Winter Injury Reports
Pine species showing symptoms of winter injury or winter burn were observed in Beltrami, Hubbard and Becker Counties this spring. Hardest hit were Scots, red, white and ponderosa pines growing along roadsides, windbreaks and in boulevards. Plantations of small trees whose tops were exposed above the snowline were also affected.
From early November through January this year, the average temperatures were considerably lower that during the same time period in last year. However, the period from late January through April was much warmer in 1997 than in 1996. By January 20th of 1997 we were 100 degree days colder than in 1996, but by mid-March we were 300 degree days warmer than the same period last year.
Trees severely stressed last summer and fall were more susceptible to winter injury, and some species like Scots and ponderosa pine seem to get winter injury every year (chronic) and should not be grown on sites prone winter injury, such as south facing stand edges, along road or yard edges.
We do not expect severe winter injury to have occurred this year in the southeastern counties, although some light desiccation damage was observed on conifers this spring. However, there will be additional decline in some species that were injured in the 1995-96 winter.