With A Little Understanding And Fond Effort, Man Can Improve On Nature

"Prune my yard trees?" the old fanner snorts. "Heck, they prune themselves!"

And it isn't just one old farmer. Lots of heedless home owners take the same view. Of course, they are quite right, too. Nature does see to it that trees shed members that have become excessive or shaded out or badly damaged. The forest floor is strewn with kindling wood. But the very fact that Nature does so provide only proves that pruning is necessary. Without question, man can do a better job.

When a tree "prunes itself the resultant stub, or an open scar on the parent member, seldom heals entirely unless it is quite small. Left as an entry for insects or fungus is an exposed area of inner tissues through which invasions will spread for years to come. Through such lesions the tree loses moisture by evaporation, or takes in water where it does not belong, causing decay. The only perfect seal is scar tissue, called callus in trees, put out by the cambium layer. Man's surgery can help callus growth close over more quickly and surely than in Nature's casual sloughing-off process.

To some people unfamiliar with them, trees are mysterious to the point of being untouchable. Many a new owner, aware that his tree is a living organism, flinches from cutting any part of it as he would from operating on his child or even his dog. Trees are much more rugged than dogs or children. They feel no pain, and they will survive a few mistakes. Coupled with some understanding of tree physiology, good intentions can soon be translated into good results.

It is not suggested that home owners go up into their big trees with ladders and ropes. Leave the high work to professionals. But by learning, with your feet on the ground, to prune your young trees and mature ones of the smaller species—say, up to fifteen-footers—you can increase and insure your property's value at small cost. All your trees will take on new interest and meaning for you. A light labor of love today will reward you through many tomorrows. If wielding tools does not suit you, study the art and teach it to a helper. Plenty of people "prune" their own trees with a bamboo pole for a pointer.

"Close contemplation of a great tree can arouse animal awe, if not reverence " (The author contemplates the Mercer Oak on the Prince ton battlefield.)

EXPOSING ROOT SYSTEMS

White Oak Root Systems.

Two small specimens (Nos. 17 and 18) in Professor Benjamin B. Stout's root study at Harvard's Black Rock Forest. Note the fierce competition between close neighbors. The workmen with pressure hoses are tracing out some of the longest lateral roots to see how far they did reach. (Photograph by Benjamin B. Stout)

WHITE OAK HT 33' DBH. 6.5"

NO. 18

WHITE OAK HT33' DBH. 72"

The diagrams above and below show (in solid line) major roots traced to their ends and (in dotted line) the trees' crown areas. Graphs show stem (—0—) and root (—x—) growth data in years and feet.

Trouble Aloft. Though contemporaries, and enjoying identical conditions, these two white pines contrast sharply in their crowns. Something must be radically amiss with the right-hand one.

A Girdling Boot Exposed

The puny pine's trunk comes straight up out of the ground on one side. Diagnosis: Its buttress roots there are probably constricted.
 
The Trouble Exposed. One errant root has strangled its neighbors and the tree, killing itself in the process. One cut, at the base of the constrictor, will relieve pressure. Water was used to lay bare this girdling.

A Tree that "Has Everything" wrong with it, that is: faulty fork, bleeding borer damage, atrocious pruning. Some surgery below, two rods and a cable above, can preserve this otherwise fine old cherry.

Let proper tools be the beginning of your new wisdom. Unless you mislay them or let the neighbors borrow, one set can last you a lifetime. You may as well start with the best.

Item one is pruning shears, the kind with heavy-duty blades so opposed that they cut closer on one side than the other. They should be at least eight inches long over-all, with broad handles for a firm grip. Ladylike "snips" are only frustrating. If your arms and fingers are short, get shears with long wooden handles. Take a fair-sized branch with you into the store and settle for no shears that will not make a half-inch cut without effort. The kind without reopening springs is least prone to rust shut. Painted red or orange rather than green, your shears will be found sooner when you drop them into grass.

Tastes differ in handsaws—straight-blade or curved—but one rule prevails for all pruning saws: at least six teeth to the inch. Coarser gauges tend to rip and tear on cuts of less than four inches, which is what most of yours will be. The so-called "speed" saws are for professionals in a hurry. For home-owner use, a 15-inch curved blade with metal or plastic grip is ideal. The curve is helpful on cuts that must be made overhead or reached out for, with reduced wrist pressure. Also, it is handy for hooking free the cuttings that hang up. If you decide you prefer a straight blade, don't get one with teeth on both edges. These look like laborsavers, but they do a lot of inadvertent damage. The upper curf hits unintended targets.

