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(>740 species). Angophora and Corymbia are often treated
as subgenera of Eucalyptus, sensu lato. The genus Eucalyp-
tus (sensu stricto) is currently divided into ten subgenera,
six of which are monotypic (having only one species).
Naturalized eucalypts belong almost exclusively to the
two largest subgenera, Eucalyptus (Monocalyptus, >140
species) and Symphyomyrtus (>360 species) (Table 1).
Most eucalypts are trees (10 to >50 m in height), some
are “mallees” (multistemmed from ground level, usually
<10 m in height), and a few are shrubs. Eucalypts are the
tallest nonconiferous trees in the world. Several species
(E. regnans, E. grandis, E. deglupta) reach more than 70 m
in height. The tallest known specimen of E. regnans was
110 m. The tallest known living specimen of this taxon in
Tasmania is 99.6 m tall. The maximum age of eucalypt
species, estimated from dendrochronological (tree-ring)
and radiocarbon measurements, is between 400 and 600
years. Interestingly, in spite of the otherwise enormous
range of adaptations among eucalypts, shade-tolerant
subcanopy species are not known.
The eucalypt breeding system is one of mixed mating
with preferential outcrossing. A reduction in fruit (cap-
sule) production, seed set, and seedling vigor has been
demonstrated after self-pollination. However, eucalypts
generally do not need any special pollinators. They are
pollinated by many species of bees and wasps and, to a
lesser extent, by birds, mammals, and wind.
Most eucalypts are well adapted to frequent fi res. The
most common adaptations are lignotubers and epicormic
buds. The lignotuber is a woody swelling at the base of
the stem; most eucalypts sprout from lignotubers. The
epicormic buds (buds present in the outer bark) allow the
sprouting of new branches from stems (after a fi re or after
a severe winter). Some species are able to sprout from both
lignotubers and stems (combination sprouters). Another
adaptation to fi reprone environments is serotiny (most
seeds are kept in fruits and released only after fi re). Some
successful invaders among eucalypts are obligate seeders,
depending completely on seed production (E. conferru-
minata, E. grandis). Seeds can be shed in large numbers
(up to 4,000 seeds per m2). However, eucalypts produce
very small seeds, usually 13 mm long and less than 2 mg.
Some species have seeds even lighter than 0.5 mg (e.g.,
E. grandis and deglupta). Eucalypts produce seeds with no
obvious endosperm (tissue that surrounds and nourishes
the embryo). Therefore, the newly emerged seedlings are
sustained by cotyledon photosynthesis, and their roots
have to reach suitable substrate very soon.
Eucalypts are the dominant species of the wet coastal
and near coastal parts of Australia. However, some species
Early Detection and Rapid Response / Endangered and Threatened
Species / Herbicides / Invasion Economics / Islands / Lag Times /
Risk Assessment and Prioritization
Clout, M. N., and P. A. Williams, eds. 2009. Invasive Species Management:
A Handbook of Techniques. Oxford: Oxford University Press.
Genovesi, P. 2007. Limits and potentialities of eradication as a tool for
addressing biological invasions (385400). In W. Nentwig, ed. Biological
Invasions. Ecological Studies, Vol. 193. Heidelberg: Springer-Verlag.
McNeely, J. A. 2001. The Great Reshuffl ing: Human Dimensions of Invasive
Alien Species. Gland, Switzerland: IUCN.
Myers, J. H., D. Simberloff, A. M. Kuris, and J. R. Carey. 2000. Eradi-
cation revisited: Dealing with exotic species. Trends in Ecology and
Evolution 15: 316320.
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of invasive species. Occasional Paper 26. Gland, Switzerland: IUCN.
University of California, Davis
Stellenbosch University, Matieland, South Africa
Over 800 species of eucalypts (Angophora, Corymbia, and
Eucalyptus) are native to Australia and a few Pacifi c islands.
These genera include some of the most important solid
timber and paper pulp forestry trees in the world. Besides
pines, eucalypts are the most commonly and widely cul-
tivated exotic trees. Almost 20 million ha (200,000 km2)
of eucalyptus plantations exist in tropical, subtropical, and
temperate countries. In many countries, eucalypts are the
most common and conspicuous nonnative trees. Over 70
species are naturalized (reproduce and maintain their pop-
ulations) outside their native ranges. However, given the
extent of cultivation, eucalypts are markedly less invasive
than many other widely cultivated trees and shrubs. Rea-
sons for this relatively low invasiveness are still not com-
pletely understood. Conclusions about positive or negative
environmental and economic impacts of eucalypts are often
anecdotal, highly controversial, and context-dependent.
Eucalypts (family Myrtaceae, subfamily Leptosper-
moideae) are currently classifi ed into three genera: Ango-
phora (14 species), Corymbia (113 species), and Eucalyptus
05_Simberloff10_E_p169-222.indd 20305_Simberloff10_E_p169-222.indd 203 9/13/10 10:02:33 AM9/13/10 10:02:33 AM
From Daniel Simberloff and Marcel Rejmánek, editors, Encyclopedia of Biological Invasions,
Berkeley and Los Angeles: University of California Press, 2011.
Naturalized Species of Corymbia and Eucalyptus
calophylla C, LS Australia (Western Australia), Hawaii?, New Zealand?
citriodora B, LS Australia (Victoria, Western Australia), California, Hawaii?, India, South Africa, Zimbabwe
cifolia C, LS Hawaii, New Zealand, South Africa
maculata B, LS Australia (Victoria, Western Australia), South Africa?
torelliana B, LS Australia (Queensland), China, Florida
botryoides S, CS Australia (Norfolk Island, South Australia, Victoria, Western Australia), Hawaii, New Zealand
bridgesiana S, LS Hawaii, South Africa?
camaldulensis S, CS/SS Argentina?, Australia (Western Australia) Bangladesh, California,a,b Cyprus, France, Greece,
Hawaii,a India, Israel, Italy, Pakistan, Portugal, Spain,a,b South Africa,a,b Zimbabwe
cinerea S, LS Hawaii, New Zealand, South Africa
cladocalyx S, SS Australia (Victoria, South Australia, Western Australiab), California, Hawaii?, South Africaa
conferruminata S, OS, often confused Australia (Victoria, Western Australia), California, South Africaa,b
with E. lehmanii
crebra S, LS Hawaii, South Africa?
deanei S, LS Hawaii, South Africa?
deglupta S, OS Hawaii, Malaysia?
delegatensis E, OS New Zealand, South Africa?
elata E, LS New Zealand, South Africa?
