in Vietnam Consequently, importation of orchard-grade seed from Queensland will provide an immediate source of high quality planting stock Orchard-grade seed of PCH produced in other countries (e.g Brazil and South 18 Africa) may also provide similar advantages but has not been tested in Vietnam Further, importation of seed from countries such as South Africa may present unacceptable quarantine risks due to the presence of pitch canker Development of local sources of genetically improved planting stock should receive an immediate priority: Continued development of PCH clonal seed orchards in coastal areas of central Vietnam known to be suitable for seed production in this species Progeny testing of all potential seed orchard parents to provide field test data as soon as possible Expansion of the PCB breeding populations and establishment of clonal seed orchard(s) in northern Vietnam Vegetative propagation of elite PCH material – e.g control-pollinated seed from crosses amongst the most outstanding locally selected plus-trees – to provide an immediate source of high-quality planting stock Acknowledgements Support and funding for this project is provided by AusAID and the Ministry of Agriculture and Rural Development via the CARD project 033/05VIE Data presented has in some cases been previously published, and appropriate acknowledgements provided in the text where ever this was known The many insights and constructive suggestions provided by Prof Le Dinh Kha to this report are gratefully acknowledged Miss Nghiem Quynh Chi has provided invaluable support to completion of this review through organization and assistance with travel and project meetings related to the project, and translation of this report into Vietnamese References Baylis, W B H and R D Barnes (1989) International provenance trials of Pinus caribaea var bahamensis In: Breeding tropical trees: Population structure and genetic improvement strategies in clonal and seedling forestry Proc IUFRO Conf., Pattaya, Thailand, November 1988 (Eds Gibson, G.L., Griffing, A.R and Matheson, A.C.) Oxford Forestry Institute/Winrock International, Arlington VA pp 283-290 Birks, J S and R D Barnes (1990) Provenance variation in Pinus caribaea, P oocarpa and P patula ssp tecunumanii University of Oxford, Tropical Forestry Papers No 21, Oxford Forestry Institute, Department of Plant Sciences 40 p Brawner, J T., M J Dieters and D G Nikles (2005) Mid-rotation performance of Pinus caribaea var hondurensis hybrids with both P oocarpa and P tecunumanii: hybrid superiority, stability of parental performance and potential for a multi-species synthetic breed Forest Genetics 12(1): 1-13 Dieters, M J and D G Nikles (1997) The genetic improvement of Caribbean pine (Pinus caribaea Morelet) - building on a firm foundation In: Proc 24th Southern Forest Tree Improvement Conference, Orlando, FL., June 10 - June 12, 1997 Gainesville, Fl, University of Florida, pp 33-52 Duncan, P D., T L White, and G.R Hodge (1996) First-year freeze hardiness of pure species and hybrid taxa of Pinus elliottii (Engelman) and Pinus caribaea (Morelet) New Forests 12: 223-241 Dvorak, W S., K D Ross and Y Lui (1993) Performance of Pinus caribaea var hondurensis in Brazil, Colombia and Venezuela Bulletin on Tropical Forestry No 11 Raleigh, NC, CAMCORE, North Carolina State University 47 p Gibson, G L (1982) Genotype-environment interaction in Pinus caribaea University of Oxford, Commonwealth Forestry Institute, Department of Forestry 112p 19 Gwaze, D P (1999) Performance of some interspecific F1 pine hybrids in Zimbabwe Forest Genetics 6(4): 283-289 Hodge, G R and W S Dvorak (2001) Genetic parameters and provenance variation of Pinus caribaea var hondurensis in 48 international trials Canadian Journal of Forest Research 31: 496-511 Johnston, A J., M J Dieters, H S Dungey and H M Wallace (2003) Intraspecific hybridization in Pinus caribaea var hondurensis I Performance for growth and form traits Euphytica 129: 147-157 Kha, L.D., Phi Quang Dien, Doan Van Nhung (1989) Growth of Pinus caribaea in Vietnam In: Breeding tropical trees: Population structure and genetic improvement strategies in clonal and seedling forestry Proc IUFRO Conf., Pattaya, Thailand, November 1988 (Eds Gibson, G.L., Griffing, A.R and Matheson, A.C.) Oxford Forestry Institute/Winrock International, Arlington VA pp 376 Kha, L.D., Phi Quang Dien, Phan Thanh Huong, Can Thi Lan (2002) Prospects of introduction of Pinus caribaea into Vietnam Journal of Agriculture and Rural Developmant, April 2002, pp 340-342 Kha, L.D (2003) Selection, breeding and propagation of some main plantation tree species in Vietnam Agricultural Publishing House, Hanoi, Vietnam 292 p Nikles, D G (1966) Comparative variability and relationship of Caribbean pine (Pinus caribaea Mor.) and slash pine (Pinus elliottii Engelm.) Raleigh, NC, PhD Thesis, Dept of Forestry, NCSU 201 p Nikles, D G (1996) The first 50 years of the evolution of forest tree improvement in Queensland In Tree Improvement for Sustainable Tropical Forestry Proc QFRIIUFRO Conf., Caloundra, Queensland, Australia 27 October-1 November 1996 (Eds M J Dieters, A C Matheson, D G Nikles, C E Harwood and S M Walker) Gympie, Queensland Forestry Research Institute pp 51-64 Phi Quang Dien (1989) Pine species and provenance trial in Viet Nam Forest Genetics and Tree Breeding Department, Forest Science Institute of Vietnam, Hanoi 76p Ståhl, P (1988) Species and provenance trials on pine 1976-1984 Vinh Phu, Vietnam 54p 20 ... evaluation of the performance of P caribaea, and to investigate provenance variation Of the Pinus species tested in Vietnam, Pinus caribaea has demonstrated superiority in both adaptability and growth... information on the performance of P caribaea in Vietnam; make recommendations regarding the potential suitability of P caribaea varieties in each of the major bio-geographic regions of Vietnam; and identify... (Tables 11 and 13) include all three varieties of P caribaea Relative performance of these varieties differed in these two trials – the first in northern Vietnam at Ha Tay, and the second in the Central