A FOREST CENSUS IN LYON COUNTY 401 



failing supply of water. As is well known, this tree adapts 

 itself to varied conditions of climate and exposure when forced 

 to it by artificial planting; but in this study, we consider only 

 undisturbed trees, and these box elders have been planted by 

 nature and grow in a very moist situation. 



Eleven grape vines (Plate XII, figure V) are found in the 

 tract, none of them on the river bottom, and none of them on 

 the upper half of the bluff face. They are widely scattered, 

 and evidently avivectant, all of them being located at the foot 

 of trees, up and over which they climb. It is unusual not to 

 find the wild grape on the river bottom nor in the forest on 

 the upper part of the bluff face. For the, river bottom this can 

 only be ascribed to the chance work of the birds, with some 

 help possibly toward elimination by the river floods. "With the 

 upper bluff face, the absence is probably in part due to over- 

 crowding by other vegetation, as well as to the seed-carrying 

 birds seeking out the lower, more sheltered regions, in the hot 

 months of autumn when the fruit is ripe. 



Forty-three specimens of green ash occur (Plate XII, figure 

 VI), three only on the river bottom and close to the foot of the 

 bluff, most of the river bottom being devoid of this species. The 

 next group of them is at a considerable distance up the hill, and 

 after another vacant space of several rods we find two other dis- 

 tinct groups, the one somewhat scattered, the members of the 

 other near together in a manner to indicate that the several trees 

 are the descendants of the same ancestor. Still farther up, and 

 in the drier part of the wood area, we come to two groups, which 

 also indicate by their manner of growth that each group is from 

 one ancestor, and finally, almost at the upper tree limit, where 

 the conditions for tree growth are severe, we find two individuals. 

 Contrary to expectation, the trees at the bottom where moisture 

 is abundant and protection good, do not differ in size very 

 markedly from the trees at the top, where the conditions are 

 more severe, as the largest of them vary from four to six inches 

 in diameter, except in the case of two individuals close to the 

 upper tree limit, which are stunted, and only two inches in 

 diameter. A considerable part of the upper third of the forested 

 area is devoid of ash, since it lacks sufficient moisture and is 

 over-crowded with other vegetation, but lack of moisture cannot 

 be urged for the lower third of the bluff, or for the river bot- 

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