fastigata E, OS California, New Zealand, South Africa
globulus S, CS, incl. E. maidenii Australia (Western Australia), Azores, California,a,b Canary Islands, Chile,a China,a France,
Hawaii,b India, Italy?, Jamaica, New Zealand,a,b Pe ru,b Portugal,a Spain,a South Africa,a
gomphocephala S, SS Australia (Victoria), Cyprus, Hawaii, South Africa, Spain
grandis S, OS Argentina?, California, Florida, New Zealand, Nigeria?, South Africaa,b
gunnii S, LS New Zealand, Portugal, Spain
leucoxylon S, LS Australia (Victoria), New Zealand?, South Africa
longifolia S, LS Australia (New South Wales), South Africa?
macarthurii S, LS California, New Zealand, South Africa?
marginata E, LS Hawaii, South Africa?
microcorys S, LS Australia (Western australia), Hawaii,a Sri Lanka, South Africa, Zimbabwe
muelleriana E, LS Australia (Western Australia), New Zealand?, South Africa?
nitens S, SS New Zealand, South Africa?a
obliqua E, LS New Zealand, South Africa
occidentalis S, LS Australia (Victoria), South Africa?
ovata S, LS California, New Zealand
paniculata S, LS Hawaii,a South Africa,a Zimbabwe
pilularis E, OS Hawaii,a New Zealand, South Africa
polyanthemos S, LS Australia (Western Australia), California, South Africa?
pulchella E, LS California, New Zealand
regnans E, OS New Zealand, South Africa?
resinifera S, LS Hawaii, Mexico?, New Zealand
robusta S, OS Brazil?, California, Florida, France, Hawaii,a La Réunion Island, Madagascar,a Malaysia?,
New Zealand, Portugal, South Africa, Spain, Sri Lanka, Zimbabwea,b
rudis S, LS California?, Hawaii
saligna S, LS Australia (Western Australia), Florida, Hawaii,a New Zealand, South Africa?, Sri Lanka,?,
salubris S, OS Australia (Queensland), South Africa
sideroxylon S, CS Botswana?, California, Hawaii, New Zealand, Portugal, South Africa,a Spain
sieberi E, SS New Zealand, South Africa
tereticornis S, LS California, Cyprus, Hawaii, India,a Mexico (reported as E. resinifera), New Zealand?, South
Africa, Zimbabwe
viminalis S, LS California, Hawaii, New Zealand, South Africa?
note: Naturalized (reproducing and maintaining populations without human help) species of Corymbia and Eucalyptus. Based on published records, labels on herbarium
specimens, information from experienced botanists and foresters, and personal observations. Question marks indicate lack of certainty as to whether the species is already
naturalized, or is just a casual resident. Only species reported as naturalized from at least two countries are included. Subgenera: B – Blakella, C – Corymbia, E – Eucalyptus
(Monocalyptus), S – Symphyomyrtus. Regenerative strategies: LS – lignotuber sprouter, SS – stem sprouter, CS – combination sprouter, OS – obligate seeder.
a Extensive planting.
b Species is classifi ed as invasive in a particular state (spreading spontaneously away from points of introduction).
05_Simberloff10_E_p169-222.indd 20405_Simberloff10_E_p169-222.indd 204 9/13/10 10:02:33 AM9/13/10 10:02:33 AM
area of more than 52 million ha. The most commonly cul-
tivated eucalypt is probably E. globulus (Tasmanian blue
gum, with 2.3 million ha worldwide in 2008). Eucalyptus
globulus is the primary source of global eucalyptus oil pro-
duction, with China being the largest commercial producer.
The other three most commonly cultivated eucalypts are
E. camaldulensis (river red gum), E. grandis (fl ooded gum),
and E. tereticornis (forest red gum). Current estimates of
areas of eucalyptus plantations on individual continents
and in Oceania are summarized in Table 3. The American
statistic is dominated by Brazil, with over 3.5 million ha of
plantations, while in Asia the leader is India, with over 5
million ha, including small cultivations on farms.
Eucalypt planting has accelerated recently in many trop-
ical countries. However, extensive planting in the humid
tropics has been inhibited by the incidence of pathogens
and insect pests. Only a few species, such as E. deglupta, E.
pellita, and E. urophylla, appear to be adapted to hot, humid
environments. Eucalypts, because of their rapid growth and
capacity for producing biomass, have been recently widely
mentioned as feedstock for biofuels (e.g., E. globulus, E.
grandis, E. robusta, E. saligna, E. urophylla). Widespread use
for this purpose could substantially increase propagule pres-
sure and increase the probability of local invasions.
Eucalypts have enjoyed a history of widespread planting
similar to that of pines. Given this, and the many spe-
cies involved (with representatives of most of the major
taxonomic and functional groups in the genus), we would
expect to fi nd the full range of outcomes: everything from
taxa that are highly invasive and cover large areas as invad-
ers to species that fail to recruit any offspring. Indeed, euca-
lypts, like pines, are prominent species on many national
or regional weed lists in many parts of the world. How-
ever, they have been orders of magnitude less successful as
(E. rameliana, E. pachyphylla) extend to arid regions with
annual precipitation below 350 mm. Within their native
range, most eucalypt species grow in tall forests, wood-
lands, and savannas. Seasonal fl ooding is essential for suc-
cessful regeneration of some species (E. camaldulensis).
Over 20 species of eucalypts can grow on saline soils (e.g.,
E. robusta in swampy estuarine habitats or E. camaldulensis
in valleys of old river systems). Some small trees or shrubs
(e.g., E. coccifera or E. paucifl ora subsp. niphophila) are
adapted to subalpine areas (9001,400 m) in Australia.
When Australia was settled in the eighteenth century,
eucalypts were used for farm buildings, fencing, and fi re-
wood. The fi rst eucalypt species to be cultivated from seeds
outside its native range was E. obliqua in Royal Botanic
Gardens at Kew, United Kingdom, in 1774. Other species
were soon cultivated in botanical gardens and arboreta
Areas of Eucalyptus Plantations beyond Their Native Range in 2008
Million ha
Asia 8.3 (India: >5.0; China: >2.0; Vietnam:
Americas 6.4 (Brazil: >3.6; Chile: >0.3; Argentina:
>0.2; Peru: >0.2)
Africa 2.2 (South Africa: >0.4; Angola: >0.2;
Morocco: >0.2)
Europe 1.3 (Portugal: >0.6; Spain: >0.5;
Italy: >0.07)
Oceania 0.9
cultivated.html and other sources.
