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Santalum austrocaledonicum

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Abstract

Santalum austrocaledonicum is native to the island archipelagos of New Caledonia and Vanuatu where it grows as a small, root-parasitic shrub or tree, typically with a short, crooked bole and spreading crown. It produces a highly valuable heartwood and essential oil. The species is mainly harvested from the wild and has been an important source of income for poor rural peoples for centuries. Most native populations are greatly depleted and major replanting efforts are now underway.
200
and for breeding to develop high-quality forms for
smallholder plantings in Vanuatu. In New Caledonia,
the essential oil varies mainly between individuals, and
the dierent harvesting areas present similar-quality oils.
Harvesting is regulated and new results have permitted
the delineation of conservation zones that take into
account genetics and both chemical and morphological
variation.
Description
Habit small hemiparasitic shrub or tree, 5–12m tall
with ≤30–50cm dbh; crown round, bushy, with many
individuals forking at a low level; oen with crooked
Family: Santalaceae
Botanical name: Santalum austrocaledonicum
Vieillard. In Ann. Sci. Nat., Bot., sér. 4, 16: 61 (1862).
e specic epithet refers to the location of
the type specimen from New Caledonia. Four
varieties are recognised: var. austrocaledonicum, var.
pilosulum, var. minutum and var. glabrum.
Common names: Coral Sea sandalwood,
sandalwood, Loyalty Islands sandalwood (var.
glabrum) (English); sandalwud (Vanuatu); bois de
santal, santal (French)
Summary of attributes and why diversity
matters
Santalum austrocaledonicum is native to the island archi-
pelagos of New Caledonia and Vanuatu where it grows
as a small, root-parasitic shrub or tree, typically with a
short, crooked bole and spreading crown. It produces a
highly valuable heartwood and essential oil. e species
is mainly harvested from the wild and has been an
important source of income for poor rural peoples for
centuries. Most native populations are greatly depleted
and major replanting eorts are now underway.
In Vanuatu, continuous variation is found in the com-
mercially important santalol content of its heartwood
essential oil, ranging from trees with very low (1%) to
very high (47%) oil concentrations. Trees with high
proportions of heartwood and rich in oil with high
santalol concentrations are being used for seed supply
Santalum austrocaledonicum
Above: Buds and flowers (Photo: L�Thomson)
Top right: Fruit at dierent stages of ripeness
(Photo: L�Thomson)
Bottom right: Planted tree growing in village; Erromango,
Vanuatu (Photo: T�Page)
Species accountsSantalum austrocaledonicum
201
on Isle of Pines, and less common on Grand Terre, the
main island. Var. pilosulum is restricted to near Noumea
and surrounding area at low elevations on Grand Terre.
Var. minutum is restricted to the north-west of Grand
Terre. Var. glabrum is common in the Loyalty Islands.
Santalum austrocaledonicum has not been planted
commercially outside its natural range. Experimental
plantings have been established at: Kununurra in
northern Western Australia and Atherton Tableland
in northern Queensland (Australia); Nukurua, south-
eastern Viti Levu, and Ovalau (Fiji); Rarotonga and
Mitiaro (Cook Islands); and ‘Eua (Tonga).
is species prefers warm to hot, lowland, subhumid
or wet/dry tropical climates with a mean annual, mainly
summer, rainfall of 800–2,500mm and a short to
lengthy (0–5months) dry season in the cooler months.
Altitudinal range is 5–800masl. Tropical cyclones are a
feature of the entire distribution range, occurring mainly
during the hot wet season from December to April. e
species prefers well-drained acidic to alkaline soils and
does not grow well on waterlogged soils and strongly
acidic, clayey soils.
Uses
Carvings, incense production and sandalwood oil are
the three major wood uses of S.austrocaledonicum and
they are highly valued for their therapeutic and religious
signicance. e species was exploited heavily over about
three decades in the mid-1800s and has been utilised
periodically since then. Projected rotation lengths for
plantations of this species range between 20 and 40years
reecting a moderately fast rate of growth under suitable
conditions.
