Tiwi Islands – Northern Territory

Acacia Mangium – Weed ? … tiwi may 2009

Posted by tiwiccbb on May 12, 2009



Potential weed grown in NT plantations

Posted Tue May 5, 2009 11:05am AEST

The Northern Territory Government has confirmed it is investigating a plant being grown on plantations on the Tiwi Islands as a high risk weed.

The forestry company Great Southern is growing the plant, Acacia Mangium, on 29,000 hectares of land on Melville Island to export as woodchips to countries in the Asia Pacific region.
The Environment Department’s Diana Leader says acacia is being examined as a potential weed because of its prolific seed production, rapid growth and strong competitive ability against other plants.
“It’s become a potential weed in the tropical environment because of its rapid and extremely vigorous growth in the right places,” Ms Leader said.
“It has prolific seed production and it can tolerate very acidic soils and low nutrient status soils and has a strong competitive ability and relative freedom from natural pests and diseases.”
But she says it will be another 12 months before a weed status on acacia is finalised.
“We do firstly an assessment of its weediness and then a look at the feasibility of controlling it and when we get the results from that, as to whether they come out having a high risk, then we look at cost-benefit analysis to see whether or not it would be able to be managed.”

Below is a link to one article concerned about the invasiveness of acacia mangium when it escapes.
“…This species has been cultivated in various
places as a forestry tree and has escaped from plantings (PIER 2003). With a history of weediness elsewhere and limited distribution on Maui, this species is a good candidate for eradication and control.
“…Invasiveness: According to PIER (2003), Acacia mangium can become naturalized where planted and is known to spread on Saipan, Pohnpei, Yap, Sabah, Africa, Melville Island, and northern Australia.”


On Tue, May 13, 2008 at 11:18 AM
, Benedicto Q. Sánchez wrote:

Hi, all,

I’m sure you’ll find this article interesting. As we know, wild. uncultivated (and sometimes introduced but invasive) crops in agroforestry areas are also considered NTFPs.

Others proved to be beneficial, but some evolved to be a pest. How can we differentiate?

Regards and all the best,

Benedicto Q. Sánchez
Program Coordinator
BIND Dr 1 Adela Arcade, Don Vicente Bldg.,
Locsin St., Bacolod City 6100,
Negros Occidental, Philippines
Telefax 6334) 433 8315
Telephone: (6334) 432 1510
E-mail: bindbcd@…, bqsanch@…
URL: http://www.bindnegros.org

Unless we properly manage resources like forests, water, land, minerals and oils, we will not win the fight against poverty. And there will not be peace. —Wangari Maathai, Nobel Peace Prize Award 2004

———- Forwarded message ———-
From: The Overstory
Date: Tue, May 13, 2008 at 9:41 AM
Subject: The Overstory #206–Underutilised crops and invasive species
To: Benedicto Sánchez

Publication date: May 12, 2008

The Overstory #206–Underutilised crops and invasive species
By Nick Pasiecznik and Hannah Jaenicke


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The Overstory #206–Underutilised crops and invasive species
By Nick Pasiecznik and Hannah Jaenicke


: –> Paradoxical impacts of plant introductions
: –> What plants are both crops and invasive?
: –> Who takes the blame if an introduction goes wrong?
: –> Balanced information provision
: –> Weed risk assessments
: –> Monitoring and surveillance
: –> Predefined control and management strategies



Underutilised crops have the potential to provide great social and
nutritional benefits to the rural poor as well as the global community
at large, and it is increasingly recommended that they are identified,
researched and promoted in much the same ways and levels of resourcing,
as the world’s main staple food plants. Underutilised crops are defined
as “species with under-exploited potential for contributing to food
security, health (nutritional/medicinal), income generation, and
environmental services” (Jaenicke and Höschle-Zeledon, 2006). Whilst
many underutilised species are traditional and local crops, in certain
circumstances new introductions from elsewhere will also be considered,
for example to increase the useful biodiversity of agro-ecosystems
(Dawson et al., 2007). Thus, it is important to consider all possible
steps to ensure that striving to achieve this goal does not,
accidentally, have the reverse effect. This paper presents past errors
and the current and future dangers of introducing exotic crops to new
areas, describes existing procedures that will reduce the risks, and
suggests a set of recommendations for professionals working with
underutilised crops.


