Earlier this year, Cariboo North MLA Coralee Oakes expressed concern about the current spread of spruce beetle in the northern Interior.
Noting she had been talking to several groups, including forestry and First Nations, the MLA said there is a significant fear that it’s very much like the mountain pine beetle invasion.
“It has an epicentre right now, but they’re studying it… we have to become more proactive.”
Oakes noted the epicentre for the mountain pine beetle showed up in Tweedsmuir Provincial Park and the government of the day decided to study it.
Instead of going in and working with partners to nip it in the bud, Oakes said they waited and the pine beetle issue quickly became a full-blown epidemic.
However, Jeanne Robert, who is the Omineca-Northwest regional entomologist for the Ministry of Forests, Lands, Natural Resource Operations and Rural Development, told the Quesnel Observer there are significant differences between the pine beetle and the spruce beetle, which is being monitored annually.
“We monitor the population of spruce beetle every year across the province with our aerial overview survey.”
She added they originally detected higher than normal populations of spruce beetle in 2014.
“The province declared an outbreak north of Prince George and around Mackenzie in October 2015.”
At that time the spruce beetle covered 150,000 hectares in the Omineca region.
It increased in 2016 to 210,000 ha, Robert said, adding the 2017 aerial overview study showed the spruce beetle covered an area of 340,000 ha.
“The entire coverage area for the province is a little bit over 500,000 ha – most of it is concentrated in the region north of Prince George and right around Mackenzie.”
Beetle differences
Wherever there is a spruce forest, there is spruce beetle, she explained.
“This isn’t a foreign invader. This is an endemic insect that’s always been there.”
Usually spruce beetles feed on dead, down and dying spruce trees to maintain themselves, Robert said.
However, she noted the tree has to be recently dead, because after a year, the beetles can’t use it.
“That’s why the blowdown [trees that have been knocked down by wind] are a perfect habitat for spruce beetle.
“Trees like these have a little bit of that green phloem [vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves] is usable for a year.”
The phloem is the area under the bark where spruce beetle larvae feed.
Normally, spruce beetles keep the population going by living off the sick and dying spruce trees, she said.
“But, historically, it’s not unusual for spruce beetles to have a population reach a threshold and then move from dead and dying trees into healthier, standing green spruce trees.”
These outbreaks usually last for five to seven years, she said, adding they had a similar one in the 1990s.
“They’ve happened in the Yukon, Alaska and the United States, so they are not unusual events in the grand scheme of things.
“Some would even argue that without regular spruce beetle outbreaks, we wouldn’t have spruce ecosystems the way they are at this moment.”
Ecosystem differences
Robert said spruce ecosystems are different from those of lodgepole pine.
“We all witnessed what happened with the mountain pine beetle outbreak and how in the pine ecosystems very large tracts of trees turned red over a couple of years. So, we could really see the outbreak expand rapidly. It was a huge unprecedented outbreak….”
The key difference, she noted, is the spruce ecosystem tends to be more diverse with a mix of spruce and balsam trees, and they tend to be longer cycling ecosystems.
Robert added spruce ecosystems tend to be in wetter areas and have an uneven age class.
“You have younger trees growing up under older trees that are at the prime of their existence.”
So, they’re not trees of the same age over a large area like we see with the lodgepole pine, Robert noted.
“When there are [spruce beetle] breakouts, they tend to be in patch distributions where they take out the large trees, which allows the younger ones underneath to grow up.
“Spruce beetle outbreaks are very important for spruce ecosystems to maintain their diverse age and trees species.”
These are normal drivers for spruce ecosystems, she explained.
However, Robert noted she has some concerns with this current spruce beetle outbreak.
Read about these concerns and treatments to stem the spread of spruce beetle-attacked trees in Part 2 of this series, on Friday April 20.
