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Hazelnuts in the Pacific Northwest: New challenges and opportunities for resilience

By Charlotte Venner
May 19, 2026

10 MIN READ

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In 1858, an English sailor named Sam Strickland brought the first cultivated hazelnut (C. avellana) to the Pacific Northwest of the United States and planted a tree in Scottsburg, Oregon. As demonstrated by the existence of one native hazelnut species on the West Coast (C. cornuta var. californica), hazelnuts flourish in the gentle climates across Washington and Oregon.¹ Today, these states now produce 6%–7% of the world’s hazelnuts², and Willamette Valley in Oregon, a 3 million-acre valley bordered by Portland to the North and Eugene to the South, grows 99% of hazelnuts produced commercially in the U.S.³

Hazelnuts thrive in moderate conditions and are now growing in a world of increasing extremes. As climate change increases the likelihood of extreme heat, drought, and precipitation, hazelnut crops in the Pacific Northwest could succumb to weather shocks or related blights. Amidst these risks, there are also opportunities for resilience in hazelnut production, primarily related to the plant’s own resistance to hazards and the commitment of those in the region dedicated to preserving and protecting this nut.

The Pacific Northwest: An ideal climate for hazelnuts

The climate of the Pacific Northwest is an exceptionally good fit for Hazelnut cultivation: Oregon State University reports that, “the dominant feature controlling the distribution of commercial hazelnut production in the United States is the moderate climate of the Pacific Northwest coastal valleys.”⁴

Hazelnuts require “a moderate climate with limited instances of harsh weather”, according to the U.S. Department of Agriculture,^5-6 with reliable precipitation, mild winters, and moderate, not-too-hot (20-25°C/68-77°F) summers. Washington and Oregon’s wet winters were consistent enough that, according to Andrew Waring, Global Sales Director at Laurel Foods LLC, “hazelnuts in Oregon have traditionally been produced without irrigation, relying solely on natural rainfall.” The narrow band of temperatures in this region, moderated in part by the Pacific Ocean, is also ideal for hazelnut physiology, keeping plants warm enough in the winter and protected from drying and scorching in the summer.

The Probable Futures map of climate zones at 0.5°C of global warming (Earth’s warming level between 1971 and 2000) shows the typical climate of the Willamette Valley, Oregon: temperate, with a warm, dry summer.

The map of days above 38°C (100°F) at 0.5°C of warming shows how rare scorching days were in an average or cool year, historically:

As the global average temperature rises, the climate of the Pacific Northwest is changing. Extreme temperatures and erratic precipitation are disrupting the stable patterns to which hazelnuts are adapted and introducing climate risks to hazelnut production.

Climate challenges

There are two primary ways that climate swings can impact hazelnut production: By damaging the plants themselves, and by setting conditions in which pests and diseases thrive.

Extreme heat and dryness

High temperatures can inhibit photosynthesis, dry plants out, damage kernels, scald husks, shells, and leaves, and even disrupt growth stages in hazelnuts.^7-8-9 Specifically, when summer temperatures exceed 30-35°C (86-95°F), especially for sustained periods, physiological stress and physical damage can impact hazelnut reproduction and yield.^10-11-12 As global average temperatures increase, extreme heat will become more frequent and sustained in the Pacific Northwest.

Rick Peterson, Vice President of Sales & Marketing at Willamette Hazelnut, reports that, in the Willamette Valley, “weather has trended drier in recent years […] especially summers are drier than historically.” Higher temperatures increase evaporation, dry out soil, and disrupt regular precipitation patterns. At current warming levels (1.5°C of warming), the Willamette Valley is already experiencing more damaging hot days above 38°C (100°F) than in a historic climate. While a cool year may still avoid these extreme temperatures, in an average year, every additional day could impact hazelnut production.

The Probable Futures maps of future warming scenarios confirm Waring’s summation that “trends in Oregon indicate a warmer and drier hazelnut growing environment with sustained heat durations.” We are likely to reach 2°C of warming in the 2040’s, followed by 2.5°C in the 2050’s and 3°C in the 2060’s. Over these warming scenarios, maps show the days above 38°C (100°F) in an average year increasing past two weeks of these high temperatures. In a warmer year, the Willamette Valley could see over a month of scorching heat.

The transformation of this temperate Pacific Northwest climate towards warmer average temperatures can also be seen on the climate zones map. At 2.5°C of warming, the climate of the Willamette Valley transitions permanently from having warm summers to hot summers.

