It may seem trivial to worry about fire damage to one little oak tree in the park when historic wildfires have devastated vast sections of the West. But this microcosm can give us insight and help us develop a more proximate empathy with victims of the larger horror. (Mike Davis in this article compares the big fires to a nuclear war.) We have been fortunate so far to escape these mega-infernos in our little town.
This young Holly Oak was our “Plant of the Week” here on February 22, 2019. It looked like this:
Then in the July 4 weekend this year, two stupid kids invaded the poorly marked Nature Area, where people are off limits, and set off a model rocket, starting a grass fire that consumed more than two acres before five units of the Berkeley Fire Department contained it and put it out.
The burned area is home to jackrabbits, ground squirrels, and gopher snakes. I walked the burned area a week later and could find little evidence of their fate. They may have escaped, or they may have survived, or died, down in their burrows. At least one ground squirrel emerged from its hole; it had either survived below or fled and returned.
A snail had no options; its shell lay on the blackened ground.
Bleak though it seemed to human eyes, the ground held some interest for the resident flock of Rock Pigeons, who went foraging through the charred stumps of grasses.
The Holly Oak, meanwhile, had the leaves on its southeastern and lower branches burned off. Higher leaves on its northwesterly side remained on the tree but looked as if they had been toasted; they showed no signs of green.
Two and a half months later, in the last week of September, the little Holly still held on to a crown of leaves that look as if they had come out of a toaster. It remained the tallest plant in the burned acres.
The black and grey ash on the ground seems to have settled in or blown away, leaving the surface looking a seasonally more normal brown. The grasses remained charred stumps, although a few tentative green shoots emerged from the middle of many of them.
In one patch, light green spikey grasses are emerging energetically.
Nothing restrained the weeds, notably the Wild Radish (Raphanus raphanistrum), which found the conditions just ideal, and may become the new dominant species in the area. We really have quite enough of this plant in the park already.
We won’t know whether the Holly Oak survived until the rains come, (if they do). The Holly Oak is an evergreen species and presumably relies on its green leaves for energy year round. It has no green leaves now and is getting no support from its crown.
There has been limited study of the effects of fire on oaks, and little of that has been devoted to Quercus ilex. But there are grounds for optimism. One study of Q. ilex in Spain, in an area with large wildfires, reports that even if the trees burned to a stump (“stool”), many of them resprouted and eventually regrew. But not all.
Another study noted that this type of oak shows great resilience to injuries, including fire. We’ll see. Given favorable conditions, the Holly Oak is capable of growing into a mighty tree and living a long time. Some specimens In Malta are said to be between 500 and 1,000 years old, and a Holly Oak in Wexford, Ireland, reportedly planted in 1648, measured 20 m (65 ft) in height with a crown spreading some 43 m (141 ft).