White pine chlorosis in Northern Illinois: Iron deficiency or not?

Abstract

Eastern white pine (Pinus strobus L.) is a prized ornamental. Its natural habitat includes a wide range of soil texture and moisture conditions, leading to the assumption by many that this species can be planted almost anywhere. Its performance in human-altered landscapes demonstrates otherwise. One malady, symptomized by chlorotic foliage, has been dubbed "white pine decline," and because alkaline soil is often associated with this condition, iron deficiency has been postulated. Our studies, conducted over a wide range of soil textures throughout northern Illinois, confirm the negative role of soil alkalinity but lead us to reject the hypothesis of iron deficiency. On the contrary, our data suggest iron efficiency by this species.