Woodland Management: Understand the History to See the Future

Planting trees has long been seen as an act of faith, action, and stewardship.  Trees provide numerous benefits. They protect the soil, provide valuable food, fodder, and habitat, and maintain water and nutrient cycles, just to name a few. But not seeing the forest for the trees is a recipe for disaster.

As a young person I recall hearing that when Europeans arrived in the “new world,” a squirrel could travel from the east coast of the Atlantic to the Mississippi River without touching the ground. It created  a vision of the entire eastern half of North America as a deep, dark, heavily canopied forest. 

The reality was much different. The landscape was a patchwork of open woodlands, savannas, prairies, pine barrens, and mixed aged forests in an early successional stage, kept that way by fire and animal impact. Sites that evolved to true deep forest were protected from fire and grazing by aspect, slope, excess moisture, or by barriers such as swamps and water.   

Present Day Forests and Woodlands 

Today, many of our forests and woodlands are overgrown. Forest ecologists are using harvest as a means of mimicking past disturbances such as wind and fire, but this fails to have the same effect as fire itself, or the historic plant harvesting by grazing and browsing animals. Timber harvest removes nutrients from the landscape, while fire and biological harvest cycle and store many nutrients on site. Beyond the historic ecological context of these landscapes, many forest and woodland parcels today are too small for the large forest harvesting equipment that dominates the logging industry, limiting management options.

 Many woodlots in agricultural landscapes were grazed into the 1960s, 70s, and 80s as part of diversified farming operations, keeping them in some semblance of the more open woodland and savanna ecosystems that once dominated much of the Midwest. But as the beef and dairy industries consolidated and animals left the land, these sites began to fill with early succession trees and shrubs, eventually leading to more closed-canopy “forests” that provided perfect growing conditions for buckthorn and other aggressive species that lack economic value, disrupt nutrient cycles, and degrade wildlife habitat.

Discussing ecological site conditions at Sherburne National Wildlife refuge. Notice the brush and hazelnut in the background, before grazing. Without management this would grow to eight feet or more.

Photo by Karl Hakanson

Vast areas of our Midwestern landscape are facing these conditions, overstocked with fast growing trees, and an understory of nitrogen-loving and shade tolerant shrubs, most often buckthorn. Deemed “invasive species,” these nitrogen-loving plants form monocultures that lack diversity and provide little human or wildlife value. Abandoned pastures, farm woodlots, parks, and recreation areas are just some of the sites that are facing this challenge. Fortunately there are solutions.  

Understand the Problem

The answer to this problem is first understanding that you’re not dealing with an invasive species issue, you’re most likely dealing with a management issue. There are no easy answers to controlling invasive brush, and taking a long-term approach is the key to success. Next is understanding the ecological context that has shaped the plant community, both historically for the last 10,000 years and more recently. Are the soils, geology, rainfall patterns, and aspect of the site consistent with drier conditions that allowed fire to play a dominant role in shaping your landscape in the past?  What evidence is there of recent management and disturbance? Getting to know the ecology of your land will help you set better goals and expectations.

Here are some resources for the steps to a long-term management plan. 

• Explore and learn about your land through resources such as the Web Soil Survey and MN DNR Ecological Classification System. 

• Connect with other landowners and practitioners through non-profit organizations such as the Sustainable Farming Association and the Savanna Institute where you can see on the ground examples of brush management.  Bonus: the SFA’s Dirt Rich podcast on managing buckthorn and brush which I was a part of.

• Seek out professional and financial resources through your local Soil and Water Conservation District, USDA Natural Resources Conservation Service  and the Minnesota Department of Natural Resources, who can guide and mentor you in developing a long term management plan.

• 

These agencies and organizations can help develop a plan to reduce the species of concern to a manageable level, establish vegetation consistent to your site’s natural history, and prescribe an ongoing maintenance program that fits your goals and desired outcomes.

Goats browsing brush at Sherburne National Wildlife Refuge to restore Oak Savanna habitat

Photo by Karl Hakanson

A long-term management plan will likely involve reducing the tree-stocking levels of your woodlands to open up the site and allow more sunlight to reach the ground, spurring grass and forb establishment. Growth of this type of vegetation will allow for integration of prescribed fire, mowing, and/or grazing livestock, which will help to harvest biomass and keep your woodland in an early and productive successional stage, enhancing wildlife habitat, restoring nutrient cycles, and protecting water quality.  

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