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White Pine Decline

Karen Rane and Tom Creswell, Plant Disease Diagnosticians

Decline is an all-too-common ailment of Eastern white pines (Pinus strobus)

in Indiana. Affected trees will first appear off-color (either pale green

or yellow-green when compared to healthy white pine trees), with shorter

needles and short annual twig growth. Later, the bark of the branches may

appear wrinkled, and the foliage becomes brown. Symptoms of decline

commonly develop after a tree has been in a site for 8 to 20 years.

The problem is related to root stress. White pines grow best in slightly

acidic, well-drained soils high in organic matter. The alkaline, heavy clay

soils found throughout much of Indiana are not favorable for optimum white

pine growth. Drought, excessive moisture and soil compaction are additional

stress factors that can contribute to decline. Declining pines attract

insect borers, which will damage the inner bark tissues, accelerating the

tree's demise.

Unfortunately, once the foliar symptoms develop, the roots of the tree have

already been damaged and there is little that can be done to reverse the

decline process. Dead trees should be removed, since these are attractive to

insect borers that may invade adjacent trees. The best management practice

to reduce decline in white pine is to plant this species in a site that is

optimum for its growth. For more information on this problem, check out

Healthy White Pine

White Pine in Decline