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Stale Ilorlicnltiira! Society. 



arising' from the inner side of the canihium ring goes to form wood, 

 while that produced on the outside is the bast. The amount of wood 

 produced is many times greater than the bast. 



Owing t'o cHmatic variations, the cambium tissue of woody i)lanls 

 exhibits a periodical activity which results in the formation of annual 

 rings of growlli. Tn tlie spring, during the period of rapid growth, 

 larger cells are produced tlian in the latter part of the season. For this 

 reason, a difference is perceptible between the early tvood, which is com- 



Fig. 2. A Silver Maple tree ruined by ignorant pruning. Notice the splitting of the 

 stubs and the exposed wood. I'hotographed in December. 



posed of large cells especially active in the conveyance of water, and the 

 late zuood, consisting of narrow cells which iinpart strength to the stem. 



Throughout the greater part of the temperate zone, the formation 

 of wood ceases in the latter part of August, until the following spring, 

 when the larger elements of the early wood are again developed. The con- 

 sequent contrast in the structure of the early and late wood marks ofif the 