Naturalized Corymbia and Eucalyptus by Regenerative Strategies
Number Regenerative Number
Subgenus of Species Strategy of Species
Blakella 3 Lignotuber 28
Corymbia 2 Stem sprouters 4 (1 invasive)
Eucalyptus 10 Combination 4 (2 invasive)
Symphyomyrtus 30 (6 invasive) Obligate seeders 9 (3 invasive)
note: Numbers of naturalized Corymbia and Eucalyptus species by subgenera
and by regenerative strategy. Only species reported as naturalized in at least two
countries are included. Derived from Table 1.
in Europe as botanical curiosities and ornamentals. Once
in cultivation, eucalypts appealed to foresters because
of their fast growth (even on nutrient-poor soils) and
because they yielded a variety of timber and nontimber
products. Productivity of properly designed plantations is
2070 m3 ha–1 year–1. Today, eucalypts provide saw tim-
ber, plywood, fi berboard, pulp for paper, poles, fi rewood,
charcoal, essential oils, honey, and shelter. They are also
considered to be suitable trees for biofuel production.
To date, the total area of eucalyptus plantations has
been increasing exponentially. The global extent of euca-
lypt planting outside Australia reached 15.6 million ha in
the 1990s—more than four times the global total in the
1970s. In 2008, the total area of eucalyptus plantations was
estimated at 19.6 million ha. This is an area larger than the
state of Washington, or the nations of Austria and Hungary
together. Only one genus of trees is more extensively culti-
vated than eucalypts: Pinus (pines), with a global plantation
05_Simberloff10_E_p169-222.indd 20505_Simberloff10_E_p169-222.indd 205 9/13/10 10:02:33 AM9/13/10 10:02:33 AM
2.0 and 5.5 m s–1. Lower terminal velocity values mean that
seeds can be carried by winds for longer distances.
HIGH MORTALITY OF SEEDLINGS. As noted above, euca-
lypts produce very small seeds (usually <2 mg) with no
obvious endosperm. Therefore, the newly emerged seed-
lings are sustained by cotyledon photosynthesis, and their
roots have to penetrate into suitable wet substrate very
quickly. As a result, eucalypts can successfully regenerate
from seeds only on wet, bare soil free of litter. However,
seedlings in wet environments frequently die because of
damping off caused mainly by parasitic fungi (Botrytis,
Colleotrichum, Cylindrocladium, Fusarium) and water
molds—oomycetes (Phytophthora, Pythium). Moreover,
if there is any dense vegetation around, tiny eucalyptus
seedlings are necessarily losers. Therefore, the window of
opportunity for eucalyptus seedlings is rather narrow.
seems that the majority, if not all, of ectomycorrhizal
fungi (EM) associated with eucalypts outside Australia are
Australian species that have spread with their hosts. How-
ever, the importance of EM for establishment, growth,
and spread of introduced eucalypts is not clear. There has
been no example reported from exotic eucalypts that can
compare with the dramatic response to mycorrhizal inoc-
ulation reported from exotic pine seedlings in Australia
or South Africa in the early years of their introduction.
With their more fi nely branched root systems and evo-
lutionary adaptation to low phosphorus soils, eucalypts
seem to be less dependent on EM than pines. The lack
of EM may be not important for seedlings transplanted
from nurseries, but, as some ecologists have suggested, it
may be crucial for spontaneous establishment of seedlings
away from plantations. However, colonization of eucalypt
roots usually does not start with EM, but with ubiquitous
nonspecifi c vesicular-arbuscular endomycorrhizae (AM)
(Gigaspora spp., Glomus spp.). It is possible that AM play
a more important role in initial eucalypt seedling estab-
lishment than EM.
Finally, we may ask whether some eucalypt species are
inherently more invasive than others. Or is it only propagule
pressure (the extent of planting) that makes some species
more often naturalized, and some of them even somewhat
invasive (spreading spontaneously over 100 m from points
of introduction)? Tables 1 and 2 show that the majority of
species naturalized in at least two countries (30) belong to
the subgenus Symphyomyrtus. This seems to be just propor-
tional to the size of this subgenus (>360 species). Still, all
six species that can be classifi ed as invasive in at least one
invaders than pines and several other widely planted trees,
including many fl eshy-fruiting trees (e.g., Elaeagnus angus-
tifolia, Ligustrum spp., Psidium spp., Morella (Myrica) faya)
and legumes (e.g., Acacia spp., Prosopis spp., Leucaena leu-
cocephala). Where eucalypts have invaded, they have very
seldom spread considerable distances from planting sites,
and their regeneration is frequently sporadic (Fig. 1). Given
that many eucalypts produce very large quantities of seeds,
and in light of their diverse adaptations for dealing with
disturbance (notably fi re), their poor (or at best mediocre)
performance as invaders is enigmatic. Many other Austra-
lian trees, including taxa that evolved under the same con-
ditions as Eucalyptus, are much more invasive in other parts
of the world (e.g., Melaleuca quinquenervia, Hakea spp.,
and many species of Acacia). What makes this difference?
Are eucalypts inherently less invasive, or are they just a tick-
ing time bomb? There seem to be three major reasons for
the limited invasiveness of eucalypts: (1) relatively limited
seed dispersal, (2) high mortality of seedlings, and (3) lack
of compatible ectomycorrhizal fungi.
eucalypts are very small, but they have no adaptations for
dispersal (wings or fl eshy tissues) that would help them to
proceed from local establishment (naturalization) to inva-
sion. The passive release of seeds is undoubtedly aided by
wind. However, all rigorous studies of eucalypt seed disper-
sal and seedling spatial distribution show that in general,
seeds are dispersed over quite short distances. This is in
agreement with measurements of terminal descent veloci-
ties of their seeds. While terminal velocities of seeds of
invasive pine species are between 0.7 and 1.5 m s–1, and for
invasive maples (Acer) between 0.9 and 1.2 m s–1, terminal
velocities of seeds of all tested eucalypt species are between
FIGURE 1 A stand of Eucalyptus globulus on Santa Cruz Island,
California. Saplings of eucalypts are usually found only close to planta-
tions. (Photograph courtesy of M. Rejmánek.)
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Of all widely used plantation species, eucalypts have
attracted by far the most criticism. There are four main
concerns: (1) excessive water use and suppression of food
crops growing nearby, (2) suppression of ground vegetation
(possible allelopathic effects) and resulting soil erosion,
(3) increased fi re hazard, and (4) generally poor wildlife
value. There is some substance to each of these concerns.
country belong exclusively to the subgenus Symphyomyr-
tus. There seems also to be a somewhat larger proportion
of subgenus Eucalyptus species among commonly planted
eucalypts with no evidence of naturalization (Table 4). On
average, seeds of species in the subgenus Symphyomyrtus
are smaller (a notable exception, however, is E. globulus)
than seeds of species in the second largest subgenus—
Eucalyptus (>140 species). Therefore, terminal velocities
of Symphyomyrtus seeds should be less, and they could be
dispersed somewhat longer distances by wind. Also, none
of the species classifi ed as invasive in at least one country
is a straight lignotuber sprouter (LS). This could also point
to the primary importance of seed dispersal in invasive-
ness. Nevertheless, the more straightforward explanation is
that species classifi ed as invasive have been planted more
extensively (see notes in Table 1). Then, however, reasons
for their extensive planting may be correlated with their
growth and timber characteristics that are associated with
particular regenerative strategies.