–> Paradoxical impacts of plant introductions

The introduction of harmful species, including a range of plant pests,
both accidentally and intentionally has caused great concern. ‘Pests’ is
used here in its broadest sense, as defined by the International Plant
Protection Council of the FAO, as “Any species, strain or biotype of
plant, animal or pathogenic agent injurious to plants or plant products”
(IPPC, 2007). A large number of these species have caused such
significant negative environmental and/or economic impacts that they are
now collectively called ‘alien invasive species’. Alien invasive
species, independent of which of the myriad of definitions are used
(e.g. Richardson et al., 2000; McNealy et al., 2001; CBD, 2002; Colautti
and MasIsaac, 2004), have been widely described as the second greatest
threat to biodiversity after habitat loss (e.g. IUCN, 2001). A suitable
working definition for invasive species (not necessarily ‘alien’) used
here, is, “organisms that cause, or have the potential to cause, harm to
the environment, economies, or human health” (Pasiecznik, 2007).

The reasons for the introduction of new plants and the pathways they may
take to get from A to B are varied indeed, and this can either be
accidental or intentional, with crops obviously the latter (Pasiecznik,
2004). A number of well-know invasive plants have been accidentally
introduced into many countries of the world, including many now common
agricultural weeds. Some are also fodder species that also fall in the
invasive/resource category. Most recorded invasive plants were
intentionally introduced, however, for ornamental and landscaping
reasons, though the horticultural industry is increasingly aware of the
risks posed and steps are being taken to reduce potential negative
impacts (e.g. Anon., 2001) as the costs of controlling any future
invasive plants is likely to be greater than the economic benefits
accrued from sales (Barbier and Knowler, 2006). Related to this are
plants introduced for their environmental services, such as for hedges,
windbreaks, erosion control, etc., and many others introduced
principally for fuel, whether firewood as in the past, or for biofuels
at present.

–> What plants are both crops and invasive?

A number of crops, even globally important ones, are also noted as
invasive species somewhere in the world (Table 1), for example the
tomato (Solanum esculentum), recorded as invasive on the Galapagos
islands, and okra (Abelmoschus esculentus), invasive in parts of the
USA. These widely grown and globally important plants may provide useful
lessons for new introductions of underutilised crops. There are also a
number of species that have proved to be invasive to some, but a boon to
others – plants that that do not clearly fall into either the “crop” or
“invasive” categories, or in reality, fall into them both at the same
time. However, very few studies have been conducted on such plants, and
their potential costs and benefits to local communities.

One such study looked at prickly pear cactus (Opuntia ficus-indica) and
black wattle (Acacia mearnsii) in South Africa, both of which have
endured substantial and costly eradication programmes, but local
communities both desired a greater area under each, as they gained a
substantial proportion of their income from them (Shackleton et al.,
2007). Several others have analysed Prosopis juliflora in Kenya, but
results are inconclusive, with Choge et al. (2002) noting community
benefits at the time of surveying, but that the balance was likely to
shift towards a need for control in later years as infestations spread.
Nonetheless, it appears that these studies prove the paradox – what is
invasive to one person, may be a source of livelihood to another.
However, on a personal and daily basis, the case may be even more
integral than this, i.e. that the positive and negative effects may
impact on the same person at the same time.

–> Who takes the blame if an introduction goes wrong?

Many crops are being promoted for further introduction that have been
recorded as invasive (Table 1), thus care should be taken. However,
there are currently no standard procedures for allocating blame for the
introduction of plants that eventually become invasive, in any more than
a subjective and non-legally-binding way. Therefore, there has been
little to motivate those involved in plant introductions to take extra
care. However, things are now changing and it would be wise for those
involved to take note, as following a number of high profile and high
cost cases involving invasive species, there are increasing calls for
measures that follow the “polluter pays” principle. There are advances
related to ornamental species, with for example Barbier and Knowler
(2006) using a model to compare opposing economic values using purple
loosestrife (Lythrum salicaria) in the USA and concluding that there was
a need for a “introducers pay” tax to put limits on the uncontrolled
spread in the trade in invasive ornamental species, and spread of the
species themselves.

Related to this, the Australian government has for some time adopted a
‘white list’ approach, whereby species can only be introduced if they
are on a list of approved plants that have passed a weed risk
assessment, as opposed to the standard ‘black list’ approach that means
that any plant species can be introduced with the exception of those
that have been identified as posing an unacceptable level of risk.
However, the ‘white list’ concept has been challenged under the World
Trade Organisation as an approach that is against the principles of free
trade; the Australian government argues that it is valid as it is based
on sound, scientific principles.

A recent example of attempts at firmly placing the blame on those who
introduced an invasive plant, albeit for good intentions, is the case of
Prosopis juliflora in Kenya. Planted widely in the 1980s as a fuel and
fodder tree, it was noted as invading a decade later though no steps
were made to counter this, and in 2004, the National Museums of Kenya
brought a court case on behalf of the Il Chamus community of Baringo
District, who claimed that their livelihoods had been seriously
compromised by the introduction of this tree. It was made initially
against the FAO for funding the initial planting, but FAO claimed
immunity from prosecution as a UN organisation. The case then continued
against the government of Kenya, the Il Chamus demanding wholesale
eradication and/or being allocated new land to settle on. In December
2007, Kenya’s high court ruled in favour of the community, their lawyer
noting that “the court has decided that the environmental well-being of
people is the same as human rights” (Reuters, 2007). The settlement is
yet to be decided, but this has potential ramifications for other
governments and organisations, involved in the international movement of
plant species.

Thus, government departments, and national and international public and
private organisations involved in the introduction of new plants might
do well to agree upon a set of necessary steps to take before and after
plant introduction, as otherwise they may be liable to pay for any
negative impacts that might result. In an increasingly litigatious
global culture, the fear of a multi-million dollar court ruling may have
a greater impact than any voluntary code or demand for ethical choices
from concerned professionals.

–> Balanced information provision

Professionals involved in promoting underutilised crops must accept and
acknowledge honestly any records that indicate the potential of these
species to become invasive. The stakes are too high to allow personal
pride and professional stature to cloud good judgement, and we must be
open, be it with our ‘pet’, specialist species, or any group of species
that we are working with. There is an increasing range of web-based
information sources that can now be used to assess actual and potential
invasiveness of any plant species. For example, the Forestry Compendium
(CABI, 2005), places an exclamation mark inside a warning triangle for
those species where a risk is noted (though not restricted to
invasiveness), and then takes the reader to a text section describing
what risks exist. CABI is also developing an Invasive Species
Compendium, due for completion in 2008-9. A brief selection of existing
databases on invasive plants is given in Table 2.

–> Weed risk assessments

Assessing the risks associated with the introduction of a new organism
to an area is a procedure that originated with national plant quarantine
services over a century ago. Pest Risk Analysis (PRA) was developed to
provide an answer to the question of “what to do?”, leading to a
quantitative result from qualitative data, and allowing the organisation
to make a management decision. This principle has been developed after
many decades of work, lead by plant protection organisations, national,
regional and international, which culminated in an international
standard on how to set up such a process by the International Plant
Protection Council. This has since been revised to incorporate both
risks to the environment, and risks posed by living modified organisms
(LMOs), and is otherwise known as ISPM No.11 (IPPC, 2004). Using this
concept as a basis, other countries have developed their own PRAs
specifically for plants, called ‘weed risk assessments’ (WRAs). By far
the most advanced are those established in Australia, based on sound
scientific principles (e.g. Panetta, 1993), and culminating in a system
adopted at a national level (Pheloung, 1995). This has since been
adopted and slightly adapted for use in Hawaii and other high islands of
the Pacific (PIER, 2007), and PIER have hundreds of completed WRAs
freely available to the public via their website (Table 2) that provides
a valuable indication of the potential invasiveness of the species
concerned. Other systems based on different criteria have been drawn up,
for example in the USA and South Africa, but none seems to be as simple
but accurate as the Australian/Pacific system.

–> Monitoring and surveillance

A final but important problem lies in how to classify, and what to do
with, “sleeper weeds”. The term is being increasingly used, especially
in Australia (Grice and Ainsworth, 2003; Groves, 2006), to describe
plants naturalised in an area but not (yet) invasive, that have proved
invasive elsewhere. Thus, an introduced crop or plant in any given area
may become invasive at some point in the future, depending on changes to
the local ecology, environment, land-use, or any other of a range of
possible ‘triggers’. Examples include the spread of dryland legumes
after overgrazing and/or drought, exotic fig trees (Ficus spp.) in
Australia following the introduction of a bird that very effectively
spread its seeds, or the introduction of exotic earthworms into Hawaii
that provided valuable forage for (previously introduced) wild pigs that
caused extensive ground disturbance which in turn facilitated the spread
of the fire tree (Myrica faya). Also, a USDA-funded study of potential
risks of invasion from exotic plants in the USA concluded that most of
the potential alien invasive plants of the future were likely to have
been already introduced, making monitoring and surveillance more
important than any preventative measures at the country’s borders (C.
Parker, Consultant, pers. comm.). Work in many parts of the world has
indicated that effective monitoring is practically and financially
impossible if left to governmental or other agencies alone, and should
involve the general public as much as possible. Thus, successful
monitoring depends in a large part on good extension and education, with
for example, ‘Wanted’ posters illustrating colour pictures of the plant
in question, telephone numbers of who to contact in case such a plant is
seen growing wild, radio programmes, and other adaptations of
agricultural extension practices that have proven effective in the past.

