Soil Water 



The percent of water (by weight) held within the surface inch of soil was estimated 

 gravimetrical ly the day of, and the morning after each fire near the 20 permanent points. 

 At 10 of these sampling points soil water was also estimated within the 1- to 4-inch 

 (2.54- to 10.16-cm) level. The results indicated the amount of water gained through 

 condensation or lost by vaporization as a result of the broadcast fires. 



Soil Heating 



The maximum temperature within the upper 6 inches (15.2 cm) of soil was estimated 

 by using Tempilaq (Tempil Division, Big Three Industries, Inc., South Plainfield, N.J.). 

 Rectangular asbestos strips having six full-length depressions scored on both sides 

 were used. Each depression was filled with Tempilaq of a different melting point be- 

 tween l^'F (4S''C) and 500°F (246°C) . One strip was referenced to each of the 20 per- 

 manent points and the upper edge of each strip was positioned along the soil -duff 

 interface . 



Root Kill 



On the day of burning, the numbers of dead and living roots were counted at the 

 same 10 locations where the preburn soil water samples were taken down to the to 

 4 inch (0 to 10.16 cm) level. This consisted of exposing a vertical face of soil 

 10 inches (25.4 cm) wide and 6 inches (15.2 cm) deep. This surface was sprayed with 

 orthotolidine solution (Shearer 1975) that indicated which roots were respiring 

 (living). The numbers of living and dead roots greater than 0.05 inch (0.13 cm) in 

 diameter at this interface were counted. Living and dead roots were counted again 

 about 2 weeks after burning, near the point where the postfire soil water samples were 

 taken. Both the numbers of dead and living roots were recorded. 



RESULTS AND DISCUSSION 



Prescribed Fires 



The burning was accomplished during the period from September 8 through September 

 13, 1975 (fig. 1 and 4). No block was burned entirely within the prescription estab- 

 lished for duff reduction and mineral soil exposure (see p 1) because (1) cool, wet 

 conditions prevailed for several weeks prior to burning preventing drying of fuel, and 

 (2) burning could not be postponed for a year due to time requirements imposed on the 

 R^D Program to complete its overall research objective. Block 11 (shelterwood) was 

 not burned because both the preburn fuel and the duff water samples were above pre- 

 scription limits (see p. 2). In each of the other units, preburn sampling indicated 

 that the 0.0 to 1 inch (0.0 to 2.54 cm) diameter fuels were within prescription 

 limits, while the upper duff water content was consistently too high (table 1). 



7 