Considering the amount of planting, eucalypts are rela-
tively noninvasive species. If their potential spread is
the only concern, then eucalypts should not be planted
near rivers and streams. Temporarily fl ooded or eroded
banks are suitable habitats for spontaneous establishment
of their seedlings (Fig. 2). Moreover, their seeds can be
dispersed for long distances by running water. However,
there are other concerns.
FIGURE 2 Eucalyptus camaldulensis
is invasive along hundreds of kilome-
ters of rivers in South Africa’s West-
ern Cape province. The images show
(A) a general view of E. camdulensis
established in the Berg River, (B) the
extreme persistence of adult plants
due to their ability to sprout from the
roots, and (C) microsites for seedling
establishment. (Photographs cour-
tesy of D. M. Richardson.)
Eucalyptus Species with No Conclusive Evidence of Naturalization
Species Subgenus Regenerative Strategy
acmenoides Eucalyptus (Monocalyptus) Lignotuber sprouter
bosistoana Symphyomyrtus Lignotuber sprouter
erythrocorys Eudesmia Lignotuber sprouter
fraxinoides Eucalyptus (Monocalyptus) Obligate seeder
jacksonii Eucalyptus (Monocalyptus) Lignotuber sprouter
macranda Symphyomyrtus Lignotuber sprouter
paucifl ora Eucalyptus (Monocalyptus) Lignotuber sprouter
preissiana Eucalyptus (Monocalyptus) Lignotuber sprouter
pulverulenta Symphyomyrtus Lignotuber sprouter
punctata Symphyomyrtus Lignotuber sprouter
radiata Eucalyptus (Monocalyptus) Lignotuber sprouter
smithii Symphyomyrtus Lignotuber sprouter
spathulata Symphyomyrtus Obligate seeder
torquata Symphyomyrtus Lignotuber sprouter?
note: Commonly cultivated Eucalyptus species with no conclusive evidence of
naturalization. Species listed here are relatively commonly cultivated or tested,
but the extent of their cultivation is still very limited when compared with many
major plantation species listed in the Table 1. Therefore, “no conclusive evidence of
naturalization” does not necessarily mean conclusive noninvasiveness.
05_Simberloff10_E_p169-222.indd 20705_Simberloff10_E_p169-222.indd 207 9/13/10 10:02:34 AM9/13/10 10:02:34 AM
Because of accumulated litter, dense eucalypt stands are
extremely fl ammable. The situation is exacerbated after
winter freezes, when trees drop dead branches and foliage.
During the last two weeks of 1990, a mass of frigid arctic air
moved into California, and temperatures plunged to record
lows along the Pacifi c Coast. It is very likely that fuel accu-
mulation in unmanaged eucalyptus stands contributed to
the intensity of the tragic fi re in the Berkeley–Oakland Hills
area in October 1991 (Fig. 3).
In arid and semiarid countries, where shortage of water
is a big concern, benefi ts of eucalypt plantations may be
outweighed by their negative environmental impacts:
namely, their high water consumption. In South Africa,
invasive eucalypts have been cleared over large areas as
part of a national restoration program called Working for
Water. In most areas, standing trees are felled and, where
it is practically possible, their timber is harvested. Where
recovery of the timber is impractical, felled plants are often
stacked and burned. The most challenging management
operations involve clearing river banks in large parts of
the Western Cape province of dense stands of invasive E.
camaldulensis. Clearing alone often causes destabilization
of the river banks, and research is under way to determine
the most effective ways of thinning the invasive stands
gradually while simultaneously reintroducing key native
plants to stabilize the sites and launch succession toward a
sustainable community dominated by native plants.
The fact that eucalypt seeds do not have dormancy, with
seed storage in the soil lasting less than a year, makes local
Nevertheless, it is important to realize that in many tropi-
cal countries, where eucalypts are grown on degraded soils
unsuitable for continuing to support native trees (usually
abandoned agricultural land), fuel and other products of
resprouting eucalypts can greatly reduce the increasing
human pressure on the remnants of natural forests. Even
here, however, deleterious human practices associated with
consecutive cutting cycles may eventually lead to yield
decline and forest site degradation on a long-term basis.
For long-term site quality and sustainability of biomass
production, prolonging the cutting cycles and prohibiting
or controlling litter raking appears to be imperative.
Eucalypts may be a major source of both nectar and
pollen for honeybees. Because fl owering of many euca-
lypts is abundant and lasts for long periods, some spe-
cies (particularly E. camaldulensis and E. cladocalyx) are
very valuable for the honey industry. When compared
with native vegetation, usually signifi cantly lower spe-
cies diversity of arthropods, small mammals, and birds is
reported from eucalyptus stands. For example, in Angel
Island State Park, California, 41 species of birds were
observed in native vegetation, but only 30 species in the
eucalyptus forest. However, there may be also some other
trends: approximately three times more California slender
salamanders (Batrachoseps attenuatus) were found in euca-
lyptus vegetation than in native. Even more importantly,
in California, eucalypts are major providers of shelter and
nectar to the migrating monarch butterfl y (Danaus plex-
ippus) during winter months.
Allelopathic effects of eucalypts on native species are
widely reported. Such reports are mostly based on labo-
ratory bioassays. However, some fi eld trials also point to
decline of seed germination and increase of seedling mor-
tality of some native species. If not chemical inhibition,
then at least accumulation of dead material on the fl oor of
eucalypt plantations retards regeneration of native species.
Mixed-species plantations of eucalypts with native (mainly
nitrogen-fi xing) species have the potential to increase pro-
ductivity while maintaining soil fertility and biodiversity.
Tasmanian blue gums (E. globulus) were planted in the
San Francisco area of California as early as the second half
of the nineteenth century. Having been in this landscape
for such a long time, many old eucalypts are now treated
as trees with “historical value” or as “heritage trees.” Many
people feel that eucalypts give California a “unique exotic
avor” lacking in other parts of the United States. This is
the reason why removal of eucalypts on Angel Island in the
San Francisco Bay (19901996) sparked a raging contro-
versy. In a very balanced way, the history of this episode was
described by Peter Coates.