Pests and diseases

Extreme weather associated with climate change can also make it easier for pests and diseases to take hold in hazelnut crops. Some insects, like the Filbert leafroller, have life cycles that proliferate in warmer temperatures.^13-14Michael Severeid, Chief Executive Officer at Willamette Hazelnut, confirms that “following particularly hot summers, Willamette Valley has experienced widespread increases in disease and infestation,” including significant bud rot in the two seasons following 2021’s heat dome in the Pacific Northwest and a 2015 infestation of the Pacific flatheaded borer, a pest attracted to heat-stressed young trees.

Swings in precipitation can also contribute to the spread of the Eastern Filbert Blight (EFB), a fungal disease that is highly destructive to certain hazelnut varieties, causing cankers, branch dieback, and eventual death in some trees.¹⁵ Jay Pscheidt, Oregon State University Extension’s statewide plant pathology specialist, is quoted describing EFB as a “wet weather pathogen,” saying, “If we start having heavy rains, we might see quite an explosion of this. Or it could be really dry. You could go either direction, depending on what the weather’s going to do.”¹⁶ Since the disease was discovered in southwest Washington in the 1960s, it has spread throughout the Willamette Valley, threatening commercial hazelnut orchards.¹⁷

Today, erratic precipitation due to climate change is raising this risk. The early spring of 2026 served as a prime example of this, with conditions swinging between drought that left reservoirs in the Willamette Valley more than 50 feet below normal levels to extreme rainfall that led to flooding and landslides.^18-21 As Peterson says, “Oregon State University has been working on eliminating EFB and tree disease; it is still prevalent in the region and a major concern.”

Opportunities for resilience

Although hazelnuts in the Pacific Northwest are undeniably facing a landscape of elevated risk, this crop may be well-positioned for a resilient future. First, there are some inherent qualities to hazelnuts as a crop that make them climate-resilient. Hazelnuts generally require less water than other crops, and their extensive root system allows hazelnut trees to survive drought better than crops with shallower roots.²² Even as climate change shifts precipitation patterns and increases temperatures, it’s possible hazelnuts could continue to thrive under drier conditions.²³

For those climate hazards that hazelnuts are less adapted to, like extreme heat and rainfall, pests, and disease, there are teams and consortia of researchers identifying and developing adaptive strategies.

Site selection

Site selection can be an adaptive strategy for hazelnut cultivation. Choosing a planting site with soils with good drainage can help protect crops against extreme rain events and flooding.²⁴ For some hazelnut varieties, selecting based on elevation and latitude could also help protect crops against heat and precipitation. Research has found that, for American hazelnuts, habitat suitability is projected to “decrease at lower elevations and latitudes by up to 50% by the end of the century and increase at higher elevations and inland northern latitudes by up to 30%,”¹¹ meaning that a shift to higher elevations and latitudes could help increase hazelnut yield. Resources like Oregon State University’s Growing Hazelnuts in the Pacific Northwest: Orchard Site Selection guide can help farmers looking to relocate or plant a new orchard select a resilient location.

Irrigation strategy and soil management

Peterson states that, while “historically, hazelnuts were dryland farmed,” there are now new irrigation practices, in part “due to weather patterns.” Waring supports this, saying, “the majority of new plantings, even ones that are now 15 years old, have some form of irrigation included in the management practices, most often a low-flow, high-efficiency drip system.” These irrigation systems can help protect crops during hot, dry summers, along with the planting of cover crops in between rows of hazelnut trees to protect soil.²⁶

New varieties

Lastly, new varieties of hazelnut “offer new levels of production, resistance to disease, and earlier harvest periods”, according to Peterson. The Hybrid Hazelnut Consortium, composed of the Arbor Day Foundation, Oregon State University, Rutgers University, and the Nebraska Forest Service/University of Nebraska-Lincoln, has received $3.1 million from the USDA to continue developing next-generation hybrid hazelnuts to expand commercial production in the U.S.²⁷” Already, the development of new EFB-resistant cultivars of hazelnut has helped hazelnut production in the Pacific Northwest.^28-29 At Oregon State University, Dr. Shawn Mehlenbacher is also creating new cultivars for the Oregon industry to develop resistance to EFB.³⁰

Hazelnuts in a changing Pacific Northwest

As climate change reshapes the historically mild climate of the Pacific Northwest, hazelnut cultivation will undoubtedly face rising challenges, particularly tied to heat and precipitation. However, with adaptive strategies to adjust behavior and advance genetic varieties, hazelnuts may prove a resilient crop for a less predictable future.

Charlotte Venner is Content Director at Probable Futures. She oversees written resources and communications across all Probable Futures offerings, working with language to bridge the gap between climate science and culture.

Sources:

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