Wildfire Fuels Management & Mitigation Program
The forests surrounding Kimberley, like many in the region, are increasingly at risk from the accumulation of excess dead woody material, which fuels the intensity and spread of wildfires. For generations, the Ktunaxa peoples have actively managed the land through fire, maintaining a natural balance that kept fuel loads low and fire behavior manageable. However, modern conditions, including climate change, have led to the build-up of large quantities of forest debris—such as fallen logs, branches, needles, and leaves—that contribute to more dangerous, hard-to-control wildfires.
The City of Kimberley, the Kimberley Fire Department, BC Wildfire Service and other partnering organizations are committed to addressing this growing threat through fire mitigation strategies, particularly pile burning, which is recognized as an effective and cost-efficient method for reducing these dangerous fuel loads. This webpage outlines the challenges posed by excess forest fuels, the methods for removing them, and why pile burning stands out as the most viable solution to protect our communities, ecosystems, and economy from catastrophic wildfire impacts.
Implications of Excess Forest Fuels
Deep accumulations of dead woody fuels, such as logs, branches, and litter, can create wildfires that are difficult to control, especially in the early stages. The more fuel present, the harder it is to suppress a wildfire before it grows. Large fires release intense heat, causing widespread tree mortality and leaving behind a dead forest that requires expensive treatment to prevent future fuel build-up. This process includes removing dead trees, cleaning up surface fuels, and controlling invasive species. High heat from such fires can also sterilize soils, increasing erosion risk and hindering plant regeneration, while allowing non-native species to take over. Additionally, burning large fuel loads releases harmful pollutants into the air, including particulate matter, carbon monoxide, and greenhouse gases, which negatively impact both health and the environment.
Figure 1: The prolonged and intense heat from burning large accumulations of dead woody fuels has severely degraded the forest soils. As a result, these soils are now highly vulnerable to erosion.
How to Remove Forest Fuels
There are a number of approaches that forest managers can take to remove excess forest fuels. One is to simply wait for the fuels to decompose. Another option is to physically remove the fuels from the site. The third option is to treat them on-site but change their structure. The fourth option is to treat them on-site through burning.
Decomposition
Dead plant material decomposes through bacteria, fungi, soil invertebrates, and fire. In hot, dry ecosystems like those around Kimberley, decomposition is slow, and the more material there is, the slower the process. Historically, dead plant material accumulated at around 2-3 kg/m² (20-30 metric tonnes/ha), mostly consisting of leaves, needles, grass, and small branches, with occasional downed logs. Today, this accumulation has increased to 8-15 kg/m² (80-150 metric tonnes/ha)—a 400-500% rise. Climate change and droughts are expected to slow decomposition even further, while increasing tree mortality and the amount of material to break down. Fire was historically the main means of decomposition in these ecosystems, burning through light fuel loads quickly and with little smoldering. This frequent, low-intensity fire cycle kept the ecosystem resilient. However, today's denser fuel beds lead to hotter, longer-burning fires with more severe consequences.
Physical Removal
Some dead woody fuels can be physically removed from a site, but this is usually limited to sound logs. The process is costly and ecologically disruptive, as it is not feasible to remove and process rotten logs, branches, stumps, litter, or duff for use in products. Even sound logs have limited market value, often being used for bioenergy (pellets, chips, biodiesel) or thermal heat (firewood for heating). In both cases, the removal, processing, and transport must be heavily subsidized.
Treatment On-Site - Non-Burning Methods
Several on-site treatments, such as chipping and mastication, can help manage forest fuels without burning, but these methods only rearrange the material, rather than reducing the overall fuel load. Chipping grinds fuels into small pieces and spreads them back onto the site. Mastication involves grinding larger woody material, including both standing trees (live or dead) and downed logs. These methods are effective for breaking down larger fuels, but they don’t address the full range of materials—such as smaller branches, needles, leaves, stumps, and duff—which remain untreated.
