Exploring the Wildland-Urban Interface in Halifax, NS
Mapping forest fire risk in the Eastern Chebucto Peninsula Backlands
Human-Nature Interaction
The rising cost of urban living, population growth, and the desire to live in close proximity to nature has fueled development and suburban expansion into near urban wilderness areas [1]. In Halifax, Nova Scotia, population growth and development in and around the Eastern Chebucto Peninsula Backlands (ECPB) has led to the intermingling of human settlement and wilderness areas. This area is known as the wildland-urban interface (WUI) [2].
Increased development near sensitive ecological areas poses many environmental challenges, such as habitat fragmentation and biodiversity loss [3]. In addition, increased development near forested areas exacerbates the risks and impacts of forest fire. The Acadian Forest Region (AFR), which spans Halifax Regional Municipality, is prone to natural fire disturbance [4]. Consequently, development in the WUI increases the risk of wildfire, particularly because most fires in Nova Scotia are human caused.
Wildland-Urban Interface
The ECPB is an ecologically sensitive area located West of the Halifax Peninsula [5]. It is bordered by Purcells Cove Road to the East and Herring Cove Road to the West. This near urban wilderness area hosts several ecosystem types many of which are prone to fire disturbance [6]
A disturbance refers to any relatively discrete event (such as a fire, windstorm, or insect infestation) that disrupts the physical structure and (or) resource availability of an ecosystem - Taylor et al. 2020
In the ECPB, the WUI is defined as the two kilometer buffer zone around civic address points. A two kilometers buffer was applied as it represents the distance that embers from a fire are likely to travel [8,9]. Civic addresses located within the WUI are shown in Map 1. Note that civic addresses within a 2 kilometer radius of the ECPB boundary but located on the Halifax Peninsula were excluded.
Environmental Challenges & Fire Risk
In terms of fire risk, not all ecosystems are created equal. Within the ECPB there are four distinct forest ecosystem types: spruce pine, spruce hemlock, mixed wood, and coastal [10]. Some ecosystems, such as spruce pine are adapted to fire, whereas other ecosystems, such as coastal barrens, are at low risk to fire disturbance. Understanding the ecological characteristics of how fire behaves within each ecosystem type is an important component of understanding and mitigating risk to fire.
Spruce Pine
Spruce-Pine is a nutrient poor forest ecosystem often associated with fire disturbance. This forest ecosystem type is often associated with black spruce (Picea mariana) and jack pine (Pinus banksiana). Jack pine has serotinous cones. This means that the cones are sealed shut with resin and only open following exposure to high temperatures. Jack pine dominated ecosystems, such as the one found in the ECPB, are adapted to fire. This ecosystem type represents HIGH fire risk.
Spruce-Hemlock
This ecosystem type represents mid to late successional softwood species such as red spruce (Picea rubens), white pine (Pinus strobus), and Eastern hemlock (Tsuga canadensis). This ecosystem type is characterized by infrequent disturbance events such as wind throw, insect infestation, and fire. This ecosystem type, particularly when nearing climax, represents MEDIUM fire risk.
Mixed Wood Forest
Tolerant hardwood is characterized by mid to late successional species such as sugar maple (Acer saccharum), beech (Fagus grandifolia), red maple (Acer rubrum), and white ash (Fraxinus americana). This ecosystem type often has a heavy understory with both regenerating tree species as well shrub species. Stand replacing disturbance events are rare. Fire risk is LOW in this ecosystem type.
Coastal Forest
This ecosystem type is dominated by black spruce (Picea mariana), white spruce (Picea glauca), and balsam fir (Abies balsamea). It is influenced by cool, moist climatic conditions and is located in close proximity to the Atlantic ocean. Fire is not a common disturbance in this ecosystem type. As such, the fire risk in this region is LOW.
Who is most at risk?
Civic address points were classified based upon the type of forest they were located in. For instance, civic addresses located within spruce pine forest were classified as represent high risk, civic addresses located within spruce hemlock forest represent a medium risk, and civic addresses located within either tolerant hardwood forest or coastal forests are considered low risk.
Fiery Past
In 2009, a large fire swept across the ECPB. The fire, believed to be human caused, forced thousands of evacuations and destroyed eight homes.
This image appears on the Halifax Field Naturalist website and was taken from the Dartmouth Harbor. Photo credit: Ross O'Flaherty [11]
Regenerating Landscape
While a traumatic experience for those living in the WUI, the 2009 fire presented an opportunity for natural regeneration to take place. This photo (taken in February 2021) showcases the regenerating landscape. Because the 2009 fire destroyed many of the older trees, the risk of another large fire in this part of the ECPB is low.
