Selection of cold-tolerant Eucalyptus species and provenances for inland frost-susceptible, humid subtropical regions of southern China

Abstract

SummaryInland humid subtropical regions of China’s southern provinces have substantial areas of land potentially available for forest plantation development. Such development would help address a substantial deficit in domestic production compared with demand for timber and fibre raw materials. However, the tropical and subtropical eucalypt varieties that are the basis of highly productive and commercially successful plantations in China’s warmer coastal regions have proved poorly adapted to inland regions which are characterised by hot humid summers and frequent winter frosts and cold events with temperatures down to –8°C or lower.To evaluate a range of Eucalyptus species and provenances for plantation development in this subtropical environment, three species–provenance trials were established in southern and central Hunan province from 2001 to 2004. Included in these trials were 64 provenance seedlots representing 22 species and a locally selected Eucalyptus camaldulensis clone. Five of these seedlots represented somewhat improved sources from South Africa, whilst the others were unimproved natural stand provenances. Species that demonstrated the best growth and survival at age 6 years were E. amplifolia var. amplifolia, E. benthamii, E. dunnii and E. dorrigoensis. Species which showed reasonable performance in at least one trial and warrant further investigation include E. saligna × E. botryoides and E. deanei. Whilst E. macarthurii had the best cold tolerance, it had relatively poor performance for growth and survival. Provenances from imported improved sources (from South Africa) in most cases proved inferior to, or no better than, the best natural-stand provenances of the same species, providing salutary guidance for prospective growers.