Wood—the heartwood is close-grained, very nely
and evenly textured, hard, durable and renowned as a
carving material. It has a specic gravity of 0.92 and
weighs 897–1,137kg/m3. Timber seasons well when
dried slowly. e wood can be worked to a smooth nish
and takes on a satin-like polish. e heartwood has been
used for many centuries for carvings, prayer poles and
other religious artefacts, valuable handicras, fuel for
funeral pyres, cons and joss sticks.
Non-wood—pure distilled sandalwood oil products
have demonstrated anti-inammatory and antimicrobial
properties. e oil has been used topically to treat fungal
and bacterial skin infections and inammation related
to sunburn and joint and muscle pain. Inhalation of the
oil fragrance has a mild sedative eect and contributes
to relieving anxiety, sleep disorders and promoting
relaxation and a feeling of wellbeing. Sandalwood oil
has been used as a coolant, astringent, antipyretic and
aphrodisiac. It is also used to treat migraines, erysipelas
(skin bacterial infections), gonorrhoea and cystitis.
bole in open situations and straight bole in denser forest
situations. Bark greyish, rough, longitudinally ssured.
Leaves opposite, usually in 1plane, decussate on erect
new growth, simple, entire, glabrous, dark green/shiny
above, dull light green/glaucous below; initially long and
thin in seedlings and young plants, becoming narrowly
elliptic or ovate, lanceolate or obovate, 4–6× 1.5–2.5cm,
tapering equally to the base and blunt tip, as they
mature; there is wide variation in foliage characteristics
between trees and populations. Inorescences terminal
and axillary panicles of bisexual owers. Flowers small
(±5mm across), tepals 4 or rarely 5, remaining greenish-
white to cream through to maturity; yellow disc lobes
alternate with tepals and anthers; long unicellular hairs
occur at base of each lament and extend to anther;
pollen shed via longitudinal slits in anther; stigma
typically 3-lobed (rarely 2- or 4-lobed), fused into a
single style. Fruit subglobular or ellipsoid, single-seeded
drupe, green and rm, ripening red, turning purplish-
black and thinly eshy when mature; longitudinal ridges
4, square calyx scar at the apex; size can vary between
populations. Seed kernel woody, enclosing light-coloured
endocarp and single seed.
Like many of the sandalwood species, S.austrocale-
donicum trees can ower at an early age, from about
age 3years onwards. Fruit take about 3months to reach
maturity and fruiting is generally abundant on each tree.
Distribution
Santalum austrocaledonicum occurs naturally in the
island archipelagos of New Caledonia and Vanuatu in
the south-western Pacic. In Vanuatu, it mainly occurs
on the islands of Aneityum, Aniwa, Efate, Erromango
(north-western, western and south-western areas),
Espiritu Santo (western coast), Futuna, Malekula and
Tanna. In New Caledonia, the distributions of the four
varieties are distinct. Var. austrocaledonicum is common
Species accountsSantalum austrocaledonicum
202
ere is signicant tree-to-tree variation in percentage
heartwood—in Vanuatu, it was reported to vary from
1% to 73% with a mean of 27%. Similarly, heartwood
santalol content in Vanuatu varied from 1% to 47% with
a mean of 20%. Populations on the northern islands of
Espiritu Santo and Malekula had a higher frequency
of trees with elevated levels of santalols. Total oil yield
also varied between trees with a range of 0.1–8.0%. No
geographical pattern was identied for trees with high oil
yields.
Deployment of improved germplasm has progressed
in Vanuatu with the establishment of elite graed seed
orchards on several islands (Efate, Espiritu Santo and
Malekula). ese orchards consist of a genetically diverse
range of trees with an average of 33% α-santalol. Seed
produced from these orchards will be used to improve
the sandalwood plantation resource in Vanuatu for both
livelihood and conservation benets.
