Pruning Guides

                                                       Pruning by Numbers

Written by Alan Haigh, All rights reserved. Reprint permission required.

The basis of this formula I am about to describe is employed by many commercial apple and pear growers in Washington state and elsewhere. It may have been devised to provide simple guidance to minimally trained pruning crews called on to train hundreds of acres of free-standing fruit trees. A free-standing tree is defined as one at least 40% the size of standard that requires no support at maturity at most sites.

These growers instruct their workers to remove any branch that exceeds 1/3 the diameter of the trunk at its point of attachment to the trunk. Until a tree begins to bear fruit all other branches are left on the tree except rubbing or broken branches. Permanent scaffolds are not selected until trees begin to bear fruit.

For many varieties of apples and pears, this is all that is required to bring a tree into productivity as quickly and efficiently as possible. Of course, there are some exceptions which will be discussed later. What is less known is the idea of applying the 1/3 rule (or at least at least a ½ rule) not just to scaffolds but to secondary and often even to tertiary branches. In other words, maintain a central leader on each scaffold and remove every secondary branch that exceeds 1/3 to ½ the diameter of the scaffold at the secondary branches point of attachment to the scaffold.

A big part of the theory behind this involves the “economy of wood”. Using ratios as a guideline for removing crowding wood encourages the development of a tree that uses the least amount of structural wood possible to hold the largest amount of small, fruitful, well light exposed wood. This may be a confusing concept when read off the page, but as you prune your trees it will gradually make sense over time.

You can use this formula on apples, pears, peaches, plums, apricots, cherries and even mulberries. You may elect to train peaches and most other stone fruit to a three or four scaffold open-center after about 3 years. Even if you do, selecting scaffolds from only “moderately vigorous wood” creates scaffolds that are dependably strong, precocious (early fruiting) and a relatively compact tree. Incidentally, in my experience, three scaffolds are usually all that are needed to produce the easiest to manage and most productive open center tree.

It is commonly recommended that apples and pears be maintained as central leaders because in studies it has been shown to use space and light most efficiently for these species. Think of a central leader tree as two or three open-center trees growing on top of each other with each subsequent tree being about half the size as the one beneath it. Incidentally, in a home orchard where absolute efficiency isn’t essential, you can train your apples and pears as open center trees, if you prefer. It is a less complicated form to maintain.

Note the expression “moderately vigorous wood”. It is very important to understand the relationship between a branch’s diameter and its vigor. The relative diameter of a scaffold branch at its point of attachment to the trunk strongly influences its access to sap. Think of a branch like a hose- the wider the diameter of a hose, the more water that can pass through it at any given pressure.

Because the pressure that pulls sap through a scaffold is provided by evaporation from leaves and the resultant capillary pull, the number of leaves and their relative exposure to the sun is the other determining factor of a scaffold’s access to sap.

So how does access to sap affect a scaffold’s relative vigor? Well, access to sap is the same as access to the roots and the roots provide water and most of the essential minerals for plant growth. This means that a scaffold with a smaller diameter stem functions in the manner of a dwarf fruit tree while a larger diameter stem functions more like a standard. The smaller diameter stem tends to store relatively more of its carbohydrates and sends less to the roots creating a cycle of fruit productivity at the expense of vegetative vigor.

If you are patient and give it enough room, an excessively vigorous scaffold will eventually become fruitful. But if you try to keep it in bounds and aggressively cut it back, the branch will tend to remain vegetative, probably partially because of a greater ratio of nitrogen to carbohydrate. The nitrogen is brought up from the roots and when you prune a branch the remaining buds have access to more of it and everything else brought up from the soil.

Speaking of the ratio of nitrogen to carbohydrate, it is important to realize that a branch’s access to carbohydrate is strongly influenced by its relative access to sunlight. This means that in order for a branch to be fruitful it needs adequate light. However, the carbohydrate-nitrogen relationship is a little tricky because greater exposure to sun also draws more sap.

