Root-growth in Trees. 161 
erly set, and if cultivation is begun the first year, 
the roots will go deep enough to escape the plow. 
The roots of trees spread much farther than the tops. 
I will give some examples from trees of which we 
have carefully measured the tops and roots. Fig. 17 
shows a standard Howell pear tree set in 1889 and 
photographed in 1895. It grows on a hard clay knoll. 
The full spread of the top is seven feet. Two roots 
were laid bare, and they ran off in one direction to 
a distance of twenty-one feet. Assuming that they 
ran an equal distance in the other direction, the 
spread of roots was forty-two feet, or just six times 
that of the top. And yet it is commonly said that 
the spread of roots and tops is about equal! Now, 
these roots were long and whip-like. The soil was 
so poor that they were obliged to search far and 
wide for pasture. Compare Fig. 18. This is a Fall 
Orange apple, also set in 1889, in rich, well tilled soil. 
Here the roots are in good pasture, and they remain 
at home; yet their spread is twice that of the top. 
The top of this tree had a diameter of eight feet, 
and we followed the roots eight feet upon the side in 
which we dug. These object lessons enforce the im- 
portance of tilling all the land between trees. 
But these figures teach another lesson. Even 
at their highest point, the roots of Fig. 17 are 
eight inches below the surface. They escape the 
plow. A like remark applies to Fig. 18. Now 
look at Fig. 19. This tree is the same age as 
the others, but has always stood in sod. The 
roots ran ten feet in one direction and the total 
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