Replanting decisions post-storm vary based on goals, say forestry experts
The damage left by the late July storm leaves many landowners with important decisions concerning what species to plant or whether to plant at all
MADISON, WI -- Last July, more than 20 tornadoes touched down in heavily-forested northern Wisconsin. If you have forested land affected by the storms, there are several options for managing your property. The first step is to assess your goals, said Jeremiah Auer, a forest regeneration specialist at the Wisconsin Department of Natural Resources (DNR).
Planting conifers usually promises the fastest financial returns and is the most reliable for regeneration success, Auer advised. Planting hardwoods usually provides better habitat for popular wildlife species. And in the right situations, choosing not to plant trees can be beneficial for wildlife and save upfront costs.
Choosing to plant
Conifers have always been the most popular choice for planting, Auer said. Top species include red pine, white pine, jack pine, and white spruce. Red pine is usually the best economic choice because of its fast growth and straight form.
“From a timber point of view, red pine is really an incredible tree,” said Auer. “In some cases you can get to selling wood from the first thinning in only 25 or 30 years.”
Landowners should wait before planting red pines, Linda Williams, a forest health specialist at the Wisconsin DNR, told the Forest Data Network for a September story on tornado salvage. That’s because an insect called the pales weevil thrives in recently-killed pine stands. In the year following a major disturbance like a tornado, weevil populations explode and live trees can be harmed, including seedlings. The best practice is to delay planting for two years following the disturbance. In this case, that would mean waiting until at least spring of 2021. Red pines are the most susceptible, but other conifer species can also be damaged by pales weevil, so it’s best to be cautious.
Conifers, however, aren’t the only game in town.
“Hardwoods have become more and more popular over the last 25 or 30 years,” said Auer.
Although many hardwood species command high market prices, they are generally planted for wildlife purposes. That’s because they grow more slowly and seedlings have lower survival rates than conifers. Auer said that red oak is easily the most popular choice in northern Wisconsin, because it often survives well in open areas, produces acorns, and has high market value. There is also a shortage of regenerating oaks in Wisconsin, and disturbances like tornadoes can provide opportunities for oaks to succeed.
Auer said that he often advocates for planting a mix of conifers and hardwoods. This increases the chance that some trees will regenerate successfully. It creates more economic and ecological diversity on a property, so it can help landowners feel more sure of benefitting from their forest in an uncertain future.
Choosing not to plant
Choosing not to plant immediately can be the best option if you want to save money and let the forest recover naturally. Wisconsin forests are adapted to regenerate after disturbances like tornadoes, and they are sometimes resilient to salvage logging. Auer said that in salvaged areas it’s hard to depend on regeneration from seed, but many hardwood species can reproduce prolifically through root or stump sprouting. These include oaks, red maple, basswood, and aspen. If these species were abundant before the storm, chances are they’ll be abundant afterwards, as fast-growing sprouts.
Additionally, windstorms often leave many small to medium sized trees standing. This “advanced regeneration” tends to be from shade tolerant species like sugar maple. Auer said that loggers usually take care not to damage these trees in salvage harvests, because they give a big headstart for reforestation.
Sometimes, however, it can take years or decades for an area to be tree-dominated again. From a wildlife standpoint, this can actually be a good thing. Open areas with a mix of shrubs, grasses, forbs, and small trees make for very diverse habitat. Woody debris left by a windstorm or salvage harvest is often seen as an eyesore, but it also creates rich habitat and obstacles to deer browsing of seedlings, Auer said.
If you want your land to regenerate with trees, you can always wait a few years to see what grows back, and then decide to plant in any areas that aren’t meeting your goals. Some extra site preparation may be needed if shrubs or grasses become too dense for replanting, so you should keep this in mind before you delay planting.
Every forested property is unique, and the extent of tornado damage is variable. So it’s impossible to generalize about what will work best for everyone. If you want an expert opinion or a plan for how to approach reforestation after a windstorm, a consulting forester can help you assess your options. For more technical information on planting trees and information about ordering trees from the state nursery, the DNR tree planting website is full of information to get you started.