Restoration of slash pile burn scars to prevent establishment and propagation of non-native plants

Logging and burning of the resultant woody debris is a management tool to reduce fire risk. Burning of the debris as piles affects the underlying soil biota and soil physical and (or) chemical properties. The resulting disturbance created by the burns may create opportunities for the establishment and spread of non-native plant species. Here, we test three restoration treatments on recent, approximately 1-year-old, pile burn scars, including an arbuscular mycorrhizal fungal (AMF) inoculant (present or absent), a ground cover (straw or no straw added), and different seeding types (native seed mix, agronomic seed mix, and no seed). The most effective treatment in reducing undesired non-native species cover was the seeding of agronomic species; here "native" and "non-native" groups exclude sown agronomic species. Undesired non-native cover was 15.1% in plots with no seed, 9.1% in plots with native seed added, and 3.5% in plots with agronomic seed added. Total vegetation cover, mostly through the increase of agronomic species, was increased by seeding and by the application of straw cover. Commercial AMF inoculum was an ineffective treatment, suggesting that a better understanding of host specificity is warranted. Restoration efforts should be directed at burn scar sites after burning to ameliorate the effects of invasive species colonization, and the use of agronomic species may prevent non-native invasive plants from establishing.