Plant Science Leaders - Brian Van Hezewijk

Canada is one of the most forested countries in the world—approximately 40% of its land surface area is covered by forests. Complex forest ecosystems are critical to the atmosphere as they absorb about one-third of the carbon dioxide emitted by humans. They are also important for global industries like lumber, paper, pharmaceuticals, tourism, and more.

Perhaps most importantly, Canada’s forests are home to countless plant and animal species, all of whom depend on the health of their ecosystem to survive.

But modern challenges like climate change and invasive species are pushing some forests to their limits. Dr. Brian Van Hezewijk, a leading entomologist with the Canadian Forest Service at the Pacific Forestry Centre in British Columbia, has dedicated his career to understanding insect population dynamics and the forces that drive them.

Conviron sat down with Dr. Van Hezewijk to discuss his research and how his insights can help understand insect species amidst changing environmental conditions and safeguard forests for future generations.

The Science of Population Dynamics

Dr. Van Hezewijk’s research aims to understand the ebb and flow of insect populations, particularly forest pests. His research focuses on two primary groups: native defoliators like the western spruce budworm, and invasive species such as the spongy moth. These insects, while small, can have outsized effects on forest health.

“Population dynamics really means figuring out why populations of certain insects dramatically increase, leading to outbreaks, or why they suddenly disappear,” he explains. At the heart of this investigation are factors that influence birth and death rates. Natural predators, diseases, nutrition, and mating success all play roles in these cycles.

For native pests like the western spruce budworm, outbreaks occur roughly every 15–20 years, causing significant damage to forest ecosystems. “While these pests don’t typically kill trees outright, prolonged outbreaks weaken tree health, reduce growth, and make forests more susceptible to other threats, like fungal pathogens and bark beetles,” Van Hezewijk notes.

The Climate Connection

Climate change has added another layer of complexity to Van Hezewijk’s research. Extreme weather events, such as the 2021 heat dome in British Columbia, are pushing insect populations into uncharted territory. Temperatures reached the high 40s during the event, raising critical questions about how temperature extremes impact insect lifecycles and their ripple effects on forests.

“We’ve always had good data on insect behavior at moderate temperatures, but this heat event pushed us beyond anything we’ve previously studied,” Dr. Van Hezewijk recalls. The team is now extending their models to include higher temperature ranges, seeking to understand how extreme heat affects insect growth, reproduction, and survival.

This research is especially urgent, as rising temperatures may either inhibit or accelerate pest outbreaks. “It’s not yet clear which way it will go,” Van Hezewijk says. “Some insects may do well in warmer climates, while others may struggle to survive. The implications for forest ecosystems could be profound.”

Balance Matters

Forest ecosystems need natural balance. Too many pests, like the western spruce budworm, can strip trees of their foliage, weakening their ability to sequester carbon and produce healthy growth. On the other hand, invasive species, like the spongy moth, can bring new challenges by disrupting established ecological balances.

“A less healthy forest isn’t just an ecological concern—it’s also an economic one,” Van Hezewijk explains. “Weakened trees produce lower-quality lumber. They’re more susceptible to other pests and diseases.”

Van Hezewijk’s research tackles these vulnerabilities head-on, focusing on how to disrupt pest outbreaks before they cause widespread damage and permanently alter forest ecosystems.

From Field to Lab

Studying forest insect populations happens both in the forest and the lab. Van Hezewijk’s research team uses newly acquired Conviron plant growth chambers to simulate environmental conditions and study insect behavior under controlled settings. The experiments are labor-intensive and meticulously detailed, with hundreds of insects monitored daily throughout their life cycles.

“For one experiment, we rear about 800 insects in individual containers, tracking their growth and development at specific temperatures,” he explains. “This process takes about six weeks for each batch, and we repeat it multiple times across many different temperatures.”

The data gathered from these experiments is crucial for building predictive models that inform pest control efforts. However, maintaining precision requires reliable equipment. “Our older growth chambers were approximately 35 years old and prone to malfunction,” he recalls. “Equipment failure can lead to months of lost work. With new chambers, we can maintain the consistent conditions we need.”

Practical Applications

The findings from Dr. Van Hezewijk’s research have direct applications for forest management. Predictive models based on his work help with timed interventions, such as pesticide applications, to target insects at their most vulnerable stages. This precision minimizes environmental impact while also maximizing effectiveness.

Beyond immediate pest control, Van Hezewijk hopes his research can eventually shape broader forest management policies. For example, understanding how pests respond to climate change could guide decisions about which tree species to plant in certain regions.

“If we know certain areas are more likely to experience severe pest outbreaks,” he noted, “we can prioritize more resilient tree species in those places.”

A Lifelong Fascination

Van Hezewijk’s interest in entomology dates back to childhood. “Even as a kid, I was capturing bugs in jars and studying them,” he says. This early curiosity eventually led him to the field that has fascinated him throughout his career.

One defining moment in his career came during a hike in Northern Ontario. Spotting a patch of insect eggs parasitized by tiny Trichogramma wasps, he collected them on a whim and nurtured them in his lab. Months later, at a conference, he discovered a pest consulting company in Vancouver was seeking these very wasps to control a raspberry pest.

The serendipitous discovery led to a job offer and helped him on his path to become an entomologist. “Sometimes, it’s things that seem trivial that turn out to make all the difference.”

The Human Element

While big data offers powerful tools for analyzing insect populations, Van Hezewijk emphasizes the importance of fieldwork and direct observation.

“I hope people don’t get too removed from actually being out in the forest and knowing what those insects actually look like and how they live,” he says. “It’s nice to have a balance of both.”

This hands-on approach extends to his mentorship of university students, who are essential to his research. “Fieldwork gives students practical skills they don’t often get in the classroom, as undergraduate students,” he explains. As much as he loves being out in the field himself, he gives field opportunities to students whenever he can.

Still, Van Hezewijk makes sure to be out in the forest himself at least every few weeks. “I always want to be sure that what I think is feasible to do in the field actually is feasible,” he noted. “It’s easy to spend too much time at one’s desk but we should not forget the importance of getting out into the field.”

Looking Ahead

As climate change creates unprecedented challenges, Van Hezewijk’s work continues to adapt. His research now focuses more heavily on how extreme weather events can impact insect populations and forest ecosystems.

“We’re experiencing weather events far outside what we would consider normal,” he observes, noting how these changes demand new approaches to understanding and managing forest health.

By examining the complex relationships between insect populations, forests, and climate, Van Hezewijk’s work contributes to a deeper understanding of how to protect these vital ecosystems. For him, the most rewarding aspects of his role are opportunities to tackle significant ecological questions and mentor the next generation of researchers. His work, in turn, not only drives scientific advancement but also inspires others to take up the challenge of safeguarding forests for the future.