Jeanne Robert, forest entomologist, Omineca Natural Resource Region, B.C. Ministry of Forests.

BEETLE ATTACK growing in B.C.

The numbers are revealing: the spruce bark beetle outbreak in the B.C. Interior has been growing at an alarming rate—and it’s gaining momentum.By

By Jim Stirling

Graphs are cold, clinical things. But they can eloquently reveal a story.

The bar graphs chronicling development of the spruce bark beetle outbreak in north central British Columbia well illustrate the point. The graph’s bars get progressively longer after the results of each year’s aerial and ground surveys are interpreted and displayed.

In 2013, spruce beetle numbers within the Omineca Region in north central B.C. were benign. They reflected what might be expected from the beetles’ endemic role within the interconnected web of the regional spruce forest ecosystem.

In 2014, however, surveys illustrated that about 50,000 scattered hectares within the sprawling Omineca Region showed signs of infestation. And by 2015, the total area showing evidence of spruce beetle infestation had mushroomed to more than 150,000 hectares.

The trend continued in 2016 when the estimate was more than 200,000 hectares infected—and after the 2017 data was plotted, the bar registered about 375,000 hectares of forest lands affected by the spruce beetle.

Concerns about the beetles’ population surges have been growing along with the bars on the graph, but so have the management responses. B.C.’s Ministry of Forests, Lands, Natural Resource Operations and Rural Development has been and continues to share tactical information about the infestation with the regional forest industry—which once again finds itself on the front line of a beetle wood salvage challenge. The ministry and the forest industry are also communicating with a range of other partners including First Nations and the general public, explained Jeanne Robert, forest entomologist, Omineca Natural Resource Region with the Ministry of Forests.

Comparisons are inevitably drawn with the mountain pine beetle infestation in the B.C. Interior, the effects of which will be evident in the region for years, and probably decades. That infestation subsided mainly because of the forest industry’s prolonged and effective salvage work, coupled with a lack of mature and over-mature pine wood left for the beetle to consume.

The spruce beetle, say the experts, is a different proposition both in its behaviors and potential rates of spread. For example, the pine beetle thrived by consuming huge swathes of similarly aged contiguous forests of pine tree stands. Spruce beetle infestations are characterized more by patches within the spruce-balsam deciduous forest. Spruce beetles seek out mature blowdown stands as a preferred habitat. Robert said parts of the Omineca Region were subjected to violent winds and blowdown in 2010, especially among older stands. The blowdown might have contributed to kick-starting a seven-year growth cycle within the regional spruce beetle population.

Regional entomologist Jeanne Robert has begun testing spruce at various stages of beetle infestation.

But that’s where everything becomes a little hazy. Recent experiences continue to demonstrate that traditional weather patterns, and the reactions of ecosystems to them, are no longer valid.

“One of my concerns is that we have this combination of conditions,” said Robert. “It’s warmer with longer growing seasons and higher minimum winter temperatures.” One of the consequences of that and other factors is the spruce beetles are moving increasingly from a two-year life cycle to a single one, she added. Those factors in combination are putting spruce trees under increasing stress and making them more susceptible to beetle attack.

The warming and more extreme and unpredictable weather patterns are encouraging similar tendencies in other beetle and forest pest populations from Alaska to California. For example, the Douglas fir beetle is infesting at least 65,000 hectares in B.C.’s Cariboo region.

The spruce beetle doesn’t encourage early detection, further complicating plotting the extent of the infestation at any given time. “With the spruce beetle you can’t see from the air where the green attack is and that makes them harder to track,” she explained.

Ground surveys permit a more thorough investigation of an area of interest, but are expensive to conduct and need to be wisely chosen to yield the most valuable information about the infestation’s spread, continued Robert.

The mountain pine beetle epidemic and the spruce beetle infestation is putting increasing pressure on the mid-term timber supply available to the regional forest industry. The forest industry has become adept by necessity to shifting harvesting priorities and strategies to accommodate diets of beetle infested wood. Regional forest companies and their log harvesting contractors in the Omineca, including Canfor Corp., Conifex and BC Timber Sales, are working with the forests ministry and its other partners. They are strategically targeting stands where sanitation harvesting can help reduce spruce beetle populations while receiving economic value from the timber for the province and the industry.

The Ministry of Forests has formulated guidelines to assist the industry to more efficiently and effectively prioritize and plan their harvesting activities. For example, designated suppression management zones in the Omineca region recommendations have been circulated to help minimize the risks of beetle escapes as infected logs are transported, stored and milled. Air temperature is a critical controlling factor. Spruce beetles tend to fly and consequently spread when air temperatures exceed 16 degrees Celsius. Below that threshold, harvesting and mill related activities are unaffected. Up to 25 degree Celsius, night hauling and milling are recommended. When temperatures exceed that level, no log hauling or milling is requested. The objective is to reduce “no haul” windows to about six weeks in the specific suppression management zones.

Regional entomologist Jeanne Robert has begun testing spruce at various stages of beetle infestation. The goal is to learn more about the rate of wood deterioration caused by the beetle and demonstrated by development of defects like dryness, rot and decay. It’s an obvious area of interest to salvaging log harvesting companies. She cautions findings are very preliminary and further testing in different areas is planned. “But the results so far tell me a stand shelf life after infestation is quite reasonable.”

The forest ministry’s mandate also requires communication and collaboration with other industry forest-users. These include but are not restricted to parks, protected areas and special management areas such as wildlife habitat and old growth management designated areas. The ministry’s collaborative efforts are further reflected through the creation of spruce beetle working groups in 
Mackenzie and Dawson Creek.