Bark is designed to protect the tree from extreme heat and cold. Characteristics of bark are as unique as the leaves, many times just as important in identifying a tree, especially in winter when leaves are not available to use. Borers are a common insect that attacks the tree through the bark eating through the bark. Some types of scale can also attack the tree via the bark.
Leaf functions primarily to manufacture of sugars and carbohydrates, these substances are energy sources for all metabolic processes in the plant, including growth, root development, flower, seed protection, and disease resistance.
Newly planted young trees are most susceptible to death. To limit this chance, proper water, mulch, fertilizing, insect and disease control, and root collar excavation are necessary. Since 80% of tree roots are removed the need to recover may take 3 to 5 years in which proper care is critical to ensure the tree survives and thrives.
Stress is a phenomenon that affects trees and shrubs. When they are stressed, they have a lower resistance to disease and insect infestation. This is nothing new to us. When we become sick, our stress level usually is abnormally high. Plants are not any different.
Things that can stress your trees include: