A framework for testing radiata pine under projected climate change in Australia and New Zealand

Radiata pine plantation resources in Australia and New Zealand are a highly productive source of solid-wood and pulp products for domestic consumption and export. This has largely been achieved through long-term investments in tree breeding programs that select the best-performing genotypes for varied regional environments. However, climate change could threaten the realisation of genetic improvement in plantations due to suboptimal matching of improved planting stock to new climate conditions. Here, we investigate how information from genetic field tests could be utilised under anticipated climate change. We use principal component analysis and Mahalanobis distance measures to find the closest match between climate of plantation regions in the future and current climate of field test sites. By 2050, future climates of some important plantation regions are expected to match climates currently present in different regions. For example, future climates of Green Triangle, a key plantation region in Australia, will better match current climate of Western Australia. The Central North Island of New Zealand will shift to warmer and wetter climate with no current analogue, and Western Australia, to warmer and drier no-analogue climate. The latter is also likely to fall outside the climate niche where radiata pine can be grown in the future. Nevertheless, for the majority of radiata pine plantation regions in Australia and New Zealand our analysis provides a framework of how anticipated climate change can be addressed in tree improvement programs using existing field tests.