Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Forestry (pathway cause)



Forestry (pathway cause)


  • Last modified
  • 26 September 2017
  • Datasheet Type(s)
  • Pathway Cause
  • Preferred Scientific Name
  • Forestry (pathway cause)
  • Overview
  • A significant proportion of invasive species are trees that were originally introduced internationally for the perceived benefit of increasing wood production. These include trees for timber, such as Eucalyptus...

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Preferred Scientific Name

  • Forestry (pathway cause)

International Common Names

  • English: Commercial forestry; Plantation forestry; Silviculture
  • Spanish: Silvicultura
  • French: Silviculture

Local Common Names

  • Portugal: Silvicultura


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A significant proportion of invasive species are trees that were originally introduced internationally for the perceived benefit of increasing wood production. These include trees for timber, such as Eucalyptus and Pinus, especially in southern Africa, and trees for fuelwood (and non-timber and environmental benefits), such as Acacia and Prosopis in many dry areas. Such invasive trees may also be grouped with other invasive trees introduced primarily for other reasons, such as fruit production, as an ornamental, for shade, shelter or cover, etc. This pathway is likely to be of declining importance with improved access to information on potential invasiveness.


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Summary of organism types or species introduced

The principal organism types introduced are terrestrial plants, specifically trees suitable for the production of wood, but also shrubs for fuelwood, and other long-lived woody perennials such as some cacti, tree ferns, palms, etc. It is not regarded as a pathway for the introduction of forest (or other) pests and diseases, unless in the rare cases where trees are introduced as whole plants or other vegetative material (with or without soil), rather than as seed which is by far the most prevalent means. As far as is known, there have been no studies on tree seeds for the transmission of seed-borne diseases. There is also concern regarding the increased interest in genetically modifying tree species, and such modified organisms are also likely to be introduced via the forestry pathway.

Principle processes

The principle process of introduction is via seed, and not as live plants (with/without soil), though in the rare cases where this does occur other organisms could be introduced. Many were introduced in the 1800s and 1900s by government departments, and later by research institutes as part of species elimination and growth trials. Private timber companies have also been responsible for the introduction of some species, especially highly productive species, varieties and cultivars, such as of Eucalyptus, Pinus and Poplar for example. Seed of very many invasive trees is still available from mail order companies, and now can be purchased via the internet.

Geographical routes and corridors

These tend to link areas with similar climates and environmental conditions. The early records of tree introductions are over 2000 years old, from around the Mediterranean basin, generally from east to west, but this mostly concerned the movement of fruiting trees such as almond, carob and olive. There was also some, if limited, movement of tree seed along Eurasian overland routes, again mostly fruit trees and mostly east to west. With transoceanic shipping, there was a second and much larger phase of tree introductions across the Atlantic, between Europe and North America, and later between Africa and Latin America, and to Asia and Australasia and across the Pacific. The exchange between some areas was considerable, such as between South Africa and Australia.

Human-mediated history

Trees for timber only began to be introduced at the onset of plantation forestry from the 1700s. Before that time, natural forests were widespread and plentiful enough in relation to humanity’s requirements to allow unsustainable exploitation without the need for artificial regeneration, or only in rare and isolated cases. Then, from the 1800s, colonialization, industrialization and globalization saw the introduction of many tree species around the world intended for wood production in plantations. However, it would appear that the number of different forestry introduction events world-wide peaked sometime in the mid 1900s, and today, many of the trees that can grow well in non-native areas have already been introduced. Even with warnings about potential invasiveness, introductions of trees still occur, if at a lower level than before, and these are likely to continue into the foreseeable future. However, this pathway is likely to be of declining importance with improved access to information on potential invasiveness.