FIGURE 3 It is undeniable that unmanaged stands of some eucalypt
species can accumulate highly fl ammable dead material. To what
extent Tasmanian blue gum (Eucalyptus globulus) groves contributed
to the intensity of the tragic Berkeley–Oakland Hills fi re in 1991 remains
a subject of bitter discussions. This hazy but dramatic photograph of
the 1991 fi re was shot by former fi re captain Wayne Drager through a
plexiglass window, using a disposable camera on a bumpy helicopter
ight. (Photograph courtesy of Wayne Drager.)
05_Simberloff10_E_p169-222.indd 20805_Simberloff10_E_p169-222.indd 208 9/13/10 10:02:35 AM9/13/10 10:02:35 AM
contain less than 510 µg L-1 phosphorus and less than 250
600 µg L-1 nitrogen. These nutrient concentrations are at
least 2 to 10 times as high in eutrophic waters and can have
major effects on biotic communities, including the loss of
biodiversity and the invasion of nonnative species (Fig. 1).
Eutrophication is a slow natural process. The slow accu-
mulation of nutrients is especially prevalent in deposi-
tional environments, such as lakes and wetlands, where
nutrients and sediments derived from a watershed are
collected in a basin and permanently or temporarily
immobilized and stored. For example, estuaries are natu-
rally eutrophic, and hence very productive, because they
receive nutrients derived from watersheds and tidal fl ows.
Lakes accumulate sediments and organic matter and over
time convert into productive and nutrient-rich shallow
lakes and emergent marshes. Other naturally eutrophic
systems are areas along the coast where upwelling con-
veys nutrient-rich water to the surface. As an ecosystem’s
nutrient status changes over millennial time scales, so
does its community structure, with local extinction and
colonization of new species working in concert to pro-
duce species-rich and productive ecosystems.
However, the process of eutrophication can be greatly
accelerated by human activities, such as runoff of excess fer-
tilizer, sewage effl uent, and stormwater runoff. In Australia,
for example, sites affected by human activity have mean lev-
els of 780 µg L-1 N and 95 µg L-1 P compared to 300 µg L-1
N and 21 µg L-1 P at less impacted sites. Because estuaries
eradication an achievable goal. However, resprouting of cut
trees from stumps or lignotubers, which is advantageous in
some situations, makes control of eucalypts diffi cult. Con-
tinuously cutting back the regrowth can eventually kill
the tree, but this is a labor-intensive and expensive control
method. Herbicide applications (triclopyr or glyphosate) to
freshly cut stumps can greatly reduce resprouting. Because
eucalypts are valued as timber and ornamental trees in many
settings, biological control is very unlikely as an option.
Allelopathy / Fire Regimes / Forestry and Agroforestry /
Invasiveness / Mycorrhizae / Propagule Pressure / Trees and Shrubs
Coates, P. 2006. American Perceptions of Immigrant and Invasive Species.
Berkeley: University of California Press.
Díez, J. 2005. Invasion biology of Australian ectomycorrhizal fungi intro-
duced with eucalypt plantations into the Iberian Peninsula. Biological
Invasions 7: 315.
Doughty, R. W. 2000. The Eucalyptus: A Natural and Commercial History
of the GumTree. Baltimore: The Johns Hopkins University Press.
Keane, P. J., G. A. Kile, F. D. Podger, and B. N. Brown, eds. 2000. Dis-
eases and Pathogens of Eucalypts. Collingwood, Australia: CSIRO
Nicolle, D. 2006. A classifi cation and census of regenerative strategies in
the eucalypts (Angophora, Corymbia and Eucalyptus—Myrtaceae), with
special reference to the obligate seeders. Australian Journal of Botany
54: 391407.
Poore, M. E. D., and C. Fries. 1985. The Ecological Effects of Eucalyptus.
FAO Forestry Paper 59: 187. Rome: FAO.
Rejmánek, M., D. M. Richardson, S. I. Higgins, M. J. Pitcairn, and E.
Grotkopp. 2005. Ecology of invasive plants: State of the art (104161).
In H. A. Mooney, R. N. Mack, J. A. McNeely, L. E. Neville, P. J. Schei,
and J. K. Waage, eds. Invasive Alien Species: A New Synthesis. Washington,
DC: Island Press.
Ritter, M., and J. Yost. 2009. Diversity, reproduction, and potential for
invasiveness of Eucalyptus in California. Madroño (in press).
Slee, A. V., M. I. H. Brooker, S. M. Duffy, and J. G. West. 2006. Euclid:
Eucalypts of Australia, 3rd ed. Collingwood, Australia: CSIRO.
Williams, J., and J. Woinarski, eds. 1997. Eucalypt Ecology: Individuals to
Ecosystems. Cambridge: Cambridge University Press.
University of Maryland Center for Environmental Science,
Eutrophication is the natural or anthropogenic accumula-
tion of nutrients in soil or water (from Greek eu = “well” and
trophe =nourished”). Oligotrophic (low-nutrient) waters
FIGURE 1 The impacts of eutrophication on aquatic ecosystems.
(Figure developed by the Integration and Application Network of the
University of Maryland Center for Environmental Science.)
05_Simberloff10_E_p169-222.indd 20905_Simberloff10_E_p169-222.indd 209 9/13/10 10:02:36 AM9/13/10 10:02:36 AM
... On the one hand, it brings substantial economic benefits to land owners and industry [54,55]. On the other, it often has negative environmental impacts, namely decrease in biodiversity, invasion to contiguous ecosystems (rare and limited), decrease of water and nutrient availability in soil, and increase of fire hazard [54][55][56]. Nevertheless, most of these impacts may be prevented or substantially minimized by proper forest management [54][55][56][57][58]. ...
... On the other, it often has negative environmental impacts, namely decrease in biodiversity, invasion to contiguous ecosystems (rare and limited), decrease of water and nutrient availability in soil, and increase of fire hazard [54][55][56]. Nevertheless, most of these impacts may be prevented or substantially minimized by proper forest management [54][55][56][57][58]. Meanwhile, from the perspective of the exotic species, cultivation protects juvenile individuals against environmental stochasticity and preserves founder populations; thus, it may facilitate their naturalization and invasion in the arrival territories [59][60][61]. ...
... Meanwhile, from the perspective of the exotic species, cultivation protects juvenile individuals against environmental stochasticity and preserves founder populations; thus, it may facilitate their naturalization and invasion in the arrival territories [59][60][61]. Moreover, synergies may happen between the wide recurrent cultivation of Eucalyptus, outside its native range, and the flammability of its forests, especially the poorly managed or abandoned ones [46,56,62,63]. As a result, large and intense fires may create plenty of good sites for Eucalyptus natural recruitment [58]. ...
