228 AGRONOMY 



of a tree, the life of the specimen may be prolonged by filling 

 the cavity with cement. Before putting in the cement all the 

 dead wood should be removed and the cavity sterilized with 

 any good disinfectant such as corrosive sublimate or copper 

 sulphate. It is also well to give the cavity a good coat of paint 

 or tar. If it is very large, concrete may be used as a filling 

 and cement used to finish off the work. The edges of the 

 cavity should be straightened up and painted, and under 

 normal conditions, if the cement has been made just even with 

 the wood, the bark should soon grow over the wound. When 

 a limb has been partly split off from a tree, or when the trunk 

 has been split by a storm, it may often be saved by bolting it 

 together by an iron bolt extending through both parts. Bind- 

 ing the two together with wire serves only to increase the in- 

 jury, since this soon stops the movement of sap and causes 

 death to the parts. 



Topiary work. That form of ornamental gardening in which 

 trees and shrubs are sheared into grotesque forms, often sim- 

 ulating animals and the like, is called topiary work. For this 

 purpose evergreen species are usually employed. Hedges, ar- 

 bors, and arches are forms of topiary work. Other examples 

 may often be seen in old cemeteries and on large private 

 grounds. In the formal style of gardening the less grotesque 

 forms are allowable, but all are out of place on home grounds. 



PRACTICAL EXERCISES 



1. Visit parks, private grounds, and the trees along the streets for 

 examples of pruning. Do you find any trees that need pruning? any 

 that have been badly pruned ? Make suggestions for improvement. 



2. If there are no trees in the school garden to be pruned, visit a 

 bushy field or neglected roadside and practice upon the shrubs and trees 

 found there. 



3. Examine fruiting apple, peach, and plum trees, raspberry and cur- 

 rant bushes, and grapevines to discover where the fruit is borne. Later in 

 the season identify the flower buds on species that form them in autumn. 



