Wednesday, September 25, 2013

This area is called "the Cross Timbers" Why??

 Most of this north Texas area is called “Cross Timbers”. It seems that many people think that the term “Cross Timbers” is merely a made-up name. Wrong!

Actually, Denton is mostly in the Eastern Cross Timbers –the popular name for this area in “pioneer-speak”. Unfortunately, there is hardly any real “Cross Timbers” left today, having been plowed under and paved over to accommodate subdivisions, shopping malls, highways and the like. 

The origin of the phrase can be traced down several paths, depending on who’s talking. The most popular, however, has its roots in the natural geography and vegetation of this area. Most forests here run in north-south bands.  Rivers, on the other hand, run roughly east-west. The result was that pioneers (who fervently avoided dangerous river crossings) had to cross bands of north-south forest as they traveled between the rivers, heading generally west. Thus the name:  ”Cross Timbers”.

In academic, ecological terms, this area was a “savannah” which is defined as a grassland prairie spotted with trees. (Mostly post oaks and blackjack oaks in this instance). In many areas the characteristic trees were so thick that they became forests. In the 18th and 19th centuries, the Cross Timbers was a well-known geographic feature marking the eastern edge of the American grasslands.

Nowadays, however, there are embarrassingly few remnants of the Cross Timbers left. Much of the original soil has been “urbanized” by extensive construction, farming and introduction of non-natural soil. Even though 19th-century naturalists generally put the range of the Cross Timbers region over a large stretch of Texas, Oklahoma and Kansas – the original ecosystem is now found in only a few large parks, preserves and isolated patches of countryside and floodplains.

Many kinds of plants thrived in the Cross Timbers, but almost all the natural canopy trees were post oaks and blackjack oaks. Amongst them were millions of tough smilax vines (those pesky, thorny vines also called catclaw vine or greenbrier). The combination was almost impenetrable, causing the 19th century author and statesman, Washington Irving, to call the Cross Timbers “forests of cast iron”.
Washington Irving
But vegetation would not exist at all in this type of soil, if compaction and “traffic” were not limited in some way. The Cross Timbers soil is sandy, porous, unstable and nutrient-poor. Consequently, the natural vegetation is fragile and easily killed.

The Cross Timbers is tied to the sandstone geology, and is limited by the local climate; rainfall being the biggest factor. The area (which encompasses Denton) gets between 23 inches and 43 inches per year. Coupled with high summer temperatures and frequent droughts, this area is ideal for the native oaks. When artificial irrigation is introduced, many other plants will survive here, although vegetative life is still very fragile.Under sprinkler systems, much of the native vegetation may suffer from overwatering.

Despite a growing awareness of the Cross Timbers’ ecological and historic importance, what little remains is being demolished at an alarming rate.  In the words of author Richard Francaviglia  “…developers are often either ignorant or arrogant. Thus, the Cross Timbers yields to the bulldozer in many locales, especially in the suburban areas where the prime real-estate sites...entice developers.” (Dr. Francaviglia authored ‘The Cross Timbers’ and ‘A Natural and Cultural History of the North American Cross Timbers’).

Dr. Francaviglia also noted that in some areas some land developers are preserving remnants of the Cross Timbers as they carefully develop sites. Also, the opportunities for tourism revenue are huge. “Few regions present better opportunities to integrate heritage tourism with conservation than the Cross Timbers.  Descriptions of this region’s forest abound in the historic literature and the Cross Timbers was often THE most prominent feature on historic maps of the period 1830 – 1880.” 

So, as you look around a remnant of the Cross Timbers, glimpse an Eastern Bluebird perched on a limb, see a Red-tailed Hawk soar, hear a hidden Warbler or Chickadee, and photograph a mass of Bluestem grass, think of all that came before us, and imagine all that the Cross Timbers used to be.



 
OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.


 

 

 

 

 

Sunday, September 22, 2013

avian mimic


Northern Mockingbird
A few species of birds are the only living creatures, other than humans, that can imitate sounds that they weren’t born to produce. This ability to learn and imitate strange sounds is called verbal mimicry, and the species of birds that can do it are called mimics. The most notable Texas bird that can do it happens to be our state bird:  the Mockingbird. I've heard of them (technically, Northern Mockingbirds) mimicking phone ringing, computer "dings" and backing up "beeps" of trucks.




Starlings actually belong elsewhere   

Like Kudzu vine and Dutch Elm disease, starlings (technically, European Starlings) didn’t occur naturally in this hemisphere at first. An
Starling (in fall)


Starling

eccentric Shakespeare enthusiast released about 100 starlings in New York in the 1890s. Before that time they only existed in Europe. He thought it a clever idea to bring to the “New World” every species mentioned in Shakespeare’s writings, with no thought about natural prey, habitats, native-ness etc. Now we have over 200 million of them, and fewer native species.  Alas!
 

OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.