Species Transported by Cause

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SpeciesNotesLong DistanceLocalReferences
Acacia crassicarpa (northern wattle) Yes Yes
Acacia glauca (wild dividivi) Yes Yes
Acacia mearnsii (black wattle) Yes Yes
Acacia saligna (Port Jackson wattle)Introduction as a fuel/fodder tree Yes Cronk and Fuller, 1995
Acer rufinerve (grey snake-bark maple)Deliberately planted in forests Yes
Adelges tsugae (hemlock woolly adelgid) Yes
Adenanthera pavonina (red-bead tree) Yes Yes Orwa et al., 2009
Agrilus planipennis (emerald ash borer) Yes Yes Cappaert et al., 2005; Poland and McCullough, 2006
Albizia chinensis (Chinese albizia) Yes Yes
Amelanchier lamarckii (snowy mespilus) Yes NOBANIS, 2009
Amylostereum areolatum Yes Slippers et al., 2002
Andropogon virginicus (broomsedge) Yes
Artocarpus altilis (breadfruit)Widely cultivated in agroforestry Yes Yes Ragone, 2011
Brachypodium sylvaticum (slender false brome)USA: Oregon, since inroduction (prior to 1939) Yes Yes Abeyakoon and Pigott, 1975; Anzinger and Radosevich, 2008; False Brome Working Group, 2009; Ninot et al., 2000; Palo et al., 2008
Calliandra houstoniana var. calothyrsus (calliandra)Often planted in agroforestry systems Yes Yes Orwa et al., 2009
Castilla elastica (Mexican rubber tree)In its native and introduced range, established plantations provide reliable sources of propagules Yes Space and Flynn, 2002
Cedrela odorata (Spanish cedar) Yes Yes Cintron, 1990
Chromolaena odorata (Siam weed)As a contaminant of forestry Yes Chevalier, 1949
Cinnamomum burmanni (padang cassia)Planted as forestry tree, escaped in wet windward sites on Hawaiian Islands Yes Yes Wagner et al., 1999
Copaifera officinalis (copaiba balsam)Timber species Yes Yes USDA-ARS, 2014
Corymbia citriodora (lemon-scented gum)Used for timber Yes Yes Doran, 1999
Cupressus arizonica (Arizona cypress) Yes Cronk and Fuller, 1995
Dalbergia sissoo Yes Webb et al., 1984
Deparia petersenii subsp. petersenii (Petersen’s lady fern)Spore contaminated equipment and vehicles could be involved in transport. Yes
Discus rotundatus (rotund disc)Sylviculture nurseries Yes Herbert, 2010
Dreyfusia nordmannianae (silver fir adelges) Yes Yes Kirkeby-Thomsen, 1998; Nierhaus-Wunderwald and Forster, 1999
Elaeagnus angustifolia (Russian olive) Yes Katz and Shafroth, 2003
Epiphyas postvittana (light brown apple moth) Yes
Erythrina berteroana (coralbean)Used a live-fences and soil improver Yes Yes Barrance et al., 2003
Eucalyptus globulus (Tasmanian blue gum) Yes Yes
Eucalyptus robusta (swamp mahogany)Timber plantations Yes Yes Orwa et al., 2009
Falcataria moluccana (batai wood) Yes Yes
Flemingia macrophylla (large leaf flemingia) Yes Yes
Fraxinus uhdei (tropical ash) Yes Yes
Gmelina arborea (candahar)Plantation timber production Yes Yes USDA-ARS, 2016
Grevillea robusta (silky oak)Common element introduced in agroforestry systems Yes Yes Orwa et al., 2009
Halyomorpha halys (brown marmorated stink bug)Deliberate dispersal during search for overwintering sites. Yes Yes
Harmonia axyridis (harlequin ladybird) Yes Yes
Hibiscus elatus (blue mahoe)Experimental plantations Yes Yes Francis and Weaver, 1988
Hymenoscyphus fraxineus (ash dieback)infected saplings from nursery Yes Yes Kirisits et al., 2009; Schumacher et al., 2010
Impatiens parviflora (small balsam)On harvested logs Yes Trepl, 1984
Jatropha curcas (jatropha) Yes Pitt, 1999
Lachnellula willkommii (European larch canker) Yes Yes Sylvestre-Guinot and Delatour, 1983
Leptocybe invasa (blue gum chalcid) Yes Yes
Leucaena leucocephala (leucaena) Yes
Limax maximus (leopard slug)Accidental transport with vegetation and soil Yes Yes
Lygodium japonicum (Japanese climbing fern)Can move on infested timber post-harvest Yes Cronk and Fuller, 1995
Macaranga tanarius (parasol leaf tree) Yes Yes
Mangifera indica (mango) Yes Yes Bally, 2006
Megaplatypus mutatus Yes Yes
Melaleuca quinquenervia (paperbark tree) Yes
Miconia calvescens (miconia)From Tahiti to Raiatea as a soil contaminant in plants in pots. J-Y Meyer, personal observation Yes
Myroxylon balsamum (Peru balsam) Yes
Paulownia tomentosa (paulownia) Yes Yes SE-EPPC, 2003
Phytophthora alni species complex (alder Phytophthora)Forest plantation with infected nursery material Yes Jung and Blaschke, 2004
Pinus caribaea (Caribbean pine)Widely cultivated in forestry plantations Yes Yes Francis, 1992
Pinus contorta (lodgepole pine)Large plantations in the British Isles, Fennoscandia, Iceland and New Zealand Yes Elfving et al., 2001; Richardson, 1998; Richardson et al., 2008; Simberloff et al., 2010
Pinus elliottii (slash pine) Yes Yes
Pinus pinaster (maritime pine)For timber Yes Cronk and Fuller, 1995
Populus alba (silver-leaf poplar) Yes Jobling, 1990
Prosopis glandulosa (honey mesquite)As a fuelwood tree Yes Pasiecznik et al., 2001
Prosopis juliflora (mesquite)Introduced as a fuelwood tree Yes Pasiecznik et al., 2001
Prunus serotina (black cherry)At the end of the 18th century, P. serotina was recommended as a timber tree for poor soils and was Yes Cronk and Fuller, 1995; Vanhellemont, 2009
Pyrrhalta luteola (elm leaf beetle) Yes Yes
Raffaelea lauricola (laurel wilt) Yes Yes Fraedrich et al., 2015a
Raffaelea quercivora (Japanese oak wilt)Predicted but not confirmed Yes Yes
Reutealis trisperma (Philippine tung)Timber species Yes Yes IUCN, 2014
Rhagoletis cingulata (cherry fruit fly)Via its host plant P. serotina Yes Yes
Rhus typhina (staghorn sumac) Yes Yes
Rubus argutus (sawtooth blackberry)May be transported with pine seedlings Yes Shelton and Cain, 2002
Rubus parviflorus (thimbleberry)Invades disturbed areas such as clear cut forest sites Yes Oleskevich et al., 1996
Senna siamea (yellow cassia) Yes Yes Hassain, 1999
Senna spectabilis (whitebark senna)Intentionally introduced in agroforestry as a shade tree and hedgerow Yes Yes Mungatana and Ahimbisibwe, 2010; Wakibara and Mnaya, 2002
Sesbania grandiflora (sesbania) Yes Yes
Spathodea campanulata (African tulip tree) Yes ICRAF, 2008
Syzygium cumini (black plum) Yes Morton, 1987
Syzygium grande (sea apple)Species is cultivated as part of teak and timber programme in Bangladesh Yes Yes Hossain, 2003
Tabebuia heterophylla (pink trumpet tree)As a timberspecies Yes Weaver, 1990
Tabebuia rosea (pink poui)One of the most important timber trees in Central America Yes Yes Useful Tropical Plants, 2016
Tapinoma melanocephalum (ghost ant)Observed in forest environments though in low numbers Yes Yes Lester and Tavite, 2004
Tephrosia candida (white tephrosia) Yes Yes
Terminalia catappa (Singapore almond)Timber species Yes Yes Cronk and Fuller, 1995
Thekopsora areolata (cherry spruce rust)Seedlings Yes Yes Cronk and Fuller, 1995
Toona ciliata (toon) Yes Yes
Urochloa distachya (signal grass)Shade tolerant Yes Schultze-Kraft, 1992
Vernicia fordii (tung-oil tree)Planted for use in the tungoil industry Yes Yes Langeland et al., 2008
Vespula pensylvanica (western yellowjacket)Christmas tree trade Yes Yes


