coville: formation of leafmold 85 



Upland peat would have become leafmold had not the orderly 

 normal course of leaf decomposition been suspended and con- 

 ditions of acidity established which rendered the further progress 

 of that decomposition impossible. 



The rate at which leaves decay is greatly influenced by tem- 

 perature. In the cooler northern latitudes and at high eleva- 

 tions in lower latitudes the rate of decay is slower and the form- 

 ation of upland peat is more general than in warmer climates. 

 Except on calcareous soils the higher . Apalachian peaks, from 

 4000 to 6000* feet, bear an almost continuous layer of upland 

 peat, from a few inches to a foot or more in depth. Their great 

 rhododendron thickets are rooted in deep beds of upland peat. 

 The spruce forests of the higher New England mountains lay 

 down a similar formation. 



In the treeless west the decay of leaves where it is not actuallj' 

 suspended by dryness is rapid and complete. At the higher 

 elevations, however, where the land begins to be timbered the 

 organic matter does not fully decay, and in the heavily timbered 

 areas the deposit of upland peat often becomes characteristic- 

 ally deep and continuous. In fighting creeping fires in the yellow 

 pine forests at the lower elevations the favorite and most effective 

 tool is the rake, which parts the light leaf litter and puts a stop 

 to the progress of the flames. But in the dense fir and spruce 

 timber the forest ranger's chief tools are the spade and the mat- 

 tock, with which he must cut through the thick layer of dry 

 peat to the mineral soil beneath if he is to effectually combat a 

 slowly creeping fire. 



So strong is the tendency to the formation of peat under the 

 low temperatures and heavy precipitation of the high mountains 

 that even on limestone soils a superficial layer of upland peat is 

 sometimes accumulated. Such a condition exists on innumer- 

 able areas at an elevation of about 10,000 feet in the Manti 

 National Forest of Utah. On the basaltic plateau of extreme 

 northeastern Oregon, where the soil is naturally alkaline in reac- 

 tion the lodgepole pine and Douglas fir forests at elevations of 

 5000 feet and over lay down a continuous bed of peat which sup- 

 ports a characteristic acid flora. A quantitative test of one of 



