Some things to consider when you are thinking about tree removal.
How Healthy is the Tree?
If 50% of the tree is damaged, it probably should be eliminated. A tree that is in decline can continue to survive for many years but will always have limited or abnormal growth and appearance. Trees that have been damaged by herbicide frequently have misshapen leaves, but frequently can recover.
Is There Trunk Damage?
Vertical cracks, seams, dead branch stubs and large, older wounds suggest internal decay. Severe damage to the main trunk often warrants removal of the tree. If the damaged area is less than 25 percent of the circumference of the trunk, the wound could gradually heal over and no permanent injury should result.
Is the Tree Hollow?
Because the life support tissue, the xylem and phloem, of a tree is on the outer edges of the trunk many trees will live for years with a hollow trunk. The issue is possible compromised trunk strength making the tree dangerous. A guide to help in decision making is if one-third of the interior of the tree is hollow or rotten, it probably should be removed.
Are There Large, Dead Branches?
Large trees that have had their tops broken or large damaged limbs are a danger to people and property. If less than 25% of branches are damaged, the tree will probably survive. Crossed or rubbing branches should be removed. Narrow branch angles especially of the main trunk are particularly prone to splitting and should be corrected. This is best done when the tree is young. If a narrow crotch is too large to remove the two co-dominant leaders could be cabled to relieve the strain and avoid breakage. This procedure is performed by an arborist.
Has There Been Excavation Near the Tree Causing Root Damage?
If 50% of the root system is damaged, it probably should be removed.
Is the Tree Leaning?
Leaning trees are more of a hazard than those growing vertically. A sudden lean indicates breakage or weakening of roots and tree should probably be removed immediately. A tree leaning more than 15% from vertical probably should be removed.
What is the Environment in Which the Tree Lives?
Another important factor in a trees possible need for removal is its environment. Trees growing on rock ledges or near a body of water frequently have shallow root systems. The removal of nearby trees is a common problem after new construction. Trees that are suddenly exposed to sunlight are severely stressed by the sudden change in exposure. Unfortunately, trees that are spared from removal during construction often die 3-5 years later. They succumb to soil compaction, grade changes and the sudden exposure to full sun after being grown in a forest.