In late summer, the most likely problem is related to drought or heat. If trees are under drought stress, this reduces their defense mechanism in resisting insect damage or disease-causing organisms. Since most trees are so large, it may take several years for the tree to die due to insect, disease, or drought injury. Once this starts, it’s almost impossible to reverse the damage.
Another potential factor is construction. It’s important to remember to protect the root systems and trunks of trees when any grading or clearing is done. Never allow machinery to come close to the tree as the roots extend 2 to 3 times the width of the tree’s canopy. If a tree’s roots are cut due to grading, it may take the tree 2 to 5 years to finally die. Always use silt fencing or some other type of protection around desirable trees to protect them during the clearing process. Never park vehicles under the trees as this will compact the soil and damage the root system.
Lastly, improper planting and mulching practices can also lead to tree decline and death.