As promised, here are some notes about possible exceptions to the 1/3 rule. First, some varieties benefit from an early selection of permanent scaffolds. This would mean removing all but three or four branches of each tier of a central leader tree by the second year of their selection instead of just leaving all properly ratioed branches until the onset of fruiting. The 1/3 rule would still apply to the selected scaffolds.

In my experience, Fuji is slow to come into bearing if there are too many branches on the tree, even branches of low relative diameter. For a twiggy, hyper-vegetative variety like Fuji, it may be useful to eliminate all but the permanent scaffolds as soon as possible to help early development of flower buds. Fuji tends to excessively shade itself, apparently causing a tendency towards extended juvenility when grown on free-standing root stock.

Lanky varieties like Ginger Gold and Yellow Delicious may also benefit from early scaffold selection to encourage greater secondary branching. They may also benefit from heading back these scaffolds by about 30% of annual growth to make scaffolds stouter. If such heading cuts are made, come back during the growing season to retrain the scaffold to a central leader by pinching back competing buds near the heading cut and allowing the straightest one to lead. You can also wait until mid-spring to make these cuts after the tree has leafed out. This will quiet the fierce vegetative response at the point of the cut. As trees get older and have filled their allotted space it is best to prune scaffolds back to a secondary branch when heading back.

Because they are determined to fruit early and profusely, varieties such as Empire, Arkansas Black, Braeburn and Goldrush (as well as many pear varieties, especially Asians) will perform well with relatively larger diameter scaffolds. Scaffolds up to half the diameter of the trunk are fine in such cases, as long as the unions are strong, with no inverted bark. This larger ratio can also work for the scaffolds of open-center trees but may result in a less compact, later fruiting tree. It may also lead to a weaker union of branch to trunk. It will not delay peach productivity, however.

Less vigorous, more fruitful varieties may also benefit from an increased number of scaffolds, particularly if secondary and tertiary branching is sparse, which is the case with spurry varieties of apples (Goldrush, Arkansas Black), and many pears.

When pruning mature trees, the ratio rule is very useful in deciding which of two crowding branches to remove. When oversized wood is removed in favor of wood with a better ratio to the branch it is attached to you are creating a more efficient and fruitful tree.

That completes my explanation on the use of ratios to guide the training of many types of fruit trees. I continue to use the general principles here in maintenance pruning as well. I don’t automatically remove every secondary and tertiary or even quatiary branch that violates my ratio rule, but when branching becomes excessively crowded it is primarily this principle that determines which branches are removed. I won’t leave a huge empty spot in the canopy to enforce this rule, however. Replacement shoots sometimes need to be pulled and trained to grow where you need them (you can even tape them to an oversized branch you plan to remove later).

DISTANCE BETWEEN TIERS Another number that might come in handy is the distance between tiers on a central leader tree. On apple trees growing on rootstocks with vigor equivalent to M7 to EMLA 111 you need about four feet between the first and second tier and three feet between the second and third. Each successive tier should extend about half the distance from the trunk as the previous tier and the branches should have about half the diameter of branches in previous tier. This will assure that higher branches are not excessively shading lower ones. This accomplishes the efficient Christmas tree shape mentioned earlier.

Because the higher you go on the tree the better the access to the sun the upper scaffolds will gradually outgrow the lower ones and, depending on variety, may stop being fruitful if you keep trying to prune them to the desired length. If you let them grow out as far as they need to be fruitful they will shade the lower scaffolds and your Christmas tree shape will be destroyed.

Therefore, It is necessary to replace upper scaffolds every few years when the diameter gets too large. You should plan a couple years in advance for this and always leave some low vigor wood to form eventual replacements. For spurry varieties this is less of an issue.

