Improving the habitat for wildlife on your hunting property doesn't have to be an activity that decreases the financial value to increase the quality of the habitat. Often properties that are left un-managed simply to let trees get bigger become so thick or overgrown that they may appear truly wild but in reality offer less and less for wildlife in the way of quality forage and cover. Additionally a forest so packed with hardwoods may even prevent quality crop trees from reaching their full potential.
Crop trees are trees that eventually will be harvested for the sale of their lumber by the land owner or manager. These trees also produce nourishment for wildlife but with to many large hardwoods devouring the forest canopy, the production of forage on the forest floor suffers and may result in slower development of the hardwoods that will be harvested. Finding a happy middle ground for quality timber production along with providing ample habitat for wildlife can be challenging.
Crop Tree Release is an option that can help all sides when carefully thought out. Crop Tree Release (CTR) is a method of removing lesser value trees that are competing with higher value trees for canopy space(room to grow upward and outward), sunlight and water. This method is not great for trees that have already reached the last third of their life but trees that are in the first third and beginning of the middle third of their life cycle can benefit the older tress and wildlife by executing this option.
The first step in this process is to identify the highest value trees for the land owner and create a list ranking those trees. Once the list has been created now it’s time to take a walk in the woods. Work in a grid of about an acre at a time.
A good method is to mark a spot as a starting corner, walk about (70) 3 foot paces and then mark that spot, then turn the best 90 degree angle you can and walk another 70 paces, mark that spot, turn another 90 in the same direction as your first turn and then walk another 70 paces and mark that spot. That will be approximately one acre depending on your ability to turn 90 degrees and walk in a straight line. You should have a rough square acre but exactness isn’t required.
With your area marked off begin to look for those high value trees filling the canopy. When you have identified them look to see if they have room to grow and expand. If they are crowded on some or all sides, look at what is encroaching on their space. Is it another high value tree or is it a lower value tree that can be eliminated for the benefit of the higher value tree.
The image below is a one acre representation of an unmanaged hardwood forest. This example has 53 trees on it that represent the canopy over the acre, not the underbrush or smaller trees that don't compete with the top level canopy. Some trees have room to grow and some trees are crowded and would benefit from a CTR. Look over the image and then we will discuss a management technique below.
The acre is shown with a grid of 36 spaces, each space represents what the most optimal tree spacing (about 35 to 40 feet between each quality tree base). This spacing removes growth competition and allows for hardwoods to grow straight and tall at a faster rate.
What you can see from the image is a random pattern of trees. Lets assume that all of them are in the top tier of trees you would want to keep for the quality of their wood and mast forage production. They are large and small. The larger trees being in the final 3rd of their life should be left no matter what the spacing but the younger trees, depending on proximity to the older trees, may be better for the forest by eliminating them to benefit the older trees growth and forage production. By allowing to many trees that devour the canopy, you are slowing growth and also casting a darker shadow on the forest floor, preventing forage growth for wildlife.
Here is a graphic to show you what I am referring to as the 3 stages of life as it relates to the square acre used as an example.
Of the quality trees, classify them by age to evaluate if a CTR is possible and beneficial. See the graphic below. The green dot indicates the tree is the Last 3rd of it's life, the yellow dot indicates the middle 3rd and the red dot indicates the First 3rd.
Our example below shows:
Now that you have classified the trees in age groups, it is time to evaluate their potential growth and if they will benefit from CTR
For a tree to continue growing straighter, taller and wider, it needs space. Look at your Last 3rd group and review each side by asking, "is this tree going to be competing for water or sunlight with other trees?". Trees in the last third of life before harvest will benefit from at least 15' of space between them and a next tree in the canopy. Good rule is to look at the base of the tree you are reviewing and then create an imaginary circle around it with a 35' radius. Any tree within that 15' space within the canopy or any tree inside that 70 foot circle, is competition and should be evaluated.
Here is an example evaluation:
If you wish to girdle a tree, using a chainsaw or ax, cut two rings around the tree through the bark phloem and cambrium. The depth of this cut depends on the size of the tree. Small trees may only require a 1/2 deep cut where larger trees may require an inch to inch and a half. The Phloem is a layer just beneath the bark of the tree and is responsible for feeding the tree for growth. Cutting this layer completely around the tree starves the tree of the nutrients it needs to grow.The Cambium generates new phloem and sap wood and is a thin layer just beneath the phloem and above the sapwood. If you reach sapwood, you have cut far enough. Cut two complete rings around the tree about 2 to 4 inches apart to increase your success.
Crop trees are trees that eventually will be harvested for the sale of their lumber by the land owner or manager. These trees also produce nourishment for wildlife but with to many large hardwoods devouring the forest canopy, the production of forage on the forest floor suffers and may result in slower development of the hardwoods that will be harvested. Finding a happy middle ground for quality timber production along with providing ample habitat for wildlife can be challenging.
Crop Tree Release is an option that can help all sides when carefully thought out. Crop Tree Release (CTR) is a method of removing lesser value trees that are competing with higher value trees for canopy space(room to grow upward and outward), sunlight and water. This method is not great for trees that have already reached the last third of their life but trees that are in the first third and beginning of the middle third of their life cycle can benefit the older tress and wildlife by executing this option.
The first step in this process is to identify the highest value trees for the land owner and create a list ranking those trees. Once the list has been created now it’s time to take a walk in the woods. Work in a grid of about an acre at a time.