In New Caledonia, the santalol content of S.aus-
trocaledonicum heartwoods did not vary as much as
in Vanuatu. e mean percentage of α-santalol in the
concrete was 39.4% with a standard deviation (σ) of
11.2, and 16.4% for β-santalol with σ of 5.23. However,
the E-lanceol content, a molecule characteristic of New
Caledonian sandalwood, varied considerably between
individuals (mean= 13.7%, σ= 16.6). e majority of the
variation was between individuals within populations
(81% of the total variance of the molecules) rather than
between populations (19% of the total variance), so it
is challenging to delineate candidate provenances for
domestication.
Sandalwood oil is used widely in the cosmetic,
fragrance and soap industries. It has a highly sought-
aer fragrance, particularly those oils rich in santalols
which give the oil with its distinctive aroma. e oil is
also of considerable value for its exceptional binding
qualities for other fragrant components that may be
added to create a characteristic bouquet for a branded
perfume.
In terms of volume consumed, its use in the
perfumery industry currently outweighs its use in
medicinal and natural therapies. It is produced commer-
cially by steam distillation with an average commercial
yield of 3–5%. However, individual tree yields can vary
between 0.1% and 8.0%. is variation in oil content is
attributed to tree age and position of heartwood within
the tree and is also expected to be partly inuenced by
genetic and environmental factors.
Diversity and its importance
e quantity of heartwood in its timber, concentration of
oil in the heartwood and the levels of α- and β-santalol
in the distilled oil determine the market value of
S.austrocaledonicum.
Above left: Commercial S.austrocaledonicum plantation,
Summit Estate; near Mele, Efate, Vanuatu
(Photo: L�Thomson)
Above right: Loading logs of S.austrocaledonicum; Ponkil
Bay, Erromango, Vanuatu (Photo: T�Page)
Left: Boiler for distillation of essential oil, with Phila
Raharivelomanana; Maré Island, Loyalty Islands, New
Caledonia (Photo: L�Thomson)
Species accountsSantalum austrocaledonicum
203
could be due to a lack of pollinators in this particular
island, or resprouting due to numerous bushres.
Genetic diversity in Vanuatu
e genetic diversity of S.austrocaledonicum across
the islands of Vanuatu was generally higher than that
observed in the islands of New Caledonia. In Vanuatu,
population dierentiation due to genetic structure was
lowest among the three southern islands, Erromango,
Tanna and Aniwa. e small island of Aniwa exhibited
the lowest genetic diversity, not unexpectedly given the
small population size and its possible anthropogenic
introduction. Small clusters of genetically related
trees, full siblings, were observed on Espiritu Santo
and Malekula which may be the result of localised
inbreeding or due to the planting by people of seed
from a single source tree. Some level of inbreeding in
S.austrocaledonicum is likely given the general presence
of self-compatibility in the genus.
Conservation of genetic resources
(including threats and needs)
Intense exploitation of the sandalwood resource in
Vanuatu and New Caledonia occurred from the 1820s
to the 1860s until the industry became unprotable. e
resource has since recovered but is only a small fraction
of its original size. High levels of interrelatedness of trees
on some islands in Vanuatu may be a genetic bottleneck
caused by harvesting in the 1800s.
e sandalwood industry in Vanuatu is based primarily
on harvesting of wild trees of S.austrocaledonicum and
the Department of Forests has developed a conservation
strategy for the species. An inventory in 2008 found a
low aggregated density (0.4trees/ha) in known S.austro-
caledonicum regions. In the mid-2000s, the mean annual
harvest was >100tonnes, which exceeded the then
roughout New Caledonia, S.austrocaledonicum
exhibits a high level of morphological variation,
particularly in juvenile leaf morphology and seed charac-
teristics. Field experimental designs have shown that this
variation is partially under genetic control. is could
result from adaptation to local ecological conditions,
especially for rainfall, which varies markedly between the
western coast of Grande Terre and the Loyalty Islands.
