REVIEW OF PROVENANCE VARIATION IN GROWTH OF ACACIA MANGIUM Willd¹

C.E. Harwood and E.R. Williams
CSIRO Division of Forestry
P.O. Box 4008, QVT, Canberra 2600
Australia

ABSTRACT

This paper reviews the performance of FAO/CSIRO-coordinated international provenance trials of Acacia mangium established in the 1980s. Data from a total of 19 trial sites in South East and South Asia, Australia and Fiji were studied. A total of 24 local provenances from five provenance regions, including two provenances from Papua New Guinea (PNG), 19 from Queensland, Cairns Region (QCR), and one each from Far North Queensland (FNQ), Ceram (CERAM) and Irian Jaya (IRIAN), were tested. None of the trials tested all 24 provenances, and the subsets tested varied from site to site. Analysis of variance of height and/or dbh for individual trial sites showed significant differences among provenances tested at every trial site.

Height and diameter growth data were converted to mean annual increments for an analyses of variance across trial sites. There were highly significant differences in performance between experimental sites, between provenance regions, and among the local provenances within provenance regions. Growth was generally faster at near-equatorial trial sites, with mean annual increment in height around 3–4 m, and slower at sites further from the equator in Bangladesh, South China, the Island of Taiwan and Fiji. PNG provenances were consistently the best performers, closely followed by the Claudie River provenance from FNQ. Provenances from the QCR provenance region (16–18°30 S) and the CERAM and IRIAN provenances were almost always slower-growing than PNG and FNQ.

INTRODUCTION

Acacia mangium Wild has become an important plantation species in the humid tropics over the last two decades. Seed collections for international provenance trials were coordinated by CSIRO and FAO in the early 1980s (Doran and Skelton 1982; Turnbull et al. 1983). Published results from a number of provenance trials (Atipanumpai 1989; Chung et al. 1990; Hadi et al. 1990) have shown substantial differences in the growth performance of different natural provenances. Enquiries were made by the Australian Tree Seed Centre in 1990 to obtain the latest data sets from all known trials of the FAO/CSIRO seedlots. The replies received included several with previously unpublished data, enabling an analysis of growth performance of provenances across a wide range of tropical sites.

MATERIALS AND METHODS

Provenances tested

Details of the A. mangium provenances included in the trials are provided in Table 1. Estimates of key climatic parameters for provenance locations in Queensland and Papua New Guinea (PNG), calculated using the BIOCLIM computer program (Booth et al. 1988), are presented in Table 2.

Seedlots tested were all bulks from at least five well-spaced parent trees (10 or more parents in most cases), and may be considered as representing local provenances. They can logically be assigned among five geographically separate provenance regions. The term provenance region is used here to denote a broad geographic area of natural occurrence, and does not imply that local provenances from within the provenance region will necessarily have similar genetic characteristics (Turnbull and Griffin 1984). The provenance regions are as follows:

Queensland Cairns Region (QCR) - the southern occurrences of A. mangium along the east coast of Queensland, Australia, south of latitude 15 °S. In this provenance region there are many small to medium-sized populations marginal to rainforest, occurring over 3 degrees of latitude to around 18°30 S and from sea level up to about 400 m altitude. Nineteen seedlots were included in the trials.

Far North Queensland (FNQ) - north of latitude 13 °S. Limited occurrences along the margins of riverine rainforest along rivers flowing to the eastern and western sides of Cape York, including the Claudie, Pascoe, Wenlock, Olive and Jardine Rivers. A single six-tree collection from Claudie River was tested in the trials.

Papua New Guinea (PNG) - A. mangium extends across the southern lowlands of Western Province, Papua New Guinea. It is a common species here, occurring locally in populations of varying size on better-drained sites. The Western Province populations are contiguous with extensive populations in south eastern Irian Jaya (Gunn and McDonald 1991). The two PNG seedlots used in the trials were separated from one another by about 180 km.

