Designing food and habitat trees for urban koalas: Identifying short ecotypes of Corymbia intermedia

Abstract

The eucalypt trees eaten by koalas are generally tall, but urban landholders prefer to plant shorter trees that pose less danger of limbs falling from a great height or damaging powerlines. Our aim was to develop shorter eucalypt trees to provide food and shelter for koalas and other fauna in urban areas. We identified short ecotypes of Corymbia intermedia (R.T.Baker) K.D.Hill & L.A.S.Johnson growing naturally on exposed coastal headlands, and tested whether their seedlings were shorter than the seedlings of nearby tall ecotypes when planted in cultivation. Trees raised from the short ecotypes were 22-43% shorter than trees raised from the tall ecotypes, being around 5-7m tall rather than 8-12m tall after 8 years. This demonstrated that there was a genetic basis for the short stature of C. intermedia trees on coastal headlands. These shorter C. intermedia trees could be valuable food and habitat trees for urban koalas and other fauna.