My Monterey Pine Is Dying

Temperature Tolerance

• Temperature extremes can weaken or kill Monterey pines. Sub-freezing weather and temperatures above 100 degrees Fahrenheit cause dieback of needles and tender new growth. If these weather conditions are a temporary anomaly, the trees usually rebound, although they may be predisposed to damage by secondary problems, such as drought or disease. However, Monterey pines are unlikely to live long in climates where either temperature extreme is common.

Care and Culture

• Monterey pines tolerate most soil types as long as they are well drained. However, constantly damp or waterlogged soils will kill the tree in a short time, and overwatering is usually more of an issue than under-watering, because the trees are naturally drought-tolerant. Excessive shade can also lead to the slow death of Monterey pines and makes the trees vulnerable to pests and disease. Young saplings tolerate partial shade, but they prefer sunny conditions as they mature.

Pests and Disease

• Pitch canker is the single most common disease that can kill Monterey pine trees. The symptoms begin with the dieback of needles and branch tips and a characteristic honey-colored sap around the affected area. If the disease progresses to affect the main trunk of the tree, death is likely. Numerous insect pests take advantage of trees weakened by pitch canker, such as engraver beetles and borer beetles. These are evident by tiny tunnels through the bark and into the wood of the tree or on the surface of the wood under the outer bark layer.

Saving a Dying Tree

• Cultural problems, such as overwatering, are remedied by giving the tree proper care. However, problems intrinsic to the environment, such as excessive heat, make saving a dying tree a futile effort. Pests and disease are difficult to treat without specialized equipment and often the most effective chemical treatments are only available to licensed arborists. If the symptoms of pitch canker are observed, removing the affected branches with sterilized pruners can often curtail the spread of the disease and save the life of the tree.