436 Crcc''s Syste^n of Priming Forest Trees. 



to be cherished and cultivated, that it may more surely arrive at 

 that heart of oak, emblematic of the bravery of our people, and 

 which has ever been an ornament and a bulwark of defence to 

 our land. We intend to give an outline of a method by which 

 trees may be successfully cultivated, and some of our reasons to 

 prove that method to be judicious. To cultivate wood on phy- 

 siological principles, it is necessary to have a knowledge of the 

 organs which constitute the internal and external structure of 

 trees, and of the various functions that these organs perform 

 through the instrumentality of external agents. Trees are 

 generally treated as if they were mere inorganic matter ; they 

 are operated on as the ploughman operates on the ground, or as 

 the carpenter and blacksmith on the wood or iron under their 

 hands. Many eminent men have written treatises on vegetable 

 anatomy and physiology, and many have promulgated their 

 notions on the pruning of forest trees, while neither party under- 

 stood how the science of vegetable physiology ought to direct 

 the mechanical operation of pruning, so as to make it affect, to 

 the greatest extent, the growth and health of the tree. There 

 is in trees, as in animals, a vital power which presides over all 

 their functions. This power is the agent by which the ascent 

 and descent of the sap is produced, and certain internal and 

 external causes facilitate the exercise of this phenomenon. 

 Among the external causes is to be ranked the influence of air, 

 heat, light, and moisture, and the system of operating on the 

 lateral branches by shortening them. 



I shall give an outline of the principles which led me to the 

 conviction that the system of pruning by shortening the lateral 

 branches, which I brought forwai'd a number of years ago, is 

 calculated, more than any other, to secure /or the benefit of the 

 tree an extra nourishment. 



The organs of nutrition or vegetation have one common ob- 

 ject to support, namely, life in the vegetable ; and the power of 

 these organs may be greatly increased by mechanical means. 

 In order to use these means in a way to assist nature, some 

 knowledge of the physiology of plants is requisite ; either the 

 operator or the superintendant must understand how the organs 

 exert their functions, otherwise they cannot reasonably expect 

 to be successful. The different processes of the sap (or vege- 

 tative blood) of trees must especially be carefully studied, as by 

 it their growth and vigour are sustained. The sap is acquired 

 and influenced by diverse ways. In spring, the small sponge- 

 lets or extremities of the roots absorb the fluids and gases from 

 the soil, which are conveyed by an inherent power depending 

 on the life of the tree, or, more properly, the ascending sap is 

 acted on through the roots by atmospheric pressure, up through 

 the capillary tubes, till it reaches the extreme ramification of 



