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Saturday - January 08, 2011

From: Dripping Springs., TX
Region: Southwest
Topic: Shrubs, Trees
Title: Why is cedar pollen so heavy this year?
Answered by: Barbara Medford and Joe Marcus

QUESTION:

Dear Mr Smarty, Is this year a heavier than normal year for cedar pollen?? If so why?

ANSWER:

As this answer is written-January 8, 2011-the pollen count of the Juniperus ashei (Ashe juniper), aka mountain cedar, is at nearly 7,000 grains per cubic meter of air. This is the highest it has been since January 6, 2004. We're not sure what could be considered a "normal" year, but it sure is higher than it has been for the last 7 years, right?

So now, you want to know why? And, we infer from that you also want us to make it stop. From the Image Archive of Central Texas Plants, University of Texas at Austin, here are some pictures and more information, including this statement: "In the absence of fire, Juniperus ashei quickly becomes the dominant tree in open areas of the eastern Hill Country--essentially, all of the green foliage on this hillside in west Austin (photo taken in Winter) is Juniperus ashei!" 

The severity of a cedar pollen year is dependent on a number of factors: rainfall at key periods before and during the development of pollen-bearing cones, health, age and vigor of individual trees, density of tree populations, and wind, rain and temperature patterns during the season of pollen release.  Location is also a factor.  A daily comparison of the various pollen counts published by different reporting stations reveal a wide range of results. If you’re just downwind of an Ashe juniper tree and observe a yellowish-gray cloud emanating from the tree and surrounding you, you can bet that the pollen count is off the charts compared to that reported on any TV news station.  

Also, don’t discount the possibility of changes in your own reaction to mountain cedar from year to year.  Many lifelong residents of Central Texas report late-onset allergic reaction to Ashe juniper pollen with the severity of the reaction seeming to grow from year to year once it starts.

So, that's the first part of our answer-there are a whole lot of the cedars, and without risking habitations in the area, they cannot be controlled, as they historically were, by permitting wildfires to burn. One website, called People Against Cedars, has the idea of each person cutting down one cedar and planting some other tree native to the area to replace that. Somehow, while we think it's a good idea, we don't see that happening. If it's any comfort to you, read this previous Mr. Smarty Plants answer on what trees might replace the cedar elm. Unfortunately, the gist of our answer was that trees all pollinate, and a great proportion of those of us with noses are going to react negatively to some or all of those pollens.

Some of the other suggestions on what to do about cedar trees don't bear repeating on a website intended for family consumption, and aren't practical anyway. The Forest Service and the Fire Department both frown on flame throwers. Spraying a herbicide from airplanes would contaminate the air worse than the pollen, and if would kill a cedar, it certainly would do humans no good. 

About the only solution we found widely acceptable was that of treating the symptom, not the cause; i.e., take anti-histamines, especially in Cedar High Season, or injections and keep a good supply of tissues on hand. There are various members of the genus Juniperus virtually all over North America. We all have to live somewhere, and breathe there. Oh, and one more thing-did you know that the Juniper trees that produce the pollen are all MALE?

 

From the Image Gallery


Ashe juniper
Juniperus ashei

Ashe juniper
Juniperus ashei

Ashe juniper
Juniperus ashei

Ashe juniper
Juniperus ashei

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