–> Predefined control and management strategies

Some countries such as Australia and South Africa are very aware of the
risks posed by invasive plants, and have in a number of cases
established protocols on what to do if a species begins to spread,
dividing responsibilities accordingly, thus greatly reducing the time
needed to act in such an event. These take time to develop and to
formally agree who will do what in such scenarios – but if not already
in place, valuable time will be lost in dealing with an invasion in its
initial stages when eradication, control or damage limitation is much
more likely to be successful, and less costly. This is integrally linked
to monitoring and surveillance activities, but also to possibly
pre-existing “containment” strategies that may have been developed to
control plant pest outbreaks. The national and regional plant protection
organisations should thus be contacted in the first instance. Control by
utilisation may also prove to be a useful approach even after escape. In
Kenya, means to control the further spread of Prosopis have attempted to
put an economic value on the seed, thus motivating people to collect and
destroy the pods and thus check further spread (Choge et al., this
conference). It is considered that this may be the most cost effective
means of control, and, in doing so, also achieves the parallel aims of
improving rural livelihoods by putting cash incomes directly into
farmers’ pockets.


It is clear that well-meaning plant introductions have been made in the
past, and continue to be made, which through inadequate research and
information, have sometimes had the reverse effect to that intended. In
the cases reported, exotic species meant to provide natural resources to
support and improve rural livelihoods have actually made people and
their environments poorer, and most of those responsible have walked
away leaving the recipients of such “rural development” to deal with the
problems caused as best they can.

Those of us involved in promoting further plant introductions and
managing existing invasions therefore have a responsibility to make more
long-term commitments to those people whom we are supposed to be
helping. Ensuring that what we promote will not become a disaster in the
future, “staying the course” and dealing with any unpredicted invasions
at a later date, and sharing the information at our disposal with others
working in related fields are the basic minimum requirements we should
all agree to. This should become the basis for a global holistic
strategy regarding underutilised crops and invasive species.

New plant introductions will continue to happen in the future, with good
reasons and intentions. The challenge we face is to ensure that risks of
negative ecological and economical impacts following such introductions
are minimized.


1. All documentation promoting underutilised crops must include
information on whether and where the plant is recorded as being
invasive, derived from searches of the many databases and associated
literature. Clear warnings should be attached to those that have already
proved invasive anywhere in the world.

2. Weed risk analyses/assessments, based on existing models, should
be conducted on potentially invasive species prior to introduction to a
new area. Species that fail should not be introduced at any cost, and
results should be widely publicised ensuring others do not make the same

3. Underutilised crops in an area, that have proven invasive
elsewhere, should be monitored for possible escape from cultivation,
naturalisation and spread to new areas or habitats within that area.
Control and management strategies should also be agreed with the
necessary authorities in the event of future invasion.

4. Those involved in developing and promoting underutilised crops
need to provide information on their uses and management to others
involved in their control and management as invasive species.

5. A system and protocol needs to be developed for the open exchange
of information between people working on species that are both
underutilised crops and invasive species. This must aim to improve the
management of existing plant invasions and prevent further ill-conceived


TABLE 1. An example of 50 species commonly considered as underutilised
crops that are recorded as invasive in at least one country or region of
the world.