Future Risks
While the Ecological Land Classification dataset provides some insight into fire risk, it is not conclusive. Other factors, such as age of forest, disturbance history (including historic fires), and land use patterns also influence fire risks (12,13). Google Maps Street View was used to further explore the fire risk in the ECPB. Images from Google Maps Street View were captured to illustrate specific risks as well as "ground truth" the forest fire risks identified by the ELC dataset. Homes from low, medium, and high risk locations were selected to display wildfire risk.
![](https://cdn.arcgis.com/sharing/rest/content/items/e0c0d198a6ac4556ae1f6562dce8d5ec/resources/cA_9D1fMz4TWlNBd0xoAS.png?w=200)
Low Risk
This home is located within the coastal forest zone. In addition, the absence of trees and distance from forested area suggest that this home is at low risk of fire.
![](https://cdn.arcgis.com/sharing/rest/content/items/e0c0d198a6ac4556ae1f6562dce8d5ec/resources/HGZuoF9229V9Af04x8dvg.png?w=200)
Low-Medium Risk
This home is located in a medium risk area. Because of the 2009 Spryfield Fire, however, it is unlikely that this area will experience a significant fire anytime soon. This image displays standing deadwood, which is a common sight in areas affected by the 2009 Spryfield Fire.
![](https://cdn.arcgis.com/sharing/rest/content/items/e0c0d198a6ac4556ae1f6562dce8d5ec/resources/s9d8hdBGhV6yNoX__8UuC.png?w=200)
Medium-High Risk
This home is located within the spruce-hemlock ecosystem type. The presence of mature trees as well as its proximity to a large swath of mature forest make it vulnerable to fire. This area of the ECPB was not impacted by the 2009 fire. Consequently, the risk of fire is considerably higher.
![](https://cdn.arcgis.com/sharing/rest/content/items/e0c0d198a6ac4556ae1f6562dce8d5ec/resources/uF8FSw7vby5Kvh311fRn7.png?w=200)
High Risk
This home is located in a high risk area. Mature jack pine trees and dense vegetation make this home particularly vulnerable to forest fire. In addition, this area of the ECPB was not affected by the 2009 fire.
![](https://cdn.arcgis.com/sharing/rest/content/items/e0c0d198a6ac4556ae1f6562dce8d5ec/resources/ROLAyQzjUf_T4AKVFVp4s.png?w=200)
High Risk
Proximity to wilderness area as well as dense canopy layer make this home susceptible to fire. This home is vulnerable as it backs onto a dense forested area. However, the open yard and pavement acts as a fire break and will provide some level of protection.
Living within a fire-prone landscape
Fire is a natural part of the landscape. As new residents move in and memories of the 2009 fire fade, it is important that people are aware of the steps they can take to protect themselves and their properties from wildfire. The following best management practices are adapted from Fire Smart Canada's 2003 publication Protecting your Community from Wildfire [14].
Select fire resistant building material
The roof and exterior structure should be constructed with fire resistant materials such as as asphalt shingles, tile, slate, aluminum, brick, or stone. If the structure is built from combustible material (wood siding, cedar shanks, or wood paneling) it should be treated with fire retardant chemicals.
Store combustible materials away from the home
Firewood and other combustible materials, such as picnic tables, playhouses, and boats should be stored away from the home.
Vegetation Management
At a minimum, all vegetation within 30 meters of a home should be managed in two buffer zones: 10 meters and 30 meters. Firstly, a fire break zone should be established within 10 meters around the house. In this zone, all flammable materials, such as lumber, dry grass, and softwood trees, should be removed. If there is an upslope leading towards the structure, this zone should be extended as fire moves quickly up a slope. A 20 meter fuel break zone should also be established around the home. In this zone, it is acceptable to plant ornamental species, but they should be spaced out.
In addition to these three interventions, municipal and provincial governments have a number of tools useful for managing the risk of forest fire. For example, risk assessment, hazard mapping, and land-use planning are tools that both provincial and municipal governments can employ to support fire safety. For example, the Province of British Columbia has developed the WUI Risk Class Assessment Map which examines fire risk in the WUI. This tool allows for governments and local communities to better understand their risk and make more informed decisions regarding mitigation and land use planning [15].
