232 JOURNAL OF FORESTRY 



by increasing the coefficient of the useful action of hght. If heat can 

 increase the energy of assimilation and transpiration and consequently 

 the nutrition of the tree, then in a warmer climate forest trees must 

 produce under the same soil and light conditions more wood than in 

 cold climates. 



These experiments can undoubtedly be made more elaborate. In 

 suggesting them my aim is to bring out the principles involved rather 

 than the details of arrangement. 



