Raising is the removal of lower branches to provide clearance for people, traffic, buildings, or a view. [Figure 18]
Colorado State University-
Figure 18. When removing lower branches, maintain at least one-half of the foliage in the bottom two-thirds of the tree. The lowest branch should originate in the lower one-third of the tree.
University of Florida -
Raising the canopy all at once could also cause tree failure by leaving too much weight at the top of the tree. To avoid lack of balance after canopy raising the distance between the bottom and top of the canopy should be at least 2/3 the height of the tree.
United States Department of Agriculture / Forest Service Northeastern Area -
After pruning, the ratio of the living crown to total tree height should be at least two-thirds.
Use the following decision guide fro size of branches to be removed:
1) Under 5 cm diameter - go ahead,
2) between 5 and 10 cm diameter think twice
3) greater than 10 cm diameter - have a good reason
International Society of Arboriculture -
Excessive removal of lower limbs can slow development of trunk taper, can cause cracks or decay in the trunk, and concentrate foilage at the top pf the tree. Mature trees could become stressed if large diameter lower branches are removed. Most thinning removes branches 1/2 inch (1.5 cm, small trees) to 2.5 inch (6.5 cm, mature trees) in diameter. If large branches are removed, large gaps may be created in the crown, or watersprouts can result.
Raising should be part of the tree’s structural training while young. Ideally raising would be done before branches to be removed exceed a two-inch diameter. The potential for decay is high when the branch removed is larger than four inches or when a two-inch and larger branch is greater than half the diameter of the adjacent trunk (no branch collar to suppress decay).
On many trees, lower branches make-up a significant portion of the tree’s entire canopy and cannot be removed without significantly influencing tree health and appearance. When the branch to be removed is larger than two inches, consider other alternatives. Excessive removal of lower branches increases the potential for tree failure by decreasing trunk taper, causing trunk cracks and decay, and transferring weight to the top.
Tree skinning is the practice of raising up the crown of a tree to unneeded and excessive heights. Many times it is to the height that a bucket truck will reach. Lion tailing is the removal of an excessive number of inner lateral branches and foliage leaving a limb with a tuft of foliage at the end. Both of these practices may result in sunburned bark tissue, watersprouts, less photosynthesis, decrease in food production, reduced branch taper, weakened branch structure, and breakage. In combination, they will surely shorten the life of a tree.
And then, all that light let in on the previously shaded bark causes the tree to waste valuable stored energy putting out sprouts, and it can’t make the needed amount of food (sugar) (energy) because of the reduced amount of foliage
Cleaning is the removal of dead, diseased, cracked, and broken branches. This type of pruning is done to reduce the risk of branch failure, improve tree appearance, and to reduce the spread of insects and diseases. Most pruning of middle-aged and mature trees falls into this type. Trees under stress or declining trees may need cleaning every few months to ever few years. All dead wood may be removed at one time. It does not count in the total of live wood/foliage removed. In cleaning, do not remove healthy branches and live foliage. Do not clean out healthy growth in the tree’s interior.
Thinning is not removing large lower branches, which could create gaps in the crown and encourage water sprouts.
Raising is the selective removal of branches to provide vertical clearance. Caution must be taken to not remove too many lower branches. This can cause slow development of trunk taper, cause cracks or decay in the trunk, or transfer too much weight to the top of the tree.
Colorado State University-
Figure 18. When removing lower branches, maintain at least one-half of the foliage in the bottom two-thirds of the tree. The lowest branch should originate in the lower one-third of the tree.
University of Florida -
Raising the canopy all at once could also cause tree failure by leaving too much weight at the top of the tree. To avoid lack of balance after canopy raising the distance between the bottom and top of the canopy should be at least 2/3 the height of the tree.
United States Department of Agriculture / Forest Service Northeastern Area -
After pruning, the ratio of the living crown to total tree height should be at least two-thirds.
Use the following decision guide fro size of branches to be removed:
1) Under 5 cm diameter - go ahead,
2) between 5 and 10 cm diameter think twice
3) greater than 10 cm diameter - have a good reason
International Society of Arboriculture -
Excessive removal of lower limbs can slow development of trunk taper, can cause cracks or decay in the trunk, and concentrate foilage at the top pf the tree. Mature trees could become stressed if large diameter lower branches are removed. Most thinning removes branches 1/2 inch (1.5 cm, small trees) to 2.5 inch (6.5 cm, mature trees) in diameter. If large branches are removed, large gaps may be created in the crown, or watersprouts can result.
Raising should be part of the tree’s structural training while young. Ideally raising would be done before branches to be removed exceed a two-inch diameter. The potential for decay is high when the branch removed is larger than four inches or when a two-inch and larger branch is greater than half the diameter of the adjacent trunk (no branch collar to suppress decay).
On many trees, lower branches make-up a significant portion of the tree’s entire canopy and cannot be removed without significantly influencing tree health and appearance. When the branch to be removed is larger than two inches, consider other alternatives. Excessive removal of lower branches increases the potential for tree failure by decreasing trunk taper, causing trunk cracks and decay, and transferring weight to the top.
Tree skinning is the practice of raising up the crown of a tree to unneeded and excessive heights. Many times it is to the height that a bucket truck will reach. Lion tailing is the removal of an excessive number of inner lateral branches and foliage leaving a limb with a tuft of foliage at the end. Both of these practices may result in sunburned bark tissue, watersprouts, less photosynthesis, decrease in food production, reduced branch taper, weakened branch structure, and breakage. In combination, they will surely shorten the life of a tree.
And then, all that light let in on the previously shaded bark causes the tree to waste valuable stored energy putting out sprouts, and it can’t make the needed amount of food (sugar) (energy) because of the reduced amount of foliage
Cleaning is the removal of dead, diseased, cracked, and broken branches. This type of pruning is done to reduce the risk of branch failure, improve tree appearance, and to reduce the spread of insects and diseases. Most pruning of middle-aged and mature trees falls into this type. Trees under stress or declining trees may need cleaning every few months to ever few years. All dead wood may be removed at one time. It does not count in the total of live wood/foliage removed. In cleaning, do not remove healthy branches and live foliage. Do not clean out healthy growth in the tree’s interior.
Thinning is not removing large lower branches, which could create gaps in the crown and encourage water sprouts.
Raising is the selective removal of branches to provide vertical clearance. Caution must be taken to not remove too many lower branches. This can cause slow development of trunk taper, cause cracks or decay in the trunk, or transfer too much weight to the top of the tree.
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