Eucalyptus

Eucalyptus nitens, Eucalyptus gunnii, Eucalyptus urnigera, Eucalyptus dalrympleana, Eucalyptus glaucescens, Eucalyptus rodwayi, Eucalyptus globulus

General info

Eucalyptus are a flowering tree species known for their strong aromas and rich oils which make them highly flammable. They can grow as shorter shrubs or as taller evergreen trees and sometimes release sticky resins through breaks in the bark, hence being known as the “gum tree”. Mostly native to Australia, these fast-growing trees are present more in the southeast and lowland areas of England in the UK with two of the most common species being Eucalyptus gunnii and Eucalyptus globulus.

Flowers of the species have several stamens with a fluffy appearance which are enclosed in a cap (operculum) made of fused sepals and petals. The woody fruit capsule that is formed on fertilisation is called a gumnut and releases seeds into the environment. Flowers produce an abundance of nectar making them attractive to many pollinator species.

Cultivation and agronomy

Based on an 8-10 year rotation, data from early UK trials identified yields in the range of 20-30 m³ ha/yr, on a bark-free basis, equivalent to 10-15 oven dry tonnes per hectare per year. Yields of up to 48 m³ ha/yr have been reported from a commercial plantation in Cornwall. Eucalyptus produces a high-density wood, with a net calorific value of 18 GJ t, which seasons quickly and is suitable for use as a biomass fuel or timber product. Some species are more or less cold tolerant than others with E. nitens being among the less tolerant and undergoing damage and death from cold winters in the UK. On the other hand E. urnigera and E. glaucescens are two of the more cold tolerant species under consideration.

One notable aspect of Eucalyptus species in the UK is that E. nitens appears to lack, or have very limited, coppicing ability so despite being one of the highest relative yield producing SRF species (under best conditions) it is recommended that E. glaucescens, E. gunnii and E. rodwayi be utilised as they can coppice.

As Eucalyptus species are not widespread in the UK, they are a species of SRF which have very low risk of damage from pests and diseases in the UK. The colder tolerant species are also not known to be particularly susceptible to phytophthora spp. or foliar pathogens. However, Irish plantations of Eucalyptus have been impacted by psyllid pest Ctenarytaina eucalypti and leaf beetle Paropsisterna selmani which could require consideration.