Genetic diversity in New Caledonia
Due to the geographical isolation of islands across
the New Caledonian archipelago, gene ow between
islands is reduced and populations have been evolving
separately: this is leading to signicant genetic dier-
entiation as assessed by molecular genetic markers. e
populations of Grande Terre were found to be dierent
to each other, reecting the impact of anthropogenic
fragmentation which has led to the isolation of small
remnant populations. Genetic diversity within each
population was also variable between islands and
noticeably lower on the island of Maré (Loyalty Islands)
where S.austrocaledonicum appears to reproduce mainly
through self-fertilisation and by root suckering. is
Above: Variation in juvenile leaf morphology in school
planting of S.austrocaledonicum; Onerua, Mangaia, Cook
Islands (Photo: L�Thomson)
Left: Variation in heartwood colour of
S.austrocaledonicum in Vanuatu (Photo: L�Thomson)
Species accountsSantalum austrocaledonicum
204
hybrids. While the productivity benets of hybrids
are evident, consideration must be given to potential
incompatibility or other deleterious factors that could
manifest in later generations. Production of hybrids
may also have unpredictable consequences in terms of
potential disruption of a species’ genetic integrity; for
example, S.album introduced to Vanuatu was much less
resilient to high wind speeds associated with cyclones
than S.austrocaledonicum. It is unclear what eect
uncontrolled hybridisation between these two species
would have on the wind rmness, or other traits of
natural S.austrocaledonicum. ere is concern that
introduction of other varieties of S.austrocaledonicum
into the Loyalty Islands may eventually lead to loss of
the distinctive Loyalty variety (var. glabrum) through
hybridisation and subsequent introgression. Market
acceptance of, and demand for, products derived from
hybrid sandalwood is also yet to be dened and may
jeopardise the development of a niche market and
brand for pure S.austrocaledonicum oil. Sandalwood is
a culturally signicant product with a long history of
trade and consumers are sensitive to quality dierences
between species.
Authors: Tony Page, Lorraine Bottin, Jean-Marc
Bouvet and Hanington Tate
80-tonne sustainable limit. e current annual quota is
60tonnes, although harvesting rates in the mid-2010s
were between 30 and 40tonnes. While much of the wild
resource has been commercially exhausted, smallholder
plantings now represent a modest commercial supply.
In New Caledonia, the current quota is 29.2tonnes/
year, and S.austrocaledonicum can only be harvested in
the Loyalty Islands. e genetic, chemical and morpho-
logical data recently obtained supplemented this measure
by enabling the delineation of conservation zones
(evolutionarily signicant units) where seed transfer has
to be regulated.
In Vanuatu and New Caledonia, S.austrocaledonicum
is currently grown in small plantings or managed in
natural stands. It grows at moderate rates and can
produce substantial quantities of the valuable heartwood
on a rotation of 25–40years. is species has good
commercial potential; in particular, to generate cash
revenue for rural communities in remote areas. ere
is increasing interest among villagers, other small-scale
entrepreneurs and government agencies to expand the
scale of planting in both countries.
Santalum austrocaledonicum can freely hybridise with
other species, including S.album and S.lanceolatum.
is opens the potential for introgression of desirable
traits between species and/or development of vigorous
Trees for life
in Oceania
Conservation and utilisation of genetic diversity
    :      
Lex Thomson
John Doran
Bronwyn Clarke
  
 
     
Edited by
Lex Thomson
Associate Professor (Pacific Islands Agribusiness) &Adjunct Associate Professor (Agroforestry),
University of the Sunshine Coast
John Doran
Research Fellow, Australian Tree Seed Centre,
CSIRO National Collections and Marine Infrastructure
Bronwyn Clarke
Research Scientist, Australian Tree Seed Centre,
CSIRO National Collections and Marine Infrastructure
2018
e Australian Centre for International Agricultural Research (ACIAR) was estab-
lished in June 1982 by an Act of the Australian Parliament. ACIAR operates as
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permission from ACIAR, GPO Box 1571, Canberra ACT 2601, Australia,
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omson L., Doran J. and Clarke B. (eds) 2018. Trees for life in Oceania: conser-
vation and utilisation of genetic diversity. ACIAR Monograph No. 201. Australian
Centre for International Agricultural Research: Canberra. 278 pp.
