The problem with mustard is that it is prolific. It out-competes native annuals, and native and non-native grasses. In oak grasslands this can produce brush conditions that should a fire occur, it is likely to kill more trees.

A heavy growth of mustard was probably a factor in the death of the valley oak pictured above. It was burned in the 2005 Topanga Fire.

From this afternoon’s run at Ahmanson Ranch.