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 Fruit and Shade Trees:
Cold Season Damage

Joan Shaw

Oyster Stew, one of the special ops in charge of rodent control

As the leaves turn color at DragonGoose Farm and the early morning frosts become more frequent, our thoughts here turn to heading off the damage we could be facing by next spring -- from rodents, ranging from tiny voles to gophers; from deer that make their home in the river bottom below us; from sun scald caused by extremes in temperatures that damage bark and, by extension, the limbs above this damage; from temperatures plummeting to thirty or more below zero during a possible harsh season; and from an "open winter " without enough snow in the  mountains to recharge the watersheds for summer irrigation.

The Feline Special Operations

Our first line of defence against rodents is the collection of cats we 've accumulated from pet owners who feel the country is a good place to toss out their unwanted kittens. Our daughter, Melanie, has taken it upon herself to capture as many of these drop-offs as she can in order to take them to the vet to be spayed or neutered. She then cares for them until they recover, and makes sure they have shelter and food available if they care to stick around. Some of them become tame and playful, sheltering under the porches and in The Granary garage during the winter, and others take off running after their ordeal, becoming shy and feral, and sheltering in burrows in the slopes and hills surrounding our property. Feral and tame, we call them all our Special Ops in Charge of Rodent Control, a member of which is our friendly "Oyster Stew," pictured above. This crew does an excellent job of holding down the rodent population and, together with white plastic trunk protectors that Melanie puts on the more vulnerable, smaller caliper trees, they cut down the damage our resident voles inflict when they circle trees during the winter, chewing off the bark as they go, and creating a "girdle" of barkless trunk around the bottoms of the tree.

This girdling cuts off the necessary flow of nutrients that travel through the bark from the roots to the top parts of the tree. A girdled tree often leafs out in the spring and may even set flowers from what nutrients remain in the bark from the girdling damage upwards, but eventually the tree succumbs as the season progresses and these stored-up nutrients die out. We have, in the distant past, worked on several of the smaller girdled trees by "bridge-grafting." This grafting is done by cutting some green-wood twigs very early in the spring, slicing a two or three-inch section of them slantwise on each end, and pushing the raw cut flat under the remaining bark above and below the girdled trunk. In the best of all possible worlds, the process fuses the bark of the twig with the bark of the tree so nutrients from the roots have a roadway, albeit a narrow one, up to the top of the tree. This should be done every inch or two around the trunk and as soon as possible after discovering the girdling. Out of perhaps five bridge-grafted trees that we worked on, we managed to save two.

The burrowing Gophers

Gophers also do horrific damage to sometimes quite large trees, by burrowing underneath them and loosening the soil around their root systems. Then, thanks to the opportunistic voles, the bark is eventually stripped off far below ground level. We lost two mature 'Calville Blanc' apple trees to this type of damage, which was so deep into the roots there was no question of trying a bridge graft. In fact, we lifted these ruined trees right out of the ground thanks to the gophers.

'Calville Blanc' is an antique variety that has been cultivated since the 1500s. The tree bears green, rather lumpy, gourmet-type cooking and eating apples, and the two trees we'd planted eight years before had just begun to bear heavily. The loss was a painful one and, though we've replaced them, it will be many more years before the replacements will reach bearing age.

Though gophers are bigger than field mice and voles, I've often found the remains of a gopher discarded by one of our vigilant crew of felines. We humans, though, must do the largest part of the work in the case of gopher damage. A stream of water directed into the holes will discourage them, or drown them, and tilling up their burrows sends them elsewhere, too. Traps are messy and seem so cruel and bloody we seldom go to the trouble, but the noise of mowers, and other machinery seem to lower the numbers of gopher hills around here.

Gopher bait is a last resort, and I've managed to wipe out a unmanageable colony of them in a long iris bed which looked, at the time, like a low mountain range. To keep the gopher bait from the birds, I poured the pellets inside foot-long lengths of 1.5 inch pvc pipe and placed them by gopher excavations that looked more or less recent. Then I had the iris corms dug out and put aside so we could till the bed from end to end with the tines set as deep as they would go. Finally, we replanted the iris corms.  I once had these iris neatly distributed in clusters of whites, reds, and deep blues. I'm anxious to see next spring what kind of conglomeration of blooms has come out of this upheaval

The Nibbling Deer

Often, when coming up our drive in the car in the evening, we're surprised and even charmed by a deer or a group of deer bounding gracefully down the hill from the upper lawns and beds into the lower pasture bordering the river. At the same time, we feel naturally anxious about what they might have been feeding on up there. Our bigger south orchard is protected by an eight-foot-high fence, but the younger north orchard's trees are still vulnerable, as are the smaller ornamentals and younger trees and shrubs in the open parts of the gardens.

Melanie is the manager in charge of apple tree winter protection. Since the occurrence of that heavy damage to our bigger apple trees from the voles and moles, she's overseen the short coverings of ribbed sewer pipe at ground level on the larger trees and expandable white sleeves on the trunks of the smaller ones. The younger, unfenced trees up north she covers with white sleeves on the trunks and light burlap coverings to deer-nibbling height to protect the limbs, and also to keep them from being torn off by hungry deer as they browse.

Damage from deer rubbing antlersBy far the worst damage, however, is from rutting deer rubbing velvetPear tree damage from deer rubbing antlers
off their antlers in the fall. Pictured to the right and left are two examples of damage to unprotected pear trees from this activity. This damage stops the flow of nutrients above the wound, resulting in limb death and general loss of vigor. If the deer locks horns with a small tree for a bit of practice combat,  he can shred the tree to ribbons or tear it completely out of the ground.

