The impact of climate change on California timberlands

Abstract

California timber production has been declining in an era of warming, increased wildfires, land conversion, and growing emphasis on recreation. Climate change has the potential to further affect California timber production through changes in individual tree growth rates, forest dieback, and shifts in species ranges and ecosystem composition. Coupled with changes in global timber prices, themselves the result of productivity effects, these production impacts hold important consequences for California’s private timberlands. This study uses models that project tree species productivity and movement across the landscape under climate change, coupled with economic models of landowner adaptation and returns from multiple harvest strategies. Our results show that under likely price scenarios, climate change will result in an overall decline in harvested timber value relative to no climate change, with decreases of 4.9 to 8.5% by the end of the century. The magnitude of decrease depends on climate change scenario, price scenario and management option – with dollar losses totaling up to $8.1 billion in total land value (−$2.7 billion given a 4% discount rate). There is substantial spatial variation in these changes; most areas show significant declines in timber value while some show modest increases relative to a no climate change baseline. If prices are not affected by climate change, more areas experience gains in value. We find that forestry management strategies can mitigate lost value, indicating that climate change adaptation programs can yield important economic benefits. Declining timber value corresponds disproportionately to areas already experiencing timberland conversion to housing or agriculture. Policy measures to stem conversion of devalued timberlands may warrant consideration.