Ceram, Indonesia (CERAM) - A. mangium occurs on the island of Ceram in Indonesia. A small population near Piru was sampled (Turnbull et al. 1983).

Irian Jaya, Indonesia (IRIAN) - A single, small (15 ha) population at Sidei on the Vogelkop Peninsula of Irian Jaya in Indonesia (Turnbull et al. 1983).

Trial sites

Information on the trial sites is given in Table 3. Data was available from sites in Borneo (Sabah, Sarawak and South Kalimantan), Thailand, South China, the Island of Taiwan, Bangladesh, Melville Island in the far north of Australia, and Fiji. It is hoped to include data from trials in Central America, peninsular Malaysia, the Philippines, the Solomon Islands and West Africa in a subsequent paper.

RESULTS

Analysis of data from individual trials

Table 4 shows which seedlots were tested at each trial site. In addition to the different combinations of seedlots tested, there were differences between sites in silvicultural techniques such as rates of fertilizer application and weeding schedules, which undoubtedly affected growth rates. These factors make comparisons of the growth potentials of different sites only approximate.

All the trials reported here used replicated randomised complete block designs, although the size and shape of plots and the number of replications varied. Analysis of variance for each individual trial site was carried out either by the organization managing the trial, or in the course of this study. There were statistically significant differences among provenances for height and/or diameter at breast height (dbh) at every trial site (height was not measured at two of the sites and dbh not measured at one). It is assumed that for multi-stemmed individuals, dbh was the equivalent single-stem dbh (i.e. the diameter producing the same basal area). This assumption has yet to be confirmed for all sites.

Survival rates at the time of measurement were high at most sites, as summarised below:

Age at the time of measuring varied from 1.5 to 7 years, but was around 3 to 4.5 years in most cases. Examination of time series growth data from the trials at Taiwan (2.5, 3.5 and 4.5 years) and Barito, South Kalimantan (2 and 7 years) indicated that growth rates in height and diameter were constant over the first few years after planting at these sites. This suggested that comparisons between sites of mean annual increments (MAIs) would be little affected by the between-site differences in age of measurement. MAI in height and diameter was therefore calculated for each provenance at each trial site and this data was further analyzed.

Analysis of variance across sites and provenances

Because eight of the provenances in Table 1 were missing from all the Borneo sites and another five provenances present at only one of the Borneo sites, it was decided to partition the analysis into two separate analyses, one for the twelve Borneo sites, and another for the remaining seven sites in the other countries where there was a much fuller representation of provenances. The two analyses of variance looked at variation between sites, provenance regions, provenances within provenance regions (i.e. the 13 provenances in the QCR provenance region, and the two provenances in the PNG provenance region), and the interaction between sites and provenance regions.

For both height MAI and dbh MAI, and for both the Borneo and “non-Borneo” analyses, there were highly significant differences (P<0.001) between sites, between provenance regions and between provenances within provenance regions. The interaction of sites and provenance regions was also highly significant (P<0.001) for the Borneo sites but only barely significant (P<0.05) for height MAI and not significant for dbh MAI for the “non-Borneo” sites. The analyses of variance will be reported in more detail in a later publication.

Summary of performance of provenance regions across trial sites.

The performance of the five provenance regions at the different trial sites is summarised in Table 5, and illustrated for the “non-Borneo” sites in Figures 1 and 2. The MAIs shown for QCR and PNG provenance regions are the averages of the individual seedlots from those provenance regions tested at each site. As different sub-groupings of provenances from QCR and PNG were tested at different sites, the comparisons across sites are not exact.

There is a clear trend of more rapid growth at sites close to the equator, with height MAI of around 4 m at some sites. Growth at sites close to the tropic of Capricorn in South China, the Island of Taiwan and Bangladesh, and in Fiji (17°50 S) is much slower, with height MAI of only around 1–2 m. In South China, the slower growth at Leilin relative to Haikang is attributable to lower soil fertility at Leilin (Pan Zhi-gang, pers. comm. 1990).

