15 



shoots and pith of the branches. The greatest damage, however, 

 seems to be from snow pressure. The drifts generally pile up into 

 the branches on the south side of the windbreak. When they settle, 

 the branches and stems are twisted and broken. This is very common 

 in North Dakota. 



Upon the upland its average height growth is 1.36 feet a year, 

 making a total height of 27.1 feet in twenty years. For this period 

 it will produce an average yield of one-half a cord of wood a year, 

 which when sold as fuel wood at $4 a cord is worth an annual net 

 return of 13 cents an acre. These figures on growth and yield alone 

 condemn the tree for all uses except for lawn planting. 



SILVER MAPLE. 



Under natural conditions silver maple sticks closely to the alluvial 

 soils bordering streams. Where its demands for moisture are sat- 

 isfied, it grows fast and often forms a large tree. Planted upon the 

 upland its growth is generally much slower. During dry years, 

 groves of this species not infrequently die down from the top. When 

 renewed activity begins, the trees throw out colonies of sprouts below 

 the point to which it died back. These develop equally and produce 

 bushy and undesirable forms. 



At best the wood o*f silver maple is soft and of little value, and its 

 spreading branches are easily split and broken by ice and storms. It 

 has been largely planted as a street and park tree, and should be 

 limited to such a use.- 



HACKBEEEY. 



Although hackberry is widely distributed, it does not seem to be 

 abundant in any one place. In this region it is generally not com- 

 mon enough to be recognized by those who happen to see it. It is oc- 

 casionally found in natural groves, where it associates with elm, ash, 

 and boxelder. In form and habit and in the character of its wood 

 it more nearly resembles elm than any other tree of the region. 



On account of the scarcity of the seed, the difficulty in collecting it, 

 and the slowness with which it germinates, the tree has not become 

 popular among planters, and has seldom been used. 



BASSWOOD. 



What has been said about the distribution of hackberry and the 

 objection to growing young plants of it also applies to basswood. In 

 addition, it is difficult to see how such a soft- wooded, moisture-loving 

 tree could be usefully and successfully grown upon the upland. 



[Cir. 145] 