A good method is to mark a spot as a starting corner, walk about (70) 3 foot paces and then mark that spot, then turn the best 90 degree angle you can and walk another 70 paces, mark that spot, turn another 90 in the same direction as your first turn and then walk another 70 paces and mark that spot. That will be approximately one acre depending on your ability to turn 90 degrees and walk in a straight line. You should have a rough square acre but exactness isn’t required.
With your area marked off begin to look for those high value trees filling the canopy. When you have identified them look to see if they have room to grow and expand. If they are crowded on some or all sides, look at what is encroaching on their space. Is it another high value tree or is it a lower value tree that can be eliminated for the benefit of the higher value tree.
The image below is a one acre representation of an unmanaged hardwood forest. This example has 53 trees on it that represent the canopy over the acre, not the underbrush or smaller trees that don't compete with the top level canopy. Some trees have room to grow and some trees are crowded and would benefit from a CTR. Look over the image and then we will discuss a management technique below.
What you can see from the image is a random pattern of trees. Lets assume that all of them are in the top tier of trees you would want to keep for the quality of their wood and mast forage production. They are large and small. The larger trees being in the final 3rd of their life should be left no matter what the spacing but the younger trees, depending on proximity to the older trees, may be better for the forest by eliminating them to benefit the older trees growth and forage production. By allowing to many trees that devour the canopy, you are slowing growth and also casting a darker shadow on the forest floor, preventing forage growth for wildlife.
Here is a graphic to show you what I am referring to as the 3 stages of life as it relates to the square acre used as an example.
Our example below shows:
- Last 3rd - 26 Trees
- Middle 3rd - 11 Trees
- Last 3rd - 15 Trees
Now that you have classified the trees in age groups, it is time to evaluate their potential growth and if they will benefit from CTR
For a tree to continue growing straighter, taller and wider, it needs space. Look at your Last 3rd group and review each side by asking, "is this tree going to be competing for water or sunlight with other trees?". Trees in the last third of life before harvest will benefit from at least 15' of space between them and a next tree in the canopy. Good rule is to look at the base of the tree you are reviewing and then create an imaginary circle around it with a 35' radius. Any tree within that 15' space within the canopy or any tree inside that 70 foot circle, is competition and should be evaluated.
Here is an example evaluation:
- Tree 1 - This tree is in its Middle Third of its life. It does leave a little less than 15' for tree #2 to grow but should be tolerable and can stay.
- Tree 2 - This Tree is in its Last Third of its life. Tree #1 gives it some space for growth but Tree #3 is both competing for ground space and will be growing into the canopy of Tree #2.
- Tree 3 - This tree is in the First Third of its life. It is directly in the 35' radius of Tree #2. Tree #2 will benefit from the elimination of this tree.
- Tree 4 - This tree is in the Middle Third of its life. Tree #5 will benefit from its elimination due to its location within the 35' radius and canopy competition.
- Tree 5 - This tree is in the Last Third of its life. It will benefit from the removal of Tree #4 but due to the age of Tree #2, it is best to leave both Tree #2 and #5 even though they may be competing for canopy space on one side. Releasing growth on other sides will benefit them until harvest.
- Tree #6 - This tree is in the First Third of its life. This tree does not present conflict with any trees at this time and Trees #2 and #5 will likely be harvested before canopy competition occurs.
After eliminating these tree from the competition, we are left with what we see here:
In this example, the trees were not cut down, they were girdled and left to die within the forest. By girdling trees and not cutting them down, the trees die completely within two seasons and begin to provide habitat for many woodland creatures. The lack of foliage during the growing season allows for additional sunlight to reach the forest floor and stimulate the growth of quality foraging.
You may want to completely remove trees if you have a use of them or if you want to sell some of the Middle Third tree lumber. Finding a forester willing to navigate a forest and not damage your keeper trees may be challenging but if you search enough you may be able to find a small scale forester who is willing to selectively removed trees you select without damaging the trees you wish to continue growing.
If you wish to girdle a tree, using a chainsaw or ax, cut two rings around the tree through the bark phloem and cambrium. The depth of this cut depends on the size of the tree. Small trees may only require a 1/2 deep cut where larger trees may require an inch to inch and a half. The Phloem is a layer just beneath the bark of the tree and is responsible for feeding the tree for growth. Cutting this layer completely around the tree starves the tree of the nutrients it needs to grow.The Cambium generates new phloem and sap wood and is a thin layer just beneath the phloem and above the sapwood. If you reach sapwood, you have cut far enough. Cut two complete rings around the tree about 2 to 4 inches apart to increase your success.
By picking manageable sections of the forest and pacing yourself, you can make a positive change for the trees closer to harvest and for the habitat and forage that help the wildlife that live in the forest. You may even invite more wildlife to frequent your neck of the woods. As for the entire acre we used as an example above. By using the methods we discussed, in two years, the forest may appear like this image below.
This result required that 17 trees be girdle cut and left to die in the forest. It ultimately permits much more sun to reach the forest floor, allows the remaining 36 quality trees to flourish and provides additional habitat with the dead trees.
It only cost some time to make the selections and the use of a chainsaw for several hours (or ax for longer depending on your skills and strength). It is a small investment that takes time to prove worthy but in the end both the tree harvest and wildlife habitat balance out for the better.
By no means should anyone cut any trees without the property owners permission. If you are presenting this to a land owner make sure they have clarity on the end goal. Many people think that more trees mean more money and that improving habitat decreases financial success. CTR has been a proven method to balance both worlds by producing better trees and improving habitat offerings. Hopefully this helps you find a better way to improve your property or one you are managing.
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