A consistent difference in the performance of the provenance regions is also apparent. PNG was almost always the best provenance region where it was tested, although it was only included at two trial sites in Borneo. The single FNQ provenance also performed well everywhere it was included, but with slightly slower growth than PNG at most locations. These trends held true for both height and diameter increment, so the advantage in volume production of PNG and FNQ over the other three provenance regions was substantial in most cases. Results of a provenance trial in Ivory Coast, West Africa, summarised by Souvannavong (1990) are in accordance with the general trend of the superior performance of the PNG and FNQ provenances, relative to the other three regions.

At the trial sites in the Island of Taiwan and South China, one or two individual QCR provenances grew faster than PNG and FNQ, but the differences were not significant. CSIRO nos. 13237 and 13239 were the best QCR provenances in the Island of Taiwan, while 13242 was best at both sites in South China. CSIRO no. 13242 also performed as well as the two PNG provenances in Bangladesh. At Sabah Forest Industries sites A and B, the FNQ provenance was outperformed by the CERAM seedlot and one or two QCR provenances, but again these differences were not significant. At every other trial site where they were included, PNG and FNQ outperformed CERAM, IRIAN and all QCR provenances. It must be kept in mind, however, that the FNQ provenance region is only represented in these trials by a single six-tree seedlot.

The relative performance of QCR, CERAM and IRIAN was variable, with generally better performance of CERAM and IRIAN at sites closer to the equator, while QCR provenances outperformed them in South China, the Island of Taiwan, Bangladesh, Fiji and Melville Island, Australia.

Form

Form assessments are not yet available for many of the trial sites, so an analysis of site and provenance differences in form has not been attempted at this stage. The percentages of trees with single stems to two trial sites in Sabah, the site at Melville Island, Australia, and the trial in Ivory Coast, West Africa (Souvannavong 1990), are tabulated in Table 6 to illustrate the range of variation in form among provenances and the substantial differences that occur between sites.

DISCUSSION

It is clear from the results of the trials reported here, and other subsequent provenance trials, that there are substantial genetic differences between provenance regions and local provenances, because of the consistent and significant differences in their growth performance. Isozyme analysis indicates that A. mangium has low genetic diversity (Moran et al. 1989). Isozyme studies only examine a small sub-set of the genome, and therefore do not provide an absolute measure of overall genetic variation. However, it may be noted that the two Indonesian provenances had the lowest isozyme diversity and the poorest performance in the provenance trials. Their poor performance might well be due to inbreeding in populations derived from a narrow genetic base, perhaps founded from only one bird-transported seed or possibly by human introduction.

The growth rate of PNG provenances remained higher than that of most QCR provenances at trial sites with cooler winter climates in the Island of Taiwan and South China. Slower growth of PNG relative to QCR at these sites might be anticipated on the grounds that QCR provenances would be better adapted, because they originate from climates with cooler winters (Table 2). While a few QCR provenances did outperform PNG and FNQ in China and the Island of Taiwan, differences were not significant, and as noted above the interaction between provenance regions and experimental sites for the “non-Borneo” sites was only barely significant for height MAI and not significant for diameter MAI.

It was noteworthy that growth at Sabah Forest Industries trial site D, altitude 1000 m and estimated mean temperature of 20°C, was much faster (height MAI 3.46 m) than growth at the Bangladesh, South China and Taiwan sites where mean annual temperatures are in the range 22–24°C, but height MAIs were only 1–2 m. It appears that low winter temperatures halt growth for several winter months at subtropical sites (You Yintian 1989), while growth continues year-round in the mild conditions at the high-altitude equatorial site in Sabah where there is little seasonal variation in temperature. However, poor apical dominance at the highaltitude Sabah site results in trees of poor form with multiple stems (Table 6; Sim Boon Liang, pers. comm. 1990). In Thailand, periods of low diurnal temperature range are associated with rapid diameter growth, although it is hard to separate this effect from seasonal variations in rainfall (Atipanumpai 1989).

