1912.] PUBLIC DOCUMENT — No. 31. 73 



The rate of growth in cireunif(n'c]ice 4 foot from the otoiukI 

 of the trees growing on the hiwn side of the road was 9 per 

 cent, greater than of those on the mowing side for the same 

 period, thirty-two years. 



In another case, where the roadway was wider and the trees 

 smaller, the difference was 36 per cent, in favor of the trees 

 on the lawn for a period of twenty-two years. Here the soil 

 was much drier than in the preceding instance, and the trees 

 showed the effects of occasional applications of fertilizer to the 

 lawn. However, there was a marked difference not only in the 

 growth, but in the color and amount of foliage in the two 

 groups of elms. The difference between lavm and mowing- 

 conditions is more prominent in dry than in moist soil, al- 

 though it is possible for elms to receive too much water, as 

 is proved by the following instance : — 



Two rows of elms running north and south on either side 

 of a wider highway were under practically the same conditions, 

 except that one row was in a good soil underdrained and the 

 other in a wet soil where the drainage was very insufficient. 

 The difference in the growth in circumference of these 4 feet 

 from the ground for a period of thirty years was 10 per cent. 

 It should also be noted that the soil with the poor drainage had 

 been cultivated a few times, while the other had not, but the 

 drainage in the former soil was so poor that the trees made 

 little growth and were stunted in appearance. 



Elms growing in wet soils are invariably poorly formed, and 

 seldom develop into good ornamental or street trees. 



Exposure to light, as might be expected, materially affects 

 the growth of trees. A row of trees located in mowing soil on 

 either side of a narrow roadway running southeast, in thirty- 

 two years showed a difference of 11 per cent, in their circum- 

 ference 4 feet from the ground, in favor of the south or sunny 

 side of the radii. ISTo differences would occur with small trees 

 when first set out, but when they grow large enongh to shade 

 each other there are differences in the rate of gi'owth. Since 

 these trees were planted close together and the roadbed is nar- 

 row, they shade each other at the present time, and have for 

 some years past. 