Abelmoschus esculenta
Acacia karroo
Acacia mangium
Acacia mearnsii
Amaranthus retroflexus
Amaranthus spinosis
Atriplex halimus
Azadirachta indica
Berberis vulgaris
Bidens pilosa
Brassica juncea
Brassica napus
Brassica oleracea
Chenopodium album
Chromolaena odorata
Cichorium intybus
Colocasia esculenta
Crataegus monogyna
Eleagnus angustifolia
Eugenia uniflora
Gliricidia sepium
Hippophae rhamnoides
Imperata cylindrica
Ipomea aquatica
Jatropha curcas
Kigelia africana
Leucaena leucocephala
Moringa oleifera
Opuntia ficus-indica
Oxalis tuberosa
Panicum repens
Panicum sumatrense
Parthenium argentatum
Paspalum scrobiculatum
Passiflora foetida
Passiflora mollissima
Pastinaca sativa
Pithecellobium dulce
Portulaca oleracea
Prunus serotina
Psidium cattleianum
Psidium guajava
Ricinus communis
Salsola vermiculata
Solanum nigrum
Spathodea campanulata
Stipa tenacissima
Syzygium cumini
Terminalia catappa
Ziziphus mauritiana

TABLE 2. A sample of five databases containing information and
datasheets on invasive plants, as an indicator of the type and volume of
information available. There are several hundred more searchable
databases, most specific to countries, regions or organism types.

Global Compendium of Weeds (GCW).
Hawaiian Ecosystems at Risk (HEAR), Honolulu, Hawaii, USA.

The largest single database of weeds, including over 28,000 species. A
useful starting point for searches, being an updated version of a 900
page book by Rod Randall (2002).

Global Invasive Species Database (GISD). Invasive Species Specialist
Group (ISSG), Auckland, New Zealand.
Detailed information on approximately 150 invasive plants including
control and location specific data. Part of a larger database containing
470 invasive species of all organism types.

Crop Protection Compendium (CPC).
CAB International (CABI), Wallingford, Oxfordshire, UK.

A fully searchable database including almost 500 weeds and invasive
plants, along with over 2000 other plant pests. A specific Invasive
Species Compendium is currently being developed.

Pacific Island Ecosystems at Risk (PIER). Hawaiian Ecosystems at Risk
(HEAR), Honolulu, Hawaii, USA.
Information on a large number of plants which are present on Pacific
islands or Pacific rim countries. A good example of regularly updated
region-specific data that has wider value.

Invasive and Exotic Species (invasive.org).
A joint project by the Bugwood Network, USDA-FS and USDA-APHIS-PPQ, USA.

Information on 630 ‘invasive and exotic weeds’, part of a larger
database including 1000 invasive species of all organism types,
concentrating on those affecting North America.


Anon., 2001. Linking ecology and horticulture to prevent plant
invasions. Selections from the proceedings of the workshop at the
Missouri Botanical Gardens, December 2001. Missouri Botanical Gardens,
St Louis, Missouri, USA.

Barbier, E. and Knowler, D. 2006. Commercialization decisions and the
economics of introduction. Euphytica, 148(1/2):151-164.

CABI, 2005. The Forestry Compendium. CAB International, Wallingford, UK.

Choge, S.K., Ngujiri, F.D., Kuria, M.N., Busaka, E.A. and Muthondeki,
J.K. 2002. The status and impact of Prosopis spp in Kenya. Nairobi,
Kenya: Kenya Forestry Research Institute (KEFRI). 59p.

CBD, 2002. Review and consideration of options for the implementation of
article 8(h) on alien species that threaten ecosystems, habitats or
species. Addendum: use of terms. Conference of the parties to the
Convention on Biological Diversity, Sixth meeting, 7-19 April 2002.
UNEP/CBD/COP/6/18/Add.1. The Hague, the Netherlands. 5p.

Colautti, R.I. and MasIsaac, H.J. 2004. A neutral terminology to define
‘invasive’ species. Diversity and Distribution, 10:135-141.

Dawson, I.K., Guarino, L. and Jaenicke, H. 2007. Underutilised plant
species: impact of promotion on biodiversity. ICUC Position Paper No. 2.
International Centre for Underutilised Crops (ICUC), Colombo, Sri Lanka.

Grice, A.C. and Ainsworth, N. 2003. Sleeper weeds – a useful concept?
Plant Protection Quarterly, 18(1):35-39.

Groves, R.H. 2006. Are some weeds sleeping? Some concepts and reasons.
Euphytica, 148(1-2):111-120.

IPPC, 2004. Pest risk analysis for quarantine pests including analysis
of environmental risks and living modified organisms. ISPM No. 11. FAO,
Rome, Italy: International Plant Protection Convention. 26p.

IPPC, 2007. Glossary of Phytosanitary Terms. ISPM No. 5. FAO, Rome,
Italy: International Plant Protection Convention. 23p.