Conclusion
This assessment of fire risk in the ECPB highlights some of the challenges of residential development in near-urban wilderness areas. Due to climate change, Nova Scotia is anticipated to experience more frequent and more extreme forest fires [16]. Both governments and homeowners have a responsibility to ensure that they are informed about the risk of forest fire, have the tools and resources to mitigate the risks associated with fire, as well as the capacity to respond should a fire occur. The goal of this project is to provide a high level overview of the fire risks in the ECPB.
References
[1] Whitman, E., Rapaport, E., & Sherren, K. (2013). Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management. Environmental Management, 52(6), 1427–1439. https://doi.org/10.1007/s00267-013-0159-9
[2] Whitman, E., Sherren, K., & Rapaport, E. (2015). Increasing daily wildfire risk in the Acadian Forest Region of Nova Scotia, Canada, under future climate change. Regional Environmental Change, 15(7), 1447–1459. https://doi.org/10.1007/s10113-014-0698-5
[3] Whitman, E., Rapaport, E., & Sherren, K. (2013). Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management. Environmental Management, 52(6), 1427–1439. https://doi.org/10.1007/s00267-013-0159-9
[4] Whitman, E., Rapaport, E., & Sherren, K. (2013). Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management. Environmental Management, 52(6), 1427–1439. https://doi.org/10.1007/s00267-013-0159-9
[5] Hill, N., & Patriquin, D. (2014). Ecological Assessment of the Plant Communities of the Williams Lake Backlands. The Williams Lake Conservation Company. Retrieved from: https://dalspace.library.dal.ca/handle/10222/45661
[6] Department of Lands and Foresty. (2021). Forest Ecosytem Classification. Retrieved from: https://novascotia.ca/natr/forestry/veg-types/
[7] Taylor, A. R., MacLean, D. A., Neily, P. D., Stewart, B., Quigley, E., Basquill, S. P., ... & Pulsifer, M. (2020). A review of natural disturbances to inform implementation of ecological forestry in Nova Scotia, Canada. Environmental Reviews, 28(4), 387-414.
[8] Regional District of Central Kootney. (2021). Community Wildfire Protection Plan. Retrieved from: https://rdck.ca/EN/main/services/emergency-management/wildfires/community-wildfire-protection-plans.html
[9] Province of British Colombia. (2019). Wildland Urban Interface Risk Class Maps. Retrieved from: https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prevention/vegetation-and-fuel-management/fire-fuel-management/wui-risk-class-maps
[10] Department of Lands and Foresty. (2021). Forest Ecosystem Classification. Retrieved from: https://novascotia.ca/natr/forestry/veg-types/
[11] Beazley, R. & Patriquin, P. (2010). Regeneration of Forest and Barrens after the Spryfield Fire. Retrieved from: http://halifaxfieldnaturalists.ca/spryfieldfire/SpryfieldFire.html
[12] Whitman, E., Rapaport, E., & Sherren, K. (2013). Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management. Environmental Management, 52(6), 1427–1439. https://doi.org/10.1007/s00267-013-0159-9
[13] Whitman, E., Sherren, K., & Rapaport, E. (2015). Increasing daily wildfire risk in the Acadian Forest Region of Nova Scotia, Canada, under future climate change. Regional Environmental Change, 15(7), 1447–1459. https://doi.org/10.1007/s10113-014-0698-5
[14] Fire Smart Canada. (2003). Protecting your Community from Wildfire. Retrieved from: https://firesmartcanada.ca/wp-content/uploads/2018/10/FireSmart-Protecting-Your-Community.pdf
[15] Province of British Colombia. (2019). Wildland Urban Interface Risk Class Maps. Retrieved from: https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prevention/vegetation-and-fuel-management/fire-fuel-management/wui-risk-class-maps
[16] Whitman, E., Sherren, K., & Rapaport, E. (2015). Increasing daily wildfire risk in the Acadian Forest Region of Nova Scotia, Canada, under future climate change. Regional Environmental Change, 15(7), 1447–1459. https://doi.org/10.1007/s10113-014-0698-5
Map Data Credits
HRM Open Data (2021). Civic Address Points. Retrieved from: https://cataloguehrm.opendata.arcgis.com/datasets/2bc8323870fe44eab50630404713be6a_0?geometry=-64.666%2C44.516%2C-61.659%2C45.197
Department of Lands and Forestry (2021). Ecological Land Classification 2015. Retrieved from: https://novascotia.ca/natr/forestry/ecological/ecolandclass.asp