What Lassen's Fires Teach About Forest Recovery and Fighting Megafires

Why it matters

Since the mid-1980s, western U.S. wildfires have burned more land, more often and more severely, and some forests may not return as forest. Patchy openings have ecological value, but losing forest on a large scale means lost wildlife habitat, poorer water quality and lost carbon storage. Land managers need ways to make future fires less severe — and they're working with scientists such as Dani Niziolek, a former data scientist with the Park Service's Klamath Inventory and Monitoring Network, who has studied how fire shapes forests at Lassen Volcanic National Park. Using data gathered before and after the Dixie Fire, including for her master's research, she has published two studies.

Forests can recover — with time

The first study asked how well Lassen's forests have regenerated over three decades of fire, pooling conifer seedling counts from areas burned by eight fires between 1984 and 2012 and linking them to environmental conditions.

• Seedlings were more likely within 1–2 football fields of surviving forest, and more likely as years passed — seeds eventually reach deep into severely burned patches, but recovery is slow, leaving young forest exposed to reburning.
• Climate mattered less to how many seedlings returned than to which species did.
• Regrowth was common at most plots, showing a baseline resilience. The researchers concluded that California's montane forests can withstand prescribed fire and managed wildfire, making both useful management tools.

Read the study.

Taming a megafire

The second study, which Niziolek coauthored, looked at what reduced the severity of the 2021 Dixie Fire — California's largest single fire to date, at 374,000 ha — as it burned through Lassen. It asked which firefighting operations, combined with different past fire severities, worked best. Tactics ranged from offensive backfiring — burning in normal weather well before the fire arrives — to riskier defensive backfiring in extreme weather as the fire races toward the line, as well as fuel breaks and retardant.

• A surprise: heavy defensive firing in emergencies carried less risk than expected.
• Matching tactics to fire history gave the best chance of reducing severity — though the findings cover only national forest and park land in the fire's northern footprint.
• The authors call for more training in large-fire tactics, especially complex firing operations, to help forests withstand severe fires.

Prescribed burning lowers fuel loads and the severity of future wildfires; intentional fire can also backburn ahead of an advancing wildfire. NPS photo.

Read the study.

Sources

Based on Sonya Daw (Klamath Inventory and Monitoring Network), "Learning from Fire at Lassen," National Park Service, adapted from the network's Klamath Kaleidoscope newsletter, Fall–Winter 2024; a work of the United States government in the public domain. A photograph credited only by name is not reproduced.