IUCN, 2001. IUCN guidelines for the prevention of biodiversity loss
caused by alien invasive species. Prepared by the SSC Invasive Species
Specialist Group, approved by the 51st Meeting of the IUCN Council,
February 2000. IUCN, Gland, Switzerland.

Jaenicke, H. and Höschle-Zeledon, I., eds., 2006. Strategic framework
for research and development of underutilized plant species with special
reference to Asia, the Pacific and Sub-Saharan Africa. International
Centre for Underutilised Crops (ICUC), Colombo, Sri Lanka and Global
Facilitation Unit for Underutilized Species (GFU), Rome, Italy. 33p.

McNeely, J.A., Mooney, H.A., Neville, L.E., Schei, P.J. and Waage, J.K.,
eds, 2001. Global Strategy on Invasive Alien Species. IUCN, Gland,

Panetta, E. 1993. A system for assessing proposed plant introductions
for weed potential. Plant Protection Quarterly, 8:10-14.

Pasiecznik, N.M. 2004. Pathways for plant introduction. Invasive plant
overview, invited paper. In: CABI, Crop Protection Compendium. CAB
International, Wallingford, UK.

Pasiecznik, N.M. 2007. Definition and scope of ‘invasive species’ and
practical applications for the development of an Invasive Species
Compendium. Appendix 2. In: CABI: Report of the annual CABI Compendium
workshop and the Invasive Species Compendium initiation workshop. USDA,
Washington DC, 15-17 November 2006. CABI, Wallingford, UK, 30-32.

Pheloung, P.C. 1995. Determining the weed potential of new plant
introductions to Australia. A report on the development of a Weed Risk
Assessment System commissioned by the Australian Weeds Committee and the
Plant Industries Committee. Agriculture Protection Board, Western
Australia, Australia.

PIER, 2007. Information of risk assessments. Pacific Island Ecosystems
at Risk, Hawaii, USA. http://www.hear.org/pier/wra/wralinks.htm

Reuters, 2007. Kenya to compensate locals for planting shrub. Planet
Ark, December 13, 2007.

Richardson, D.M., Py_ek, P., Rejmánek, M., Barbour, M.G., Panetta, D.F.
and West, C.J. 2000. Naturalization and invasion of alien plants –
concepts and definitions. Diversity and Distributions, 6:93-107.

Shackleton, C.M., McGarry, D., Fourie, S., Gambiza, J., Shackleton,
S.E.and Fabricius, C. 2007. Assessing the effects of invasive alien
species on rural livelihoods: case examples and a framework from South
Africa. Human Ecology, 35:113-127.


This article was excerpted with the kind permission of the authors and
publisher from:

Pasiecznik, N.M., and Jaenicke, H. 2008. Underutilised crops and
invasive species ­ understanding the links. Paper presented at the
International Symposium “Underutilized plants for food, nutrition,
income and sustainable development”, Arusha, Tanzania, 3-7 March 2008.
(c) International Society for Horticultural Science (ISHS)


Nick Pasiecznik is managing consultant for Agroforestry Enterprises,
specialising in research, development and training in agroforestry,
drylands, timber processing, and is a leading expert on Prosopis
species. Other interests and experience include forestry, agriculture
and land-use systems, organic production, invasive species and plant
taxonomy. He can be contacted at: Agroforestry Enterprises, Villebeuf,
71550 Cussy-en-Morvan, France; E-mail: ;
Tel: +33 (0)3 85546826.

Hannah Jaenicke has been Director of the International Centre for
Underutlised Crops (ICUC) since October 2005. She has a MSc in plant
breeding and a PhD in plant physiology. She developed her career in
international development and plant propagation at the World
Agroforestry Centre (ICRAF) in Nairobi 1992 – 2001, after which she
became Deputy Manager of the Forestry Research Programme of the UK
Department for International Development. In that position, Hannah was
closely involved in the day-to-day management of a large number of
diverse and interdisciplinary research projects worldwide as well as
strategy development. She was also instrumental in the development of a
training course on science communication and advocacy. Hannah can be
reached at: International Centre for Underutilised Crops (ICUC), PO Box
2075, Colombo, Sri Lanka; E-mail: .


(extracted from Table 2 above)

Global Compendium of Weeds (GCW).
Hawaiian Ecosystems at Risk (HEAR), Honolulu, Hawaii, USA.

The largest single database of weeds, including over 28,000 species. A
useful starting point for searches, being an updated version of a 900
page book by Rod Randall (2002).

