The Importance of Fire in the Natural Environment
on Nov 19, 2024As rangers, we work closely with many natural elements, facing both positive and challenging aspects of the environment, including major natural disasters. One of the most impactful of these is fire. While fire is a natural part of many ecosystems, it can be incredibly destructive, especially when it threatens infrastructure built within reserves and the people living there. However, fire also plays a crucial role in supporting environmental health, offering benefits like clearing dead vegetation and promoting new growth. Like most things in nature, fire has both advantages and disadvantages.
We will be looking at both the negatives and positives of fires, man-made and natural.
Overall, fire becomes hotter and more intense as temperatures rise, especially in conditions of low humidity and strong winds. In extreme cases, it can reach a point where it cannot be stopped, requiring us to prioritise the safety of those fighting it. The topography of the land is also a critical factor as fire spreads faster uphill than downhill because heat rises. Additionally, fire needs oxygen to grow and continue spreading, which is challenging to control in open environments where there's no practical way to restrict oxygen supply to an open fire.
When a wildfire occurs, it's essential to contain it before it causes severe damage or becomes uncontrollable. One common strategy is to create a backburn (burning from the opposite direction if wind allows, so that the two fires meet and extinguish each other).
For any controlled burn, timing is critical. You must carefully assess factors such as temperature, wind speed and direction, humidity, and fire index levels to prevent the fire from spreading out of control. Fire and wind can be a dangerous combination, especially since fire generates its own internal wind, making it difficult to predict how it will behave as it grows.
Negative impacts
Fire poses a significant threat, especially for reserves like ours. If a wildfire were to devastate the entire reserve, wildlife would naturally disperse, only returning after the first rains bring fresh grass and foliage. During this period, game viewing becomes challenging, as grazers and browsers move to areas with abundant vegetation, and predators follow their prey to survive.
Fires can lead to the loss of animal life. Although most animals will instinctively move away at the first signs of fire, by scent, sight, or sound, some smaller animals, like tortoises, chameleons, and even young cubs, may be unable to escape quickly enough and can perish in the flames.
If a particular area is burned too frequently, it can deplete the soil’s nutrients, ultimately making it nutrient-poor. As with many things, too much of a good thing can lead to negative consequences.
Additionally, wildfires can cause severe infrastructure damage, especially to lodges and staff accommodations. When fires become uncontrollable due to high temperatures and strong winds, entire buildings can be lost, resulting in substantial damage. To prevent such incidents, it’s essential to be cautious with controlled burns. We often create ‘firebreaks’ around lodges, burning a small, controlled area on cooler, low-wind days to prevent future fires from spreading too close. This proactive approach helps protect key structures from potential wildfire damage.
Positive impacts
When used under the right conditions, fire can offer several ecological benefits. Fire impacts the decomposition of vegetation in various ways, including:
- Rapid mineralisation – as vegetation and trees burn, they release nutrients back into the soil immediately, which contrasts with the years required for natural decomposition.
- Fire alters key soil properties - physical, chemical, and microbiological - enhancing the soil’s capacity to sustain natural life.
- Fire slows decomposition in the upper litter layer but accelerates it in the lower litter layer, which helps maintain soil nutrient levels.
- Fire reduces the activity of other decomposers such as fungi and microorganisms.
- Fire increases the temperature sensitivity of decomposition, making it more adaptable to temperature changes.
- Fire decreases the efficiency with which microbes process carbon.
- Fire raises soil temperature and reduces moisture, resulting in shorter intervals between fires.
Overall, when managed carefully, fire can play a valuable role in nutrient cycling and ecosystem health.
Controlled burns allow us to harness the benefits of fire while minimising its potential harm. We carefully choose days with favourable conditions for burning, depending on the type of fire we aim to create, either a ‘cold fire’ or a ‘warm fire.’
A cold fire burns quickly across the soil surface, consuming mainly grasses and small branches lying on the ground. This type of fire minimises damage to larger vegetation, helping to clear the underbrush without impacting the ecosystem's more mature plants.
A warm fire burns slowly over the surface, on a very warm day that burns any invasive species or even dead trees that are still around, a natural clean up.
We carefully select specific areas for controlled burns, as burning the same area every year would deplete the soil’s nutrients and overall quality. By rotating burn areas, we ensure that wildlife has access to unburned sections with vegetation, allowing them to remain within the reserve. After the first rains, the burned areas flourish with nutrient-rich new growth, attracting animals from far and wide to feed on the lush vegetation.
During this time, the ground is cleared of dense underbrush, making animal sightings exceptional. The open landscape allows for clear, unobstructed views of animals resting or moving through the area, enhancing the quality of sightings. The abundance of fresh vegetation also draws a remarkable diversity and number of animals to our reserve.
Burned areas can additionally attract species that prefer more open spaces, as the cleared ground provides ideal habitat conditions for them.
- Spontaneous combustion can also be common in certain parts, when the temperatures start rising, dry organic material can spontaneously combust causing fires.
- The sun’s heat can also ignite wildfires, especially as our maximum temperatures can be extremely high.
- Sparks from rock falls are less common but also a factor that causes wildfires.
There are several natural ways a fire can ignite, each playing a role in the occurrence of wildfires:
- The most common cause, especially during the summer months when the dry vegetation from the end of winter meets the onset of thunderstorms. Lightning strikes can easily ignite dry grasses and other vegetation.
- Spontaneous Combustion can also be common in certain areas. Rising temperatures can cause dry organic material to spontaneously combust, leading to fires.
- Intense sunlight can also trigger wildfires, particularly during periods of extremely high temperatures.
- Sparks from rockfalls are less common but also a factor that causes wildfires, especially in dry conditions.
Each of these factors can contribute to the ignition of wildfires, often depending on the prevailing environmental conditions.
From this, it's clear why fire plays a crucial role in conservation and why it must be managed carefully. The key difference is that, through controlled burns, we can reduce the risk of uncontrolled wildfires. By conducting these burns, we can manage the fire's behaviour and intervene quickly if it gets out of hand, as we are equipped and on-site to control it. Without fire, vegetation would eventually overtake the landscape, making it difficult for animals to move freely. Over time, this would deplete the soil of its essential nutrients, negatively impacting the entire ecosystem. That’s why it’s important to continue this natural process but in a safer and more controlled manner.
Blog by Ruan Mey (Earth Lodge Ranger)
