Crop Tree Release

Crop Tree Release 2017-04-18T17:21:04+00:00

Crop Tree Release (Stand 4N)-J


Management Goals

  • Promote growth of high-value trees for wildlife or future timber
  • Release selected species – American beech (Fagus grandifolia), yellow birch (Betula allegheniensis), sugar maple (Acer saccharum) and black cherry (Prunus serotina)
  • Enhance wildlife habitat by creating snags (standing dead trees) and increasing coarse woody debris (large, dead wood on the ground).
  • Apply special management within the Vernal Pool Buffer Zone, where salamanders are protected by downed wood, shade from a mostly intact forest canopy, and moisture from decomposing leaves and twigs in the duff layer.

Stand Description/History

Unlike much of the surrounding area, the tree species and defined soil horizons (layers of soil that can take many years to develop) suggest that this forest was never a farm field, but may have been a woodlot or sugarbush in the past. This area escaped the heavy logging of the 1980’s that much of our forest is still recovering from, and we see that today in the large, shade-tolerant trees throughout the stand. With relatively little human disturbance, this area of our forest has become a unique and special place!

Black Bears & Beech Trees

One unique feature of the stand is its large number of  American beech trees with claw marks from bear climbing. These marks indicate that the trees are good hard mast (nut) producers, because it was worth a bear’s energy to repeatedly climb for them. It also suggests that the tree may be genetically resistant to beech bark disease, a combination of insect and fungal pathogens that attack beech trees. Wounded trees (such as those with claw marks) are more susceptible to the disease, so only a “resistant” tree will likely remain disease-free after years of bear climbing.

What is CTR?

Crop Tree Release (CTR) is a silvicultural technique that promotes the growth of individually selected trees. Before starting up the chainsaw, a forester walks the area and flags crop trees to retain, and marks trees to be cut around each crop tree. By removing competition (neighboring trees that take up space and light), the crop tree is provided more resources and space to grow.

Through this forest improvement method, landowners can increase both economic and ecological value of a stand. Crop trees can be chosen with various criteria in mind. Most often, they will be healthy, commercially-valuable species that will later be harvested for timber. By releasing timber trees, the landowner is making an investment toward the future value of their forest. Crop trees might also be chosen because they are a species that is uncommon or useful to wildlife (for example, the beech trees in this area).

Pre and Post Treatment Diameter Distribution

Stand Data


Basal Area: 111 ft2/ac 

Acceptable Growing Stock (AGS): 58%


Basal Area: 87 ft2/ac 

Acceptable Growing Stock (AGS): 68%

Show Me the Money!

Crop Tree Release should be thought of as an investment toward the future value of a forest. But how can you recoup the immediate costs?

The work at this site was funded by a cost-share program through the Natural Resources Conservation Service (NRCS), a government agency that helps subsidize forestry and agricultural work on private lands. More information and grant applications are available at

Depending on the species composition of the stand and accessibility, a landowner may also be able to sell the removed trees for firewood, timber, or other uses.

Skilled and ambitious landowners can also save costs by doing some of the work themselves. A good option might be to have a forester mark the trees for you and then do the cutting yourself.  If you plan to fell trees in your woods, be sure that you have the proper training and safety equipment!

Tim Girdling

Girdling (killing a tree by cutting through it’s outer layers of phloem and cambium) can be an easy way to release crop trees, while creating standing dead trees that are valuable to wildlife.

Tips For Success

  • CTR is best applied to forest stands where trees are large enough to be well-established, but small enough to benefit from added growing space (most trees should have diameters of 5-15 inches)
  • Crop trees must be healthy and wind firm (well rooted and stable). Look for trees that have large, living, symmetrical crowns, and avoid those with wounds, cavities, rot, or dead branch tips. Choose species that are adapted to site conditions.
  • Try not to remove too many trees– only cut down trees with crowns touching the crop trees. Removing too much of the canopy doesn’t benefit the crop trees, and may even cause epicormic sprouting (growth of new branches low on the tree trunk) which reduces the timber value of the tree.


Management Timeline

– Prior to 1941

As one of the farther woodlots of a large farm tract, this forest probably supplied timber and firewood for the farm. Unlike areas closer to Ten Mile Square Rd, there is no evidence that it was ever cleared for agricultural use.

– 1930

Tree ring growth suggests a thinning or natural disturbance, causing an increased growth rate in remaining trees

– 1941

Based on the earliest aerial photos, this area was forested, mostly with large hardwoods

– 1966

Property was bought by a pulpwood producer, who conducted a liquidation cut (removal of all valuable trees, with little regard for the health or future value of the stand). The remaining forest consisted of widely spaced maple, ash and beech trees

– 1985

Forest management plan prepared by Richard Carbonetti reported a basal area of 53 ft2/ac and a mean diameter of 10.6 inches DBH, showing the stand to be very understocked (having too few trees for optimal growth and wood production)

– 2004

With support from board member Lydia Spitzer and founder Bill Manning, NorthWoods acquired this stand as part of our demonstration forest

– 2012

With NRCS cost-sharing, Crop Tree Release treatment was applied to part of the stand and established as a sustainable forestry demonstration site by the NorthWoods Forest Stewardship Institute