Global Invasive Species Database (GISD). Invasive Species Specialist
Group (ISSG), Auckland, New Zealand.
Detailed information on approximately 150 invasive plants including
control and location specific data. Part of a larger database containing
470 invasive species of all organism types.

Crop Protection Compendium (CPC).
CAB International (CABI), Wallingford, Oxfordshire, UK.

A fully searchable database including almost 500 weeds and invasive
plants, along with over 2000 other plant pests. A specific Invasive
Species Compendium is currently being developed.

Pacific Island Ecosystems at Risk (PIER). Hawaiian Ecosystems at Risk
(HEAR), Honolulu, Hawaii, USA.
Information on a large number of plants which are present on Pacific
islands or Pacific rim countries. A good example of regularly updated
region-specific data that has wider value.

Invasive and Exotic Species (invasive.org).
A joint project by the Bugwood Network, USDA-FS and USDA-APHIS-PPQ, USA.

Information on 630 ‘invasive and exotic weeds’, part of a larger
database including 1000 invasive species of all organism types,
concentrating on those affecting North America.
Publisher: Permanent Agriculture Resources
Editor: Craig R. Elevitch

The Overstory is distributed by Agroforestry Net, Inc., a nonprofit
501(c)(3) organization based in Hawaii.
Address: P.O. Box 428, Holualoa, Hawaii 96725 USA
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Aloisa Zamora-Santos
Non-Timber Forest Products Exchange Programme for South and Southeast Asia
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One Response to “Acacia Mangium – Weed ? … tiwi may 2009”

  1. Anonymous said


    Growth and competition between seedlings of an invasive plantation tree, Acacia mangium, and those of a native Borneo heath-forest species, Melastoma beccarianum

    An introduced plantation tree species, Acacia mangium Willd., is becoming invasive in the Brunei region of Borneo. To examine its invasive potential, a greenhouse, additive series experiment (target-neighbour) involving seedlings of A. mangium and those of a common native heath-forest (kerangas), Melastoma beccarianum Cogn. was carried out under low and high light regimes in intra-and interspecific combinations over a 6-month period. Significant variations in growth parameters (other than biomass allocation patterns) existed amongst seedlings from different treatments. A major part of this variation in growth could be attributed to the main factors of target species, neighbour species, and competition (seedling density). For the growth variables examined, the target-species response was not consistent across light regimes. Under high light conditions, Acacia was the better competitor; the Lotka-Volterra competition coefficient effect of Melastoma on Acacia was lower (α = 0.30) than the effect of Acacia on Melastoma (β = 0.54). However, the reverse occurred under low light conditions with Melastoma gaining the upper hand (α = 1.45 and β = 0.44). These results show that light (and hence disturbance) can strongly influence the pattern and intensity of both intra- and interspecific competition between invasive and local flora species. Relatively intact forest is unlikely to be invaded by Acacia trees (as they are poor competitors under this scenario). On the other hand, the Acacia trees can easily invade disturbed forests, especially those prone to recurring drought and fire, and over time convert the habitats to nearly monospecific stands, as is presently being observed in Brunei.

    Invasive in India


    “…Now we come to the more controversial species. The first is Acacia mangium. It can grow up to 30 meters. It is a native of Australia (Queensland), Molluccan islands, Papua New Guinea and Indonesia. Large scale plantations have been developed in Indonesia and Malaysia. However, it is invasive in the sense that it replaces the local trees. In Tamilnadu the Forest department is cutting these trees.

    A. mangium is a fast growing species with numerous seeds and therefore it outperforms other trees. Each tree produces a kilogram of seed per yer year which is about 80,000 to 110,000 seeds. The result is that it stifles the growth of the native trees and disturbs the ecological balance. The tree has been found invasive in Sabah, Africa and Melville Island in Australia. The plus point of the specie is that it has rapid growth, and is tolerant of very poor soils. It can go upto 30 metres, 15m and 40 cm girth in 3 years and 23 metres in 9 years. Wood chips are used as paper pulp, and timber is used for buildings and furniture. A hybrid of A. mangium and A. auriculiformis have been found to be more vigorous and better timber. ”

    Invasive in Brazil

    Twenty invasive alien species were recorded in the Paulo Cesar Vinha State Park during a survey carried out in 2006/2007 with the Federal University of Espirito Santo.

    The main invasive alien species that threaten the park biodiversity are acacia (Acacia mangium),…”


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