1. Mary Sisock, Ph.D. UVM Extension Forestry
Crop Tree Release
Mary Sisock, Ph.D.
UVM Extension Forestry
When your working in the woods your often focused on the trees you want to take out. Crop tree release is all about focusing on which trees you want to leave. These trees are called crop trees.

2. Crop Trees?
Trees that produce or have the potential to produce desired benefits.

3. What are your Objectives?
Forest health (vigor)
Improve wildlife values
Enhance aesthetics
Increase the quality or quantity of forest products
So the first step in crop tree release is clearly identifying your goals. What benefits are you managing for? Your goals determine what is and is not done in your woods. What trees are allowed to grow and which ones are taken out.

4. Selecting a Crop Tree Criteria will vary by objective
Which of the trees in the picture are the crop trees? It depends. The criteria for selecting a crop tree will vary by your objectives.

5. Wildlife Crown is large, healthy, and in or above the main canopy.
Mast-producing species (prefer hard over soft).
Trees with dead branches and open cavities are desirable.
Species variety is highly desirable.
Expected longevity of 20+ years.
You can see here that trees with widely different characteristics might be chosen in order to provide food and a variety of habitats for wildlife.

6. Timber Crown is large, healthy, and in or above the main canopy.
High-value commercial species.
High-quality tree with:
No defects
No sprouts on butt log.
No lean, low forks, etc.
Species well adapted to the site.
Expected longevity of 20+ years.
A crop tree can also meet more than one objective. For example, a tall, straight red oak that is suitable as a timber tree will also provide food for wildlife for many years.

7. AESTHETICS Select trees and species that are: Longevity of 20+ years.
unique in appearance or character,
produce attractive flowers and colorful foliage
have attractive or unique bark.
Longevity of 20+ years.
No matter the objective, trees that have a significant number of years left make better candidates as crop trees because they have more potential to respond to being released.

8. Trees Compete Light Water Space Nutrients
So what do I mean when I talk about releasing trees? Trees are not able to move around to get what they need to survive so they compete with their neighbors to get the resources they need.

9. Releasing from Competition1 2 4 3
Releasing a crop tree means that you are releasing it from competition with other trees. If you think about dividing the crown of a crop tree into quarters you ideally want the tree to be free to grow in all directions. Note that not all trees next to a crop tree are competitors. Trees whose crowns are well below the crop trees crowns are not significant competitors.

10. Free to Grow
By removing or killing trees whose crowns are competing with the crop tree more essential resources are made available to the chosen tree. Ideally the crop tree would be free to grow on all four sides. This of course is not always possible as for example when two good crop trees are next to each other.