ACIAR Monograph No. 201
ACIAR Monographs – ISSN 1031-8194 (print), ISSN 1447-090X (online)
ISBN 978 1 925746 17 4 (print)
ISBN 978 1 925746 18 1 (online)
Technical editing by Mary Webb, Canberra
Design by Nebojsa Dolovacki
Printing by CanPrint Communications
Front cover: ‘Nui Afa’—a traditional variety of coconut (Cocos nucifera) selected for
production of bre or coir in Samoa (Photo: Roland Bourdeix, (1) CIRAD, UMR AGAP,
F-34398 Montpellier, France; (2) AGAP, Univ Montpellier, CIRAD, INRA, Montpellier
SupAgro, Montpellier, France)
Back cover: Fast-growing Eucalyptus deglupta which has a range of uses, including timber,
stream-bank stabilisation, shade and honey production—planted specimen, Kolombangara,
Solomon Islands (Photo: Bronwyn Clarke, CSIRO Australian Tree Seed Centre)
Contents
5
Contents
Foreword .................................................................................................................................................................................3
Preface ..................................................................................................................................................................................... 7
Acknowledgments ...........................................................................................................................................................8
Abbreviations ...................................................................................................................................................................... 9
Introduction (Bulai and Thaman) .........................................................................................................................11
Conserving and making ecient use of forest genetic resources
(Bush and Thomson) ...................................................................................................................................................15
Germplasm availability and propagation requirements (Clarke and Taylor) .......................... 23
Species accounts ............................................................................................................................................................27
Acacia auriculiformis (Pinyopusarerk, Midgley and Thomson) ������������������������������������������������������������������ 28
Acacia colei (McDonald, Thomson and Rinaudo) �������������������������������������������������������������������������������������������31
Acacia crassicarpa (Midgley and Thomson) ������������������������������������������������������������������������������������������������������ 35
Acacia koa (including A. koaia) (Friday) �������������������������������������������������������������������������������������������������������������39
Acacia mangium (Arnold) ���������������������������������������������������������������������������������������������������������������������������������������� 42
Acacia torulosa (Cunningham and Yaou) �����������������������������������������������������������������������������������������������������������46
Acacia tumida (McDonald and Thomson) �������������������������������������������������������������������������������������������������������49
Agathis macrophylla (Keppel, Thomson and Senivasa) ��������������������������������������������������������������������������������52
Araucaria cunninghamii (Nikles and Arnold) ��������������������������������������������������������������������������������������������������� 55
Artocarpus altilis (Ragone) ���������������������������������������������������������������������������������������������������������������������������������������60
Barringtonia edulis and B. procera (Thomson and Sam) ������������������������������������������������������������������������������� 65
Calophyllum inophyllum (Thomson, Bennett and Doran) ��������������������������������������������������������������������������69
Canarium indicum (Randall, Walton, Nevenimo, Poienou, Moxon, Hannet and Wallace) ������������ 73
Casuarina equisetifolia (Pinyopusarerk and Midgley) ������������������������������������������������������������������������������������ 77
Cocos nucifera (Bourdeix and Batugal) ����������������������������������������������������������������������������������������������������������������81
Corymbia citriodora (Lee) �����������������������������������������������������������������������������������������������������������������������������������������86
Endospermum medullosum (Thomson, Palmer, Doran and Viranamangga) �����������������������������������������90
Eucalyptus camaldulensis (Arnold and Luo) ������������������������������������������������������������������������������������������������������94
Eucalyptus cloeziana (Lee) �������������������������������������������������������������������������������������������������������������������������������������100
Eucalyptus deglupta (Davidson, Gunn and Spencer) �����������������������������������������������������������������������������������104