THE HIGHWAY ANALOGY OF BRANCH STRUCTURE Consciousness of ratios will, in itself, lead to the development of a more efficient tree structure but it may also be useful to think of wood as a transport structure similar to a highway system (although functionally, it more resembles a power grid). The scaffolds are like a 12 lane super highway while secondary branches are your 4 lane highways and tertiary your 2 lane roads. You can call the smallest wood down to spurs as your alleys and driveways.

Highways are expensive to build and maintain just as wood is expensive (energy-wise) to build and maintain. The least amount of asphalt or wood required to satisfy the needs of transport the better. Another ratio issue is about access to territory for each scaffold. If the first tier has three scaffolds then each scaffold should have dominion over one third of the circle that the tier encompasses. The scaffold should ideally be trained in a reasonably straight line from the trunk, dividing its territory (1/3 of the canopy “circle” in a 3 scaffold tier) down the middle, or 60 degrees on each side.

In other words, if you looked at the tier from above as a two dimensional circle, each branch should occupy one third of that circle- like a pie cut into 3 equal pieces. Before you prune you should study the scaffolds to determine where the border lines are between scaffolds- where wood from one is encroaching on another’s space. When two smaller branches are crowding each other this will guide you to which one to remove- it will be the one attached to the encroaching scaffold.

So the three or four scaffolds of each tier should have approximately the same amount of small wood connected to them. This will happen just by respecting each scaffolds allotted space.
For secondary branches it’s a little more difficult to determine how much tertiary wood should be on it but generally the amount of smaller wood on a branch should coincide with its relative diameter. As trees grow, secondary and tertiary branches will often become over-sized with too little space available to grow enough small fruiting wood to justify the branches access to sap. By guiding the growth with the removal of this kind of wood, the vigor balance of a tree is maintained.

This completes my mathematical explanations of training fruit trees. Unfortunately it still falls short of providing a complete road map. Following these guidelines, you will certainly wind up with a reasonably open tree that has access to adequate light throughout the canopy; however, the issue of exactly how open the tree needs to be is not completely addressed.

I’ve always been fond of the old time appleman’s explanation that an apple tree should be open enough that you can through a cat through it. PETA members, please forgive me, but I find the image humorous- just don’t try it at home.

Exactly how open a tree should be will depend on a lot of factors. In more southern areas too much exposure may cause sunburn. Trees in relatively shady sites or further north will benefit from being pruned more openly and will also often benefit from substantial summer pruning of annual wood to allow sun to reach the leaves that serve the fruit.

What I’ve tried to cover in this article is essentially a general explanation of structural training and maintenance of fruit trees. An extremely important issue not addressed so far is any explanation of the detailed pruning required to best manage the fruiting wood.

This subject can get quite complicated as each species and many varieties within species have their own particular fruiting habit- peaches only bear (and leaf) on wood from the previous year (1-year wood)- many apples and pears bear their best fruit on 2-year wood and/or the tips of shoots formed the previous year. Some species and varieties within species bear all or most of their fruit on older, knobby and short pieces of wood called spurs which require renewal pruning.

Because of the wide range of factors involved in making the best decisions in this kind of detail pruning I will save this general subject for another article. To master the art of pruning you must prune and observe the results and then adjust based on the information your trees provide you. Be courageous and remember that most of us have a strong predisposition to remove too little wood.

Here’s a link to another guide “Training and Pruning Apple and Pear Trees” published by the American Society for Horticultural Science which you can download.


Here is some additional thought on the pruning subject.

Helpful Tree Information for Pruning Guidance

There is no specific recipe to clearly instruct someone how to prune any fruit tree. There are far too many variables between species and cultivars on various root-stocks to make simple instructions possible. I have found that a general knowledge of tree physiology is very helpful in developing pruning technique.

Here are some factoids that run through my mind as I prune. Hopefully they are mostly accurate but I definitely recommend further reading. Harris’s book “Arboriculture” published by Prentice Hall is a good place to go for reliable and useful information. Read the book just before pruning season and things start to sink in. Used earlier editions are quite affordable and contain almost all the useful info as the latest edition.

