iqiq] ' WATERMAN— ROOT SYSTEMS 27 



Mitchella re pens, with Aspidium spinulosum, Adiantum pedatum, 

 and Botrychium virginianum. 



Burned area. — The northern and central portions of the forested 

 strip have been burned, in some parts repeatedly, in others not so 

 recently. In the much burned portions the tree specimens are 

 young and somewhat stunted. In the other portions the trees are 

 larger and the undergrowth thicker. The species include Betula 

 alba, Primus virginiana, and P. pennsylvanica, with the more 

 xerophytic relics of the mesophytic undergrowth, and much Pteris 

 and Equisetum. 



Border zone formation. — ^Where the climax forest, still untouched, 

 extends to the shore, a zone 50-100 yards in width shows a very 

 characteristic difference in species. The trees are Thuja, Ostrya, 

 Tilia, and Abies balsamea, with Celastrus scandens. The line of 

 demarcation is not sharp, but the climax trees, especially hemlock, 

 mingle with the others almost to the edge of the cliffs. The 

 characteristic border zone species are*not found farther back in the 

 climax forest. 



Dune complex vegetation.— On the open dune complex 

 there are found a number of forest patches, apparently growing in 

 valleys between former fixed dunes whose summits have been 

 entirely blown away. The interiors of these patches present all 

 the characteristics of a heavy forest, and their evaporation rate is 

 almost as low as that of the climax forest, but the vegetation is 

 characteristic of the border zone already described, containing 

 especially Thuja and Abies, and is marked by some trees reaching 

 2 ft. in diameter, but not over 30 ft. in height. The undergrowth 

 is similar to that of the climax forest, but is especially characterized 

 by Viburnum acerifolium, Rhus toxicodendron, and Aralia nudicaulis. 

 On the edges, next to the open sand, are found Arctostaphylos, 

 Linnaea, and Juniperus horizontalis. These apparently originate 

 in the fixed area and extend out onto the sand, forming a protective 

 covering, which frequently contains also Juniperus communis. 

 Buried trees and occasional graveyards are to be found all over the 

 moving sand area. 



There is not much forest reproduction on the moving sand, and, 

 unlike some similar regions, there are no young stands of Pinus 



