36 



Some attempts have been made to sculpture the surface of the 

 cement to imitate the bark, but this is objectionable from many 

 points of view. 



The cost of filling or tinning trees need not be excessive nor be- 

 yond the reach of most individuals or towns. Considerable experi- 

 menting and careful observations, however, must be made in order 



Fig. i6. Showing cavity in valuable yellow oak being pre- 

 pared for filling. 



to ascertain the best method of treating cavities. Most of the clean- 

 ing of the cavities at the present time is done with mallets, chisels 

 and other tools, but a rotary cutter driven at high speed by a gaso- 

 line engine or other power would greatly facilitate this work, and we 

 are now experimenting with such a machine. 



