Creating Healthy Woods and Improved Deer Habitat through Forest Thinning

Forest owners have many reasons for owning their property. This may include things like improving timber production, creating wildlife habitat, protecting water quality, enhancing recreational opportunities, and many others. If your reasons include creating healthy woods and improving deer habitat, a thinning may be the right forest management practice for your woods.

This stand would benefit from a thinning. The trees are

overcrowded and there is little growth in the

 understory besides fern.

Forest thinnings are conducted in overcrowded stands when they are still relatively young, from 15 to 50 years of age however, thinning can benefit older woods. By design, thinning reduces competition among neighboring trees. Foresters thin trees to improve growth rates and overall tree vigor. Wildlife biologists thin trees to improve wildlife habitat by increasing understory growth and mast (acorns and nuts) production.

Thinning frees desirable trees from neighboring trees competing for growing space. Trees need room to grow and expand their crowns. If they are too close, they compete for resources, primarily light. The focus is on improving growing conditions for selected crop trees by removing competing poor quality and less desirable species. The trees left are evenly spaced, released, and encouraged to grow.

Trees compete for light. To grow, they need room 

to expand their crowns.

Most stands of trees originally have thousands of seedlings and sprouts per acre. As they grow, competition for light, water, and nutrients increases. The most vigorous trees become the dominant and co-dominant trees in the stand - their crowns are above or make up the main canopy level. The less vigorous trees are crowded by their neighbors; their crowns become misshapen and restricted. These trees become the intermediate and suppressed trees in the canopy - their crowns are below the main level of the canopy, receiving little light from above. Of the thousands of seedlings beginning life in a forest, less than 100 per acre may survive and thrive to become a mature forest. 

Forest thinning provides the opportunity to select and encourage the dominant and co-dominant trees you want, those that meet your objectives. These trees can provide for future timber production, wildlife habitat or myriad other values. For example, thinning around an oak tree will improve its growth rate and vigor and may very well increase the amount of acorns it produces.

Trees selected to leave are marked with flagging

or paint prior to any cutting occurring.

Improved deer habitat is an added wildlife benefit of thinning. Deer are browsers, tree and shrub twigs, buds, and leaves make up a primary component of their diet. A deer’s system can easily digest woody browse. They will feed on it year round. Browse is the most important source of deer nutrition in forested environments. During winter and early spring it is a vital source of nutrition as most other food sources are unavailable.

Thinning trees in winter puts tops on the ground that deer can browse during lean times. Once the tree hits the ground, deer have access to the tender buds and twigs on the top of the tree, which are generally nipped off within weeks. Thinning overcrowded trees also increases the amount of sunlight reaching the forest floor. The increased sunlight provides ideal conditions for new seedlings and herbaceous plants to get started, providing food and cover for deer as well as other wildlife.

Winter and early spring thinning provides deer

browse during a critical time of year.

In addition, hardwood tree stumps often re-sprout after cutting. Stump sprouts provide additional woody browse for deer. Sprouts may remain within the reach of deer for years, providing a valuable food source. Some deer habitat managers recommend hinge cutting trees during thinning operations. Hinge cut trees are cut half-way through allowing the tree to fall to the ground. The “hinge” keeps the tree alive to continue producing leaves and vertical shoots.

Red maple stump sprouts provide deer

with a source of woody browse.

This hinge cut ash is producing stump sprouts

and sprouts along the stem as browse.

Thinning operations can be either commercial or non-commercial, depending on the products being removed and available markets. Often thinning provides no immediate return beyond improved wildlife habitat. In small diameter stands, where there are few markets for pulpwood and/or firewood, landowners may do the work themselves or pay a contractor to cut trees. A commercial thinning provides an income opportunity as the landowner sells the trees being removed. Commercial thinning generally occurs later in stand development when trees removed have reached small sawlog size or is in an area where good markets for pulpwood exist. 

In a thinning, the most important decision is selecting which trees to keep for the future. Focus on the value of the future forest and leave trees that meet your ownership objectives. No matter what you manage for, leaving trees with the highest potential future value is important. Remember, in many cases trees that are good for wildlife are also good timber trees.

This young hardwood stand was thinned pre-commercially.

A professional forester or wildlife biologist is an important ally when designing a thinning treatment. Some landowners choose to work directly with a logging contractor who buys timber; however, these individuals may not have the training and experience to implement a proper thinning. If you choose to do most of the planning on your own, it is advisable to use a forester to conduct any timber sale, including a thinning, as they have knowledge of markets and buyers and can ensure the practice improves the overall well-being of your woods.

This stand of yellow poplar could be thinned commercially.

Unlike regeneration harvests, thinning does not result in large canopy openings. The gaps created between crop trees are small enough that remaining crowns expand and close back together over time. Therefore, it is important to have the proper spacing among crop trees. If the openings are too large, tree replacement from regeneration (seedlings and sprouts) will be necessary. In addition, the light reaching the forest floor might initiate competitive plants or encourage invasive species establishment including invasive exotic trees, shrubs, vines, and grasses. It is important to monitor any harvested area for undesirable vegetation and control it before it gets out of hand.

Thinned the previous growing season, this white pine stand 

shows a flush of new herbaceous growth and stump sprouts.

In many areas deer populations exceed the habitat carrying capacity and over-browsing is common. If sprout growth is browsed completely to the stump consider reducing deer numbers. Implementing additional management practices that improve habitat is also desirable.

Sprouts heavily browsed down to the stump, like this black gum, 

may be an indicator of too many deer for the available habitat.

