The hills south of Hiller Highlands, just across route 24, were swept bare by the 1991 fire. Anything that was there besides eucalyptus has been unable to compete, and now it’s a fire-prone monoculture. That suits eucalyptus fine—keeps down those riffraff oaks and madrone, thank you.
The hillside forest was partially cut down maybe ten years ago, then again just a couple years ago. Each wave of attack remains obvious on the landscape. Eucalyptus is like the hundred-headed Hydra in the Odyssey: every head you cut off grows two new ones in replacement. Hercules defeated the Hydra with his sword in one hand and a torch in the other, cauterizing the wound after each head he struck off.
We can only reclaim these slopes by poisoning the stumps, herbicide-haters be damned. For a successful example, see the new slopes along Skyline Boulevard between Broadway Terrace and Elverton Drive, a wedge of land belonging to the Sibley park that has been reclaimed from just this state, exposing some excellent outcrops.
Oakland Geology 
15 January 2009 at 1:03 pm
I think you are talking about this location. It’s a south-facing slope, and what grazers remain are relatively few in numbers compared to what “used” to run wild on those slopes. Eucalyptus will continue to dominate,
unless it is attached by geophiles bearing glyphosate :-)
The “wedge” you talk about appears to be here, showing an Oak grassland.
Without more grazers, I suspect that the wedge will get brushy over
the coming years, with coyote bush making up most of it. I don’t think it can be maintained in its current state without significant human effort
(which is fine, as it is in an urban area).
I very much enjoy your writing, combining as it does walking and geology.
[Thanks. I mis-edited this post and wiped out your first link, but now it definitely points to the location of this photo. –Andrew]