190 



is native farther south, but in Connecticut has become thoroughly 

 estabHshed on the sand plains and elsewhere. It is the only 

 example known to the writer of a recently introduced tree which 

 can be considered of ecological importance. It spreads quickly^ 

 largely by means of root suckers, grows rapidly, and frequently 

 forms light forests over considerable areas. As a rule, however^ 

 the red cedar, gray birch, and pitch pine are the first arborescent 

 forms to appear. These may come in together, giving rise to a 

 mixed growth; or one or another, according to chance, may pre- 

 dominate.* Red cedar, as along the trap ridges, usually forms 

 rather open groves. Gray birch {Betula populifolia) may form 

 dense stands, but the trees never attain a large size. Pitch pine 

 alone, of the three, is capable of developing forests, and where this 

 species predominates, the pioneer tree stage is apt to be of much 

 longer duration than otherwise. Fig. 8 shows a pitch pine stand 

 near Farmington. Some of the trees here are over i8 inches in 

 diameter. The slight shade produced by the foliage overhead here 

 is not sufHcient to exclude from the ground underneath many of 

 the herbaceous and frutescent forms characteristic of the pre- 

 ceding stages, but along with these occur some species which 

 attain their optimum development under more mesophytic 

 conditions. The ultimate fate of a forest like this is suggested 

 by the predominance on the forest floor of oak seedlings and the 

 scarcity of pitch pine seedlings. As a matter of fact, owing to- 

 the ability of the pitch pine to endure fire, this particular forest, 

 which is situated along the railroad, will probably continue 

 indefinitely in its present condition. But under normal con- 

 ditions oak and hickory would succeed the pitch, pine, and there 

 seems to be no reason to doubt that under favorable circum- 

 stances the forest might at some future time become quite as 

 mesophytic as the climax type described in connection with the 

 trap rock succession. 



* According to R. C. Hawley and A. F. Hawes (Forestry in New England, 

 p. 352. New York. 1912), "gray birch is a species which requires a bare soil 

 for a seed bed, while red cedar can start well under more adverse conditions, 

 even in a thick sod. This difference in the habits of the two species explains 

 why pure stands now of one species and then of the other are met with on old 

 fields." 



