Dramatic Needle Browning and Canopy Die-Back of Eastern White Pine (pinus strobus)

摘要

During the spring of 2016, a dramatic decline of eastern white pine (Pinus strobus) has been observed throughout portions of New England and New York State. Needles of mature trees became straw-colored to brown before they are prematurely shed from the canopy. In some cases, only a few main branches were symptomatic while for other trees, the entire canopy exhibited the symptoms (Figure 1). One feature of the decline is that despite significant needle browning and premature shedding in the canopy, the currentseason's needles developed normally and appeared healthy. However, as the growing season has progressed, even these needles have become symptomatic on some trees. Based on observations from arborists, landscapers and homeowners made to the UMass Plant Diagnostic Laboratory (UMPDL), white pine decline seems to be especially severe in southeastern New Hampshire, eastern Massachusetts and eastern Connecticut. The cause of this dramatic decline event is not fully understood, as there are several interactingstresses that must accountedfor. At present, pathologists and forest ecologists in the region suspect some type of winter injury was at least partly responsible for this dramatic and widespread decline event. In addition, needle blight and trunk and branch cankering pathogens are also contributing to white pine decline and mortality.