Since the international trials reported here were conducted, seed collections for further research including single-tree collections from a total of several hundred parent trees have been undertaken by the Australian Tree Seed Centre in many natural provenances of A. mangium, particularly in the PNG, FNQ and QCR provenance regions (Gunn and Midgley 1991; Gunn and McDonald 1991). The individual tree collections have been used to establish the base populations of a number of breeding programs. However, nothing is known to date about the genetic gains in growth and form that may be obtained by crossing between different provenance regions of A. mangium.

ACKNOWLEDGEMENTS

We are very grateful to those organizations and individuals listed in Table 3 who provided trial data, much of it unpublished. Dr. Garth Nikles assisted in assembling the data and provided valuable comments on an earlier draft of this paper. Mr. Patrick Milimo assisted with data compilation, and Mr. Tom Jovanovic calculated climatic parameters for provenance origins using the BIOCLIM computer programme. The Seeds of Australian Trees project, funded by the Australian International Development Assistance Bureau and managed by the Australian Tree Seed Centre, provided resources to enable the preparation of the paper.

REFERENCES

Atipanumpai, L. (1989). Acacia mangium: Studies on the genetic variation in ecological and physiological characteristics of a fast-growing plantation species. Acta Forestia Fennica 206.

Booth, T.H., Hutchinson, M.F. and Jovanovic, T. (1988). Niche analysis and tree species introduction. Forest Ecology and Management 23, 47–59.

Chung, Jeng-Der, Hsui, Yen-Ray, Chang, Tein-Yuang and Yang, Jenq-Chuan (1990). Provenance variation of tree height, dbh and volume in A. mangium at young ages. Quarterly Journal of Chinese Forestry. 23, 77–86.

Doran, J.C. and Skelton, D.J. (1982). Acacia mangium seed collections for international provenance trials. Forest Genetic Resources Information 11, 48–50. FAO, Rome.

Gunn, B.V. and McDonald, M.W. (1991). Seed Collections of Eucalyptus urophylla, E. pellita and Acacia species from Indonesia, August-November 1990. Australian Tree Seed Centre.

Gunn, B.V., and Midgley, S.J. (1991). Progress in seed supply of 4 selected tropical Acacia species by the Australian Tree Seed Centre. Paper to ACIAR Workshop on Tropical Acacias, Bangkok, Feb. 11–15 1991.

Hadi, T.S., Adjers, G. and Vuokko, R. (1990). Performance of different provenances of Acacia mangium at 30 months after planting on an alang-alang (Imperata cylindrica) grassland site in South Kalimantan, Indonesia. Technical Report II/IV, June 1990, Indonesian Ministry of Forestry, Directorate General of Reforestation and Land Rehabilitation.

Miller, R.R. and Hepburn, A.J. (1989). A review of the growth of Acacia Mangium at the Bengkoka afforestation and settlement project, North Sabah. Regional Symposium on Recent Development in Tree Plantations of Humid/Subhumid Tropics of Asia. Universiti Pertanian Malaysia, 5–9 June 1989.

Moran, G.F., Muona, O. and Bell, J.C. (1989). Acacia mangium: A tropical forest tree of low genetic diversity. Evolution 43, 231–235.

Souvannavong, O. (1990). Recherches sur Acacia mangium Willd., especé de plantation d'avenir en zones tropicales humides d'Afrique centrale et occidentale. pp. 79–91, Vol. 1(2), IUFRO 19th World Congress, Montreal.

Turnbull, J.W. and Griffin, A.R. (1986). The concept of provenance and its relationship to infraspecific classification in forest trees. pp. 157–189 in B.T. Styles (ed.) Infraspecific classification of wild and cultivated plants. The systematics Association Special Volume no. 29. Clarendon, Oxford.

Yuo Yintian (1989). Introduction and utilization of Acacia mangium in China. Chinese Academy of Forestry Report, 277p.

