-4- 



1. Ahlgren, C.E. 1963. Some basic ecological factors 

 in prescribed burning in northern Minnesota. p. 

 143-161 in Proceedings 2nd Annual Tall Timbers 

 Fire Ecology Conference, Tall Timbers Research 

 Sta., Tallahassee, Florida. 



Burning reduced the litter layer from 3" to 1", 

 caused greater average temperature fluctuation for 

 one year, and increase in pH , total soil N, 

 phosphates, Mg , K, Ca. Soil P increase and 

 moisture decrease continued through the 2nd 

 season. Soil o.m. was not significantly 

 affected. Plant growth in soil from burned plots 

 was better than in unburned after the first rain. 



Ahlgren, I.F. 1974. Effects of fire on organisms, 

 p. 47-72 iji T.T. Kozlowski and C.E. Ahlgren 

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



Based on a review of literature, the author 

 suggested that effects on soil organisms are 

 greater in forests than grassland. Populations 

 may be immediately reduced, but some subsequently 

 increase to greater than preburn levels. Many 

 population reductions do not seem to be directly 

 caused by heat of fire. However, postfire changes 

 vary greatly. 



3. Ahlgren, I.F. and C.E. Ahlgren. 1960. Ecological 

 effects of forest fires. Bot. Rev. 26:483-533. 



This paper summarizes literature to date on the 

 effects of fire on soil, soil organisms, and plant 

 succession. Generally, increases in soil 

 temperature extremes, Ca, P, and K were shown; N 

 reports were contradictory. 



4. Ahlgren, I.F. and C.E. Ahlgren. 1965 Effects of 

 prescribed burning on soil microorganisms in a 

 Minnesota jack pine forest. Ecol. 46:304-310. 



Plate counts and carbon dioxide evolution showed 

 that numbers and activity of microorganisms 

 decreased immediately after fire but increased 

 greatly following the first rainfall, attributed 

 to leaching down of ash materials. Streptomycete 

 populations increased in the 3rd season. Species 

 composition changes were not studied. 



