[permaculture] Ecosystem Diversity & Bio-mass: Prairies vs. Forests
peace at totalaccess.net
Mon Jul 8 12:16:17 EDT 2002
You must have lived pretty close to where we live now, about 15 miles east, north-east of Elgin, Texas.
>> I lived in an oak forest in Central Texas, east of Austin, for years in the late sixties and most of the seventies (where I met Scott Pittman in 1968, by the way) and it had sprung up as a result of the land -- mostly sandy loam -- being "cottoned out" in the late 1800's. <<
The history of the decline of Texas ecosystems is an extremely fascinating line of study and I agree that nearly all of the tree growth on the black land prairies and in the present oakwoods is secondary growth. What I would like to come to understand is what was there before the Spanish arrived and how the diversity and bio-mass of a healthy native Texas grassland compares with that of a healthy native Texas woodland.
There's a thirty year period from about 1820 to 1850 that is described as being the Golden Period of the Southwestern Stockman. This is just after the decline of the Spanish Mission grazing system, where tens of thousands of horses, goats and cattle had been set out to graze freely on the Texas prairies. The Spanish had also introduced large scale burning to Texas and its Natives as early as 1570 or 1590, which was enthusiastically taken up by the earliest Anglo exporers in the early 1800's.
Around 1850, by the time the wild Spanish horses, mules and cattle were rounded up and slaughtered, and the buffalo were hunted out, almost all of Texas had either been burned, improperly grazed, logged, over hunted, plowed or developed. The Anglo settlers quickly filled the void left by the absence of the bison and Spanish livestock with their own domestic livestock and have continued to improperly graze ever since.
This Golden Period is the freeze frame image most of our grandparents have in their mind's eye of Texas in its natural state and as how it should be now. However, by this time about seven feet of biomass in the form of soil humus, leaf litter and standing vegetation had been stripped off of the state. Three out of four of the great contiguous forests in Texas had been or would soon be cleared - including a bamboo forest at the mouth of the Brazos River on the Gulf Coast.
There's a book out called, "The Explorer's Texas," by Del Winager. He's gone through the logs and journals of the first Spanish and Anglo explorers and created some descriptions based on the explorers' earliests accounts.
Winager says the most common description of the Texas prairies was as a sea-scape. Rolling, wave-like hills, with tall grasses swirling back and forth in the wind. Woodlands filled the riperian areas resembling shorelines behind the grasses, spaces that felt like bays and coves were common and small islands of trees called mottes formed out in the open. It was the perfect living envoronment for edge-dwellers like ourselves, which is why it was disturbed so quickly by the settlers.
Most important to note, however, is the prominant presence of woodlands in the Texas prairie landscape.
>> Was that [1900 - 1925] before the juniper and mesquite had gotten a foothold? <<
The tall straight cedar was a preferred timber throughout Central Texas by the earlists settlers and at least 100 year old stands of mesquite (meaing no significant fires for that period) are reported to have existed in the South Texas Brush Country. They had quite a foothold before we arrived, though they hadn't been perceived as "invasive" until after the 1900's.
I believe the trees and woodlands were kept in check by the bison more than fire. Improper grazing, burning and mechanically clearing juniper and mesquite are probably what are provoking them out of their original habitats - which were considerable. I would also conjecture that humus rich soils, several feet deep broke down plant litter rapidly and that even when lightning struck, fires were much harder to get going than today because the land is now so much more brittle and tender than it was 500 years ago.
It may be that there were vast treeless expanses in the Great Central Plains or Prairies but I believe that such treeless-ness ends at the line between the Texas High Plains and Rolling Plains. One of Texas largest contiguous forests is reported to have been in the Rolling Plains. Even supposed desert bioregions such as the Trans Pecos are famous for dwarf oak forests.
I'm all for prairie restoration, but I would like to see the definition of prairies to include a fair proportion of woodlands, and for every acre of land cleared of trees and or burned in the name of restoration, a like number of acres should be restored to native woodlands.
For the real scoop on environmental and social justice issues check out the archives of Democracy Now! http://www.webactive.com/webactive/pacifica/demnow/archive.html
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