Polesaws, with teeth slanted toward you for pull-cutting, have curved blades that fit into "heads" socketed for 8- to 16-foot handles. Blade and handle are replaceable. When the one wears dull it is not worth resharpening. The other, being of light, brittle wood, has a way of breaking when you drop or step on it. The expense of keeping on hand a spare blade and pole is not exorbitant. The most important and expensive part of your polesaw is its head. Avoid the kind where the blade is fastened in by a wing nut, which a knock can loosen. Better are flat nuts or heavy cotter pins or countersunk screws. Be sure your head has a slot in the back to hold your paint brush. A lot of reaching and clambering is saved by pole-painting your high cuts.

Pole-pruners, like shears, should be selected for rugged-ness and for having the cutter so offset that it will slice flush when laid on properly. The kind operated by a Ian-yard through screw eyes along the pole will stand up longer and repair more easily than the more expensive type on which a hand-lever actuates a rod to the cutting head.

Tree paint (wound dressing) has in recent years become handily available to home owners. It even comes now in handy aerosol cans, for spraying on. The different brands vary little in composition. An asphaltum base with turpentine or mineral oil added is standard. Keep it thinned with linseed oil or it will blister on the wounds. It does not speed callus growth, but it protects wounds until callus covers them by keeping out the fungi of decay. Don't try to "make do" with lead or copper house paints. They peel, and may poison tender tissues. Shun creosote and roofing tars.

Orange shellac, brushed over the bark and sapwood around the edges of a cut before covering the whole wound with tree paint, is desirable but not essential.

The question of when to prune trees is moot even among treemen, but their differences are largely quibbling. In a general way all will accept the classic rule, "Prune when the tool is sharp," which has few exceptions.

Some people think it is perilous if not criminal to prune a tree in bud or leaf. Such dogmatism is absurd and it ignores the advantage to be gained, whether pruning for health or appearance, by distinguishing clearly between dead and live members. Spring pruning gives wounds the benefit of spring growth to quicken healing. "Bleeders" like most of the maples, boxelder, linden, walnut, yellow-wood, and the willows and birches are best left untouched until after their leaves are well out—more because their copious sap is messy to work in than because the trees may "bleed to death." Sugar maples tapped year after year live to ripe old ages.

Trees pruned young, to shape their lasting characters, will bear fewer lasting scars than trees shaped late in life. But as with repentance, better prune late than never.

Let the home owner approach his first pruning job—a deciduous 15-footer—with this framing thought in mind: in what ways would this tree look different if it were in perfect condition?

Obvious at once are any broken or dead branches. Questionable are branches that look crowded or are actually touching one another. More puzzling are a lot of branches and twigs and shoots each of which may have good right to be there but all of which, in the most untutored eye, add up to unhealthy overgrowth and confusion. How to proceed?

Begin with your handsaw on the breakage and dead-wood. Lay on the teeth at the member's basal swelling, on the upper side, and saw downward flush to the trunk or parent member. Go slowly at first, until you learn your tool's balance and reach.

Branches more than an inch thick, and bearing some weight, will tend to sag and tear away before you finish your downward cut. (See Fig. 3.) Prevent this by steadying the branch with your free hand. Or, before you start cutting down, make first a shallow upward cut into the underside of the branch's base. On branches two inches thick or more, take this precaution by making three cuts: one from below, a few inches away from the base; the next close above, down from the top until the branch snaps off; the last, down through the base to flush off the stub (Fig. 4). If a forking branch is pruned, make the trial cut upward to come flush (Fig, 5).

Among the dead branches that you prune, there may be some whose bases have rotted back into the parent member. For now, leave these lesions alone except for painting them over. They may require some knife or chisel work, which will be described in a later chapter.

Among the breakage there may be some branches damaged only out toward their ends, leaving sound parts that you may want to save. Cut these back for now to the nearest good fork or shoot. Such truncated members can be reconsidered when you prune the tree's other live parts.

With breakage and deadwood out of the way, next stand off and squint at your tree through half-closed eyes. Perceive its "habit"—how its members grow to give it characteristic outer shape and inner pattern. Identify the main members and keep them in mind to preserve and accentuate. Against their basic symmetry, superfluous members will stick out like extra thumbs. Don't hesitate to lop them. Some trees are more prone than others to proliferate interfering branches, including linden, dogwood, hawthorn, hackberry, mulberry, boxelder, and many of the maples. All these trees will stand a lot of "tailoring."

