Ask Mr. Smarty Plants

No, it isn't true—Juniperus ashei (Ashe juniper) is native to the Texas Hill Country. What is the evidence that supports this?  It was certainly abundant in the Hill Country 165 years ago when Ferdinand Lindheimer, a botanist collecting and studying plants in Texas in 1845, described hills and ravines covered with cedars.  Moreover, the evidence goes even further back than the 1800s. Studies of Pleistocene deposits from Central Texas showed ancestral cedar pollen mixed with deciduous hardwoods dating as long ago as 125,000 years.  Those populations of ancestral cedars probably became mostly extinct in Central Texas during the Ice Age some 10,000 to 13,000 years ago, but remnant bands re-established themselves in Central Texas and have been here for thousands of years since.  You can read more about this in an article by Bill Ward, Mountain cedar—does it deserve such disdain? from the Native Plant Society of Texas.   

Before the 1900s when Texas was sparsely settled there were widespread tall grass prairies that often burned and the fires destroyed any young cedars that had managed to sprout there.  Additionally, when the tall grasses did not burn for several years, young cedars could not compete well with these grasses that overshadowed them. The reason Ashe juniper or mountain cedar is now a problem is because of the way the land is used.  Now the land is fenced and broken up into pastures that are often overgrazed.  Additionally, fires are not allowed to burn unchecked. This gives the cedars the opportunity to take over—and they do!

You might also like to check out a recent Mr. Smarty Plants question and answer about why little other vegetation grows underneath our Ashe junipers.