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The main means of entry are by land, sea, or air, via the postal service of packets of seed. Few countries apart from Australia, New Zealand and some Pacific islands, have ‘black lists’ prohibiting the entry of seeds of selected species. Otherwise, such trade and transport of tree seed is legal if accompanied by a phytosanitary certificate (not always a requirement). Where restrictions exist, increased intervention of post would reduce illegal introduction of seed, as is significant in New Zealand at least, and more scrutiny of seed imports would reduce the risk of introduction of potential invasive tree species.

Education is also an important aspect; of foresters, those involved in forestry-related businesses, and researchers in forestry institutes and departments (Pasiecznik and Jaenicke, 2008), as well as the public at large. The general public may only order and plant a small amount of seed, relative to the other groups, and these are more likely to be ornamental herbaceous plants anyway. Education of forestry professionals may be the most cost-effective means of preventing further introductions. This could be linked to a further expansion of a global registry of weed risk assessments on forestry species. An Australian system has been adopted by Pacific Island Ecosystems at Risk (PIER), and many trees have been fully assessed, results presented as a single page summary sheet and made freely available via the internet. This provides a guide as to which species may be invasive, and others could be analysed in the same manner.

The possibility of regulating businesses involved in international trade is diminishing in parallel with the deregulation of global ‘free’ trade. However, the introduction of voluntary codes for nurseries in Australia is providing valuable lessons, though one of these is that self-regulation of profit-driven companies is largely influenced by financial gains and losses, and is having only a limited impact to date. Thus, further regulation of introductions appears necessary, in compliance with WTO SPS measures, fully transparent and based on sound scientific methodology. Existing international standards such as ISPM No. 11 (FAO, 2004) originally focusing on impacts on agriculture, now include impacts on biodiversity, the environment in general, and genetically modified organisms, and steps are being made to aid in its enforcement (Quinlan et al., 2003). The biosecurity implications of forestry as a pathway for invasive species is also acknowledged (Cock, 2003), but whether this will impact on new and firmer regulations is yet to be seen.

