By Jim Stirling

The thwack of helicopter blades in the cold Cariboo air is becoming a familiar sound to Williams Lake area residents. For the last three winters, a targeted sanitation logging program of stands infected by the Douglas-fir beetle has been underway.

The aerial component is part of a suite of control efforts jointly designed to contain the beetles’ spread around susceptible fir stands on Crown land in the Cariboo-Chilcotin region of south central British Columbia.

Annual survey interpretation indicates the strategies are having an impact and proving effective in helping control the rate of spread of the beetle into new Douglas-fir stands.

The how and where decisions about deploying the varying beetle containment methods can be distilled into a single word: collaboration.

“It’s a very collaborative process and involves lots of people sharing information and viewpoints,” summarized Jennifer Bowman, resource manager for the Cariboo-Chilcotin Natural Resource District of the Ministry of Forests, Lands, Natural Resource Operations and Rural Development based in Williams Lake, B.C.

The catchment area for collaboration includes a wide representation from the regional forest industry. It includes tenure holder representatives, log harvesting contractors, forest health experts and the managers of the community forest.

The Douglas-fir beetle typically focuses its attack on small groups of susceptible trees. The location of these small groups of beetle-infested trees helps indicate what type of treatment method or approach is likely to prove the most effective control. The selective heli-logging of beetle-infected fir trees, for example, is a treatment option for steeper slope sites with regulated access. The treatment method gains traction in areas of high outdoor recreation value—which are common in the greater Williams Lake area—and where there are visual impact issues, explained Bowman. The heli-logging of infected stands help protect adjacent fir stands from the beetles.

Sarver Wood Fibre Ltd., is the forest ministry’s heli-sanitation logging contractor. The firm is owned and operated by the four Sarver brothers and offers a range of logging services from its base in 100 Mile House, B.C.

The Douglas fir beetle is endemic to regional forests and the forest ministry has tracked past infestation surges and trends, noted Bowman. The last major Douglas fir beetle outbreak in the Cariboo-Chilcotin Natural Resource District peaked in 2008-9 and affected about 68,550 hectares. Aerial surveys made during the summer of 2018 indicated Douglas fir beetles were affecting about 48,584 hectares in the regional natural resource district.

Whatever is happening on the regional landscape base can influence beetle populations. It sounds contradictory that a landscape ravaged by the worst forest fires in its recorded history during 2017 might have caused the Douglas fir beetle populations to track upwards. But that may well be the case.

“The beetles stick around because the pine trees have become weakened by the forest fires’ intensity,” believes Alex Tranq, senior silvicultural resource technologist with the forests ministry in Williams Lake.

The Williams Lake beetle management unit treatment plan for 2018 included several other initiatives. An interesting one was the application of an anti-aggregate pheromone called methyl cyclolexnone. The substance transmits the message to other Douglas fir beetles that a tree is already fully occupied by beetles. It’s used to help disrupt beetle attacks in vulnerable areas including parks and protected areas, residential properties and old growth management areas.

Trap tree felling is another useful tool in the beetle containment arsenal. It’s used in the spring to attract adult beetles to a prime habitat for disposal. The falling and burning of specific beetle-infested stems is also a control option when others aren’t readily available. Use was also made in 2018 of funnel traps installed in regional log yards.

The Douglas fir beetle populations will dictate future control strategies in the region. “I would hope the heli-logging control program will continue at least through 2020,” said Tranq. “After that we will have to wait and see.” Landscape management is a volatile subject during a warming climate period. It’s also one with worrying implications for the regional forest industry. It’s facing high fibre costs driven by a shrinking working forest land base on which beetle attacks and wildfires play significant roles.