Hill: Penobscot Vegetation 389 



growth. These trees grow to maturity and succeed the 

 hardwoods as the dominant species. 



Where coniferous forests are cut over and the ground 

 cleaned up the usual tendency is for a broadleaf wood of 

 gray and white birch, poplar and red maple to develop. 

 This is apt to be so dense that at first seedlings of the con- 

 ifers are unable to grow. Eventually, however, as in the 

 case after a fire, the spruce and fir will again become domi- 

 nant. 



The presence of slash left on the ground after lumbering 

 operations is a constant fire menace, since the dead branches 

 and twigs furnish fuel for a very hot fire which utterly de- 

 stroys the humus. As noted above, it is only occasionally 

 and with difficulty that vegetation is able to reclothe such 

 an area. 



The most striking feature of the vegetation after a forest 

 has been cut over is the presence of clearings in which sev- 

 eral distinct stages may appear before the trees become re- 

 established. The first of these consists of herbaceous spe- 

 cies such as : 



Pteridium aquiUnum Aralia hispida 



Panieum implication Solidago nemoralis 



Carex debiliti var. Rudgei Aster lateriflorus 

 Polygonum c'dinode Erechtites hieracifoUa 



Epilobium angustifolium Lactuca hirsuta 



These are followed almost immediately by a dense growth 

 of raspberries which may completely cover the area. Other 

 shrubby species frequently associated with the raspberries 

 include : 



Betula popidifolia Primus pennsylvanica 



Ribes prostratum Acer rubrum 



Rubus cdleghaniensis Sambucus racemosa 



This "bramble association", as Gates (12) terms it, is 

 best developed after the slashing of a coniferous wood, where 

 the ground is left covered with branches. The thickets 



