Taking A Hard Look At Whither Pruning Almonds

Whither PruningAlmond growers have traditionally pruned their trees, and the practice went unquestioned for many years. Perhaps it was a holdover from caring for fruit trees, says University of California Cooperative Extension farm adviser John Edstrom. After all, many of the state’s original almond growers started as peach growers, and the trees are closely related. However, many of the very good reasons for pruning peach trees simply don’t apply to almonds. Peach growers prune their trees mainly to increase fruit size and improve color, neither of which apply to almonds. Edstrom has now been studying the issue for nearly a quarter of a century, and he’s convinced that when it comes to yield — the primary reason almond growers prune — there’s no advantage to pruning. The first pruning trial was planted at the Nickels Soils Lab in Colusa in 1979. Edstrom and his colleague Bill Krueger took over the trial in 1984, and at the time he too thought pruned trees would fare better. But not any more. “The yield was at least as high, and certainly no lower, in the minimally pruned trees,” he says. “It’s a shocking piece of data in almond culture.” Many growers have remained skeptical, especially since the original trial was on a high-density (7 feet by 22 feet) hedgerow block with questionable soils. So in 1997 he planted a second trial to better reflect the state of the industry. It was planted in good soil with a more standard spacing of 16 feet by 22 feet and irrigated with microsprinklers. “It’s a nice, strong orchard by any standard,” he says. “And it too showed that minimally pruned trees yield at least as well as traditionally pruned trees.” (See chart.)

Minimal Vs. Unpruned

While many growers use the term “unpruned,” Edstrom is quick to note that’s not entirely true. After the first leaf, it’s important that an almond tree is pruned during dormant season. This pruning is mainly for limb training, he says. Three or four primary limbs are selected, and all competing limbs are removed to provide the tree with a sound structure. After that initial pruning, however, the trees are left alone. Edstrom adds that it’s not just the trials he and Krueger have performed that bear out his conclusion. His Cooperative Extension colleagues have conducted similar trials throughout California almond country, and have garnered similar results. Edstrom understands why growers are skeptical; he himself once was. He thinks a lot of it stems from the fact that a pruned block of trees looks a lot cleaner and better-maintained than a block that hasn’t seen pruning shears in many years. “People will get embarrassed if their trees don’t look as good,” he says. “But it’s hard to argue with the facts.” Yet another fact is that pruning obviously costs more than simply leaving the trees alone. In addition, growers who prune have to dispose of the clippings, says Edstrom. While in the past that wasn’t that big a deal because they could simply be burned, air quality regulations have been instituted in recent years that prohibit burning in many areas.

Take A Hard Look

Some growers still insist that they need to prune to let in light so the lower fruiting wood doesn’t get shaded out as the trees age. However, if that were a big concern, Edstrom thinks the minimally pruned trees in his original trial would have started yielding less than the pruned trees. He understands the concern, however, and will continue to monitor the trees carefully as they age. “How much light do we need to maintain? We really can’t say for sure,” he says. “But my hunch is that it’s really not going to turn out to be that big a deal.” Edstrom emphasizes that he doesn’t want to be so presumptive as to simply tell growers not to prune. However, he’s heard many reasons for pruning, and most of them don’t hold up. According to Edstrom, growers shouldn’t prune just because: – Your trees look better. – Your labor contractor recommends you do it. – The grower across the street does it. – You’ve always done it. Instead of looking at the issue from that angle, Edstrom suggests growers take the opposite approach. “You need a strong reason to make a pruning cut,” he says. “Think about it before you do it.”

