Supercharge Your Woods: How to do “partial timber harvests” right

2011 workshop series for Minnesota logging contractors and family woodland owners addressed financial and ecological benefits of “intermediate stand treatments.”

Watch a 5-minute video from the 2011 field days:

(A larger version of the video is here)

It’s a simple law of nature: In order to survive, trees have to grow at least a little bit each year.  Unfortunately, when conditions get crowded, trees can’t pick up roots and move around to find more breathing room. Just like the plants in your garden, trees that don’t have enough growing space, won’t grow well.

The result of this crowding is weak trees that become vulnerable to everything from ice storms to insect outbreaks. Stand productivity (and therefore, value) is reduced. Eventually, this can lead to permanent stagnant growth.

Overcrowded, unthinned red pine crowns. Click for a better view.

This situation is all too common in Minnesota.  “Every day I drive by Norway pine plantations that just about make me cry” says Chad Converse, a Motley-area consulting forester.  “These stands were planted 30-plus years ago at 8 by 8 foot spacing and haven’t been touched since.”

What Chad means is that, because the trees are so tightly spaced, they are overcrowded; the stands have small crowns with little foliage. Because foliage is important for the photosynthetic engine, these trees lack the energy they need to thrive, grow fast, and fight off insect and disease problems.  Tight spacing also limits tree diameter growth, reducing tree and overall stand value for those owners interested in selling timber.

A series of workshops across northern Minnesota this summer and fall have been designed to help logging contractors and family woodland owners understand how to avoid this situation.

Well-designed partial harvests, commonly called “intermediate stand treatments,” can help those working with, and owning woodlands to avoid stagnant, overcrowded stands in the first place; it can also help them out where such stands already exist.

Workshops will be offered as follows, with most of each day spent outside. More details on the Supercharge Your Woods workshops are here:

  • July 7, 2011:  Bob and Ingrid Sonnenberg Tree Farm, New York Mills
  • August 25, 2011:  Aitkin area
  • October 6, 2011:  Brimson

There is no cost to attend; however, each workshop is limited to 25 participants.  The workshops are being planned cooperatively by the Minnesota Forest Resources Partnership, Minnesota Logger Education Program, University of Minnesota Extension, UPM-Blandin Paper, Potlatch Corporation, National Association of Conservation Districts, and the Minnesota Department of Natural Resources.  The workshops are funded by a grant from the Weyerhaeuser Family Foundation.

More information on dates, details, and registration is available at

A 9 year old aspen-birch mix after manual thinning. Click for a better view.

Not all intermediate treatments are the same.  “On Blandin lands, we use a mix of pre-commercial thins to benefit aspen and release treatments to promote conifers along with commercial thins, where the harvested products are large enough to be used in our mills,” says forest ecologist Cheryl Adams of UPM-Blandin Paper Company in Grand Rapids.  “While the pre-commercial thins cost us money, they more than pay for themselves over the life of the stand through improved growth.”

Family woodland owners, with nothing more than a brush saw or chainsaw, can often manage their own pre-commercial thins, as the trees removed tend to be relatively small.

In some woodlands, intermediate treatments can also be used to encourage growth of certain species, favoring those species best suited to the site.

There are downsides to intermediate treatments too.  Maneuvering harvest equipment through a stand while avoiding damage to residual (un-harvested) trees can pose a challenge to logging contractors.  “That’s the biggest problem I hear of from loggers,” says Dave Chura of the Minnesota Logger Education Program.  “The way these stands are marked, it’s difficult to get to the trees.  This means more time spent moving through the woods, slower production, and higher costs.”

The low value of harvested products can also be a challenge, as some landowners expect a larger financial return than is possible during early treatments.  But while today’s harvest equipment tends to allow a softer environmental footprint, that equipment carries high costs both for ownership and operation.  While, as Adams notes, these costs are perhaps best viewed as investments, that can be a hard sell, particularly in today’s economy.

Finally, while well-designed intermediate treatments kick the woods into high gear, poorly designed treatments can do the opposite.  Harvesting only the largest, best-formed, or merchantable trees can seriously degrade the long-term productivity and health of the stand.  Often referred to as high-grading, this approach leaves only the worst and weakest trees on the site.  With rare exceptions, these trees will generally continue to stagnate even after their competition has been removed.

High-grading can produce a short-term financial return but seriously limit future productivity and tree health.

Carbon and productivity benefits

Trees are about 50% carbon by dry weight.  They obtain carbon from the atmosphere, making tree growth an important strategy to reduce atmospheric carbon levels.

The CFC student thinnings stand, thinned 4 times. Click for a better view.

A century-old Norway pine stand at the University of Minnesota’s Cloquet Forestry Center illustrates the impressive productivity and value gains from intermediate treatments.  The stand originated naturally around 1910.  On one side of the road, the 40-acre stand has been thinned four times: in 1950, 1960, 1970, and 1985.  On the other side of the road, the stand has never been thinned.

Focusing on carbon dynamics, both stands have sequestered approximately the same amount of carbon during the past 100 years.  However, in the un-thinned stand, almost 40% of that carbon has returned to the atmosphere, or is in process of doing so, through mortality and decomposition of dead wood.  In the thinned stand, almost all of that natural mortality has been “captured” through thinning and turned into wood products.  Read more on the carbon dynamics in the “student thinnings” red pine stand here.

The four thinnings have also dramatically increased the financial return.  Including interest on revenues from products sold (compounded at 5% annually) plus the value of standing timber on the sites, the thinned stand has a total value of over $6,000 per acre, many times that of the un-thinned stand.

Doing it right

“In my experience, the vast majority of landowners want to leave their land in better shape than they found it,” says University of Minnesota Extension Forester Eli Sagor.  “While they’re willing to invest both money and sweat equity in their woods, they want to know those investments will pay off.”

A recent woodland workshop for loggers and landowners.

The purpose of the Supercharge Your Woods workshop series is to help landowners and logging contractors understand their options.  Tour stops will address practical considerations associated with intermediate treatments including operational, financial, and ecological considerations.  Hands-on activities will address tree selection for a variety of landowner objectives as well as expected financial returns and other future considerations.

To learn more about the workshops, visit


The University of Minnesota Extension Forestry team.

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  1. What about the deciduous forests of SE Minnesota? Dorer Forest. It’s been said that the state needs to value the northern forest more like the southern forests. Economic value can be achieved quicker through higher valued trees rather than pulp.

    1. We would have loved to offer a Supercharge Your Woods workshop down south Mike, but it just didn’t fit this time around. You’re absolutely right about the great opportunities that intermediate treatments offer in the hardwood systems of southern Minnesota through faster growth and focused growth on the highest value trees.

  2. Will you be covering how to improve nontimber forest products (tree and vegetation based) opportunities when planning intermediate treatments. Some of these opportunities may be as important as wood values–more likely in the short term than in the longer term.
    In my biased opinion a discussion of intermediate treatments for private landowners is incomplete without considering ntfp. thanks.