This category includes all other factors that may damage black walnut, e.g., frost, birdpeck and other bird damage, decay, flooding, herbicides, mechanical damage, unexplained dieback, or any other type of damage for which the exact cause is not known. Generally, there are few control measures. The best solution is to prevent initial damage to the trees by following recommendations for site selection and care of the trees.

Description
    Birdpeck is caused by the yellow-breasted sapsucker, Sphyrapicus varius. Damage to black walnut normally occurs during late winter or early spring when sap is flowing on warm days. The sapsucker feeds directly on the sap and not on insects. It may drill test holes into several different trees. Once a favorite tree is found, the bird usually returns to that tree often until it may be nearly girdled with peck holes.

Injury
    Holes made by the sapsucker normally heal over quickly but they cause defects and stain in the wood, reducing the value and quality of products made from it.

Control
    No control measures are known at this time.

BIRD DAMAGE

Description and Injury
    Breakage of the main stem of young black walnut trees by perching birds has occasionally b,een reported. Red-wing blackbirds and owls are the birds most commonly seen in association with this type of damage.

The main stem of the tree or branches are broken but usually remain hanging on the tree.

Control
    Erecting several tall poles at various places within the plantation may provide the birds with more desirable perches than fragile young trees.

DECAY

Description and Injury
    Decay here refers to any soft, spongy, unsound, hollow, or open area in the bark of a tree that appears to be rotting away. This part of the tree is dead and the decay is caused by fungi that live on dead wood. A hollow trunk or one that is decaying on the inside is not always evident from the outside.

    Not all stain-producing fungi cause decay, but stain itself reduces the value of the wood.

    Any mechanical- or fire-caused damage to a live tree leaves an open wound, that may be invaded by wood-decay or wood-staining organisms.

Control
    Avoid any injury to black walnut trees that may allow the entrance of decay organisms. Prune trees properly and only during late fall and winter, when the trees are dormant and decay fungi are least prevalent.

DIEBACK

Description and Injury
    Dieback refers to the dead branches or tips of branches in the crowns of otherwise apparently healthy trees. The cause is usually difficult to determine and may be due to poor drainage, herbicide damage, poor site, root rot, climate, flooding, disease, insects, or some unknown factor.

Control
    Plant healthy trees on proper sites, provide adequate weed control, and maintain the vigor of trees by pruning dead or diseased branches and thinning out undesirable trees in crowded plantations.

FROST DAMAGE

Description and Injury
    Frost damage in black walnut occurs when warm spells in spring, which cause buds to break, are followed by late frosts. This results in wilting, blackening, and death of the already expanded leaves and death to buds that were just beginning to break. The trees recover and put out new leaves, but forks and crooks often occur in young trees. Trees and plantations located in frost pockets are particularly susceptible. As trees grow taller they become less susceptible to occasional light frosts. Young trees may be stunted by repeated frost damage and tend to be bushy with many forks.

Control
    Do not plant walnut trees in known frost pockets.