210 PRACTICHL ARBORICULTURE 
\ A of 99 deg. west longitude, is com- 
posed of decomposed rocks which 
formed the great mountain ranges, 
and is almost entirely sand. 
In this arid belt the tree growth is 
very slight except along the margin 
of water courses, and is confined to 
the families of trees which possess 
vigorous roots capable of penetrat- 
ing deeply into the sub-soil of the 
plains, or rock crevices of the moun- 
tains. 
Under irrigation this sand pro 
duces excellent tree growth, mois- 
ture being the only requisite to in- 
sure this result. 
Now the sandy soils of Florida 
and other Gulf States are just as cap- 
able of producing wood growth as 
are the sands of the plains of the 
west. But the same requisite of ~ig- 
orous, deeply penetrating tap voor 
ystem exists, in order that a proper 
hold upon the soi mav be secured 
and an ample nutrition as is pos- 
sessed by the Pinus poiderosa ot 
the plains. 
wn 
The pecan has a strong, penetrat 
ing tap root, and it thrives in Flo: 
ida sand. The standard pear has 
a similar strong root system which 
finds moisture in the deeper sub- 
soil no matter how diy the surface 
sand may seem to be. 
The Cuatalpa specioss has 7 comb: 
nation or deep, vigorous, fleshy roots 
and other surface feeding roots, but 
upon the deeper tap roots are the 
main dependence. 
A sand may, from absence of hu- 
mus or vegetable mould, be unable 
A CAPALPA TREE EXWIBEPED AT THE Can a tna Be agiawk eal ate eae 
WORLIFS EAE] HEIGHT. (ou REET, to produce profitable grasses or farm 
EAE SORE ees crops, or, from prolonged droughts in 
summer these crops may be total or partial failures, but deep below the 
strata so affected there is ample moisture and nourishment for deep feed- 
ing trees. 
