Seeds That Survive Fire

Wildfires can destroy entire landscapes, leaving behind scorched vegetation and damaged ecosystems. Yet beneath the surface, some plant seeds may possess an unexpected ability to withstand intense heat and begin growing again.

Researchers at the University of Canterbury in New Zealand have discovered that certain native plant species can survive temperatures of up to 80°C. In one surprising case, exposure to heat actually encouraged seeds to germinate.

Published in the New Zealand Journal of Botany in October 2026, the findings could improve understanding of how native vegetation recovers after wildfires.

Why Scientists Studied Fire-Resistant Seeds

Wildfires are becoming an increasingly important environmental concern in New Zealand, raising questions about the ability of native ecosystems to recover.

Researchers wanted to understand whether seeds buried in the soil could withstand the temperatures experienced during fires. The team compared several native plants with introduced species originating from environments where fires are more common.

Scientists initially expected the introduced plants to demonstrate greater heat resistance because of their evolutionary exposure to frequent fires. However, the results revealed unexpected differences between individual species.

Native Plants Show Surprising Resistance

One of the most interesting discoveries involved Carmichaelia australis, a native broom species known locally as mākaka. Its seeds survived laboratory heating to 80°C, and exposure to these temperatures actually stimulated germination.

This suggests that heat can sometimes help overcome the conditions preventing seeds from beginning to grow. Another native plant, kōwhai, also survived temperatures reaching 80°C. However, unlike mākaka, heating did not break the hard seed coat's physical dormancy, meaning the seeds were not stimulated to germinate.

These differences reveal that surviving heat and responding to it with germination are separate biological abilities.

Why Some Seeds Cannot Survive

Other native species proved considerably more vulnerable. The researchers found that māhoe, tī kōuka, also known as the cabbage tree, and matagouri seeds were killed by exposure to high temperatures.

This suggests that intense fires could destroy seeds stored in the soil, reducing opportunities for natural regeneration. In areas where these plants are common, recovery may depend on surviving vegetation or seeds arriving from surrounding habitats. The findings highlight why different native species may respond very differently to the same wildfire.

Invasive Plants Have An Advantage

The study also revealed the remarkable heat resistance of gorse, an invasive plant introduced to New Zealand. Gorse seeds survived temperatures reaching 100°C, the highest tested by the researchers. Furthermore, exposure to temperatures of 60°C and above stimulated germination by breaking seed dormancy. This helps explain why gorse frequently appears in large numbers following fires.

Its ability to survive intense heating and germinate afterwards may give it a competitive advantage over more vulnerable native vegetation. Consequently, wildfires could encourage the spread of invasive plants in some landscapes.

What This Means For Forest Recovery

The findings offer valuable insights for conservationists working to restore damaged ecosystems. Understanding which seeds survive heat could help predict how vegetation communities change after wildfires. However, the experiments were conducted under controlled laboratory conditions. Actual fires involve varying temperatures, heating durations, soil depths and environmental conditions.

Further field research is therefore needed to determine how reliably these findings reflect natural wildfire events. For New Zealand's native ecosystems, the discovery provides a more detailed picture of survival and regeneration.

Some plants may possess greater natural resilience than previously assumed, while others could require additional conservation support as wildfire risks increase.