Protecting Young Trees from Hungry Deer
Top: Employee Ruth Merrill-Pastori levels a post for an exclosure area. Bottom: The view along the boundary of the exclosure.
Construction of deer exclosures on the Chequamegon-Nicolet NF increase seedling survival rates.
Contributed by Juliet Gifford, 715-362-1386
On the Eagle River-Florence District of the Chequamegon-Nicolet National Forest, Wildlife Biologist Mike Peczynski has been leading the hemlock and cedar tree regeneration effort. Northern white cedar, eastern hemlock, Canada yew and yellow birch are less commonly seen regenerating on the District because deer eat the seedlings and saplings.
Peczynski and his staff have been designing and building various-sized deer exclosures and then planting the seedlings and saplings inside the exclosures in hopes that regeneration will be more successful without the presence of deer herbivory.
"Trees such as hemlock, yellow birch, cedar, and Canada yew are species that often have a hard time regenerating, even under good conditions," said Peczynski. "Providing fences eliminates one of the impediments of their successful regeneration - deer herbivory."
To date, eight deer exclosures of various sizes ranging from 0.5 - 2.5 acres have been built on the District in hardwood stands where mature hemlock and yellow birch are already present. Metal T-posts, combined with either plastic deer fence or steel field fence, are used in the construction of the exclosures. The height of the fences range from 6.5 - 7.5 feet and 600 - 1,320 feet of fence are used per exclosure.
Peczynski is pleased about the regeneration effort and hopes to construct more exclosures in the future. He is looking at building exclosures in canopy gaps around the District not to only prevent deer from eating cedar, hemlock, Canada yew, and yellow birch, but also to protect naturally regenerated white ash and basswood. Ash and basswood are shade-intolerant species and are rarely seen regenerating outside of canopy gaps or other large open areas in the Forest.
"Fencing improves the survival of seedlings and saplings, but there is still some mortality occurring from other causes such as excessive shade, dry site conditions, competition for other vegetation, and in some cases, rodent damage," Pecynski added.
The monitoring of existing exclosures has demonstrated that a little protection is making a big difference in seedling survival. Many yellow birch and hemlocks planted as 8-10" tall seedlings in the mid 1990's are now exceeding six feet or more!