Source: The Conversation – Canada
A field research team member holds a test tube containing blacklegged ticks. (Roman McKay/University of Ottawa), CC BY After a cold Canadian winter, most of us look forward to the spring and summer months to get outside and experience the natural world, whether it’s hiking, biking, gardening or birdwatching.
In recent years, however, our outdoor activities have been challenged by a range of issues stemming from climate change: increased heatwaves, lower air quality due to wildfire smoke, more intense and frequent storms and more ticks.
Over the last decade, there has been a steady northward expansion in the range of blacklegged ticks (deer ticks), and associated cases of tick-borne illnesses like Lyme disease, in Canada. Many of these expanding risk areas overlap with major population centres.
More people may now come into contact with ticks in backyards bordering woodlands, or while hiking in forests and recreational greenspaces.
Current recommendations for Lyme disease prevention mainly focus on personal protection measures to avoid tick bites, such as wearing long pants, tucking them into socks, applying repellent containing DEET or icaridin, doing a tick check and promptly removing ticks after time spent outdoors.
These are valuable actions; however, it can be difficult for people to do these actions properly and consistently. A recent study by our team at the University of Ottawa has identified woodchips as a useful tool for keeping ticks off high-use walking or hiking trails in peri-urban and suburban woodland trails.
This project has been many years in the making, and pilot testing was completed by the University of Ottawa INSIGHT lab in 2020. The most recent study spanned two years and was implemented on two Ottawa Greenbelt trails managed by the National Capital Commission (NCC).
Read more: What are the risks of contracting West Nile virus from a mosquito in Canada?
Preventing disease with woodchips Over the last decade, there has been a steady expansion in the range of blacklegged ticks in Canada. (Unsplash/Kitera Dent) There is an increasing need for preventive strategies to protect humans from ticks and the diseases they carry, while also preserving environmental and animal health.
This approach to disease prevention is referred to as integrated control, or as a One Health approach. One Health interventions often target multiple components of disease transmission. In the case of ticks, these interventions aim to protect people directly, change the environment ticks like to live in and target the animals ticks feed on.
While a recent review study found that many recent tick control studies call for increased use of integrated strategies, few studies have actually tested these strategies in field experiments. We found that when woodchips were distributed along trail borders at the forest edge, the number of blacklegged or deer ticks along these trail segments was reduced by nearly half.
Our team also target-sprayed some of the woodchip segments with deltamethrin, a type of insecticide, at the beginning of each season in late spring. Impressively, the number of ticks was reduced by nearly 99 per cent along trail segments with deltamethrin-treated woodchips.
An environmentally sustainable solution This targeted treatment of woodchip borders using deltamethrin holds promise as a method of effectively reducing ticks, while also limiting the impact of the insectide on other insects, like pollinators, by avoiding broadcast spraying into surrounding trees and shrubs.
This intervention approach also holds promise for environmental sustainability.
It used recycled ash tree woodchips from the NCC ash tree removal program, diverting land waste and providing land managers with a way to use woodchips from tree removal programs on site, in a way that benefits trail users.
Importantly, the study uses woodchips as an environmental management approach to target ticks where they live and feed. Ticks tend to spend most of their time below leaf litter to avoid drying out but climb blades of grass or low vegetation while searching for a passing host on which to feed.
One of the trails researchers placed woodchips along in the Ottawa Greenbelt. CC BY-NC This project was not without its challenges. The 2022 derecho storm disrupted field research activities in the project’s first year, and trial-and-error revealed that an all-terrain vehicle (ATV) was most efficient for distributing the woodchips along trail edges.
With storms predicted to increase in frequency and intensity throughout future years due to climate change, the feasibility of control interventions that make changes to the landscape need to be carefully considered.
The need for ATV access means that this type of intervention will likely be most feasible on wide, high-use paths with well-established tick populations, if it is implemented at a larger scale in the future.
Finally, although the woodchips were successful in reducing the number of ticks near the trail edges, the method relies on people staying on marked paths and avoiding off-trail areas where ticks may be present. While this is a practical solution, it should always be paired with other measures to reduce tick bites, like wearing repellent spray containing DEET or icaridin and completing tick checks.
Ultimately, our study identified woodchips as a potentially cost-effective way to reduce the number of ticks found on woodland recreational trails in peri-urban settings. In the future, this approach could be considered for use in similar settings, and paired with a robust tick surveillance program to evaluate results.
With ticks on the rise, strategies like this might help Canadians better enjoy the outdoors and stay tick-safe.
Katarina Ost received funding from the CIHR-CGS-D grant for her PhD research.
Manisha Kulkarni receives funding for research on ticks and tick-borne diseases from the Natural Sciences and Engineering Research Council of Canada, Canadian Institutes of Health Research, Public Health Agency of Canada, and Canadian Foundation for Innovation.
Original source: https://analysis1.mil-osi.com/2026/06/14/how-woodchips-can-help-keep-ticks-off-trails/