Scientific name: Eucalyptus globulus Labill.
Common names: blue gum, Tasmanian blue gum, common eucalyptus
Note: in Portugal, the most area occupied by this species corresponds to plantations by Man and not natural dispersal/invasion. The species is included as invasive because, on one hand, it has seen its invasive behaviour in many situations in the country and, on the other hand, its wide distribution creates a high propagule pressure which constitutes an increased risk. Additionally, this species is considered invasive in many regions with Mediterranean type-climate.
Risk Assessment score: 21| Value obtained according to a protocol adapted from the Australian Weed Risk Assessment (Pheloung et al. 1999), by Morais et al. (2017), according to which values above 13 mean that the species has risk of having invasive behavior in the Portuguese territory | Updated on 30/09/2017.
Last update: 01/07/2021
How to recognise it
Flowering: October to March.
It is distinguished from other species of Eucalyptus (and from E. globulus subsp. maidenii (F. Muell.) J.B. Kirkp.), present in Portugal by having solitary fruits and flowers.
Characteristics that aid invasion
Species of very fast growth.
It propagates vegetatively, sprouting vigorously from stumps (used in the pulp industry).
In Portugal, for a few years now, seed germination has started to be observed, including outside the stands, mainly after the plantation abandonment and wildfire occurrence, which create empty niches.
Native distribution area
Southeast Australia and Tasmania.
Distribution in Portugal
Mainland Portugal (all provinces), Azores archipelago (islands of São Miguel, Santa Maria, Terceira, Graciosa, Pico, Faial and Flores), Madeira archipelago (Madeira and Porto Santo islands).
Geographic areas where there are records of Eucalyptus globulus
EEurope (Spain), South Africa, western USA (California, Hawaii).
For forest production.
Preferential invasion environments
Frequently cultivated all over the country, having started to appear with invasive behaviour in places that are more humid and less subject to frost.
Impacts on ecosystems
The seedlings form continuous mats, inhibiting the development of other species.
In areas where it proliferated in an unwanted manner, it may demand expensive control methods.
Natura 2000 Network habitats more subject to impacts
– Riparian mixed forests of Quercus robur, Ulmus minor and Fraxinus angustifolia along the great rivers (91F0);
– Salix alba and Populus alba galleries (92A0);
– Riparian formations on intermittent Mediterranean water courses with Rhododendron ponticum, Salix and others (92B0);
– Arborescent matorral with Laurus nobilis (5230);
– Galicio-Portuguese oak woods with Quercus robur and Quercus pyrenaica (9230 pt1);
– Quercus faginea and Quercus canariensis Iberian woods (9240);
– Quercus suber forests (9330).
Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.
The control methodologies used for Eucalyptus globulus include:
Hand pulling: preferential methodology for seedlings and small plants. When in more compacted substrates, hand pulling must be made during the rainy season as to facilitate the removal of the root system. It should be guaranteed that no stumps and main roots in the ground.
Cut followed by destruction of the stump: preferential methodology for adult plants. Cut of the trunk as close to the ground as possible and posterior destruction of the stump. It should be done before seed maturation.
Physical + chemical control
Cut stump method: applied to adult plants. Cut the trunk as close to the ground as possible and immediately (in the following seconds) apply herbicide (active substance: glyphosate or triclopyr) to the cut stump. If shoots should latter on appear, these should be immediately eliminated by pulling or foliar application of herbicide (active substance: glyphosate or triclopyr). On stumps with shoots that are not possible to cut again (ex. very small surface) cuts may be made of +/- 45º overlapped on the vertical surface with the active vascular cambium nd apply there the herbicide (active substance: glyphosate or triclopyr).
Foliar application of herbicide: applied on young sprouts of 1 to 1,5 m high. It should be done upon the plant’s greatest growth rate. Spray with herbicide (active substance: glyphosate or triclopyr) limiting as much as possible its application to the target species.
Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.
Gassó N, Basnou C, Vilà M (2010) Predicting plant invaders in the Mediterranean through a weed risk assessment system. Biological Invasions 12 (3): 463-476.
Land EO, Coelho RM, Silva L, Carvalho JA (2008) Eucalyptus globulus Labill. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna terrestre invasora na Macaronésia. Top 100 nos Açores. Madeira e Canárias, Arena, Ponta Delgada, pp. 363-366.
Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental. Imprensa da Universidade de Coimbra, Coimbra, 183pp.