Using a climatic niche model to predict the direct and indirect impacts of climate change on the distribution of <scp>D</scp>ouglas‐fir in <scp>N</scp>ew <scp>Z</scp>ealand

Abstract

Abstract Climate change is likely to have major impacts on the distribution of planted and natural forests. Herein, we demonstrate how a process‐based niche model ( CLIMEX ) can be extended to globally project the potential habitat suitable for D ouglas‐fir. Within this distribution, we use CLIMEX to predict abundance of the pathogen P haeocryptopus gaeumannii and severity of its associated foliage disease, S wiss needle cast. The distribution and severity of the disease, which can strongly reduce growth rate of D ouglas‐fir, is closely correlated with seasonal temperatures and precipitation. This model is used to project how climate change during the 2080s may alter the area suitable for D ouglas‐fir plantations within N ew Z ealand. The climate change scenarios used indicate that the land area suitable for D ouglas‐fir production in the N orth I sland will be reduced markedly from near 100% under current climate to 36–64% of the total land area by 2080s. Within areas shown to be suitable for the host in the N orth I sland, four of the six climate change scenarios predict substantial increases in disease severity that will make these regions at best marginal for D ouglas‐fir by the 2080s. In contrast, most regions in the S outh I sland are projected to sustain relatively low levels of disease, and remain suitable for D ouglas‐fir under climate change over the course of this century.