Winterburn Of Evergreen Trees

Evergreen tree winterburn is a largely human invention. Mature trees naturally tend to drop their seeds only as far as the wind will take them, which is often not far from themselves. These seeds germinate and grow in the shade [or partial shade] of taller, more mature trees, or where taller weeds and shrubs provide some protection from drying wind and harsh winter sunshine. Most tender little seedlings therefore expect this natural isolation, so why are we humans planting them in an open field??

Some seed requires that it be eaten by a bird, run through its acidic digestive system, and pooped out before it will germinate, but that is a story for another time 🙂

See also:
Evergreen Seedling Planting Instructions
Evergreen Seedling Planting Videos
Evergreen Seedling Weed Control
Evergreen Seedling Potting Instructions
Evergreen Seedling Temporary Storage Instructions

Evergreen Windbreaks and Privacy Screens
How Trees Sequester Carbon
Starting A Christmas Tree Farm

Causes of Evergreen Tree Winterburn

We humans tend to plant trees to fill in the wide open spaces which we ourselves created in the first place. In the Spring, Summer and Fall this human environment is often just fine for young trees. But when Winter comes, the only shelter the little trees will get is from complete snowcover. If there is no snow or a young tree is poking out above the snow in an open area, it will get hit by a double-dose of sunshine: both direct sunlight from above and sunlight reflected upwards from the white snow below, adding up to literally a bad sunburn and desiccation [freeze drying] of the needles. The double-dose of sunlight bakes the moisture out of the needles, but since the ground is frozen the tree cannot replenish that lost moisture. This results in needle death, which may not become noticeable until early Spring.

Winterburn of concolor fir seedlings Winterburn of douglas fir seedlings Winterburn of norway spruce seedlings Winterburn of red pine seedlings

Photos showing winterburn of various species of evergreen trees

Winterburn is generally not enough to kill a young tree, since the small tree will replace those lost needles with new Spring growth. An easy way to determine if a young tree is not dead but rather suffering from winterburn is to inspect the buds in the Spring. Break open one of the buds at a low point on the tree. If the bud is moist and green inside and/or seem to be swelling with warmer Spring temperatures [or especially if they break open!], the tree is alive and well…it’ll just look rather ugly for a year or two until new growth hides the old bare branches and trunk.

If your trees were planted in the Spring and had good growth all summer and then suffered that first winter, they’ll probably be OK…they just need time. If your trees were planted in the Fall, the possibility of death is higher because their root systems had far less time to get established in the new soil before the stresses of winter hit. The best thing to do is wait until Spring to see if the buds start swelling and/or breaking open. The best solution for Fall planting is to do so at the earliest possible time to allow for as much root development and establishment as possible.

Commercial growers install shade netting or even move entire crops of young trees into full shade to prevent winterburn. You can use any method to block sunlight, as long as your method does not completely seal off the tree from it’s environment. White foam rose bush covers found at garden centers and big box stores are a good solution, as are upside down 5 gallon buckets with a brick on top and a few air holes, or large diameter white PVC pipe held down with stakes and lines. Whatever you do, make sure your shade solution is secure…Old Man Winter laughs at poorly engineered solutions. His laughter still echoes through our building.

You can also just sit back and hope for a couple of feet of snow, or just let the trees take their lumps…both of which require no work at all 🙂

Once the trees have reached several feet high, they are far enough away from the snow that winterburn is no longer a significant issue.