The Ecological Benefits of Forest Fires
The dying embers of destructive forest fires contain the spark of new life.Posted Sep 3, 2015
This has been the summer of forest fires in North America. Hundreds of fires still rage across the US and Canada as fire season winds down. To the thousands of people who have suffered loss of homes and property, there is no silver lining to a forest fire.
It is hard to imagine anything more dramatic and terrifying than a forest fire blazing its way through everything in its path. It seems like the ultimate picture of destruction. While there is no doubt that these fires can threaten lives and property, and break down years and often decades of lush growth; all is not lost. There can be hidden benefits that come with forest fires. In many instances, forest fires are natural occurrences that play a vital role of renewal in the cycle of forest life.
The big picture
Even a large and severe fire does not usually wipe out an entire forest. Temperatures and conditions vary within a fire, which cause it to burn in patchwork pattern. Fire ‘refuges’ are often scattered throughout a forest. These are naturally occurring, moist areas that are protected from a burn and are capable of supplying a seed source to help repopulate the surrounding burnt areas after a fire.
Fires also open the forest canopies to allow sunlight to reach the forest floor, benefitting the many plants that are shade intolerant and cannot compete with more shade tolerant plants. The Sequoias (also known as giant Redwoods), for example, utilize the pattern of periodic opening of the forest canopy to enable saplings to become established by having access to newly available sunlight.
Fires are a great way of clearing out the clutter. They can break down nutrients and minerals in burning plants and other debris such as old logs, leaves and dense undergrowth and restore them to the soil, thus making for a more fertile area. The increase in available nutrients in the soil after the fire also helps create the perfect condition to boost microbial life in the forest floor.
Fire often clears out any invasive weeds, insects and disease that may have been affecting a particular forest site, providing a chance for the area to have a fresh start with native species.
New grasslands are sometimes created after a fire, and there are many species of grazing animals that can benefit from the change. The natural order of species within the food chain adapts and re-establishes to the changed ecology. Life goes on.
Not as vulnerable as you may think
Plants can be remarkably adaptable to the scourges of a forest fire, and some are even dependent on fire for their existence.
In dry areas where fires occur frequently, some tree species have developed thick bark, which makes it possible for them to endure reoccurring low intensity fires. It’s common to see trees in the forest with charred bark, evidence of their ability to endure and even thrive from the reduced competition and by securing nutrients made available in a fire’s aftermath.
Some North American and European pines have thicker bark and a large crown base that is high up in the canopy, another strategy evolved to survive forest fires. The Ponderosa pine is a good example, with its vulnerable, flammable parts high above the path of most fires, it does not easily succumb.
In the densely tangled brushwood of chaparral areas found typically in the southwestern US and Mexico, there are plants with leaves coated in flammable oils that serve the purpose of encouraging hotter fires because they have fire-activated seeds that need the heat to germinate.
Some trees, such as the Lodgepole pine or Jack pine, are known to have ‘serotinous cones’, which means their seeds are sealed with a waxy coating that is melted away by the heat of the fire and then released for germination in the newly improved mineral rich soil. These pines, in addition to White birch and Aspen, are all species that thrive in full sunlight. Periodic forest fires are key to their survival.
Similarly, Sequoias produce cones that only release their seeds when the cone scales dry out. These magnificent giants rely on fires for their abundance and renewal.
Life springs from the ashes
Don’t be fooled by the gray landscape after a fire. There is a lot of living going on in a fire’s aftermath, with new species quickly sprouting to make use of newly available nutrients.
Fireweed is often one the first species to bring a new blush of color to the barren post-fire landscape. Its pink-purple flowering stalk flourishes in the wake of a forest fire, and fireweed is essential for reintroducing vegetation into a burn site. It dies back as other plants slowly grow in, but the seeds stay in the soil for many years, waiting for a new fire or disturbance to open up the space and bring light again to renew germination.
In the pinelands of New Jersey you can witness the adaptability of the Pygmy pitch pine which is known for its thick fire resistant bark. If the trunk gets damaged by fire, new growth quickly sprouts from the wound. Wherever an opportunity presents, new life takes hold and springs forth.
Aspen, alder and birch are able to quickly begin to establish themselves in burned areas and can often be seen sprouting from stumps and roots of burned trees. These relatively short-lived species prepare the soil for follow-up species which develop the mature forest.
A case for fighting fire with fire
It may seem counter-intuitive to start a fire, but there are trained professionals that do just that. A well-managed burn that is controlled enough to stay at low or moderate temperatures can remove dead and decaying plant material that can act as fuel for future forest fires. This helps reduce the risk of greater damage a more severe fire may cause. It is only high intensity fires that burn up into the canopy causing damage to the crowns of the trees.
It’s not just the above ground structure of trees that need protection. If temperature below ground is increased only slightly, as is the case with a controlled, lower temperature fire, there is less damage caused to the roots of trees and plants that are deep in the soil.
Maybe it’s not as bad as it appears
It has been said there is a time for everything, and that everything has its season. It is always difficult to witness the seeming destruction of leafy green forests but it may ease our minds a little if we can remember that there are many cycles to the ecology of a forest, just as there are many cycles to life. It goes on, adapting, striving, and re-establishing itself on it’s own new terms. Even in the embers, there is the spark of new life.
A bridge of silver wings stretches from the dead ashes of an unforgiving nightmare to the jeweled vision of a life started anew.
– Aberjhani, “Journey through the Power of the Rainbow”
T.J. Blackman resides on a tiny island where she lives happily among the trees. She has various works in progress, including a novel that she works on while she is not writing articles for sites that pique her interest.