Topics: ,

Leave a Reply

Nuts Stories
Nuts
April 10, 2017
Study Shows No Harm in Wildflower Plantings Near Almond Orchards
While conventional wisdom may suggest having more than one forage opportunity may detract from bee activity, research shows planting wildflowers boosts bees interest. Read More
Crop Protection
March 31, 2017
New Product Offers 2-in-1 Insect and Disease Control for Specialty Crop Growers
Crossover Pro offers early protection from insects, powdery mildew, rust, and leaf blight. Read More
Nuts
March 30, 2017
Lichens Thrive in Your Orchard During a Wet Year
Above average rainfall has created the perfect environment for growth. Read More
Nuts
March 28, 2017
How to Determine Optimal Almond Tree Spacing
Determining the proper row spacing for an orchard should be based on more than production and equipment access, and growers should also ponder the number of trees per row. Read More
Irrigation
March 26, 2017
Tips to Maximize Water Efficiency in Your Almond Grove
Editor’s note: Spencer Cooper joined the Almond Board of California last fall as Senior Manager, Irrigation and Water Efficiency. Western Read More
honeybees
Citrus
March 25, 2017
New Videos Offer Tips on Planting Pollinator Habitats
A new video series on planting flowering habitats is designed to help growers support crop pollinators. Read More
Nuts
March 24, 2017
Foreboding Fungus Vexes Almond Growers
In parts of California, almond growers have recently become concerned about Ganoderma root and butt rot. To put this concern Read More
Nuts
March 15, 2017
Efforts to Thwart Nut Thefts Ramping up in California
Ordinance revisions to end cash sales, include a 10-day hold on payments. Read More
Crop Protection
March 10, 2017
Nematicide Now Available in California, Arizona
Velum One from Bayer also suppresses foliar diseases, increases yields. Read More
Nuts
March 6, 2017
Almond Board of California Announces Board of Directors
The 2017 Board of Directors kicked off March 1. Read More
Citrus
February 28, 2017
Trump Set to Ditch Controversial Water Rule
WOTUS could be on the way out after an executive order calls for a top-to-bottom review. Read More
Nuts
February 27, 2017
Using Drones To Scout Almonds From Above
At California State University, Fresno, scientists are studying how drones can save almond growers water — and help them use less labor too. Read More
Mycelial fans armillaria root rot
Nuts
February 27, 2017
Getting to the Root of Devastating Stone Fruit Fungus
Armillaria root rot is a death sentence for trees and replant sites; however, researchers are looking to breed fungus-resistant rootstocks to make replanting economically feasible. Read More
Florida potato field in bloom.
Citrus
February 22, 2017
New Insecticide Available to Combat Sucking, Chewing Pests
Minecto Pro from Syngenta has received EPA approval for use in specialty and vegetable crops to control lepidopteran and other pests. Read More
Managed bee hive boxes around a blueberry field
Nuts
February 11, 2017
Beehive Thefts on the Rise
More than 2,000 hives were reported stolen last year from California almond orchards, and growers are cautioned to keep an eye out for unmarked hives. Read More
The Latest
Nuts
April 27, 2017
Keep an Eye Out for Phytophthora in Your…
After several years of drought conditions, increased water salinity, and a wet winter, your nut orchard may be more susceptible to root rot than you think. Read More
Citrus
April 26, 2017
Perdue Sworn in as Ag Secretary
USDA launches Twitter account to help promote the industry. Read More
GenNext Growers
April 22, 2017
Next Generation of Leaders Gets Yearlong…
Almond Leadership Program enters its ninth year with the 2017 class. Read More
Nuts
April 10, 2017
Study Shows No Harm in Wildflower Planti…
While conventional wisdom may suggest having more than one forage opportunity may detract from bee activity, research shows planting wildflowers boosts bees interest. Read More
Crop Protection
March 31, 2017
New Product Offers 2-in-1 Insect and Dis…
Crossover Pro offers early protection from insects, powdery mildew, rust, and leaf blight. Read More
Nuts
March 30, 2017
Lichens Thrive in Your Orchard During a …
Above average rainfall has created the perfect environment for growth. Read More
Nuts
March 28, 2017
How to Determine Optimal Almond Tree Spa…
Determining the proper row spacing for an orchard should be based on more than production and equipment access, and growers should also ponder the number of trees per row. Read More
Irrigation
March 26, 2017
Tips to Maximize Water Efficiency in You…
Editor’s note: Spencer Cooper joined the Almond Board of California last fall as Senior Manager, Irrigation and Water Efficiency. Western Read More
Citrus
March 25, 2017
New Videos Offer Tips on Planting Pollin…
A new video series on planting flowering habitats is designed to help growers support crop pollinators. Read More
Nuts
March 24, 2017
Foreboding Fungus Vexes Almond Growers
In parts of California, almond growers have recently become concerned about Ganoderma root and butt rot. To put this concern Read More
Nuts
March 15, 2017
Efforts to Thwart Nut Thefts Ramping up …
Ordinance revisions to end cash sales, include a 10-day hold on payments. Read More
Crop Protection
March 10, 2017
Nematicide Now Available in California, …
Velum One from Bayer also suppresses foliar diseases, increases yields. Read More
Nuts
March 6, 2017
Almond Board of California Announces Boa…
The 2017 Board of Directors kicked off March 1. Read More
Citrus
February 28, 2017
Trump Set to Ditch Controversial Water R…
WOTUS could be on the way out after an executive order calls for a top-to-bottom review. Read More
Nuts
February 27, 2017
Using Drones To Scout Almonds From Above
At California State University, Fresno, scientists are studying how drones can save almond growers water — and help them use less labor too. Read More
Nuts
February 27, 2017
Getting to the Root of Devastating Stone…
Armillaria root rot is a death sentence for trees and replant sites; however, researchers are looking to breed fungus-resistant rootstocks to make replanting economically feasible. Read More
Citrus
February 22, 2017
New Insecticide Available to Combat Suck…
Minecto Pro from Syngenta has received EPA approval for use in specialty and vegetable crops to control lepidopteran and other pests. Read More
Nuts
February 11, 2017
Beehive Thefts on the Rise
More than 2,000 hives were reported stolen last year from California almond orchards, and growers are cautioned to keep an eye out for unmarked hives. Read More