Human-released carbon > climate warms > forests severely burn > hikes are lost:
Large majority of trees killed in
North Complex Fire: 
Feather Falls
Dome Trail

Large majority of trees killed in Dixie Fire:
Posey Lake 
Green Island Lake
Frog Mountain
Saucer Lake
Blue Lake

Humboldt Peak
Kings Creek
Chambers Creek Bridge

Humboldt to Cold Sprs
Twin Meadows

Many trees killed in Dixie Fire:
Sifford Lakes
Devils Kitchen

Conard Meadows
Butt Mountain 
Myrtle Flat

Most trees burned along drive for miles, hike partly burned
Grassy Creek
Mount Harkness
Rainbow Lake

Exceeds CHA drive time Policy (carbon emissions reduction)
(2 hrs for dayhike, 3 hrs for overnight backpack (shuttles double the drive time))
Humboldt to Cold Sprs
Hat Creek Headwaters
Magee Peak (from Magee Trailhead)
Arkright Springs
Hat Creek Rim shuttle
Twin Meadows
Conard Meadows
Cache Creek Ridge
Cache Cr Ford


Other Reasons
Thomes Gorge  part of trail obliterated by firebreak repair bulldozer

Butt Mountain  1/2 mile of trail obliterated by firebreak bulldozer.  Also many trees burned in Dixie Fire

Kanaka Peak  hike burned

Black Lake  replaced by Triangle Lake semi-loop (longer version same hike area)

Castle Dome  too much traffic noise from I-5

Grass Valley Bald Mtn hike not good enough for length of drive