Hill: Penobscot Vegetation 385 



Association-types of blueberry barrens 



Blueberry barrens, because of their economic value, are 

 of steadily increasing prominence in the Penobscot Bay re- 

 gion, particularly in the eastern portion, and they will be 

 considered in some detail. The development of these bar- 

 rens shows a series of changes in the reverse direction from 

 these previously described. In this case the start is made 

 with a forest already present on the land. This is cut off 

 and the land burned over. The result is the destruction of 

 the original stand and of the humus as well. The usual 

 growth of herbaceous plants and shrubs springs up and 

 eventually a birch-popple wood comes to occupy the area. 

 This wood is burned over in its turn and this process may 

 be repeated several times. The continual destruction of 

 the sprouts weakens and kills the roots, and more and 

 more humus is destroyed. Finally it becomes impossible for 

 trees to compete with the hardier plants and a barren re- 

 sults. In such localities only a few scraggly growths of 

 red maple, white and gray birch and cherry sprouts are to 

 be found. Shrubs and herbs, however, are conspicuous. 

 Together with masses of blueberry bushes are such con- 

 spicuous species as : 



Pteridium aquMnum Kalmia angustifolia 



Car ex scoparia Gaultheria procumbens 



Myrica asplenifolia Gaylussacia baccata 



Rubus idaeus var. canadensis Lysimachia quadrifolia 

 Lechea intermedia DierviUa Lonicera 



Epilobium angustifolium Solidago sp. 



Aralia hispida Anaphalis margaritacea 



The blueberries are by far the most abundant plants in 

 these barrens and the species represented are Vaccinium 

 pennsylvanicum and its variety nigrum, and Vaccinium cana- 

 dense. 



The productivity of the barrens is maintained by burning 

 the land periodically. This is usually done in the spring im- 



