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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. [ABSTRACT FROM AUTHOR]

• A 3-PG.d simulator was used to compare management strategies against G. platensis. • Above 25% defoliation applying treatments was always better than doing nothing. • Treatments can save more than 100 m3/ha and 1500 € ha−1 regardless of site quality. • Augmentative biological control surpasses chemicals for low-medium attack levels. • Chemical treatments were the best alternative under heavy defoliation attacks. Around 1.5 million ha of the Iberian Peninsula is currently occupied by Eucalyptus globulus , the preferred species for commercial plantations due to its fast growth and wood technological properties. However, these economically important plantations are being heavily damaged by Gonipterus platensis (Col: Curculionidae), an invasive species native to Australia which was established in the Peninsula, in the nineties. A classical biological control with the release of the egg parasitoid Anaphes nitens (Hym: Mymaridae) was launched in the Peninsula. Yet, in the colder regions, in the North of the Peninsula, the parasitoid is not efficient enough to control the weevil population. The resulting damage overcomes more than 200 million euros every year. Current control strategies rely on the application of insecticide (acetamiprid) or augmentative biological control (ABC) with yearly releases of A. nitens in spring. However, uncertainties about the best option persist. In this study, chemical and ABC treatments were submitted to a cost-benefit analysis with the aim of determining their viability against the weevil, based on a treatment efficacy and stand productivity trade-off analysis. A simulation tool (3-PG.d) was used to simulate the growth of E. globulus stands, under four defoliation intensity scenarios mimicking the removal of 25, 50, 75 and 100% of the spring new leaves biomass. Each defoliation scenario was combined with three treatments: (i) chemical (acetamiprid), (ii) ABC+ (optimistic approach), and (iii) ABC- (pessimistic approach). For each treatment, several plans of yearly treatments were tested. The Net Present Value (NPV) and the harvested volume were used to compare all treatment alternatives. The best treatment decision, based on a cost-benefit analysis comparing economic results and harvested volume, varied with the intensity of defoliation. Treating was always better than doing nothing, except for the 25% defoliation scenario. ABC+ offered the best economic results, relative to other treatments, for 25, 50 and 75% defoliation scenarios. ABC- was only as good as the chemical treatment for the 25 and 50% defoliations. Under the heaviest weevil attack (100%), applying insecticide was the best alternative, overcoming both ABC treatments. These results show that augmentative biological control was a strategy to consider for this study, and thus, may be a strategy to be considered in the future. The 3-PG.d simulator showed that it can be an asset for forest managers aiming at integrating chemical and/or biological treatments against forest pests in stand management decisions. [ABSTRACT FROM AUTHOR]

• Modeling the impact of defoliation on tree growth is an important tool for Integrated Pest Management (IPM). • A 3-PG based simulator was developed to integrate a Gonipterus platensis species-specific defoliation module. • Different scenarios of defoliation intensity under varying site conditions were simulated. • Wood volume losses of 74% and 85% were predicted for defoliations of the upper third of canopy of 75% and 100%, respectively. Growth losses due to insect defoliations are difficult to estimate. The lack of appropriate tools that account for defoliations in growth simulations makes difficult the task of forest managers to project growth, and thus, the expected economic income. The present work integrates defoliations in the 3-PG forest growth model in order to provide a tool that allows forest managers to estimate Eucalyptus globulus stands growth losses under a set of defoliation scenarios by simulating attacks of the Eucalyptus snout beetle Gonipterus platensis. To mimic these attacks, different amounts of the upper third of the canopy were removed, from 0 to 100%, depending on the scenario intensity, and considering only spring season attacks or both spring and autumn attacks in the same year. A set of E. globulus virtual stands, representing a range of site productivities, were submitted to constant yearly consecutive defoliations since age 2 up to 10. Simulation results showed that, for scenarios that removed 50, 75 and 100% of the upper third of the canopy, volume losses averaged 54, 74 and 83%, respectively, at age 10 with just the spring attack, reaching 69, 82 and 88%, respectively, with also the autumn attack. Removing only 25% of the upper third of the canopy produced relevant losses only if the stands were attacked in both seasons. Lighter defoliations tested seemed to have a marginal effect on stand growth regardless of site quality. The tool was also used to evaluate a field assessment methodology of G. platensis defoliation attacks on a set of real stands by comparing observed and estimated volumes at age 10. Estimations showed increasing volume losses with increasing defoliation intensities. When evaluating the field assessment methodology, results suggest that a single field visit to assess the G. platensis attack level in the whole lifetime of a stand is insufficient to make reliable growth loss estimations. The integration of the impact of defoliations in the 3-PG growth model revealed to be potentially useful as a forest management decision tool. [ABSTRACT FROM AUTHOR]