84 coville: formation of leafmold 



what was once such a spot, let him not undertake the herculean 

 task of growing roses and a bluegrass turf. Let his lawn be of 

 redtop and his shrubs be azaleas, laurel, and rhododendrons. 



Another factor that contributes to the suspension of leaf decom- 

 position is the acid leachings from each new deposit of autumn 

 leaves. Various acidity determinations show that after lying 

 exposed to the weather over winter, leaves ordinarily have only 

 one-fifth to one-tenth the aciditj^ they possessed when they fell 

 to the ground. It has been found experimentally that the leach- 

 ings from fresh leaves will serve to acidulate an underlying soil 

 of moderate alkalinity. Unless therefore the conditions of a 

 locality are such as to effect the decomposition of one year's 

 leaf fall before the next year's deposit takes place, a permanent 

 acid leaf cover is established. In many of the oak forests on the 

 sandy coastal plain eastward from Washington there is a perman- 

 ent accumulation of such material. The roots of the trees and 

 undershrubs bind the half-rotted leaves into a dense mat. The 

 principal trees are oaks. The principal shrubs that make up 

 the dense underbrush belong to the Ericaceae and related fam- 

 ilies. There is no mellow leafmold nor any of the leafmold plants. 



This kind of mat or turf is of such widespread occurrence, is 

 so distinct in its appearance, and so characteristic in the type of 

 vegetation it supports that it should have a name of its own, in 

 order that it may come to be recognized as one of the important 

 phenomena of nature. 



Because if its resemblance to bog peat in appearance, structure, 

 and chemical composition, and because it supports a type of 

 vegetation similar to that of bog peat, it has been proposed to 

 adopt for it the name upland peat. As defined in an earlier 

 publication-^ upland peat is ''a nonpaludose deposit of organic 

 matter, chiefly leaves, in a condition of suspended and imperfect 

 decomposition and still showing its original leaf structure, the 

 suspension of decomposition being due to the development and 

 maintenance of an acid condition which is inimical to the growth 

 of the micro-organisms of decay." 



^ Coville, 1910, p. 34. Experiments in blueberry culture. Bulletin 193, Bureau 

 of Plant Industry, U. S. Dept. Agri. 