Eucalyptus pellita (Harwood) �������������������������������������������������������������������������������������������������������������������������������� 108
6
Contents
Eucalyptus urophylla (Dvorak, Doran and Rimbawanto) ����������������������������������������������������������������������������� 112
Falcataria moluccana (Macdonell and Baskorowati) ������������������������������������������������������������������������������������116
Flueggea flexuosa (Pouli, Vigulu and Thomson) ����������������������������������������������������������������������������������������������119
Garcinia sessilis (Thomson, Thaman and Vainikolo) ������������������������������������������������������������������������������������122
Gliricidia sepium (Midgley) ������������������������������������������������������������������������������������������������������������������������������������ 126
Grevillea robusta (Kalinganire, Harwood and Clarke) ���������������������������������������������������������������������������������� 130
Gyrinops ledermannii and G. caudata (Lata, Damas and Fazang) ������������������������������������������������������������ 133
Hibiscus storckii and three undescribed Fijian Hibiscus species (Thomson and Braglia) ��������������� 136
Inocarpus fagifer (Thomson) �������������������������������������������������������������������������������������������������������������������������������� 140
Intsia bijuga (Thomson, Thaman, Martel and Elevitch) ������������������������������������������������������������������������������143
Macadamia integrifolia and M. tetraphylla (Hardner and Topp) ���������������������������������������������������������������147
Mangifera foetida (Hong, Ramanatha Rao and Chung) �������������������������������������������������������������������������������152
Melaleuca cajuputi (Rimbawanto and Doran) �������������������������������������������������������������������������������������������������155
Melaleuca quinquenervia (Doran and Lê Đinh Khá) ������������������������������������������������������������������������������������� 159
Metrosideros excelsa (Dawson) ����������������������������������������������������������������������������������������������������������������������������� 162
Meterosideros polymorpha (Friday) ���������������������������������������������������������������������������������������������������������������������166
Musa troglodytarum (fe‘i) (Englberger, Daniells, Lorens, Vezina, Lusty and Kepler) ������������������������ 170
Ochroma pyramidale (Midgley and Jenkin) ������������������������������������������������������������������������������������������������������175
Pandanus tectorius (Thomson, Thaman, Guarino, Taylor and Elevitch) ���������������������������������������������� 179
Piper methysticum (Lebot) ������������������������������������������������������������������������������������������������������������������������������������� 184
Pometia pinnata (Thomson and Thaman) ����������������������������������������������������������������������������������������������������� 188
Pterocarpus indicus (Thomson) ��������������������������������������������������������������������������������������������������������������������������� 192
Santalum album (Thomson, Rimbawanto and Doran) ������������������������������������������������������������������������������ 196
Santalum austrocaledonicum (Page, Bottin, Bouvet and Tate) ��������������������������������������������������������������� 200
Santalum insulare (Butaud, Bianchini, Bouvet, Defranoux, Lhuillier and Raharivelomanana) ����205
Santalum yasi (Thomson, Bush and Bulai) ����������������������������������������������������������������������������������������������������� 210
Swietenia macrophylla (Thomson, Baskorowati and Doran) ��������������������������������������������������������������������214
Syzygium malaccense (Hong, Ramanatha Rao and Chung) �����������������������������������������������������������������������217
Tectona grandis (Pedersen and Gua) �����������������������������������������������������������������������������������������������������������������220
Terminalia catappa (Thomson and Evans) ������������������������������������������������������������������������������������������������������224
Terminalia richii (Thomson, Pouli and Alatimu) ��������������������������������������������������������������������������������������������228
Xanthostemon melanoxylon (Gua, Thomson, Tutua, Sirikola and Wilson) ������������������������������������������ 232
Appendix 1. Author contact details ................................................................................................................. 235
Appendix 2. Seed and propagation information .....................................................................................240
Selected bibliography ............................................................................................................................................... 253
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