No. 4.] TREE SURGERY. 441 



484,000 trees were pruned. The field for observation was 

 limited, therefore, mainlj' by the capacity of the observer. 

 The special series of experiments above refeiTed to consist 

 of more than five hundred operations, the results of Avliich 

 were watched and the records kept by Mr. F. II. ]\Iosher. 

 These amputations were quite evenly divided between fruit, 

 forest and ornamental trees. Among fruit trees, the apple 

 predominates, the pear and cherry being next in number. 

 Among the forest trees, the elms, maples, birches, oaks and 

 ash predominate, followed by hickories or walnuts, and va- 

 rious ornamental trees. Coniferous trees were also included, 

 as the white pine, red cedar, spruce, etc. Records were 

 kept of the age and condition of each tree at the time of the 

 operation, together with its average annual growth. The 

 soil Avas described, the position in regard to shelter, the ex- 

 posure, and any other facts of interest, as the condition of 

 the limb when amputated. The size of each wound at the 

 time of the operation was given. The tree in each case Avas 

 tlrawn sufficiently to show the natiu^e and position of the 

 wounds, and a 3'early record was kept of the healing. This 

 was done both by drawings and measurements, it being stated- 

 in each case in which months, if any, growth was made. 

 These examples were not all taken from a limited locality, 

 but were somewhat widely scattered through the towns and 

 cities in the infested district, Somerville, Cainbi'idge, Brook- 

 line, Everett, Chelsea, Maiden and Medford being chiefly 

 represented . 



AVitli this exposition of the opportunities enjoyed for 

 observation, and tliis recital of the manner of obtaining the 

 data from Avhich this paper is made up, we will pass to a 

 brief consideration of that Avithout some knoAvledge of Avhich 

 no pruning can be done intelligently. 



The Manner of the Tree's Groavth. 

 It is noAv believed that the roots absorb Avater from the 

 soil together with material for building up the tree, all of 

 Avhich passes upward through the trunk, limbs and twigs to 

 the leaves, where Avater is evaporated and carbonic. acid gas 

 is absorbed from the air. This upward cmTent is strongest 