Below, to the left, is the damage done to a Fuji apple tree from antler-rubbing. Notice the weak and damaged limbs above the rubbed-off bark. This Fuji was just outside the protection of the deer fence around the main orchard and therefore vulnerable to the browsing and combative deer. Too late, we realized that its trunk, at the least,  should have been covered with a protective sleeve.

Deer damage on apple tree showing resulting weakened limbsThe Merciless Sun  – and Frost

 Here is an insidious bit of damage that fooled us into thinking some of our apple trees in the fenced-in orchard had a disease that was killing off limbs and producing small apples. An Extension Agent from Utah State University here in the valley, Loralie Platero, took a look at the damage we were puzzled about and told us it was not a disease, but the effects of Sunscald.

This type of damage occurs here in the winter when the temperature at the surface of young, thin-barked trees can plunge at night to as low as minus thirty -- in occasional years to minus forty -- and then shoot up during the following afternoon to as high as eighty degrees above. Bark located on the south and southwest side of the young trunk is most vulnerable to these constant extremes in temperature. The repeated  shrinking and stretching resulting from such extremes of temperature eventually destroy the intercellular structure of the cambium, separating it into raw wounds on the trunk. This broken bark, in turn, interferes with the flow of nutrients upward through the cabium, as with the wounds from rutting deer. To the right and below is a Healed sun-scald scar on Red Boxelderlong-healed sunscald scar on a Red Boxelder tree, now with the thick, corkier bark of a ten-year-old tree and, happily, immune to Sunscald.

Our agent, Lorelie, suggested painting our orchard trees on the south sides of the trunks with white latex paint. We've been more careful in recent years in covering our ornamental and young shade trees outside the orchard in white expandable trunk protectors to guard against voles and deer, so we've serendipitiously protected them against sunscald, too, without realizing it. Interestingly, the spring we noticed so much damage to our apple tree limbs followed the winter we were lax about covering the entire trunks of these trees with their expandable white plastic protectors.

The Reluctant Precipitation

    Poor drainage, poor apple trees -- Our central area of Cache Valley  was covered by the Cache Bay of prehistoric Lake Bonneville which covered a large part of the state of Utah. Over the millennia, the constant washing away of the mountains surrounding this ancient bay by rain deposited a deep layer of fine silt in the central portion of the Lewiston area. Because of the enormous weight of the water above it, this sediment was subsequently pressed into an impermeable layer of clay (called hardpan) some hundreds of feet thick. Lake Bonneville and its associated bay is long gone, but its effects shape Lewiston's soil and agriculture.

Although Lewiston's sandy loam is fertile, permeable, and easily cultivated, the underlying hardpan created millenia ago supports a water table, that measures as shallow as ten inches below the surface. And, although the water table drops seasonally, and in areas measures as far down as sixty inches, it is still rather high for the roots of apple trees which can't stand wet roots. Apple trees planted by early settlers there did poorly, often dying from a lack of oxygen.

    On the other hand -- DragonGoose Farm, located on the edge of a cut bank formed in the past by the Cub River just below us, has loam that goes down, in some areas, to seven feet or more, with the loam above it superbly permeable and well suited to apple trees. This excellent drainage is fine during normal water years, but it puts the more deep-rooted trees in danger of the opposite problem -- drought.

    Drought -- We've been plagued by more than five years of drought or near-drought in Utah, including our own Cache Valley in its northernmost end. Cache Valley's average precipitation (in the form of either rain or snow melt) is 17 inches from October 1 to the following September 30, called the Water Year. This amount is enough to keep the surrounding watersheds charged for summertime irrigation from the canals and ditches criss-crossing the valley. When precipitation falls much below 17 inches a year, however, and when these precipitation-poor years continue for as long as they have recently here in the valley, our watersheds cannot produce enough water through the summer to produce crops.

In the case of apple orchards, the lack of water goes a long way toward reducing apple production as well as weakening the trees. In the fall of 2001, for instance, our irrigation water -- geared to Lewiston's alfalfa and grain producers -- was cut off on September 9, not allowing a last, thorough watering to carry the apple trees over the winter. This year, expecting something like the same early cutoff, and having in the meantime put in an underground sprinkling system in the larger orchard, we managed to keep the apple trees hydrated well enough to feel they'll survive the winter in good shape. This season's apple crop, nevertheless, could have been much better, and the lack of water over what turned out to be a fairly harsh winter, only tended to exacerbate already existing problems like Fireblight, Sunscald damage, and late frosts.

So we, with other farmers in the area, not to mention the army of dedicated skiers in our midst, are praying for a very snowy winter and a good show of spring rains.

After all, the drought can't go on forever,

Joan Katherine Shaw
August 2002

Photos by Joan Katherine Shaw

Additional pages on DragonGoose trees

Living with a Venerable Tree
Cold Country Apples
Apple List

Online sources for apple tree catalogs and online ordering:

Rocky Meadow Orchard & Nursery
Sonoma Antique Apple Nursery
Cummins Nursery

Books on Repairing Tree Damage:

American Horticulture Society Pruning and Training (This book has received tremendous reviews from gardeners, which isn't surprising since the AHS is the definitive organization for American gardeners)
Arboriculture, Richard W. Harris, et al. (A wonderful compendium of the totality of tree care, though pricey)
Manual of Woody Landscape Plants, Michael A. Dirr (Damage,care, and repair of nearly 2,000 woody plants are discussed in this concise reference work)
Pirone's Tree Maintenance (I have the sixth edition of this book and wouldn't be without it)

Helpful books on apples and apple growing:

Apples for the 21st Century, Warren Manhart
The Book of Apples by Joan Morgan and Alison Richards
The Apple grower , a Guide for the Organic Orchardist, by Michael Philips
Apples by Roger Yepsen

Link to browse for apple books:

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