Once a tree species is introduced, the issues understandably change. Monitoring systems need to be developed and employed for ‘sleeper weeds’, i.e. trees known to be invasive elsewhere but which are not, currently, invasive in the area in question. As for those which are already invasive, there is the simple standard choice of eradication, control or containment.

Mechanical, chemical, cultural or biological control methods have all proved effective, on their own or in various combinations, on most invasive trees on which they have been attempted, and there is a wealth of species and location-specific information that can be found in other datasheets. A recent approach has seen the development of ‘control by utilization’ as a new convergent concept from diverse land-use managers and researchers as a means to control a number of invasive plants from around the world. It is seen as more applicable to trees than to other organism types, as trees have a known economic value (which was why they were introduced in the first place), and the necessary technologies for harvesting and processing are relatively simple, e.g. conversion of small roundwood from weedy trees to marketable timber (Pasiecznik et al., 2006). Prosopis, for example, has seen advances in control by utilization (Pasiecznik, 2001; 2002; 2006). 


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Binggeli P; Hall JB; Healey JR, 1998. An overview of invasive woody plants in the tropics. School of Agricultural and Forest Sciences Publication, 13.

Cock M, 2003. Biosecurity and forests: an introduction - with particular emphasis on forest pests. Biosecurity and forests: an introduction - with particular emphasis on forest pests. Rome, Italy: Forestry Department, FAO. [Forest health and biosecurity working paper FBS/2E.]

FAO, 2004. Pest risk analysis for quarantine pests including analysis of environmental risks and living modified organisms. Pest risk analysis for quarantine pests including analysis of environmental risks and living modified organisms. Rome, Italy: IPPC, FAO. [ISPM No. 11.]

Haysom K; Murphy S, 2003. The status of invasiveness of forest tree species outside their natural habitat: a global review and discussion paper. Rome, Italy: FAO.

Low T; Booth C, 2007. The Weedy Truth about Biofuels. Melbourne, Australia: Invasive Species Council, 46 pp.

Pasiecznik N, 2004. Cinderella species and what happens after midnight? Wallingford, UK: CABI, unpaginated.

Pasiecznik NM, 2001. Prosopis - management by exploitation, not eradication, required to control weedy invasions. In: ACOTANC 2001, the 9th Australian Conference on Tree and Nut Crops. 13-19 April 2001, Perth, Australia.

Pasiecznik NM, 2002. Prosopis (mesquite, algarrobo): Invasive weed or valuable forest resource? Prosopis (mesquite, algarrobo): Invasive weed or valuable forest resource. Coventry, UK: HDRA, 2 pp. [HDRA Policy brief (datasheet).]

Pasiecznik NM, 2006. Limits to Prosopis biocontrol: utilization and traditional knowledge could fill the gap. Biocontrol News and Information,, 27((1)):5N-6N.

Pasiecznik NM, 2007. An introduction to pathways for plant introduction. The Overstory, 192. Hawaii, USA: Permanent Agricultural Resources.

Pasiecznik NM; Brewer MCM; Fehr C; Samuel JH, 2006. Turning trees to timber. A chainsaw milling manual. Coventry, UK: HDRA, 40 pp.

Pasiecznik NM; Jaenicke H, 2008. Underutilised crops and invasive species - understanding the links. In: Underutilised Plants for Food, Nutrition, Income and Sustainable Development, International Symposium, Arusha, Tanzania, 3-7 March 2008. Colombo, Sri Lanka: ICUC.

Quinlan MM; Pasiecznik NM; Sastroutomo SS, 2003. Assessing the environmental risks of invasive species using ISPM No. 11 (Rev. 1): where to start. In: International Workshop on Invasive Alien Species and the IPPC (International Plant Protection Convention), 22-26 September 2003, Braunschweig, Germany.

Tewari JC; Pasiecznik NM; Harsh LN, 2001. Plantation forestry and success of various tree species in arid tropics: Indian experience. In: ACOTANC 2001, the 9th Australian Conference on Tree and Nut Crops, 13-19 April 2001, Perth, Australia.

Links to Websites

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FAO Invasive Forest Trees
Invasive Woody Plants
Pacific Island Ecosystems at Risk (PIER)


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UK: CABI, Nosworthy Way, Wallingford,


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1/5/2008 Original text by:

Nick Pasiecznik, Consultant, France