Scirpus olneyi and Spanina patens were grown in mixed stands in containers (surlace area: 900 cm2) and burned during the fall and winter on 6 dates (Burn 1, 8 October; Burn 2, 23 October; Burn 3, 8 December; Burn 4, 20 December; Burn 5, 6 February; and Burn 6, 20 February). Plants in 18 separate containers were burned on leach date and 18 containers were left unburned as a control. Biweekly counts were made of the number of culms of each species per container from 5 October to 18 April. A positive linear relationship (P < 0.05) was noted between culm production of both species and minimum temperature following burns. However, the regrowth of S. olneyi increased at a greater rate with increasing temperature than S. patens. The data indicated that photoperiod (decreasing day length) reduced the regrowth rate of S. patens. The mean density of S. olneyi approached or equaled pre-burn densities by the 4th week following burns, but S. patens did not approach the pre-burn density until the 8th week. The mean density of S. olneyi per container was greatest throughout the study period in the Burn 1 group (X = 52.8) and declined gradually to Burn 6 (X = 21.8). However, the mean density of S. patens increased 49.4% from the 1st 3 burn dates (Burns 1,2, and 3) (X = 21.8) to the last dates Burns 4, 5, and 6, (X = 47.5).
