Helping Joshua Trees Recover After the 2023 Geology Fire

Joshua Tree National Park vegetation staff Annika Bjorksten, Saani Borge and Mary Ciambrone put up cages to protect low sprouts of a burned Joshua tree from being eaten. NPS / O. Anderson.

The fire

The human-caused Geology Fire started on June 10, 2023, along Berdoo Canyon Road, one of Joshua Tree National Park's designated backcountry routes. The park's fire management plan calls for putting out any wildfire in western Joshua tree (Yucca brevifolia) habitat at once, to protect a species greatly threatened by climate change. Despite high winds, an aggressive response — including fire retardant dropped from aircraft and engines driven off-road in wilderness — held the fire to 1,033 acres by the morning of June 11.

Why fire is so hard on Joshua trees

In the Mojave Desert, fires historically came rarely — more than a century apart in some places — so Joshua trees are not adapted to them.

• Severe fires generally kill 80% or more of the Joshua trees they reach.
• After a fire, with few small plants left, rodents eat the surviving trees and their sprouts at the base, killing even trees that lived through the flames.

The Geology Fire's severity varied. Because it spread fast in the wind, and because plants were sparser across 60% of the burned area, about 30% of the estimated 10,000 Joshua trees inside the fire's perimeter died.

Saani Borge, Rily Bellias and Annika Bjorksten wrap a Joshua tree's trunk in hardware cloth so it is not eaten while it recovers. NPS / O. Anderson.

The recovery plan

The park's Burned Area Recovery plan sets out ten restoration islands of 2.5 acres each inside the burn, to help native perennial plants re-establish:

• Planting: container-grown western Joshua trees, with the shrubs and grasses that grow alongside them, so the islands become seed sources for the burned area.
• Caging: plantings and surviving Joshua trees protected from animals.
• Seeding: native seeds sown in shaped seed pits.

Work so far

Field work in the park is mostly done from October to May, and the funding arrived only in March 2024, leaving little time before the summer heat. Even so, staff:

• surveyed the burned area and set up all 10 restoration islands, placed where runoff will concentrate rainfall;
• caged 100 Joshua tree sprouts and 100 surviving trees, and marked 100 uncaged sprouts and 100 uncaged trees for comparison, to test whether the cages work;
• began growing the container plants for planting out;
• collected seeds — though the heat arrived before the seed pits could be dug.

Field work was to resume when cooler weather returned later in 2024.

Sources

• National Park Service, "Promoting post-fire recovery of western Joshua tree habitat", Joshua Tree National Park. https://www.nps.gov/articles/000/promoting-post-fire-recovery-joshua-trees.htm
• Rewritten in hubnx's own words.