What is mountain cedar? KSAT Explains

San Antonio is in prime location for pollen allergies from mountain cedar, Texas’ most misunderstood tree

First thing to know about mountain cedar: they technically aren’t cedar trees at all.

What we call “cedar trees” are a type of juniper tree -- specifically Ashe juniper -- named after William Willard Ashe (1872-1932), who was a pioneer forester for the United States Forest Service.

True cedar trees reside near the Mediterranean Sea, around Europe and northern Africa. However, juniper trees here in Texas do bear at least some resemblance to cedar trees.

“So a lot of the explorers, when they were first coming to the western United States, encountering these trees, they just referred to them as cedars because of that resemblance,” says Karl Flocke -- a woodland ecologist with Texas A&M Forest Service.

BOOKMARK: Live, local pollen count

Where do mountain cedar trees reside?

This map displays where mountain cedar (technically juniper) trees reside in Texas. (Texas A&M Forest Service)

Cedar resides throughout Texas, even up west of Fort Worth, stretching into parts of Oklahoma and Arkansas.

But a dense cedar forest exists in the Texas Hill Country. Karle Flocke says this is, “because they really thrive on limestone soils, hilly environments, areas that don’t have very deep soil at all.”

The Hill Country is home to more than 35 million tons of cedar (juniper) trees, according to the Texas A&M Forest Service, which measures trees by weight.

It’s in this part of Texas -- around San Antonio, Austin, and throughout the Hill Country -- where we really feel the impacts from cedar pollen.

Cedar Fever

Did you know that there are male and female mountain cedar trees?

The female cedar trees, which are only distinguishable by their juniper berries, produce no pollen or allergies whatsoever... that’s the job of male trees!

From December through mid-February, tiny cones on the male cedar trees produce pollen. Once those cones open, exposing the pollen, the grains are then carried by the wind to the waiting female trees. And, unfortunately, into our eyes and sinuses as well.

According to Shannon Syring -- who is a Certified Pollen Collector that has been providing KSAT with the pollen count for years -- a typical mountain cedar season peaks at 20,000 to 32,000 grains per cubic meter of air. That’s roughly a 3-foot by 3-foot space.

Allergist Dr. Dennis Dilley says all that pollen in the air makes for “itchy eyes, watery eyes, sneezing fits, followed by just copious amounts of mucus.”

With “cedar fever” impacting many people every year, it’s no wonder that some grow to hate mountain cedar and its dreaded pollen.

Perhaps it’s that dread that’s helped inspire myths about the tree. So, let’s do some myth-busting!

Myth #1: Cedar trees are invasive

This is false. Mountain cedar trees are native to Central Texas.

According to Mark Bird, City Arborist for the City of San Antonio, “we have geological evidence of them being here for a very long time.”

In the past, people around the Hill Country have used cedar wood as a natural resource, building fences and other infrastructure.

Bird says, “if you look at some of the old pier and beam houses, you can still see the cedar posts that are supporting those houses.”

That being said, poor land management in the past 70 years or so has led to a general increase in all trees across the Hill Country, including both oaks and junipers.

However, if you clear land, Ashe junipers are often the first trees to regrow.

So it’s the quick regrowth of cedars that has lead to the belief that the tree is invasive. But when you break it down, mountain cedar is undoubtedly native to Central Texas.

Myth #2: Mountain cedar trees worsen the drought

This myth comes from the belief that cedar trees use more water than other trees across the Hill Country.

But, according to Mark Bird, “it’s not true that they take up any more water than any of the other valued trees in our area, like an oak tree.”

It is true, however, that the needles or leaves of a mountain cedar tree do trap some rain, especially when the trees are packed together. So a dense forest of mountain cedar trees may prevent light precipitation amounts from reaching the soil.

But during healthy rain events, heavily forested mountain cedar can actually direct rainwater into the Edwards Aquifer.

Karl Flocke says that “having that dense layer of needles on the ground can really help to retain water on the ground, soak in and infiltrate, as opposed to running into creeks and rivers where it might just go away as flood water.”

Myth #3: You can build up immunity to mountain cedar allergies

We’re only exposed to mountain cedar pollen for a few weeks each year. That’s not enough time for our bodies to get used to the pesky pollen -- even if you’ve lived here for a long time.

According to Dr. Dilley, an Allergist at Dilley Allergy and Asthma Specialists, “people don’t naturally develop immunity to cedar. Once you’re allergic, you’re allergic.”

This all has to do with our DNA -- we’re genetically predisposed to our own set of allergies.

So, unfortunately, we’re left to deal with a mountain cedar allergy year after year.

Some people swear by natural allergy drops or even a tea made from the female mountain cedar juniper berries. While there is no hard evidence that these natural remedies work, Dr. Dilley says, “if it makes you feel better, that’s okay, too. There’s no harm in doing those things.”

The most common and effective treatment for seasonal allergies is over-the-counter medications.

However, if you’re taking these medications and still find it difficult to function, Dr. Dilley suggests seeing an allergist right away -- who can provide steroids to relieve severe symptoms.

Doctors can also administer the only proven, long-term way to reduce a severe allergic reaction: allergy shots.

These shots work by desensitizing your immune system. Through the shots, a gradually increasing amount of pollen is introduced to the body, creating a blocking response.

The good news? Allergy shots are covered by most insurance providers. However, it is recommended that you meet your deductible before getting the shots.

Myth #4: Cutting down trees will eliminate allergies

In the city of San Antonio, it is legal to remove cedar trees from your property -- and you may want to for various reasons. Maybe you’d only rather have oaks on your property. Maybe you just don’t like the looks of the cedars.

But if you think the few cedars on your property are causing your allergy issues, remember that there are still thousands of trees in the Hill Country. If a cold front kicks up the winds from the north in the wintertime, that pollen is still going to be an issue.

So, love them or hate them, we’ve got to learn to live with Texas’ most-hated and I would argue -- most misunderstood -- tree.

Find more KSAT Explains episodes below.

About the Authors

Sarah Spivey is a San Antonio native who grew up watching KSAT. She has been a proud member of the KSAT Weather Authority Team since 2017. Sarah is a Clark High School and Texas A&M University graduate. She previously worked at KTEN News. When Sarah is not busy forecasting, she enjoys hanging out with her husband and cat, and playing music.

Myra Arthur is passionate about San Antonio and sharing its stories. She graduated high school in the Alamo City and always wanted to anchor and report in her hometown. Myra anchors KSAT News at 6:00 p.m. and hosts and reports for the streaming show, KSAT Explains. She joined KSAT in 2012 after anchoring and reporting in Waco and Corpus Christi.

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