Pine beetles drying out atmosphere

The initial effects of the mountain pine beetle were apparent as forests withered and changed from green to red.

But at a conference dealing with all things water, attendees learned that there’s more to come from the pest’s infestation.

During a presentation at the One Watershed-One Water conference, Todd Redding, a watershed management specialist with FORREX, told participants that death of large portions of B.C.’s forests will effect the amount of water that hits the ground and that can have can potentially effect everything from infrastructure to water quality to aquatic habitat.

“Basically, as you remove forest canopy you remove the ability to intercept water,” he said.

Interception is the process where water falls onto the tree and evaporates back into the atmosphere.

Forests also suck water out of the soil and put it back into the atmosphere.

“So when you remove those two things, you have the same amount of water coming in, but less going back out into the atmosphere,” he said.

“So more water could potentially make more water for streamflow.”

In the winter, the buffer that the forests provide is similar as snow melts slower when it’s in a forested area.

Increases to streamflow could cause scenarios like opening up more water for streamflow—which is a good thing—but it could also raise the occurrence of floods, while decreasing water quality.

“These changes could effect aquatic habitat, water quality, and create geomorphic hazards, such as changes in channels, channel erosion and potential landslides from when soil gets too wet and loses strength,” said Redding, noting that the problem may not occur everywhere.

“Planners and water purveyors need to be aware of the risks inherent with those potential changes as flooding could have impact on infrastructure if bridges or culverts are sized properly for higher water flows.”

Although Redding can say with certainty that there will be changes, he noted that it’s not possible to point to one specific area and map out the future.

“I can tell you there will be more water, your peak flows will be earlier and your snow’s going to melt faster, but I can’t tell you ‘for this point on the landscape it’s going to be like this’ because the site-specific variability is really high so it’s hard to accurately predict all those things.”

In the meantime, he recommends governments and businesses address the dead forested areas in a variety of ways, and not always turn to clearcutting an deadened area.

When the dead stands stay put, they still have a function in the water cycle by keeping erosion at bay, and providing an interception point for moisture.