Ash trees naturally shed plant material throughout the year. When material begins dropping outside of expected seasons or takes on unusual forms, it can signal a serious underlying problem. Identifying the source of the debris is the first step in understanding the tree’s health. Droppings generally fall into three categories: benign seasonal shedding, waste products from insect activity, or material resulting from disease and structural decline. Recognizing these subtle differences is important for any homeowner concerned about the well-being of their ash tree.
Identifying Natural Seasonal Debris
The most common and non-threatening debris is related to the tree’s reproductive cycle and seasonal maintenance. Ash trees produce distinctive winged seeds called samaras, which are a predictable source of material falling to the ground. These oar-shaped, dry seeds typically hang in clusters on female trees and begin to drop in late fall or early winter, often remaining on the tree well past the time leaves have fallen.
Normal leaf shedding involves leaves changing color, usually turning golden yellow or occasionally reddish-purple, before dropping in autumn. Some ash species naturally shed their leaves while they are still partially green, a process that conserves nitrogen for the tree’s next growth cycle. Minor quantities of small, healthy twigs may also drop, particularly following high winds or heavy storms, as the tree naturally prunes weak or damaged growth.
This natural shedding contrasts sharply with premature leaf drop, which can be an early indicator of stress. A tree under severe drought conditions may shed healthy green leaves in mid-summer to reduce water demand and preserve resources. Understanding the timing and appearance of this debris helps establish a baseline for healthy shedding against which problematic droppings can be measured.
Droppings Caused by Insect Infestation
Debris resulting from insect activity is often a combination of insect waste and wood material disturbed during feeding. One common sign is the presence of honeydew, a clear, sticky, sugary liquid that coats leaves, branches, or surfaces below the tree, such as patios or cars. This substance is not tree sap but is the liquid waste product, or frass, excreted by sap-sucking insects like aphids and scale.
While honeydew is harmless to the tree, it can lead to the formation of sooty mold, a black, soot-like fungus that grows on the sugary coating. A more damaging sign of infestation is the presence of wood fragments and sawdust from wood-boring insects. Other borers will expel a mixture of sawdust and excrement that accumulates in bark crevices or at the tree’s base, but the Emerald Ash Borer (EAB) does not.
EAB larvae pack their sawdust-like frass tightly within their serpentine feeding tunnels, or galleries, directly beneath the bark. The most visible sign of EAB activity is “ash blonding,” where woodpeckers seeking the larvae flake away the outer bark, exposing the lighter inner bark in patches. Finding tiny, capital D-shaped exit holes, approximately 1/8-inch wide, confirms the presence of EAB, as these are created by the adult beetles emerging from the tree.
Debris from Pathogens and Structural Failure
When debris is composed of large pieces of bark or significant deadwood, it often points to a problem with the tree’s internal structure or a severe disease. Large patches of bark shedding, distinct from the flaking caused by woodpeckers, can indicate internal decay or disease. For instance, certain fungal cankers can invade the bark, causing sunken areas where the overlying bark eventually cracks and sloughs off.
Premature leaf drop accompanied by discoloration or spotting is a symptom of fungal disease, such as Ash Anthracnose. This pathogen thrives in cool, wet spring weather and causes brown or black blotches on the leaflets, which causes them to distort and drop early. This type of debris is a reaction to disease rather than normal seasonal shedding.
The most dangerous form of debris is the dropping of large, dead branches or significant portions of the crown. This structural failure is often a late-stage symptom of severe infestation or disease. Ash trees compromised by EAB, for example, lose their structural integrity as the larvae damage the vascular system, making the dead wood prone to sudden and complete failure.