Perennial Agriculture in the Northwest

Much of the Northwestern US has a Mediterranean-like climate, with wet winters and dry summers, making the region ideal for perennial fruit and nut cultivation. Nearly one quarter of the land area in the Northwest (Oregon , Washington, and Idaho) is devoted to agricultural production, contributing to ~3% of regional GDP. The Northwest is also a leader in specialty crop production, producing the majority of the nation’s apple, pear, and cherry crops, as well as virtually all of the US-grown blackberry, raspberry, and hazelnut crops. These crops collectively account for more than $2.5 billion in  production and sales.

While short-term climate change may increase orchard productivity, changes in the geographic distribution of climatically suitable cultivation locations over the mid-term have been less explored. Not only might climatic changes shift the geography of suitable cultivation locations for current Northwest perennials, but may also allow for crops (e.g. almonds) that are currently limited to more southerly latitudes to expand into the Northwest.

This work calculates horticulturally relevant metrics such as chill hour and chill portion accumulations, heat zones, growing season PET, and dry days per month. In addition, crop-specific metrics are calculated for selected specialty crops, including GDD accumulation, projected timing of chill accumulation, projected timing of bloom and crop maturation, and projected frost risk. Further, this research uses a suitability model to delineate the thermal niche for selected specialty crops under current and future climate scenarios, and pairs these results with additional considerations for assessing site suitability (e.g. irrigation needs). Ultimately, these data will be turned into ‘tools’ with a web-based interface, leveraging ongoing work with the Northwest Climate Toolbox.