How forestry affects the snowpack and moisture has been the subject of study for years, but new techniques are giving foresters and researchers a more accurate picture.
Two research projects were the subject of a public meeting at Selkirk College’s Grand Forks campus on May 2, hosted by the Kettle River Watershed Advisory Council. Two guest speakers led talks on their research projects: Kim Green on hydrological modeling in forest management and Cydney Potter’s research looking at LiDAR to study peak snow water storage in the environment to monitor forest recovery and regenerating stands.
Last February, the council discussed some forestry-related subjects it wanted to feature in public meetings and these were voted on, explained RDKB watershed planner Kristina Anderson.
“This is to help bring more awareness and education to the public,” she said at the beginning of the presentation. “I’ve been really excited to see this and it shows the research component that is tied to forestry management.”
First to speak was Green, who presented her research on hydrological modeling to support forest management and working outside the equivalent clearcut area (ECA). Her research looks at site-specific watershed conditions, simulating land cover, tying in climate change and providing estimates in hydrological change.
Forest management often uses geographic information systems, (GIS), which she said provides a general understanding of what impacts to the environment occur during “disturbances,” including harvesting, fires and replanting practices.
“The outcomes of these types of assessments are based on a general understanding that impacts can occur given some level of development in a watershed,” she said.
They also use ECA, which she described like bookkeeping. The problem with current ECA modeling is it treats all watersheds as equal, she said, which they are not.
“We have to ask, is this treating all watersheds as the same box?” said Green. “There’s a real problem doing our watershed assessments this way. We’re not getting the information we need to understand different watersheds.”
To help solve this problem, she’s been using hydrological modeling, which is a math-based algorithm using data to predict and monitor how water moves through a watershed. They can more accurately determine the effect of a disturbance, be it logging or a fire, in individual watersheds.
This isn’t new technology, said Green. BC Hydro has been using it for years to monitor the province’s water supply. This is the first time it’s been used in forestry planning.
Using a mature forest stand as an example, Green talked about how much snow makes it through the branches of the trees to the ground, which is a natural process. Clear that stand then there is much more precipitation making it to the ground. As well, there is no longer shade slowing the snowmelt. Therefore, two major processes are changed because there are no longer trees upholding them.
They take data from daily precipitation, input it into the algorithm and use it to move water through the streams and rivers of the watershed. The simulations are constantly tested for accuracy, Green said.
The results have been exciting, allowing planners and researchers to look at smaller areas more accurately. The hope is forestry can use hydrological modeling to move from the current inventory-based planning, to more risk management.
Another innovative research project was presented by Potter on her research using LiDAR to monitor the snowpack changes that come from disturbances more accurately, which she said complements Green’s research.
As part of an ongoing multi-year study, starting in 2019, she and her research team were looking at how recovering and juvenile stands affect the snow water melt of an area. Such research was conducted by taking snow tube samples. This is often challenging field work, with a lot of manual labour and physical variables that need to be accounted for. Her team acquired a quadcopter-type drone equipped with a LiDAR camera to fly over sites to take laser measurements.
Data collected has been far more accurate, Potter said, even as technology has improved over the years.
“We can actually see the layers around trees and separate them,” she said. We’ve also been able to take data and combine it as technology improved to get a more detailed picture of the forest canopy and ground.”
Some results have already been fascinating. She discovered the snowpack is significantly affected by the age and height of the trees. Young trees, around three to five feet tall, tend to cause faster snowmelt due to their proximity to the ground. Snow accumulates around the trees, then the trees absorb heat from the sun, causing faster melt. However, as the trees mature, they hold more snow in their branches and provide more shade, slowing snowmelt.
This could mean forestry planners may want to rethink the location and size of a harvest and replant, she said, knowing how the age of trees affects snowmelt.
While these research projects have been informative, Potter, Green and Anderson all stressed this doesn’t mean planning should be mostly computer-based in the future. There is still a need for field work to collect on-the-ground information for accurate planning.
