and/or aluminum, having a coarse texture with cracked coatings on sand grains 

 or distinct silt size dark pellets present, or satisfying certain chemical criteria. 

 The chemical criteria are a) the ratio of pyrophosphate extractable Fe + Al to 

 clay is at least 0.2 (if Fe is>0.1%, percent carbon is substituted); b) at least half 

 the amorphous Fe and Al is complexed with organic matter; and c) the index of 

 amorphous material accumulation [(CEC — %clay/2)x(horizon thickness)] must 

 be at least 65. Furthermore, the spodic horizon has a specific depth requirement 

 dependent on the soil temperature regime and the presence or absence of an Ap 

 horizon. Spodic horizon requirements for soils lacking an Ap horizon must be 

 met below a depth of 12.5 cm for frigid or warmer soil temperature regimes (Ap 

 horizons are not present in mountainous regions such as the area of sampling). 

 Cryic or pergelic soil temperature regimes have no requirement for depth. 



The studied soils all have morphological characteristics of Spodosols. All 

 pedons have at least one subsurface horizon meeting the chemical property 

 criteria for spodic horizons. Typical spodic horizon characteristics of wide C/N 

 ratios, low base status, high extractable acidity, and accumulations of illuvial C, 

 Fe, and Al characterize each pedon (Table 1). At least one subhorizon in each 

 pedon meets the requirement that the ratio of pyrophosphate-extractable Fe + 

 Al to clay must be at least 0.2 (Table 2). The requirement that at least half the 

 amorphous Fe and Al must be organically bound, that is the ratio between 

 pyrophosphate-extractable Fe + Al and dithionite- citrate extractable Fe + Al 

 must be at least 0.5, is also met in at least one subhorizon. Index of amorphous 

 material accumulation is not a limitation in classification of these soils as spodic, 

 since the B horizons of non-orthods as well as orthods in the area have an index 

 well above the required 65. However, one must keep in mind that in applying 

 the criteria of Soil Taxonomy, only that qualifying part of the spodic horizon 

 below 12.5 cm. is used. The B21h horizon of Pedon 1 is an example. The index 

 of accumulation for this horizon is 448. The depth of this horizon is from 5 to 

 13 cm. Soil Taxonomy requirements are for the 12.5 to 13.0 cm. part of this 

 horizon to be used for spodic horizon determination. The accumulation index 

 for this part on an equal weight basis is 28 and hence does not qualify for 

 spodic. None of the pedons have a continuously cemented horizon (Table 3). 

 Cracked coatings on sand grains are not readily evident and dark pellets of silt 

 size, if present, are probably hornblende remnants. 



Four pedons (pedons 1, 6, 7, and 9) fail to meet the depth requirement for 

 classification as spodic under frigid temperature regimes. We have used the 

 surface of the mineral soil as the point of reference for depth measurements. 

 However, Soil Taxonomy is not specific as to the point of measurement. If the 

 surface of the forest floor were used as the point of reference, all pedons would 

 easily meet the depth requirements of spodic horizons. The thickness of 021 and 

 022 horizons ranged from 3.5 to 9.0 cm. Hoyle (1973) has reported the 

 importance of humus (022 horizon) as the main source of nutrients for forest 

 vegetation in the study area. The significant role of these horizons in nutrient 

 cycling suggests to us that they should be included in depth measurements. A 

 more critical question than reference point for measurement, however, is 

 whether a depth requirement is even needed for mountainous soils within the 

 frigid zone. The soils of the sample area have long been considered to be 

 Orthods, and are managed as such. Yet, four of the nine soils apparently do not 

 meet depth requirements for classification as Orthods. In view of the chemical 



