I went up the Sister Elsie Trail in Haines Canyon in Tujunga today (11/10/2007) and did some brush clearing.
The worst brush that I was aware of is the first quarter mile or so on the left branch of the trail after the junction where the right branch of the trail goes up to rejoin fire road 2N76. Accordingly, I brushed the section from the stream crossing to about a tenth or so of a mile up the trail.
The very worst section of the trail was a knot of ceonothus interspersed with poison oak. It had grown almost a bridge across the trail. It wasn't much fun trimming overhead poison oak (guess where the PO goes as you cut it), but it's done now, so the worst of the brush on that trail is gone. I also trimmed a couple of yucca.
I may work my way up a little further in a couple of weeks. In the mean time, enjoy a far more open trail.