Category Archives: Vulnerability

Check it out: Is climate change or forest management causing megafires?

By Sonia A. Hall

Mountainous landscape with smoke billowing up from wildfires

The Bobcat Fire, one of 2020’s megafires that resurfaces the question of whether forest management or climate change is driving these fires.

In response to the recent—and in California, ongoing—megafires, many have been asking whether the cause is climate change or forest management. Erin Hanan wrote a blog article arguing that this is not the right question, because in many cases both contribute to what is happening. The drivers of fire activity are complex, and the relative importance of these different drivers varies from one location and ecosystem to another.

Check out Hanan’s article to explore the five key things we need to know about the causes of the current wildfire problem. Understanding these five things can help us navigate the question of what is driving increased fire activity and, most importantly, can help us determine what can be done to reduce such large fires in the future.

Hot, Dry Summers Take a Toll on Trees in Western Washington

By Patrick Shults, Washington State University Extension

Tops of two conifer trees, one showing dead branches at the very top, with green canopy below

Western redcedar with a dead top as a result of drought stress. Photo: Patrick Shults, WSU Extension.

The coastal Pacific Northwest is home to some of the best tree-growing conditions in the world.  Fertile soils, plenty of rain, mild temperatures, and short dry seasons allow trees to pack on solid growth each year.  These conditions also give them a significant advantage in protecting themselves from insects and disease with tactics like pitching sap to flush out bark beetles, isolating roots infected with fungus, and compartmentalizing wounds.  However, these defenses are only possible when trees can avoid environmental stressors and, given a changing climate, certain stressors are expected to become more frequent.

Trees in this area have evolved to handle an annual dry season and, generally, mild temperatures during that time ensure they don’t suffer too much stress.  However, in the last decade the coastal Pacific Northwest has experienced unusually stressful conditions.  The summers of 2015, 2017, and 2018, for instance, were very dry and also particularly hot, which worsens moisture stress in trees.  While it is difficult to attribute any given year to climate change, climate modeling suggests hotter summers like these may be a new normal, and a drive down I-5 in western Washington will show many trees have already paid a price. Continue reading

Acting to Prepare for Severe Droughts in the Yakima River Basin

By Mengqi Zhao, recent PhD graduate, Washington State University

Collage of three photos, with plants in greenhouse, a dry pond with no vegetation, and a sprinkler over a crop, close up

Figure 1. Under low water availability conditions, the reliability of irrigation systems can be enhanced through strategies that improve water supply when it is needed or reduce water demand. Examples include greenhouses (left), aquifer recharge (recharge pond, top right), and irrigation technology (bottom right). Photos: Mengqi Zhao (greenhouse and pond) and Kay Ledbetter, Texas A&M AgriLife Research, under CC BY-NC-ND 2.0 (sprinkler).

For more than fifty years, individuals and organizations in the Yakima River Basin (YRB) have been working toward improving water availability, especially for agriculture. The mismatch between rainfall (and snowmelt) timing and the irrigation season has focused these efforts on strategies for increasing water storage. However, farmers frequently encounter insufficient irrigation water supply and large demands from agricultural activities, resulting in prorationing across irrigation districts during every severe drought of record since 1970s. In the Pacific Northwest, projected water scarcity situations under future climate change scenarios could increase to 68% of years in the 2080s if no actions are taken, compared to only 14% of years on average historically (Vano et al., 2010).

Facing such frequent low water availability conditions, what methods can improve the reliability of irrigation systems? How might people’s decisions on adopting those methods affect system vulnerability to droughts? The fundamental solutions to these questions rely on strategies that either improve water supply when it is needed or reduce water demand. Continue reading

Forest Insects and Disease – Watching for Weirdness

By Chris Schnepf

Close up of a sapling with sporulating blister rust

Blister rust has to have very high humidity to successfully infect white pine needles. Photo: John Schwandt.

When it comes to climate change, many people focus on raw physics: how much more precipitation or less, the number of frost free days, how many days a year above or below certain temperatures, the length of the fire season, etc. These dimensions are all important to reflect on and study, but it may be that some of the most significant climate change effects could be things we can’t even imagine – what some people might refer to as “global weirding.”  Continue reading

Check it out: New Studies in the Region Discuss Wildfires in the Future and How Fuel Treatments May Affect Them

By Sonia A. Hall

Fire burning up a shrub steppe slope, with a conifer tree in the foreground

The lightning-sparked Carlton Complex Fire in July was the largest in the state’s recorded history, burning 256,108 acres and destroying 322 residences. Photo and caption: Washington Department of Natural Resources, on Flickr, under CC BY-NC-ND 2.0.

Pacific Northwesterners, especially those of us living and breathing in the inland Northwest, expect wildfires every summer. It’s not about if, but about when, where, and how severe they will be, both in forest and rangeland landscapes. As with many other aspects of natural resource management, climate change continues to add a layer of complexity and uncertainty both in terms of the patterns of fire expected in the future, and in terms of the response of land managers. The USDA’s Northwest Climate Hub’s April 2020 newsletter highlighted the findings of two scientific articles that are addressing questions around future patterns in wildfires and what can be done to prepare. Continue reading

An Integrated View of Water Vulnerability Across the Northwest

By Paris Edwards, USDA Northwest Climate Hub

Water systems across the Northwest sustain crops, livestock, ecosystems, people and power production. These highly managed, interconnected networks of rivers, reservoirs, canals, and pipelines are economic mainstays for the region, and play a foundational role in food and energy security and sustaining natural resource livelihoods.

Top photo shows a large city with a snowcapped mountain in the background. The bottom picute shows rolling hills, with stripes of brown earth or green crops, with a town in the middle.

Figure 1. Water vulnerability depends on a combination of hydrology and social resilience. Densely populated subbasins (top photo) face contrasting challenges to sparsely populated and highly agricultural subbasins (bottom photo). Differences may include precipitation variability and dominance of low-elevation snowpack, economic dependence on natural resources, and poverty rates. Photos: Top – Portland, Oregon, Wikipedia user Truflip99 under CC BY-SA 4.0; Bottom – A town in the Palouse, Washington, Lynn Suckow under CC BY-SA 2.0.

However, climate change has begun to challenge water resources by increasing temperatures, decreasing snowpack, and altering the timing and amount of available water (Regonda et al. 2005). Current water management systems are designed around historical norms and trends that are rapidly becoming outdated, due to increasing climate variability and uncertainty about future resources. As a region, we now have to reconsider how best to plan around and adapt to expected change in order to reduce and avoid negative consequences to the overall food-energy-water system and to community well-being. But where is such adaptation planning particularly urgent? We synthesized data from across the Northwest to answer this question. Continue reading