Deer browse is having a major impact on my forest’s ability to regenerate. Is there anything that I, as a forest landowner, can do about it?
You are not alone! White-tailed deer overpopulations pose a major biodiversity threat in forests and other ecosystems across much of the United States, with dire impacts on native trees and plants, wildlife such as ground-nesting birds, and forests’ ability to regenerate. While some methods of mitigating deer browse – such as erecting large deer exclosures, brush walls, and landscape-scale culling programs – aren’t practical for a typical forest landowner, there are steps you can take on your own land to discourage over-browsing.
1. Make a mess! Deer prefer to travel the path of least resistance. Through forest management, we can use this preference to our advantage. For example, instead of cutting trees, treetops, and branches (“slash”) to make them lie flat on the forest floor, leave them un-lopped to make as big a mess as possible. This will create areas that deer can’t easily access, thus protecting tree seedlings and understory plants, which can grow underneath the slash that remains for years on the forest floor. This approach also provides improved cover and foraging habitat for smaller wildlife species such as insects, rodents, birds, and their predators. And it can benefit forest hydrology by slowing surface water flows, spreading water out and helping it sink into the soil.
In my forest, I look for opportunities to create bigger and longer-lasting messes. For example, when I noticed that treetops and branches tend to compress after a winter or two, I started hinge-felling smaller-diameter trees at waist height. This creates a higher and more durable barrier to deer browse, providing trees and plants with more long-lasting protection.
2. Create lots of regeneration at once. Natural tree mortality – and the ensuing regeneration – often comes in dribs and drabs: one or two trees die, creating a small pocket of regeneration, which makes it easy for deer to browse all the young trees of species they favor. This is why, for example, a forest with lots of oak trees in the overstory may have few oak seedlings in the understory. One benefit of working with a forester and a logger to actively manage your forest is that you can create lots of regeneration at once, thus overwhelming the local deer herd’s ability to browse it all.
3. Plant and protect trees. In some cases, where deer overpopulation simply doesn’t allow trees of certain species to grow, it may be necessary to supplement natural regeneration with some planted trees. Planting trees is a big commitment – planted trees must be protected from deer browse until they are 5 to 6 feet tall, and fences or tree shelters will need maintenance each year – but this can be an effective way to ensure preferred-browse tree species are able to regenerate. Work with your forester to decide which tree species are best suited to your forest.
4. Hunt does. The most direct and effective method for reducing deer populations will always be to kill deer. One of the major drivers of deer overpopulations is the loss of their historic apex predators (wolves and cougars) and the decreasing ability of their current apex predator – humans – to reduce their population, due to an increase in posted land, suburbanization and fragmentation, and decreasing numbers of hunters. Because a buck can mate with multiple does, killing bucks does little to reduce deer populations in the long-term, so where deer are overpopulated, it is important to prioritize killing does. If you’re not a hunter, consider becoming one. If you are a hunter, prioritize doe hunting, and if you allow others to hunt on your land, ask them to do the same. If you are reluctant to make your land entirely open to hunters, consider posting it “hunting by permission only” and be responsive to inquiries, giving permission to a select group of hunters.
While recreational hunting can help reduce deer populations, it’s important to be realistic about how much impact it can have. Where there are more than 40 deer per square mile (which is the case in most of white-tailed deer’s range), research suggests that recreational hunting alone will not sufficiently reduce the population. In these areas, “culling” – where professionals come in and kill high numbers of deer over an extended area – will likely be necessary to reduce populations to a level that can be maintained by recreational hunting.