Save the forests, save the world
Summary
Globally, forests provide a buffer against climate change by sequestering carbon in the soil and in tree biomass. Conserving forests helps to mitigate climate change. Unfortunately, forests and their stored carbon are under threat from invasive insect pests and diseases. Fei et al. (2019) used plant community surveys collected by the USFS Forest Inventory & Analysis program to estimate carbon losses associated with invasive insects and diseases. They compared tree mortality of host species in invaded versus uninvaded plots and converted mortality rates to carbon losses. Fei et al. estimated that elevated mortality rates caused by 15 prominent invasive pests lead to losses of 5.5 TgC/year, which is comparable to trees lost annually in the U.S. to forest fire. Further, these 15 forest pests could increase mortality in over 40% of forest trees across the U.S., leading to increasing loss of forest carbon.
Take home points
Mortality rates were greatest for trees affected by laurel wilt disease (Raffaelea lauricola), chestnut blight (Cryphonectria parasitica), butternut canker (Sirococcus clavigignenti-juglandacearum), dogwood anthracnose (Discula destructiva), red pine scale (Matsucoccus matsumurae), Emerald Ash Borer (Agrilus planipennis), and Dutch Elm Disease (Ophiostoma novo ulmi).
83 total pest species were found to cause ecological harm to forests in the U.S. That list is available as a supplemental table here.
Management implications
Invasive species alter carbon storage and reduce the effectiveness of climate mitigation. This paper makes a strong argument for better policy and regulation to prevent the introduction and spread of forest pests (e.g., through Tree-SMART trade)
Keywords
Forest, invasive pest, invasive pathogen, climate change mitigation