How trees survive and thrive after forest fires
Uncontrolled forest fires can devastate anything in their path. Plants and trees cannot move or and run away when fire descends on their habitat, but due to the frequency of these natural and ever increasingly human influenced disasters, many species have adapted to survive.
Some plants and trees are classified as pyrophytes or ‘fire resistant’ species. Pyrophytes have developed an ability to tolerate fires, and can actually thrive in the aftermath of a blaze.
Trees have various ways of tolerating and regrowing after fire. For some trees with extensive root systems, this can be especially beneficial as their roots can give them the capacity to ‘resprout’ after their above ground presence has been completely destroyed by fire. Resprouting trees include the strawberry tree (Arbutus unedo), the evergreen oak tree (Quercus ilex), Pistacia lentiscus or ‘Mastic’ tree and the kermes oak tree (Quercus coccifera).
Some plants in fire prone areas actually need fire, either directly or indirectly, to successfully germinate. Plants, such as Cistus produce seeds that remain buried in the ground and are capable of withstanding high temperatures. The aftermath of a fire provides an ideal opportunity for these buried seeds to germinate, as fires often create large areas of open space with plenty of light. Without competition from other plants and with new mineral resources that are generated from fire ashes, these plants are able to flourish.
In environments where hot, fast moving fires are frequent, some species of pine tree have adapted and developed thick, hard cones that are literally glued shut with a strong resin. These “serotinous” cones can hang on a pine tree for many years, long after the seeds inside have matured. When faced with fire, the resin melts, which opens the cones, releasing seeds that are then then distributed by wind and gravity.
Despite nature’s resilience, it must not be forgotten that human behaviours are intensifying forest fire incidences. Forest fires increase carbon dioxide levels in the atmosphere, contributing to the greenhouse effect and climate change. Ashes destroy much of the nutrients and erode the soil, which can cause flooding and landslides. Unnaturally severe fires can destroy forests, even those that have adapted to fire and overall regeneration of vegetation is a challenging process. As a result human intervention such as actively supporting soil restoration methods are needed to continue to protect our world’s forests.