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Fire regimes are changing in several regions of the world. In those regions, some exotic species may be better adapted to new regimes than the native species. This study focused on identifying the microsite characteristics associated with the occurrence of post-fire Eucalyptus globulus regeneration from seeds, outside the species native-range. This information is important in helping to assess the naturalization status of the species, to understand its invasion risk, and to manage wildlings in plantations. To characterize the establishment niche, pairs of microsites (sapling presence/absence) were sampled in four salvage-logged plantations of E. globulus two years after fire (20 pairs/plantation). Microsites of wildlings from three size classes and control microsites were established in one of these plantations (20 quartets) in order to characterize the recruitment niche and to assess ontogenic niche shifts. Two post-fire wildling cohorts were identified. The first emerged just after fire and was abundant. The second emerged after logging and was scarce, probably due to seed limitation. First-cohort wildlings were observed in microsites characterized by a high incidence of fire-related variables (charcoal, ash, increased soil pH and K). The aggregated distribution of these wildlings and their association with other species may indicate the existence of facilitative relationships and/or the exploitation of resource-rich patches. All these factors were relevant for first-cohort persistence and likely also for its establishment and recruitment. Second-cohort wildlings occurred in microsites where salvage-logging disturbance was evident, showing the importance of this disturbance for its emergence. Wildling size diversity was explained by the two recruitment events and by the asymmetrical competition between wildlings and adults. No niche shifts were detected. The high densities of E. globulus wildlings found established in burnt plantations indicated naturalization was in progress. The timing of major recruitment events and the phenology of the species should be considered for monitoring this regeneration and scheduling control interventions, if required.
... Within those places, it has quickly spread as an introduced species, helped by the efforts of the timber industry, which values eucalyptus wood because of its rapid growth rate, especially-but not exclusivelyto obtain pulpwood as raw material for the production of white paper (Stanturf et al. 2013). Some places where eucalyptus plantations have caused important conflict are South America, India, California, and the Iberian Peninsula (Rejmanek and Richardson 2011). ...
... There, where eucalypti are planted, no other trees are allowed to grow, so they do not affect productivity (Periódico Resumen 2014). At the same time, due to high water absorption rates in eucalypti, soils dry fast, lowering the presence of water in the ecosystem (Rejmanek and Richardson 2011). Additionally, herbicides and other chemicals are widely used, polluting the land and water (Gonçalves de Souza and Lopes 2017). ...
... Altogether, repeated over and over after several rotations of planting and harvesting trees, eucalypti monoculture provokes a tremendous impact on biodiversity (Calviño-Cancela 2013; Proença et al. 2010;Rodríguez-Suárez et al. 2011). These trees are also accused of facilitating the presence and spreading of wildfires (Rejmanek and Richardson 2011). This is why they have been labeled desertos verdes (green deserts), because they dry the land, ending with water and life, as well as because of the monochromatic endless green of the plantations. ...
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In Brazil, since the early 2000s, different documentaries have raised awareness about the problematic issues that tree plantations, especially eucalyptus, provoke, as they are propagated across the country. By means of interviews and a mix of investigative and expository styles, these films address and denounce the controversial role and power of the timber industry. However, in the last few years, other works have approached the relationships between planted forests and local ecosystems, offering an alternative perspective. This essay analyzes two recent films on the issue, the short film Gerais, and the 78 min long Do pó da terra, released in 2015 and 2016, respectively, while looking at another short documentary, Desertos verdes: plantações de eucaliptos, agrotóxicos e água, released in 2017, a straightforward documentary that advocates against eucalyptus plantations, interviews specialists and activists, and shows data that work as a report about the situation. In Gerais and Do pó da terra, forest plantations are not central narratives, rather, the focus is on specific communities and their customs. Through testimonial, observational, and poetic modes, they discuss the challenges faced by local inhabitants as their unique lifestyles and sociocultural expressions are threatened. Thus, this essay explains how, instead of images of destruction and the specificities of eucalyptus environmental effects, these documentaries choose to show the connection of local people and their art with the land, their daily life, and the changes they face. By crucially emphasizing the different timelines in play, that of western modernity, and that of alternative understandings of life–nature, they differ from other approaches towards filming environmental conflict that stress the immediacy of the situation. These two films offer a more intimate perspective of human beings, in interplay with their ecosystem, which allows for reflection on how they cohabitate and look forward.
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Eucalyptus globulus Labill. is a widespread forest tree species, reported as naturalized across the introduced range, often showing abundant natural regeneration after wildfires. This paper studies a post-fire cohort of seedlings derived from a small, isolated E. globulus stand in central Portugal. The aim is to better understand the genetic dynamics and dispersal mechanisms of naturally established E. globulus populations in the introduced range. The seedling density at 55 m from adult trees was 12,000 ha−1, the farthest seedling being registered at 101 m. Post-fire expansion occurred in a southward direction, in accordance with predominant wind. Seedlings had significantly lower levels of genetic diversity (Ae = 5.8.; He = 0.8) than adult trees (Ae = 6.5; He = 0.8). Crossings were strongly unbalanced, with only eight trees contributing to the sampled seedlings, and one single tree contributing to 52% of these seedlings. Moreover, the co-ancestry amongst seedlings more than doubled (from θ = 0.03 to 0.076), and the population status number was around one third of the value registered for the adult population (from Ns = 16.2 to 6.6). Despite its isolation, external pollen was detected in the stand, and appears to have travelled at least 700 m, contributing to 22% of the offspring. Overall, the seedling cohort is much less diverse than the parent trees, with expected lower resilience and persistence to environmental stresses.
Recent studies on patterns of biological invasions in several plant families have confirmed general findings (e.g., taxa with larger native range sizes are more likely to become invasive; and taxa with longer residence time in new regions are more likely to naturalise) and highlighted some context-specific findings relevant for management (e.g., resistance to Phytophthora is a pre-requisite for successful naturalisation in Proteaceae). We explore these issues for the plant family Myrtaceae, specifically by contrasting taxa with fleshy fruits with those with dry fruits to develop hypotheses around the role of seed dispersal in the invasion process. To this end we: 1) compiled a comprehensive list of introduced Myrtaceae; 2) determined the degree of establishment of each species in its introduced range; 3) compared the distribution of native, introduced, and invasive ranges; 4) assessed traits associated with the degree of establishment; and 5) assessed the magnitude and types of impacts of invasive Myrtaceae. A slightly higher proportion of dry-fruited species have been introduced than fleshy-fruited species [170 out of 2257 (7.5%) vs. 236 out of 3741 (6.7%)], though the difference was not significant. However, introduced dry-fruited Myrtaceae have naturalised more frequently than fleshy-fruited taxa [90 out of 170 (53%) vs. 40 out of 236 (17%)], whereas naturalised dry-fruited taxa have become invasive at a lower rate [22 out of 90 (24%) vs. 18 out of 40 (46%)]. Invasions of fleshy-fruited taxa seem to be more common on islands. Although invasions by fleshy- and dry-fruited species had similar impact mechanisms and magnitudes, naturalised fleshy-fruited Myrtaceae are more likely to have impacts on islands than dry-fruited confamilials. Synthesis Fleshy- and dry-fruited taxa of Myrtaceae differ in rate of transition along the invasion continuum and where invasions and impacts occur. We speculate that seed dispersal abilities, lack of competitors, and the availability of areas suitable for germination might explain these differences.
