-22- 



68. Tarrant, R.F. 1956. Effects of slash burning on 

 some physical soil properties. For. Sci. 

 2:18-22. 



Severe burning (complete removal of litter) 

 lowered the percolation rate to 30% and macro-pore 

 space to 25% of unburned in 2 soils, sandy loam 

 and sandy clay loam. Light burning did not impede 

 percolation (increased in the sandy loam); bulk 

 density decreased, macro-pore space was reduced. 

 Severely burned areas were small, discontinuous 

 patches amounting to only a small portion of plots 

 in Douglas-fir forests. 



69. Tarrant, R.F. 1956. Changes in some physical soil 

 properties after a prescribed burn in young 

 pondersosa pine. J. Forestry. 54:439-441. 



(Same material, with additional illustrations) 



70. Viro, P.J. 1974. Effects of forest fire on soils, 

 p. 7-45 ^n T.T. Kozlowski and C.E. Ahlgren 

 (eds.) Fire and Ecosystems. Academic Press, N.Y. 



Burning in Scandinavia to reduce depth of the 

 humus layer in spruce forests resulted in less 

 water retention and increased soil temperature, 

 both desired results. An increase in 

 nitrification was attributed to higher pH . 

 Changes in the C/N ratio affected microbial 

 activity. While K and Mg tended to be leached 

 into mineral soil, Ca was better adsorbed in 

 humus. Phosphorus did not change appreciably. 

 Organic matter in mineral soil was 10% less than 

 in unburned areas, attributed to increased 

 decomposition. Weight of the humus layer 

 diminished from 33 to 25 T/ha. The author 

 suggested that burning may eliminate rapidly 

 decomposable surfaces, leaving lignins which are 

 more slowly decomposed. 



71. Vlamis, J., H.H. Biswell, and A.M. Schultz. 1955. 

 Effects of prescribed burning on soil fertility in 

 second growth pondersosa pine. J. Forestry 

 53:905-909. 



Greenhouse tests were done to determine the 

 ability of soils after prescribed burning to 

 supply plant nutrients. Severely burned soil 

 showed an increase in N supply over lightly burned 

 and unburned soil. The effect was greatest in 

 surface soil, and in the first year after burning. 

 Plants growing on one burned soil showed an 



