First off, a bunch of numbers here to show that statistics don’t lie when it comes to the obvious — trees and plants are dying. Rivers no longer run. Lake levels have dropped. All of which occurs as part of a decades-long drought.
Three quarters of the West suffers from water shortages described as “moderate” with two thirds of that acreage labeled as ‘severe’ shortage, 40% termed “extreme,” and half of that category described as being in ‘exceptional’ drought.
Add in the fact that 80% of the state’s developed water use goes to the agriculture industry and all these aspects contribute to a changing climate, modified seasonalities, temperature zones readjusting, a need for increased research on new rootstock varieties, et al.
Taken together, it’s a daunting and pretty messy picture, one being studied intently by Lauren Parker, researcher at the University of California, Davis John Muir Institute of the Environment and coordinator of the USDA California Climate Hub.
“Presently, the tree nut industry in California is still in good shape with growers facing specific weather events. But having worked in the agriculture and climate space for years now, my professional interests are long term — decades into the future — and when you put that lens on it, the tree nut industry is going to be looking down the barrel of increasing stress from heat, drought, and limited quality water availability with a Sustainable Groundwater Management Act coming down the pipe.
“Perhaps not that many decades into the future, we’re going to see increasing challenges with warmer winters meaning reduced chill accumulation for perennial crops,” Parker says. “Growers are increasingly aware of these issues and the impact of climate change over a long-term perspective.”
With the southern San Joaquin Valley already undergoing water stress issues, fallowing of some acreage has become a topic of discussion. “Not an easy decision," she says. “Do they fallow and replant a few years later? Some intense conversations are going on now with Cooperative Extension personnel about optional cultivars that might better withstand the environment we expect looking a few decades out.”
Almond trees in PNW?
Of specific interest to tree nut readers of Western Farm Press was a comment Parker made to colleagues at the Cornell Chronicle where she said, “As temperatures continue to rise, almond trees could thrive in states like Washington and Oregon.” Understanding that this is logical research conjecture at this point, we wanted to know more.
“One of the big limitations, specifically involving almonds, is the intersection of what kind of climate they like to grow in versus what the future climate will look like,” she said. “The big limiting factor for places like the Willamette Valley — water issues notwithstanding — or the Columbia Basin is frost, because almond trees bloom early in the season and don’t require a whole lot of chill.
“Early bloom and later spring frosts are now quite common in the Northwest making those limitations to cultivation. However, as both winter and spring temperatures keep warming, those two variables, from a plant phonology standpoint, make things more attractive. As climate conditions change, it becomes a question of risk aversion and the cost of trying something new with the potential benefit of a higher value crop versus what else might grow on that land.
“There’s a whole lot of assessment that has to go into play, but looking towards the not-too-distant future, I’d expect to see a few of those kinds of pioneering risk-tolerant folks in the Northwest planting crops that wouldn’t have done so well in climates of the past,” she said.
“In a mid-21st century time frame, almonds will probably stay put, barring more devastating water limitations, but not moving due to any major temperature change. But if you’re talking by the end of this century, you could see some tree nut growing moving further northward as we’re already seeing with some specialty crops there, like wine grapes and coffee beans.”