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Wednesday, December 18, 2013

Dispelling Common Myths of the Ashe Juniper

Ashe Juniper, Juniperus ashei

The Ashe Juniper (Juniperus ashei), more commonly but incorrectly known as the ‘cedar’ tree, is not the bane of nature many people have come to believe.  It is as much a part of the Texas Hill Country as wildflowers and limestone.  The juniper tree can germinate on bare rock, quickly develop a thick canopy to protect the earth beneath it, and drop an enormous amount of leaf litter that can build soil and capture and hold water.  Let’s explore some of the more common myths surrounding this tree, and in the process begin to appreciate its purpose, beauty, and wildness.

Pollen produced on 'male' trees

Berries produced on 'female' trees

Shaggy bark of the Ashe Juniper

Myth #1:  The ‘cedar’ tree is not a native tree.  While you have probably heard some of the tall tales about how junipers may have arrived in Central Texas, the undisputable proof that they are native lies in fossilized juniper pollen found in our area, dating back to the last Ice Age. Additionally, in historical records dating back to the late 1600s and early 1700s, junipers are accurately described by Spanish trailblazers, missionaries, and other early settlers and explorers alike.  While native to our area, Ashe Junipers are invasive.  Naturally occurring on steep, west-facing slopes, they have spread to cover most of our terrain due to our tendency to suppress the normal wildfires that kept them within their typical boundaries.

Myth #2: The ‘cedar’ tree is a water hog.  Scientific stemflow studies have shown that the juniper does not take in much more water than any other native woody plant its’ size.  Junipers are extremely drought tolerant, and their dense canopy breaks the impact of falling rain.  This allows a thick organic litter to accumulate under the juniper, which slows down erosion and provides flash flood control. When slopes are clear-cut of juniper and native grasses cannot establish themselves, we not only lose our soil, but we may also be losing water. Eroded soil can fill the recharge cracks and limestone karsts with silt, which ultimately decreases the amount of water that percolates into the aquifer.

Golden-cheeked Warbler, Setophaga chrysoparia

Myth #3: The ‘cedar’ tree is a useless tree.  One of our endangered species, the Golden-cheeked Warbler, uses the soft bark strips of old-growth Ashe Junipers to build its nest.  Many other species of wildlife use juniper thickets as escape cover and shelter, and in the winter, its berries feed several species of birds and mammals.  Butterfly larvae, such as the Great Purple Hairstreak (Atlides halesus) and Juniper Hairstreak (Callophrys gryneus), as well as the Tortricid or Leafroller Moths, all consume the foliage.  And from a human point of view, oils provided by the juniper are used to scent perfumes and soaps, and the wood itself has been used for fuel, furniture, tools, fence posts, and just about everything in between.     

Juniper Hairstreak, Callophrys gryneus

Myth #4: Cutting down all the ‘cedar’ trees in my yard will protect me from ‘cedar fever.’ December through March is the height of ‘cedar fever’ season.  This is the time of year that juniper trees (males only, the females produce the berries) produce copious amounts of pollen, up to several pounds per tree.  Once this pollen becomes airborne, it travels hundreds of miles to reach every allergy sufferer.  Let’s face it – ‘cedar fever’ is simply a natural part of living in Austin.

In short, the Ashe Juniper helps us to define what we call ‘a sense of place.’  Combined with the wild and tumbled terrain created by our ubiquitous limestone, the character of the juniper’s twisted limbs and the smell of its foliage in the deep summer heat define the essence of the Texas Hill Country.