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Numerous eucalypts (species in the genera Eucalyptus, Angophora and Corymbia) have been introduced to South Africa over the past two centuries. Several species have become naturalized or invasive and are the focus of control programmes. Because many eucalypts are difficult to identify in the field, the distribution patterns of many species in the country are poorly documented. A recent assessment of the distribution of E. camaldulensis highlighted two invasion hotspots in South Africa: the Western Cape, and the Modimolle region in southwestern Limpopo. Records for all eucalypts (many of which list only “Eucalyptus sp.”) show similar hotspots. We conducted a rapid assessment to determine the species identity, extent of plantings, and invasive tendencies of eucalypt species at 113 localities in southwestern Limpopo. We recorded five species at the various localities, two of which have not been recorded in this area previously: E. blakelyi Maiden and E. distans Brooker, Boland & Kleinig. Two other species (E. camaldulensis and E. grandis) were observed invading river courses at numerous localities and are of concern. The South African Plant Invaders Atlas (SAPIA) and iNaturalist have only 73 records of eucalypts known from this area, in contrast to the 113 we recorded in this study. Besides providing new records of species, the survey highlighted the paucity of information on the identity and introduction status of eucalypts in South Africa. A systematic study to provide an inventory of eucalypts and their introduction status for the entire country is needed to serve as the foundation for strategies to manage species to capitalize on their benefits and minimize their impacts.
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Land use and land cover Land use/Land Cover (LULC) change is a common trend in all parts of the globe. The possible reasons might be economic, political, social or cultural motives. In Ethiopia, most of the rural and urban people are highly dependent on eucalypts for various purposes, particularly, for fuel wood and construction materials. In the study area, Western Gurage Watersheds of Omo-Gibe Basin, eucalypt plantations have become the emergent and dominant activity next to growing Enset. The specific objectives of this study were to assess the land use and land cover changes driven by eucalypt plantations over time and agro-ecological extent, and to identify socio-economic, demographic, and environmental factors that facilitated expansion of eucalypts plantation. Landsat images from 1987(TM), 2001 (ETM) and 2017 (Landsat 8 OLI) were used for detecting LULC changes. Digital image processing operations, i.e. haze removal, geo-referencing, contrast enhancement and classification, were completed using ERDAS Imagine 2011 Software. During the period between 1987 and 2017, the area cover of LULC types, namely plantation forest, Enset-based agroforestry, cereal crop and built-up areas increased in the study watersheds at the expenses of natural forests and grassland. The total forest cover declined in the study period from 1987-2000 and, then, increased from 2001-2017 as a result of expansion of eucalypts in bare land, grazing land and cereal crop land use types. The drivers for the expansion of eucalypts in the watersheds are population growth, ‘Meskel’ and ‘Arafah’ celebrations, land degradation and conservation, road development, increased access to markets, and economic factors, such as the growing need for fuel wood, construction materials, and growing need for money. The divergent interest of stakeholders, skepticism and debate around eucalypts; call for further scientific investigations and management options.
Full-text available
In a context of growing demands for wood and wood derived products, plantations of exotic tree species have globally increased. Fast growth and high productivity made Eucalyptus one of the most successful tree genus around the world. Nevertheless, this genus is often associated with negative ecological impacts on biodiversity and ecosystem functioning and the risk of expansion is considered a major threat. Eucalyptus globulus is the most planted tree species in Portugal, but common silvicultural measures, including periodic control of the understory vegetation, have traditionally limited natural regeneration. However, forest fires constitute a main driver of E. globulus dispersal and regeneration and, under the current climatic change scenario, the possible extension of the summer fire regime to previous months in spring and/or later months in autumn, may have a profound effect on E. globulus dispersal capacity. Moreover, isolated eucalypt trees, seed-trees, are often left uncut and many plantations are poorly managed potentially increasing the risk of E. globulus dispersal. To evaluate the impact of both management and fire event dates on E. globulus dispersal, we assessed the establishment of saplings beyond plantations and seed-trees surrounding areas in absence of fire and after 2017 June and October fires in managed and unmanaged conditions. Sapling survival was also analyzed two years after fire. Our results point out that sapling establishment in our study area is not a major concern in the absence of fire. Also, our findings showed that E. globulus establishment is highly dependent on the time of the year a fire occurs and that pre-fire management practices constrain E. globulus dispersal. We also found that seed-trees are high seed dispersers after fire even in managed conditions, deserving great concern. Additionally, sapling survival two years after October fire indicate that out of season fires might constitute an emerging issue regarding E. globulus expansion.
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Although native to Australia, Eucalyptus species are found throughout Europe. At present, they are located mainly in the Iberian Peninsula and Eucalyptus globulus is the most commonly planted species. Climate forecasts anticipate an expansion of Eucalyptus to other regions of Europe. The fast growth of E. globulus, together with its resprouting ability and wood properties, has promoted the use of this species in the Iberian Peninsula. The total volume of E. globulus harvested there was close to 14 million m3 in 2019. Eucalyptus species represent the main source of raw material for the pulp and paper industries and provide an important source of income to non-industrial owners. Being exotic fast-growing trees, their expansion has also been associated with negative environmental impacts. The species therefore poses a series of challenges, while also generating opportunities. The objectives of this review paper are: (1) to summarize the importance of Eucalyptus plantations in Europe; (2) to analyse the opportunities and challenges of this genus in present and future plantations in Europe; (3) to assess to what extent forest management, at both stand and landscape levels, can reduce negative impacts; (4) to make policy and management recommendations that may support the use of this genus in other European regions. These aims are accomplished based on a thorough literature review, particularly focused on research developed in the Iberian Peninsula.
