Gophers eat tree roots and can cause significant damage to trees, often killing young or newly planted stock. The gopher, a fossorial rodent, spends nearly its entire life underground, creating extensive tunnel systems that bring it into direct contact with the roots of plants and trees. These rodents are herbivores with a diet consisting primarily of underground plant material like roots, tubers, and bulbs. A single gopher can maintain a burrow system extending hundreds of feet, making them a serious threat to landscape health.
Why Gophers Target Tree Roots
Gophers target tree roots because they provide a readily available source of carbohydrates and moisture, which is particularly appealing during dry periods. The roots are easily accessible from within their tunnel networks, which are typically found between six and twelve inches below the soil surface. This subterranean feeding habit allows them to consume roots without ever being seen above ground.
The mechanism of damage involves the gopher gnawing on the root structure, often stripping the bark and cambium layer. This process can lead to the complete girdling of a root, which severs the pipeline of nutrients and water traveling between the leaves and the rest of the root system. Younger trees are the easiest to kill because their root systems are not yet robust enough to survive complete girdling.
Signs of Root Damage to Look For
The first visible indication of root damage is often a sudden decline in a seemingly healthy tree. Above-ground symptoms include the wilting or yellowing of leaves, premature leaf drop, and a generally thin canopy lacking new growth. These signs appear because the damaged roots can no longer supply the tree with adequate water and nutrients.
An affected tree may also begin to lean or show instability, especially after a windstorm, because gnawing compromises the structural integrity of the root ball. Confirmation of gopher activity involves locating their characteristic fan-shaped or crescent-shaped mounds of soil, which are usually plugged. Excavating the base of a struggling tree may reveal roots with distinct, ragged teeth marks, or the entire root system may be missing. This mechanical feeding damage distinguishes gopher activity from issues like root rot.
Physical Barriers for Root Protection
Protecting trees from gopher damage is best achieved through the installation of physical barriers at the time of planting. These exclusion methods are highly effective against this subterranean threat. The most common and reliable method is the use of a wire mesh basket, often called a gopher basket, placed around the tree’s root ball.
The mesh must be made from heavy-duty, galvanized wire, typically 20-gauge, to resist chewing and corrosion underground. The mesh opening size is generally 3/4-inch hexagonal or square, which is small enough to exclude gophers but large enough to allow for future root growth. The basket should be sized generously to accommodate the root ball and must be installed so that the top edge extends a few inches above the soil line. This extension prevents gophers from attacking the crown or lower trunk just below the soil surface, which is a common site for girdling damage.