Severe, repeated defoliation by insects such as caterpillars forces the tree to burn through its energy reserves to produce new leaves, leaving it heavily depleted.
○ Construction Damage: Root cutting, soil grade changes, or heavy equipment traffic severe- ly damage roots and compact the soil, immediately com- promising water and nutrient uptake. ○ Major Defoliation Events: Severe, repeated defoliation by insects (e.g., Spongy moth) forc- es the tree to expend massive energy reserves on re-leafing, leaving it severely depleted. Contributing Factors (The Finishers) Once a tree is compromised by predis- posing and inciting factors, it becomes a target for opportunistic pests and pathogens, which are oen the f inal cause of death. These are the secondary organisms that the tree would normal- ly fend off if healthy.
secondary pests, such as two-lined chestnut borer, Mediterranean oak borer, shothole borers, spongy moth, lecanium scale, ambrosia beetle, and many more, are attract- ed to stressed oaks. If unprotected,
they can cause rapid dieback, lead- ing to tree mortality within just a few years. • Fungal and Bacterial Diseases : These diseases oen invade severe- ly stressed or declining oaks and
Oak anthracnose is a leaf spot disease caused by a fungus that primarily affects oak trees, particularly white oaks. It leads to brown spots and dead areas on leaves, especially during cool, wet spring weather.
• Invasive Insects: Many of these
60 | Spring 2026 ArborTIMES ™
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