The effects of fire in the regeneration of a Quercus douglasii stand in Quail Ridge Reserve (California)

Blue oak (Quercus douglasii) woodlands in California have been under threat because of land conversion and low rates of natural regeneration. Low recruitment has been attributed to human disturbance and changes in fire regime. Later studies suggest that low recruitment is characteristic of Quercus douglasii and is adequate for the maintenance of the stand at large temporal scales. The objectives of the study were to evaluate the effects of fire in the structure of the oak woodland one year after the fire that affected the stand in 2005. The study site is located in Quail Ridge is located on a peninsula formed by the flooding of Berryessa Valley (California) which has helped it maintain many elements of the native flora. In the blue oak stand 14 plots were randomly located: 7 in the burned area and 7 out of the burned areas (control). The effect of fire in sexual regeneration, asexual regeneration and mortality of the trees was analyzed
The results indicated that fire does not have a significant effect in the sexual regeneration of Quercus douglasii or Quercus wislizeni.  However fire does stimulate asexual regeneration in both species of oaks, but grazing reduces the regenerative effect of fire.  Fire increases regeneration of Arctostaphylos manzanita and Heteromeles arbutifolia by stimulating asexual and sexual regeneration and eliminating competition from other species for space.  Occupancy by this chaparral species is further enhanced by the lower palatability of these species relative to both species of oaks.