A report from researchers at the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services has warned that tree planting and bioenergy needs to be managed carefully to deliver climate change mitigation benefits, or risk being counter-productive. Central to the warning is that biodiversity is essential to keeping ecosystems healthy, meaning that the “right trees must be planted in the right places” for tree-planting programmes and bioenergy schemes to be effective. At the same time, climate change itself can reduce the mitigation potential of forests, as it tends to promote harmful pathogens and insects, while also increasing the likelihood of fire. These warnings will be important for energy companies around the world that are looking to employ bioenergy and tree planting for carbon offsetting.