Each tree is allowed to have only one limb on each wire, and the limb is headed halfway to the next tree to avoid overlapping limbs. This results in a canopy with minimal structural wood and clearly defined windows.
It’s bloom time at Auvil Fruit Company’s ranch at Vantage, Washington, and manager Del Feigal can tell you precisely how much fruit he intends to harvest from a fifth-leaf Fuji planting this fall.
Feigal carries a calculator at all times, but is adept at crunching numbers in his head.
The trees are 18 inches apart, leaning in alternate directions on a V trellis with eight wires on each side. Each tree has just two limbs positioned on each wire (making 16 limbs per tree). Each limb will bear two apples, and each section of trunk between the wires will also bear two apples. That’s 48 apples per tree, multiplied by 2,420 trees per acre, which makes 116,160 apples (1,800 boxes of size 64) per acre, or around 80 bins.
He knows that each limb will produce exactly two apples because a crew goes through during bloom removing all but the best two blossoms by hand.
With Gala on the same system, he might increase the tonnage to 100 bins per acre, just by leaving one more apple per limb. The target size for that variety is 72 to 80.
Having what he calls an “organized canopy” with almost identical trees is the key to such predictability. An organized system also makes it easier to train workers during thinning and pruning, he said, “But the biggest thing is to dial in the fruit numbers you want for the fruit quality you want.”
He starts out by planting bench grafts, which gives him the ability to grow the trees right from the start in the orchard and place limbs precisely where they’re needed. “We’re in the driver’s seat,” he said.
He uses Mark rootstocks because trees on Mark grow faster in the juvenile phase than trees on Malling 9. They are also more precocious and more forgiving of being overcropped. Starting with bench grafts avoids one of the problems with Mark, which is that nursery trees tend to suffer transplant shock, he said.
The drip irrigation system and the first five wires of the trellis are installed before the trees are planted by hand with the bud union six to eight inches above the ground. Distance between rows is 12 feet.
About two months after planting, when the root systems are established, kite string is stapled to the base of each bench graft (using a desk stapler) and fastened vertically to the trellis wires. As the leader grows, it is taped to the string for support. A supported central leader grows faster than one that has to grow stocky to protect itself from the wind, Feigal noted.
As soon as the central leader grows past the bottom wire, a crew applies Promalin (benzyladenine and gibberellic acid) to encourage branching. One branch on either side is kept and taped along the wire. The rest of the branches are pruned back when they’re four to six inches long. This is repeated as the leader approaches each wire.
“We’re trying to grow the leader as a fruiting pole,” Feigal explained. “We don’t allow limbs off of it except at the wire.”
A trained “nursery” crew goes through the planting every two weeks to work on the trees. “Throughout the summer as we’re tree training, we’re summer pruning and removing or heading back unwanted limbs so they don’t become limbs. We try to build the structure that we want.”
Most of the nursery crew members are wives of year-round employees. Feigal finds that the women like the summer work and tend to be particularly attentive to details. A different crew goes through the young blocks every week doing nothing but apply Promalin.
Feigal said he used to allow extra limbs to grow from the trunk between the wires to increase early production, but there were drawbacks. Tree training cost more. And, often, those limbs would bear fruit for one or two years and then need to be removed so as not to sacrifice fruit quality in the bottom of the tree because of shading. Also, additional limbs detract from the overall growth of the tree, so it took much longer for the tree to reach the top wire and fill the space.
The limbs trained along the wires are headed when they grow halfway to the next tree, so there is no overlapping of branches from neighboring trees. Feigal said he used to allow the limbs to cross, but it made it much more challenging to balance the crop load because one limb on the wire might end up with all the fruit and the other limb none. Consistency from tree to tree is critical because it makes it easier to instruct workers. Shoots on the limbs are removed, which keeps the limb caliper small.
The limbs are permanent. “Limbs on the wires are there for the life of the system,” he said. “Only the spurs are rotated.”
As soon as the limbs are established and fill their space, Feigal applies the growth regulator Apogee (prohexadione calcium). Without Apogee, he could not be as detailed and aggressive with the pruning, he said, because the trees would respond with unwanted vegetative growth.
Although the trees have minimal structural wood, the fruit is positioned in such a way that it is protected from direct sun. The apples hang underneath the foliage along the wires, where the light is filtered.
With a strong-growing variety like Fuji, Feigal aims to have the trees reach the fourth wire and fill half the space in the first season. Tree growth is monitored and if it is less than four to six inches a week, he modifies the water and nutrient regime.
During the first summer, the top three wires of the trellis are installed and another string is attached to support the leader as it grows up to the top wire. For trees that grow weakly, he mounds soil up around base of the trunk to encourage more root growth. All blossoms are removed by hand during the second leaf.
“Fruit quality on a tree that’s being grown as a nursery tree is very poor,” Feigal reflected. “It’s not worth the money you put into it, and fruit does take away from the vigor of the tree. I don’t want vigor taken away because I still have my space to fill.”
The goal is to fill the space in the second leaf, and crop the trees in the third.