Frequency is the primary driver
The Longleaf Alliance notes that increased fire frequency tends to increase the diversity and abundance of grasses and forbs. They also note that seasonality matters, but is secondary to frequency.
How often are burns conducted?
The Longleaf Alliance states that prescribed fires in natural or planted longleaf systems should occur often—commonly every 2 to 10 years. They explain that the range in recommendations reflects the diversity of longleaf habitats and the groundcover species that influence fire return intervals.
Dormant vs. growing season burns
The Longleaf Alliance describes “dormant” and “growing” season burns as tied to plant physiology rather than fixed calendar months. In general, dormant season burns are considered late fall into winter, while growing season burns are often spring into summer (varying by location).
Dormant season
The Longleaf Alliance notes dormant season burns can top-kill over-abundant hardwood stems, but may stimulate resprouting and increase stem density of small understory trees and shrubs.
Growing season
The Longleaf Alliance notes growing season burns can be more effective at reducing small-diameter hardwoods in understory and midstory, especially after repeated early growing season burns.
They also suggest that combining or alternating dormant and growing season burns can give landowners the best chance to achieve desired outcomes.
Safety & legal note
This page is educational. Prescribed burning involves risk and legal requirements. Always use trained professionals, follow local regulations, and conduct burns under an approved plan with proper weather, staffing, and equipment.
For the ecological “why,” see Built by Fire.