Alter fire timing to recouple forage nutrients with herbivore nutrient demands

Abstract

Forests typically have limited high quality nutrition available to meet the seasonal needs of white-tailed deer (Odocoileus virginianus) during summer. Prescribed fire is used to enhance deer habitat in pyric-disclimax communities but is normally applied during the dormant season. Historically, lightning-ignited fires in pine systems occurred during summer in the southeastern US, but fire ignited by humans occurred at all times of the year and was most common in fall/winter. The different timing of prescribed fire may be important when trying to couple forage resources with nutritionally demanding periods for herbivores. We evaluated fire-timing effects (dormant season, March; growing season, June; and unburned control) on nutrient availability (crude protein, % phosphorus, and biomass) and nutritional carrying capacity (NCC) for moderate-high use forages of white-tailed deer during summer of 2018 and 2019 in nine mid-rotation loblolly pine stands. Fire increased nutrient content the year of the burn and the increase persisted into the second growing season following growing season fire. Dormant season fire increased protein- and phosphorus- based NCC for two growing seasons but growing season fire reduced biomass during the first year and delayed NCC improvement until the second year. Prescribed fire can be timed to manipulate forage quality, quantity, and improve NCC to recouple forage nutrient supply with herbivore seasonal nutrient demands. We recommend land managers consider diversifying fire timing across the landscape in pyric disclimax systems to support the changing nutrient requirements of large herbivores.