390 The New York State College of Forestry 



TREE ZONES AND TREE DISTRIBUTION IN NEW 

 YORK STATE 



A bulletin covering the trees of New York State would not be 

 complete were the subject in hand to be dismissed without at least 

 a cursory treatment of the tree zones and tree distribution within 

 the state. The following paragraphs are written with this idea 

 in mind in the hope that the reader may gain some insight into 

 the factors which govern tree distribution and which have led to 

 regional dissemination of tree species within our borders. In this 

 connection it would seem wise to discuss briefly the fundamentals 

 which underlie forest distribution and to point out that the tree 

 and tree aggregate, that is, the forest, are the logical outcome of 

 such factors, working in unison. 



DEVELOPMENT OF DENDROID PLANTS 



If our theories of evolution are tenable, the most primitive 

 plants were unicellular and therefore undoubtedly microscopic. We 

 need not concern ourselves here with the argument as to whether 

 they were aquatic or terrestrial, but all are agreed that they were 

 extremely simple, and, being unicellular, exhibited no division of 

 labor. In time multicellular plants were evolved in which division 

 of labor developed. Cell division, and consequently growth, were 

 restricted to certain cells, while others, in some cases, at least, 

 became greatly modified and served as anchors or organs of attach- 

 ment. With the development of vascular (conducting) tissue 

 division of labor progressed a step further, and the organism 

 increased in size owing to its ability to move food absorbed or 

 elaborated in one part to distant parts where needed. Finally 

 seed plants, as opposed to spore plants, arose in response to a 

 necessity' brought about by a semi-hostile environment, permitting 

 of the tiding over of the organisms during unfavorable (cold and 

 dry) seasons and insuring wider dissemination. 



But nature was yet to outdo her previous attempts at evolution 

 in the development of the dendroid plant, that is, the tree. These 

 magnificent organisms towered aloft over their humbler brethren 

 and were thus in a position, owing to their greater stature, to have 

 first call on that which is essential for the growth of all green 

 plants, namely, light. Whether trees arose as a result of direct 

 competition between plants for light, etc., or purely as the out- 