While chipping and mastication can speed up decomposition by breaking down large logs into smaller pieces, the sheer volume of material and the dry conditions of the ecosystem slow the process considerably. These treatments also fail to reduce the overall fuel accumulation, leaving up to 80 metric tonnes per hectare still on-site. When fuelbeds of chipped or masticated material burn, they tend to smolder, causing prolonged soil heating. This can sterilize soils, alter their physical properties, and increase erosion risk. Severely burned soils are also more prone to invasion by non-native plant species. Additionally, smoldering fires release harmful pollutants, including particulate matter, carbon dioxide, carbon monoxide, methane, and other toxic chemicals.
Mastication and chipping can be expensive, with costs exceeding $8,500 per hectare for mastication and up to $6,000 per hectare for chipping. While these costs are similar to those for slashing, piling, and burning, the key difference is that slashing and burning effectively remove fuels from the site, whereas chipping and mastication do not.
Treatment On-site - Burning
On-site burning treatments are designed to remove large quantities of accumulated dead woody material in a controlled manner. The process typically begins with thinning the forest stand, followed by either removing the thinned material or combining it with dead wood from the forest floor to create small piles, usually around 2 meters in diameter and 2 meters high. These piles are then left to dry for a year before being burned in the fall or winter when conditions are safe (Figure 4). This method is highly effective at removing medium-sized and large dead woody fuels, but it does not address smaller fuels such as branches, needles, leaves, stumps, litter, and duff.
Another option involves combining thinning with pile burning followed by broadcast burning. This series of treatments removes a larger quantity of dead woody material and helps increase the site’s resilience to wildfire over the long term. The process includes thinning (either manually or mechanically, with material removal where possible), piling and burning, and then conducting a broadcast burn to clear remaining fuels, including branches, twigs, leaves, needles, and some litter and duff. While this treatment can exceed $10,000 per hectare, it is the most effective way to alter fire behavior and reduce the potential negative impacts of wildfire on communities, ecosystems, and the economy. After treatment, the site is safer for firefighters to work in, and if a fire does occur, it will burn with much lower severity, reducing damage to the forest. Additionally, future wildfires will produce less smoke, particulate matter, and other harmful air pollutants.
Smoke & Air Quality
Treating fuels on-site without removing them can lead to difficult-to-control wildfires, significant ecological damage, and high levels of particulate matter and harmful emissions. Pile burning followed by prescribed burns helps convert large amounts of dead woody material into particulate matter, gases, and ash. While the timing and management of emissions are controlled by the burn managers, best practices for smoke management are regularly followed. These include notifying the public about upcoming burns, choosing burn days with favorable atmospheric conditions for dispersal, limiting the burn area to control emissions, and timing burns before expected precipitation to help extinguish the fires.
Even with these measures in place, prescribed burns still release significant amounts of particulate matter and other pollutants. However, research shows that emissions from prescribed burns are much lower than those from wildfires (Figure 5). Unfortunately, smoke from wildland fires—whether from wildfires, cultural burns, or prescribed burns—is a constant presence, and there is always some level of smoke in the air throughout the year. The goal for land managers is to treat as much accumulated fuel as possible, ensuring that smoke is emitted under controlled conditions rather than from uncontrolled wildfires.
Figure 5. Chart below. Comparison of daily particulate matter (PM 2.5) emissions from wildfires and prescribed burns in North Carolina, USA. North Carolina serves as a useful case for this analysis due to the high frequency of prescribed burns. Although emissions from prescribed burns are low (<0.4 µg/m³) during the burn season (February to June), wildfires, which occur later in the year, result in daily emissions greater than 2.4 µg/m³ (Afrin et al. 2020).
Information provided by Robert Gray, AFE Certified Wildland Fire Ecologist
Kimberley Wildfire Management Plans
- Kimberley Community Wildfire Plan Phase I
- Kimberley Community Wildfire Plan Phase II
- Kimberley Community Wildfire Plan Phase III