NATURAL AREAS AND REGIONS 



505 



f . Temperate deciduous forest 



The deciduous forest, which is charac- 

 teristic of the Mississippi valley region, 

 extends into Texas from the northeast 

 corner of the state, and continues south- 

 westward in a constantly narrowing 

 band as it grades into the savanna of 

 live and post oak which separates the 

 typical deciduous forest from the mes- 

 quite semi-desert region farther to the 

 south. The northeastern half of the 

 deciduous forest must be considered as 

 a transition area between the southeast- 

 ern coniferous forest and the oak grove 

 savanna. In this transition area the 

 longleaf pine gives place to the short- 

 leaf pine (Pinus echinata) which, how- 

 ever, has been largely cut over, replace- 

 ment being for the most part by post oak, 

 which extends westward into the pure 

 deciduous forest and oak grove savanna. 

 Throughout the region the pine occurs 

 in conjunction with various species of 

 oak (post, red, white) together with 

 hickory, maple, beech, ash and elm. 

 The rainfall of the region is somewhat 

 less than in the coniferous forest, being 

 between 35 and 45 in., while the soils 

 are essentially extensions of the more 

 eastern lignitic formations, though these 

 soils extend beyond the western limits 

 of the pine, the latter being held down 

 by the deficiency in rainfall. 



The animal life is represented by the 

 remnants of the main body of the decidu- 

 ous forest species to the north and east, 

 this arm of the forest bringing these 

 species down into Texas. Most of the 

 species are, however, represented by 

 more southern varieties of the northern 

 animals. Here we have the Virginia 

 deer, gray fox (Urocyon cinereoargen- 

 'teus subsp.), cottontail rabbit (Sylvila- 

 gus floridanus alacer} and the opossum 

 (Didelphis virginiana}. The region is 

 further populated by the western exten- 

 sion of the range of many of the species 

 common to the coniferous forest, as 

 already mentioned. Thus we get also 

 the red fox (Vulpes fulva) which, though 

 not native to Texas, has been success- 

 fully introduced into the conifer forest 



region and has spread its range into the 

 deciduous forest. 



Local conditions. The westward and 

 southwestward extensions of the decid- 

 uous forest is broken by oak grove 

 savanna on the sandy soils of the lig- 

 nitic belt. The uplands of the lignitic 

 belt originally tended to run to short 

 leaf pine, but with its (artificial) re- 

 moval, place was given to the oak grove 

 savanna. 



3. Oak grove savanna 



The oak grove savanna is, like the 

 deciduous forest, a southern arm of a 

 more extensive northern area, which 

 reaches southward into Texas from the 

 Red River region in a constantly nar- 

 rowing wedge. (This is true particu- 

 larly in the case of the upper and lower 

 cross timber; locally, as in Llano County 

 (granite area) broad stretches of oak 

 grove savanna are found.) The region 

 is in reality practically split by the tip 

 end of the deciduous forest projection 

 where soil conditions have rendered 

 the extension of this type of forest pos- 

 sible. Thus we have an area of oak 

 grove savanna lying entirely along the 

 western border of the deciduous forest, 

 and a second area separating the forest 

 from the coast, as the Fayette sands 

 extension of the region. The oak grove 

 savanna must, within Texas at least, be 

 looked upon as a sort of transition area 

 between the deciduous forest and the 

 grassland regions, and is the region in 

 which the various forests of the Atlan- 

 tic woodland type open out into the 

 steppe country. Again the rainfall is 

 less than in the preceding forest types, 

 being approximately 30 in. in both divi- 

 sions of the grove. On its western bor- 

 der the oak grove savanna thins out, and 

 much grassland appears within the 

 grove, while on the eastern border it 

 merges with the deciduous forest. The 

 dominant trees are the post oak (Quercus 

 minor}, and the black hack (Q. mar- 

 ilandica), with white and black oak 

 (Q. velutina] as sub-dominants. West 

 of approximately the 97th meridian the 

 areas of grassland increase both in 



