Tree Precocity Reframing Debate on Double-Density Hazelnuts

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Jeff Newton in a nearly four-year old PollyO orchard planted at double density at Christensen Farms near Amity, Oregon. Newton, farm manager, said he is a firm believer in the merits of double density planting (photo by M. Lies.)

Jeff Newton, farm manager at Christensen Farms near Amity, Ore., is a firm believer in double-density planting of hazelnuts. Even with today’s more precocious varieties and new emphasis on inputs that push a tree to maturity well ahead of the days when he started on the practice, Newton believes it is beneficial.

“With irrigation and high nutrition, we’re pulling them away earlier now than we used to, so the economics of it are changing, but I am still a believer in double density and I have been for many years,” Newton said.

South of Christensen Farms near Albany, as Jimmy Lee prepares to take out temporary trees in an orchard planted to the Jefferson variety, he wonders whether it was worth it to go with double density, particularly given the rock-bottom prices hazelnuts have brought the last two years.

“Looking back, maybe I would have done single density,” Lee said. “If the nut price was higher the last year or two, it probably would have been better. But it’s a pretty large expense to take the [temporary] trees out.”

Opinions on the merits of double-density planting are nothing new in a hazelnut industry that has debated the pros and cons of the practice for decades. And with new varieties pushing out faster than old varieties, the debate has been reframed.

Lee, for example, said he was expecting to get 10 years out of his double-density system. Instead, he is taking out the temporary trees after just eight years.

“We just harvested eight-year-old trees and they are already shading out one another,” Lee said. “The college said we’d probably have 10 years of double density, but with the amount of irrigation and how well the trees have performed, we’re thinking it’s time to take them out now.”

Lee was able to double his yields in the Jefferson orchard in years four through eight, which, given the price over that span and the expense to plant and take out the temporary trees, makes the economics of the practice “about a wash,” he said.

Lee also went with double density on 200 acres he planted to the Yamhill variety, which is a smaller tree than Jefferson. On those acres, he plans to keep in the double planting and hedge the trees.

“I just decided that for me, I don’t have the best ground in the world, so my trees are never going to get super big,” he said. “And I’ve got a big double-headed sickle machine that makes it pretty easy to hedge, and I have a big shredder I can shred all the brush with, and we’re burying the drip lines so we can really mechanize farming hazelnuts and get away with less labor.”

Lee, who also grew clover and grass seed crops between the rows of his tiled ground for the first four years of the orchard, believes the hedging system will generate better and more consistent yields, providing he can keep the sunlight interception high with pruning techniques.

‘Pretty Smart Practice’
Nik Wiman, orchard specialist for Oregon State University Extension, said in most cases, going with double-density planting, essentially a 10’ x 20’ or 9’ x 18’ spacing, can be beneficial.

“It’s a pretty smart practice because if you think about how slow hazelnuts come into their maturity and that for the first years of an orchard, you’re just waiting for the canopy to fill in and produce nuts, it makes sense to fill it in by planting extra trees and reap rewards earlier in terms of nut yields,” Wiman said.

But there are drawbacks, Wiman said, particularly when growers start without a clear plan for when and how they are going to remove the temporary trees.

In many of those cases, he said, growers have shown a reluctance to remove the temporary trees in a timely fashion.

“And you need to do that,” Wiman said, “because the trees start to compete with each other and, on a per-tree basis, the production will start to decrease. And if you wait too long, it could have a permanent effect on their growth form. So, there can be repercussions for waiting too long. And right now, a lot of growers are facing this dilemma because in the final years of double density, the yields get really good, and when you take out the temporary trees, you are probably going to see a yield reduction. But we only expect that to last a season or two before the permanent trees fill in that open space and they get back to where you were in terms of the production.”

Newton incidentally noted he has not encountered yield reductions in the year following removal of his temporary trees. “I’ve had orchards that go up in yield the year I take them out,” he said. “And at worst, your yield will flatline the year you take them out.”

Also at issue, Wiman said, the old model that OSU used for its enterprise budget for double density assumed nine or ten years before a grower needed to remove the temporary trees. That is no longer the case given the more aggressive growth brought on by today’s varieties and growing practices.

“I think people are finding they are surprised at how fast the trees are coming into competition,” Wiman said.

Changing Economics
Another factor driving double-density planting of late, Wiman said, is a changing economic model. “The old-school way was planting trees 22 feet apart and letting your grandkids reap the benefits of that orchard,” Wiman said. “Today, people tend to have a shorter-term outlook and need to have cash flow earlier on.”

Employee Dennis Schlegel removes eight-year-old Jefferson trees in a hazelnut orchard planted to double density at Third Knight Farms in Albany
(photo courtesy Jimmy Lee .)

Also, Wiman said, the old-school thought process was based on leaving orchards in place for multiple decades, sometimes 100 years. That’s not the current school of thought.
“Precocity is really the driving force for going high density and getting more returns out of the orchards sooner,” he said. “We are seeing a lot of that going on in Europe and Chile and elsewhere in olives and tree fruits and tree nuts. They’ve gone to high density production and figured out they can compete with a mature orchard much sooner than in the past.”
The main drawbacks to double-density planting have always been the expense and labor involved in planting twice as many trees and removing half of them. But Newton pointed out that at times growers overplay the extra expense. He noted the extra cost for trees isn’t outrageous. And, he said, a double-density system basically takes the same amount of inputs as a single-density orchard.

“You’ve got $6 trees to start with and you got a little sawdust,” Newton said. “But the irrigation and fertilizer all cost the same, and unless you have a smart sprayer, no matter how many trees are out there, it’s the same rate of Roundup you’re putting out.”

And, Newton said, with the right kind of equipment, a grower can take out the extra trees without too much expense. At Christensen Farms, for example, Newton uses a brush grinder and stump grinder to remove the trees and puts the residue back in the soil.
Newton also aggressively prunes back growth on his temporary trees in the final years before removing them, a practice that boosts sunlight interception and reduces the amount of brush needed to remove when taking out the trees.

“The bottom line is I firmly believe in double density,” Newton said. “Even where I’m growing them fast and the timeline is getting down there to where the feasibility of double density is more questionable, I still believe in it. And once the price goes back up, it will definitely be worth it.”