Habitat includes food, water, shelter, space and the arrangement of these components, though land managers and popular press most popularly discuss food. Food can easily be managed, and many times the focus is only on food plots and feeders. Native vegetation can take a back seat to these intensive management practices, but people should be aware how to manage existing native vegetation to provide a high quality diet.
An idea for a project began one October day while scouting where to put up deer hunting blinds. We had conducted a prescribed burn in August, and there were thousands of greenbrier sprouts about 6 to 10 inches tall in the burned area. When I came back a few weeks later to hunt, almost every sprout was browsed and deer tracks were everywhere.
It ended up being a successful hunting season in the burned site because deer seemed to select this site due to the food source. It got me thinking about the sprout quality. Greenbrier was abundant just across the fireguard, but deer didn’t seem to select for them outside the burn.
I initiated a demonstration project to better understand the role growing-season fire plays in the nutritional quality of woody plants.
I sampled five important deer browse species – greenbrier, poison ivy, Chickasaw plum, smooth sumac and rough-leaf dogwood – once per month from April to October. I tried to mimic how a deer would browse and handpicked only the parts of the plants I thought were the most succulent and fresh during each sample period. I sampled two different locations close to each other: one area that was not burned and one area burned during the growing season. A growing-season burn was conducted on July 13, after our July sample period. Each sample was analyzed with wet chemistry to determine the crude protein (CP) and total digestible nutrients (TDN).
In all of the plants, fire appeared to have had no impact on TDN. However, fire did have a positive impact on CP for all of the browse species except for dogwood (see charts). Plum, greenbrier, sumac and poison ivy all had an increase in CP in the burned area compared to the unburned area. Greenbrier had the largest difference between the two areas with the unburned plants having 9 percent CP and the burned plants having 27 percent CP one month after the burn. However, the CP increase did not last long. Plum and poison ivy had similar CP levels between the burned and unburned areas two months after the burn. Burned greenbrier and sumac still had higher CP levels compared to the unburned plants two months after the burn. Three months after the burn, all plants had similar CP levels between the burned and unburned treatments.
This was a demonstration project that was not replicated and was only conducted during one growing season on one ecological site. However, I would expect a similar trend on other ecological sites across multiple years. This information is important to deer managers because CP demands are usually highest in spring to late summer for antler growth, lactation and fawn growth. All five species of unburned plants fell below 14 percent CP by June, which is below requirements for antler growth (16 percent) and lactation (14 percent). However, most burned plants had CP levels above 16 percent after the burn in July.
This project indicates the best management is to burn different areas every month to provide a high level of nutrition throughout the growing season. When there is always a freshly burned area, deer have access to high levels of nutrition throughout the growing season to meet their needs. Burning several areas throughout the growing season also increases plant diversity, which is imperative to deer management.