The Texas A&M Forest Service is warning Texans of the upcoming cedar fever season, an allergic reaction to pollen released by mountain cedar trees.
According to the forest service, the Texas Hill County west of Interstate 35 is especially susceptible because of the mix of oak and ashe juniper, the state's predominant species of mountain cedar.
While the ashe juniper's pollen isn't allergenic or harmful, experts said the pollen's high concentration irritates the body.
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“Cedar fever is irritating to many due to the quantity and density of Ashe junipers in Central Texas that all produce pollen at the same time, which leads to a high concentration of pollen in the air,” said Robert Edmonson, Texas A&M Forest Service Biologist and ISA Certified Arborist.
The forest service said these trees begin producing pollen in mid-December, triggered by colder weather or a cold front. Pollen production peaks in the middle of January and subsides around the beginning of March.
“Cold fronts are marked by very dry and windy conditions with rapid pressure changes which trigger pollen cones to open and release pollen grains,” said Edmonson. “In certain conditions, you can even see the pollen blowing off trees.”
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However, since the pollen is airborne, individuals far from concentrated areas can still be affected. Eastern parts of Texas are home to redcedars, which pollinate around the same time and induce similar symptoms.
The forest service said the timing of the pollen's release can also be problematic. While many anticipate allergies in the spring, which has the highest production of ragweed pollen and mold spores, juniper trees are one of the few plants that pollinate during the winter.
University experts said cedar fever symptoms are often confused with a cold or the seasonal flu. These symptoms can include fatigue, sore throat, runny nose, partial loss of smell and a fever under 101.5 degrees.
The school's forest service said cedar fever can be treated with allergy medications and antihistamines, but a physician or health care professional should be consulted first. They also recommended watching local weather stations for pollen counts and installing higher MERV-rated air filters in home and auto HVAC systems.
However, they discouraged removing juniper trees as it may disrupt the pollen, which, when airborne, can travel for several miles.
“The male trees have larger pollen cones, while the female trees have much smaller reproductive cones, which are very inconspicuous, but that’s what is pollinated from the male trees,” said Edmonson.
The Texas A&M Forest Service's website provides more information on how to identify an ashe juniper or redcedar.