Where a young tree has a main fork low in its stem, steel yourself to amputate one leader or the other so that the survivor can take command. A close look at how the competing leaders grow will tell you which to condemn.

Direct your attention next to sucker growths. These are straight, unbranching shoots that you don't want to become important members. They only consume energy and clutter form. They may come up from the tree's roots or out of its trunk or off main members. Prune suckers ruthlessly, using your shears and pole tools. There will be more suckers next year in case you need any to fill out a pattern.

As you work upward and outward after clearing the tree's inner air space, room for the secondary branches and twiggy terminals increases. Your object here is only to lessen interference, without creating gaps in the tree's spread and crown. Gaps are not only unsightly: they expose interior stems to sunscald. Take it easy as you go and stand off frequently to study your progress. Remember, there is no fixed rule for the shape or density of any tree, unless it is this: after you have pruned, your efforts should not, like a "plumber's haircut," be too obvious. A properly pruned tree has an airy, graceful wholeness that persuades the beholder it grew just that way all by itself.

If the tree is too wide or too tall to suit you, or is threatening to become so, do not shear or head it back as you would a hedge. Single out the too long or too high members and lessen them one by one by drop-crotching—that is, cutting back to a fork where the abbreviation will look natural. (This overhead work will perfect your handling of the pole tools.)

Finally, if the tree stands where traffic or mowing machinery must pass, eye it for ample clearance and prune accordingly. Better a few less branches than any bruised ones.

Thus far we have generalized about pruning small deciduous trees. Evergreens call for different treatments, which will be discussed below. Pruning fruit trees, too, has special rules, which appear in a later chapter. Here it would be well to draw some distinctions about the pruning of deciduous species with various habits.

The leafy sucker growths on elm trunks and branches, also called "hairs" or "feathers," are somewhat necessary to these water-loving trees, especially aloft, to keep them from dehydrating. They should be pruned sparingly. But all elms should be watched closely for deadwood, which invites the bark beetles that carry dread Dutch elm disease.

Plane trees are vulnerable to cankerstain, a fungoid disease that is highly infectious, but less so in dead of winter. That is the only time planes should be pruned; and even then, disinfect the tools.

Pin oaks put out laterals so closely spaced sometimes as to look overgrown, but these should be thinned with much caution. This tree's branches support each other under loads of rain and snow.

Willows, poplars, Russian olives, and some other softwoods can be headed clear back to their main stems, where they will bush out. This is called "pollarding" and is commonly done for decorative effect.

Small species which flower early are best pruned after petal-fall. This gives them time to form new flower buds for next year. It holds good for shadblow, redbud, dogwood, fringe tree, hawthorn, magnolia, sorrel (sourwood), and mountain ash.

Locusts are an example of trees that flower late and can be pruned in dormancy or after. Since they tend to spindle up and die in the tops, it is well to head back locusts—but not honey locusts—when young. In heading or topping any tree make a slanting cut, to promote healing and shed water.

Gardenias and camellias can be kept under control just by cutting their blossoms. But your poinsettias will sprawl up out of hand if you fail to whittle them back two or three times between flowering and early autumn.

Palms are pruned simply by removing dead fronds; bananas, after fruiting, by cutting the stalks to the ground, whence sprouts will produce the next crop.

Evergreens (the narrowleaf varieties) up to fifteen feet seldom require pruning except for removal of breakage and deadwood, which is done at the trunk. Cuts on evergreens mostly heal themselves with the trees' own resins, but it does no harm to paint them anyway. Top and side trimming, to keep young evergreens in hand, is done by lopping terminals selectively, not shearing to a line. Such trimming will help spindly, shade-grown evergreens fill out, especially if it is done in spring when the foliage is soft. Firs, pines, and spruces are best pruned in late spring after they have made most of their annual growth. Arborvitae, cedars, juniper, hemlocks, cypresses, and yews (including Taxus), which all grow continuously, can be pruned any time except winter, when cut ends may dry out or freeze north of Maryland and through the Plains States. When evergreens suffer winterkill, wait until new growth can be distinguished before pruning out the damage. If damage is severe, wait until the new growth provides shade against sunscald. Whitewash on the exposed stems, too, will turn off the heat.

Mid-December is the happiest time for pruning hollies: they take it kindly then, and you can use the cuttings for Christmas greens. Prune to branch junctions or the foliage will densify and suppress next year's gay red berries.

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