Deer snacking on maple buffet

MICHIGAN STATE (US) — Deer with a sweet tooth are devastating sugar maple saplings in Michigan’s Upper Peninsula.

Since the 1950s, sustainability in northern hardwood forests has been achieved by chopping down trees in small clumps to naturally make room for new ones to spring up. Sugar maples, that have been historically successful regenerating themselves, are being devoured by hungry deer.

“We’ve found that deer, light availability, and competition from nontree plant species are affecting sugar maple regeneration in parts of the Upper Peninsula,” says Megan Matonis, who recently earned a master’s degree in forestry from Michigan State University.

“No sugar maples are regenerating in the southern area near Escanaba. In the future, this could challenge the sustainability of timber harvesting in this region.”

Details of the study are published in the journal Forest Ecology and Management.

Forest conservation is a persistent push and pull between maintaining crops of hardwoods, especially sugar maple, for the timber industry and herds of deer for hunters.

“It’s amazing how differently these two groups generally view the situation,” Matonis. “Some hunters feel there aren’t enough deer in the forests whereas ‘save a tree, kill a deer’ is the sentiment of many loggers.”

The two-year study, spanning 3,000 square miles of public and private land, examined the harvest gaps left in forests when hardwoods are cut down to see what factors affect the regeneration of sugar maples.

In the north, where heavy snows push deer south in search of food during the winter, sugar maple saplings generally are thriving in the harvested areas. Yet in the southern portion of the study area, there were areas where no saplings survive at all.

Although munching by deer seems to be the main cause of low sapling densities in the south, low light levels in small gaps and competition from other plants also play roles in poor regeneration. Sedge, a grass-like plant, appears to out-compete tree saplings in many forests following harvests.

The research was funded in by the U.S. Department of Agriculture and the Michigan Department of Natural Resources.

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