Large, old trees may contain rot at their bases or other defects that increase their probability of falling and endangering human safety and property. Sequoia and Kings Canyon National Parks conduct a hazard tree surveillance and mitigation program to protect human safety and property in developed areas.

Today, removing monarch giant sequoias that pose a safety hazard isn’t acceptable. This wasn’t always the case. In 1950, an 18-foot-diameter, 240-foot-tall sequoia leaning over cabins in the Lodge area was felled to protect human safety; in 1966, a second leaning, mature sequoia was felled near Beetle Rock. In more recent years, leaning sequoias located in pockets where root rot was present in surrounding trees were identified as hazards, but threatened structures were closed rather than felling the tree.

Hazards to human safety are still present despite efforts to identify hazards. In 1969 an elderly woman died while picnicking in the Hazelwood area when a 240-foot-tall sequoia tree fell against another sequoia, toppling the upper 130 feet of the second tree onto her picnic table. The Hazelwood Picnic Area was closed after this incident.