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Floods in British Columbia’s Fraser Valley in November 2021. Credit: UBC Applied Science
It is time to recognize the power of healthy forests in managing the world’s increasing flood risks and move towards more sustainable forestry practices and policies.
This call is highlighted in an article by UBC researchers. published in a diary Total environmental science.
Hydrologist and forestry professor Dr. Younes Alira and his graduate student Henry Pham synthesized decades of hydrological research, much of which “consistently underestimates the impact of forest cover on flood risk.” I found that “I am evaluating it.”
This has resulted in unhealthy forest management policies and practices.
cause and effect
Dr. Arilla explained that for more than a century, scientists have adhered to “deterministic” analysis. In a strategic board game analogy, this is like looking at each move individually and thinking, “If I move here, I should win.” It doesn’t take into account that the roll of the die, the cards you draw, the actions of your opponent, etc. can all change the game.
When understanding how logging increases flood risk, a deterministic approach considers only logging and attempts to understand its direct impact. However, flood risk is influenced by many things, including the amount of snow on the ground, whether the snow is melting, the amount of rain, and the characteristics of the terrain itself. These factors interact in complex ways over time.
Taking them all into account is called a “probabilistic” approach and provides a better picture of flood risk. It’s like a savvy board game player who considers all variables in the game instead of just one.
“Probabilistic approaches are already well-established in other fields, such as climate change science, and are the most accurate way to assess the impact of deforestation on flooding,” said Henry, a UBC Master of Forestry Science student. Pham said.
Forests can reduce flood risk
Dr. Arilla said this probabilistic framework is designed to understand and predict how much of the 2021 Fraser Valley flooding, for example, could be attributed to climate change, land use change, and logging. said. This approach can also be extended to investigate the causes of flood risk in other cities and regions.
He added: “As forest cover continues to be lost due to ongoing large-scale logging and wildfires, flood risks are increasing in British Columbia alone, including the 2021 Fraser Valley floods and the 2018 floods. If you want to reduce the cost of disasters such as
Pham pointed out that clear-cutting causes more severe and frequent flooding, and such flooding can have severe consequences. “They can negatively impact river ecosystems, degrade local watershed water quality, and cause sediment problems downstream.Further downstream from clear-cut logging, thousands of lives and many ecosystems can be lost. may be affected.”
“Forests serve as the most effective natural defense against increasing global flood risks due to factors such as climate change,” said Dr. Alira. “Now is the time to modernize water and forest management policies. It’s time to start leading,” he concluded. and defensible science. ”
For more information:
Henry C. Pham et al., The Science of Forests and Floods: The Quantum Leap Required, Literally and Figuratively Total environmental science (2023). DOI: 10.1016/j.scitotenv.2023.169646