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Several eucalypt species are known for their capacity to massively regenerate through seeds in recently burned areas, becoming an ecological problem in regions where the species is not native. Here we study the demography and the development of highly dense Eucalyptus globulus wildling populations established one year after a fire and test two methods to control these populations. We monitored five mixed E. globulus stands along one year, in Central Portugal. We established a set of plots in each stand, with three treatments: mechanical cutting, herbicide spraying and no disturbance (control plots). Herbicide was applied in four concentrations. We tagged randomly selected plants in the control plots to monitor their growth. The initial mean wildling density was 322,000 plants ha−1, the highest ever recorded in the introduced range. Wildling density was significantly dependent on the density of surrounding adult E. globulus trees. Wildling density in control plots decreased 30% in one year, although showing positive variations over time because of new recruitment. Despite seasonal growth differences, wildlings showed a high growth rate throughout the year, reaching 15.6 cm month−1 in the summer. The growth rate of tagged wildings was positively affected by solar radiation and negatively affected by evapotranspiration and maximum temperature. Mechanical cutting reduced wildling density by 97% while herbicide reached results between 80% for the lowest concentration and 99% for the highest concentration. Herbicide-treated plants were more likely to resprout than cut plants. Regardless of the control method adopted (cutting or herbicide), management strategies should include the follow-up of the treated areas, to detect the establishment of new recruits and resprouting.
Full-text available
In the last two centuries, several species of Australian eucalypts (e.g. Eucalyptus camaldulensis and E.␣globulus) were introduced into the Iberian Peninsula for the production of paper pulp. The effects of the introduction of exotic root-symbitotic fungi together with the eucalypts have received little attention. During the past years, we have investigated the biology of ectomycorrhizal fungi in eucalypt plantations in the Iberian Peninsula. In the plantations studied, we found fruit bodies of several Australian ectomycorrhizal fungi and identified their ectomycorrhizas with DNA molecular markers. The most frequent species were Hydnangium carneum, Hymenogaster albus, Hysterangium inflatum, Labyrinthomyces donkii, Laccaria fraterna, Pisolithus albus, P. microcarpus, Rhulandiella berolinensis, Setchelliogaster rheophyllus, and Tricholoma eucalypticum. These fungi were likely brought from Australia together with the eucalypts, and they seem to have facilitated the establishment of eucalypt plantations and their naturalization. The dispersion of Australian fungal propagules may be facilitating the spread of eucalypts along watercourses in semiarid regions increasing the water lost. Because ectomycorrhizal fungi are obligate symbionts, their capacity to persist after eradication of eucalypt stands, and/or to extend beyond forest plantations, would rely on the possibility to find compatible native host trees, and to outcompete the native ectomycorrhizal fungi. Here we illustrate the case of the Australasian species Laccaria fraterna, which fruits in Mediterranean shrublands of ectomycorrhizal species of Cistus (rockroses). We need to know which other Australasian fungi extend to the native ecosystems, if we are to predict environmental␣risks associated with the introduction of Australasian ectomycorrhizal fungi into the Iberian Peninsula.
Sometimes by accident and sometimes on purpose, humans have transported plants and animals to new habitats around the world. Arriving in ever-increasing numbers to American soil, recent invaders have competed with, preyed on, hybridized with, and carried diseases to native species, transforming our ecosystems and creating anxiety among environmentalists and the general public. But is American anxiety over this crisis of ecological identity a recent phenomenon? Charting shifting attitudes to alien species since the 1850s, Peter Coates brings to light the rich cultural and historical aspects of this story by situating the history of immigrant flora and fauna within the wider context of human immigration. Through an illuminating series of particular invasions, including the English sparrow and the eucalyptus tree, what he finds is that we have always perceived plants and animals in relation to ourselves and the polities to which we belong. Setting the saga of human relations with the environment in the broad context of scientific, social, and cultural history, this thought-provoking book demonstrates how profoundly notions of nationality and debates over race and immigration have shaped American understandings of the natural world.
In the 150 years since their introduction to the state, species in the genus Eucalyptus have become the most common non-native trees in California. A clearer understanding of the ability of different species to reproduce in the state is important for how we monitor the ecological impact of these abundant non-native trees and for predicting possible future invasions. Here we present current data on the diversity of Eucalyptus in California, which species are spontaneously reproducing, or have the potential to do so, where they can be found, how they can be identified, and our analysis, based on herbarium and field observations, of the potential ecological impacts of various species in the locations where they have been introduced. We also present a new dichotomous identification key, and botanical drawings of all naturalized species. We discuss the degree to which factors such as life history traits, commonness of planting, and native range influence reproductive behaviors of different species.
A survey of regenerative strategies in the eucalypts, including lignotuber development, was undertaken by extensive field observations, seedling trials and trials of cultivated individuals over a 12-year period. Four broad regenerative strategies were identified, viz. obligate seeders, lignotuber sprouters, stem sprouters and combination sprouters. These four regenerative strategies are based on the ability to develop a lignotuber and the regeneration strategy after whole-crown destruction. These regenerative strategies do not wholly correspond to the tree, mallee, mallet, marlock and shrub habit categories commonly applied to eucalypts. The obligate seeders include many more terminal taxa than have been previously documented as mallet taxa, with 78 western obligate seeders (the ‘true’ mallets) and nine eastern obligate seeders listed herein. Obligate seeders do not possess a lignotuber and are killed by crown-destructive events, and as such are relatively short-lived in most natural environments. A further 16 taxa are also known to be non-lignotuberous, but these are capable of producing epicormic regrowth from the trunk following crown destruction and are defined as stem sprouters. The remaining two regenerative strategies include taxa that are both lignotuberous and able to regenerate vegetatively following disturbance events. The persistent and conjecturous mallet–marlock–moort distinction is rejected, this study showing it to be dependent on stand density. Data presented indicate no significant difference in germination time or maturation time between western obligate-seeder taxa and closely related sprouter taxa. The conservation status of obligate-seeder taxa is discussed. Nomenclatural issues regarding the taxonomic distinction between obligate-seeder and resprouter sister taxa are discussed. A census of regenerative strategies for all recognised eucalypt taxa is included as an accessory publication on the web.
Diseases and Pathogens of Eucalypts
  • P J Keane
  • G A Kile
  • F D Podger
Keane, P. J., G. A. Kile, F. D. Podger, and B. N. Brown, eds. 2000. Diseases and Pathogens of Eucalypts. Collingwood, Australia: CSIRO Publishing.
Invasive Alien Species: A New Synthesis
  • H A In
  • R N Mooney
  • J A Mack
  • L E Mcneely
  • P J Neville
  • Schei
In H. A. Mooney, R. N. Mack, J. A. McNeely, L. E. Neville, P. J. Schei, and J. K. Waage, eds. Invasive Alien Species: A New Synthesis. Washington, DC: Island Press.
Eucalypt Ecology: Individuals to Ecosystems
  • J Williams
  • J Woinarski
Williams, J., and J. Woinarski, eds. 1997. Eucalypt Ecology: Individuals to Ecosystems. Cambridge: Cambridge University Press.