A well designed thinning should put your wooded land well on its way to meeting your objectives of improved forest health and wildlife habitat. A successful thinning involves planning, implementation, and monitoring. The end result is more valuable timber, a vigorous, healthy forest, and improved habitat for wildlife.

For additional information on thinning see:

- Forest Thinning: A Landowner’s Tool forHealthy Woods, University of Maryland Extension

- Intermediate Cuttings in Forest Management, University of Wisconsin Extension

- Crop Tree Management in Eastern Hardwoods, USDA Forest Service

- Create Living Thicket Cover by Hinge-Cutting, Quality Deer Management Association

By David R. Jackson

Penn State Extension

Myth of the Month

Is this deforestation?

I was working with one of our design folks on a web-based course my colleagues and I were putting together for teachers. The course is going to be called “Teach for Forests” and will be coming out in 2017.  It was interesting to note that I ran into this very myth with my course designer.  I was putting together a section on forest history which discussed the era of exploitation from the late 1800’s through the early 1900’s, when most of Pennsylvania’s northern tier was essentially clear cut.  She thought this meant the land deforested and the forest was gone.  I had to spend time explaining to her that just because the trees were cut didn’t mean the land was no longer “forest” land.

This is the same site as above in the 2nd growing season.

This was eye opening to me.  I thought that was obvious, too many it is not.  So, be careful when talking to those that are uniformed.  Be sure to explain the difference.  Deforestation is what most hear, especially teachers, about the rainforest when the forest is cut and changed to another use, most often agriculture, thus…deforested.  Harvesting timber, even clear cutting, is NOT deforestation.  That land is still considered “forest" land and will grow a new crop of trees available for harvest someday, as long as the land use doesn't change. 

Myth: Timber harvesting and deforestation are synonymous. 

Fact: A forest can be harvested and still maintained as a forest. By contrast, deforestation is the conversion of forested land to non-forested land. When deforestation involves the conversion of forested land into developed land, this change is usually permanent because developed land is almost never converted back to forested land. 

U.S. Forest Service R&D Newsletter - December 2016

Logging in Lower Burrell

I thought my readers might enjoy this news story printed online for the Tribune Review, Sunday, November 20, 2016. It was sent to me by a colleague of mine. It is essentially the same conversation I was having with folks at a Sustainable Forestry Initiative logger training course on Sustainable Harvesting Practices just this past fall. If it’s in the news, it must be the best way of doing things!  Right? Give it a read and listen to the video and let us know what you think. Maybe we could change the title to something more fitting.

Be sure to contrast this article with the post by Dan Pubanz from April 27, 2016 entitled “Why the Forestry Profession Should Harshly Criticize High-Grading.” Also, if you haven’t already red it, be sure to read the article by Dr. Jim Finley posted on June 21, 2016 entitled “Describing Sustainable Timber Harvesting: What do Words Mean?”

Logging effort above Route 56 in Lower Burrell a labor of love

A succession of loud snaps from crashing limbs are followed by a final thud as a crew of Amish loggers cut century-old hardwood above Route 56 in Lower Burrell. Although youth football fans who regularly line Flyers Field might not consider the surrounding hillside a forest, to a forester, the heavily wooded area certainly qualifies. And the mature hardwood trees are ripe for select cutting.

It's a common practice, as Pennsylvania is the largest producer of hardwood lumber in the nation, according to the state's Department of Conservation and Natural Resources' Bureau of Forestry. The commonwealth's $20 billion per year forest products industry employs about 100,000 Pennsylvanians.

“Any forest is a large garden; you pick the mature fruit,” said Tom McQuaide of Torrance, a consulting forester for Pennsylvania Forest Management timber and log sales. He is contracted to cut and sell the logs, taking bids from sawmills throughout the state.

The selective cutting of hardwood is a common way to harvest some mature trees and open up the canopy for younger upstarts, he said. “We don't like to waste them,” he said. “Overly mature trees are rotted inside.” McQuaide was hired by a private landowner to selectively cut on the crown of the hill above Flyers Field along Route 56 in Lower Burrell. They limited their activities so the cuts wouldn't change the view at the field.

A pile of red oak, basswood, white ash, hard maple and other logs sat in a staging area near Route 56. “We cut some of the nicest hardwood timber in the world,” McQuaide said. Jeff Woleslagle, spokesman for the state forestry department, agreed: “While the forests of Pennsylvania grow a variety of hardwoods, its cherry and oak are truly world class.”

McQuaide pointed to a red oak log. It's in great condition, with tight annual rings in the washed-out, red center. “This will go into furniture — a table or cabinet,” McQuaide said. No one will know for sure until the giant logs are cut lengthwise at a sawmill, then inspected for quality.

But before then, there's a lot of work for McQuaide and his crew as they take down the trees he marked beforehand. The Amish workers cut and dragged the logs with a skidder outfitted with chains on its front tires to conquer the steep terrain. Nathan Barrett, a timber harvester from Dayton, Armstrong County, carefully sharpened the teeth on the 20-inch bar of his chain saw.

The oldest tree he felled in the last week at the site was a 150-year-old red oak. Before he cut a 50-foot hard maple, he read the layout of the forest, such as the nearby slim cherry trees to find the path of least resistance and safety.

As Barrett checked out the direction of a cut and fall, McQuaide said, “You can drop it across the road and top it. That's where it wants to go.” With a loud splinter, the oak fell predictably into the cherries, then to the forest floor. After a few weeks of cutting this month, the fruits of the crew's labor were a little more than 100 trees over 25 acres. That will translate into 60,000 board feet.

Mary Ann Thomas is a Tribune-Review staff writer. She can be reached at 724-226-4691 or mthomas@tribweb.com.