56 Forest Club Annual 



Forty-nine per cent of this number were diseased in one 

 way or another, while of these infected specimens 81 per cent 

 were diseased because of bad pruning or unhealed wounds from 

 wind-broken branches and of this 81 per cent of the diseased 

 trees about eight-ninths were injured by pruning rather than 

 by breaking. While speaking of diseased trees it will be well to 

 mention here that the smoke injury is becoming quite noticeable. 

 This matter was not thoroughly studied, but from investigations 

 in other cities it. has been found to be harmful. The leaves in 

 many instances were found covered with soot, which is a hin- 

 derance to photosynthesis and respiration. The sulphur dioxide 

 gas present in the smoke not only tends to poison the leaves 

 but also to extract the water from them, thus causing an excess- 

 ive evaporation. 



From other data gathered in reference to the shape of the 

 tree it is shown that 160 trees, or 46 per cent of the total num- 

 ber examined, had irregular or suppressed crowns, or showed 

 signs of having been suppressed. Excessive crowding due to 

 very close spacing of trees is the main cause for the very poor 

 shaped crown. There were 140 trees, or nearly 42 per cent of 

 the total, that were crowded on one or more sides, and in a 

 number of cases were overtopped by other trees. Close plant- 

 ing is justified when the trees are young and first planted, but 

 as they become older some should be removed to make room 

 for the remaining trees to develop their crowns. It is generally 

 large well formed trees that are desired along a street, rather 

 than a thick stand of straggling crowded trees. The diagram 

 will show, in a measure, the close spacing of trees and the crowd- 

 ing of crowns as found on one of the streets. 



The height and diameter were also taken for each tree 

 shown in the table. For the majority of the different species the 

 height was found to vary directly with the diameter. In the 

 case of the Maple and Box Elder, however, this was not true. 

 In either of these species trees with the same diameter would 

 vary greatly in height and this was probably due to the crowd- 

 ing and overtopping of the crowns. 



About 38 per cent of the trees had crooked stems, which 

 is a simple matter to remedy, if the tree is properly handled 

 when young. A tree planted loosely in the ground is easily bent 

 by the wind and in all probability will not retain its original posi- 

 tion, as the roots will be pulled out of place on one side. This 

 leaves the tree leaning and the stem will bend as it grows, in 

 order to give the tree an upright position, thereby causing a 



