|Fraser Fir: The "Cadillac" of Christmas Trees|
Fraser fir nursery bed where seedlings are grown up to
5 years before transplanting to the field. (Photo: Mike Benson)
Typical Fraser fir planting in Western North Carolina
after about 5 to 6 years in the field. (Photo: Mike Benson)
Although growers have good management tools for weeds and insect pests, Phytophthora (pronounced fy-TOF-thor-uh) root rot threatens long-term production of Fraser fir. The pathogen, Phytophthora, produces zoospores that can swim to tree roots in saturated soil or run-off. Throughout the 11 to 15 years or more that is takes to produce a 6 to 8 foot tall Fraser fir, Phytophthora root rot is always a threat.
Fraser fir planting after about 6 years in the field. Note patch of trees killed by
Phytophthora root rot in far edge of field. (Photo: Mike Benson)
Lower branch ‘flagging’ may be the first indication that a Fraser fir has Phytophthora root rot. Once the Phytophthora pathogen has infected enough of the root system that the plant can no longer transport water and nutrients adequately, the foliage becomes yellow then turns reddish brown a short time later. The tree will eventually die from the disease.
|Lower Branch "Flagging" (Photo: Mike Benson)|
Growers manage the disease by planting healthy fir transplants into fields that are well drained. Once disease develops in a tree, however, that tree is lost. Future production in that area of the field is also threatened because the pathogen survives many years in soil.
In the future, forest tree breeders and plant pathologists hope to develop a Phytophthora resistant fir with qualities equal to the Fraser fir. So when you buy that fresh cut Christmas tree this year, just remember that the Christmas tree grower was able to overcome a lot of potential problems to provide that tree for you.
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Special thanks to Mike Benson for writing this post!