Invasive species threaten 40% of US forests.

The death of trees means that trees will not absorb CO2 as we expected them to. In addition, it means that planting trees will be less effective that it might seem. Planting a sapling does no good unless it lives to become a large tree.

If a tree is going to die anyway, it could be better to cut it down and soak it in something that will kill the pests and keep the carbon in the wood, than to let pests convert its carbon into CO2.