Zashimuddin, M., Latif, M.A., Khan, S.A. and Davidson, J. (1985). Performance of different provenances of Acacia mangium Wild in Bangladesh. Bano Biggyan Patrika. Forest Research Institute, Chittagong, Bangladesh. 12. 57–61.

¹ Manuscript received June 1991

Table 1. List of provenances included in A. mangium international provenance trials.

¹ Seedlot identifier number used by CSIRO's Australian Tree Seed Centre.

² Provenance Regions : QCR = Queensland Cairns region
PNG = Papua New Guinea
CERAM = Ceram, Indonesia
FNQ = far north Queensland
IRIAN = Irian Jaya, Indonesia

³ Number of parent trees represented in provenance seedlot.

Table 2. BIOCLIM estimates of climatic parameters for provenance locations in Queensland and Papua New Guinea

*MAT      = mean annual temperature
*MMTHM = mean maximum temperature of hottest month
*MMTCM = mean minimum temperature of coldest month
*MAP      = mean annual precipitation
*MPDQ    = mean precipitation of driest quarter

Climatic data for CERAM and IRIAN could not be estimated.

Table 3. Trial sites included in the analysis

a)   Information on the trial sites is given below, ranked as follows: Site code(s) (underlined), location, organization conducting trial and source of information.

1. SbA, SbB, SbC, SbD, Sipitang, Sabah, Malaysia (4 trial sites), Sabah Forest Industries. Sim Boon Liang (pers. comm. 1990)

2. Sfda, Bengkoka, Sabah, Malaysia, SAFODA. Miller and Hepburn (1989)

3. Swk1, Swk2, Swk3, Swk4, Swk5, Sarawak, Malaysia (5 trial sites), Forest Department, Sibu, Sarawak. Forest Silviculturist (pers. comm. 1990)

4. Sk1, South Kalimantan, Indonesia, Enso/Indonesian Ministry of Forests. Hadi et al. (1990)

5. Sk2, South Kalimantan, Indonesia, Barito Group. P. Havmoller (pers. comm. 1991)

6. Thai, Lad-Krating, Thailand, Kasetsart University. Atipanumpai (1989)

7. Chi L, Chi H, Southern China (2 trial sites, Leilin and Haikang), Chinese Academy of Forestry. Pan Zhi-Gang (pers. comm. 1990).

8. Taiw, Chung-Pu, Taiwan, Taiwan Forestry Research Centre. Chung et al. (1990).

9. Melv, Melville Island, Northern Territory, Australia, Conservation Commission of the Northern Territory. M.W. Haines (pers. comm. 1991).

10. Fiji, Nukurua, Fiji, Fiji Ministry of Forests. L.R. Jiko (pers. comm. 1990).

11. Bdsh, Keochia, Bangladesh, Bangladesh Forest Research Institute. Zashimuddin et al. (1985).

b)   Site data:

  * M.A. Temp = mean annual temperature
M.A. Precip = mean annual precipitation
n.a. = not available

** approximate values only

Table 4. Seedlots tested at each trial site

1 = tested
0 = not tested

Table 5. Mean annual increment (MAI) in height and dbh: Performance of provenance regions and overall site mean at each trial site.

^# Mean of all local provenances tested at site

* PNG seed source, but not one of the two listed in Table 1.
Not included in computation of site mean or across-sites ANOVA

Table 6. Percentage of trees with single stems at three trial sites, by provenance.

¹ Sim Boon Liang, pers. comm 1990. Percentage of trees with single stems.

² M.W. Haines, pers. comm. 1990. Percentage of trees with single stems at 3.0 m height.

³ Souvannavong (1990). Percentage of trees with single stems.

* not available

Figure 1. Mean annual increment in height of provenance regions for trial sites other than those in Borneo.

Figure 2. Mean annual increment in dbh of provenance regions for trial sites other than those in Borneo.