What follows is information that I’ve absorbed from many sources, blended with my own observations over the years. Every pruning cut I make is guided by the principles and guidelines included here.

Trees have an energy pecking order; Like other mature trees a mature fruit tree distributes its energy unevenly, tending to serve it’s fruit first, then it’s foliage and wood, and last of all its root system. This is why an immature tree has more vegetative vigor than one producing flowers, fruit and seeds. This is why the axiom that all pruning is dwarfing is not always true. All pruning of immature wood is dwarfing.

A mature apple tree with a lot of spur-wood can actually be invigorated by removing spur-wood. This is useful to know when transplanting mature trees or when trees become spur-bound (a condition of excessive production of tiny fruit and very little shoot production). It is also useful to know when an old tree is in decline and greater vegetative vigor is needed.

Because vegetative wood isn’t investing in fruit and flowers it not only creates more growth on top of the tree, but also gives more energy to the roots creating a cycle of more overall growth until flower production begins. Therefore restoring vigor on runted out trees must begin with a surge in vegetative growth.

Water sprouts are like young trees “planted” on top of another tree; The water sprouts that occur in apple and pear and some other fruit trees function as independent and sexually immature trees. A primary reason for their rapid growth is that energy is not being expended on fruit and flower formation, so it all can be spent on foliage, wood and roots. Depending on the type of apple, a water sprout usually will take at least 2 years to bare any fruit, although some varieties some year produce flower buds on one-year wood including tip bearers, but not exclusively. (Grafting such varieties may require early flower removal to achieve decent growth the first year). Some varieties take much longer. Competing water sprouts on the same tree can further delay the maturity of these shoots as they compete with each other for light and lower, more mature wood gets inadequate light to develop fruit.

It’s important to know that water sprouts are the vigorous 1 to over 3 foot shoots that sprout from large wood. Smaller shoots attached to smaller wood (“pencils”) function differently and are only removed selectively. Every year some of these pencils must be left on the tree to replace or increase bearing wood on the tree and to “feed” nearby fruit. Water sprouts are often only saved when a new branch or “central leader” is desired. New branches must often be tied or spread after the first or second year to about a 60 degree angle to reduce vigor and bring to fruitfulness.

Some varieties, such as Macoun and Northern Spy, produce only fairly to very vigorous new wood, especially when young, and the least vigorous shoots are selected to become the future fruit bearing wood. In all varieties there should be an even distribution of one year wood left on the tree every season. Vigorous water sprouts emanating from scaffolds can also be taped or tied to other wood to a horizontal position when additional secondary or tertiary branches are needed.

Branches in a tree function independently; Branches do not cooperate to form the most efficient tree possible. Branches on the same tree will essentially compete with each other while growing towards light. The only internal control is that when a branch requires more light than it can harvest to sustain itself it often dies. The common equation is that a leaf that receives less than 30% light costs more energy than it produces. That doesn’t mean that branches receiving less than 30% light automatically die. Trees will often sustain an inefficiently dense canopy probably in order to strangle competition below. Sunlight that reaches the soil can nourish competing plants.

Branches also seem to disproportionately nourish the trunk and larger wood near the point they are attached. This is indicated by research that shows the benefit of leaving temporary branches on the base of landscape trees which creates thicker trunks with better taper.

Training old apple trees (and all older trees) so that there is functioning canopy reasonably close to big wood may help strengthen that wood. This is accomplished by allowing light to reach branches low in the tree by thinning the higher branches –especially those shading the interior of the tree instead of removing interior wood and training empty wood further and further out. The lanky excessively tall trees created by years of interior wood removal can be torn apart by the increasing leverage of their top-heavy branches.

Branches are not arms and legs. Sorry, I could think of no better way to put this. The point is that individual branches, no matter how large are not essential to the well being of a fruit tree. A branch is only as important as the light that its leaves harvest. Often trees are trained with a surplus of big wood. Removing big wood, even scaffold branches should not put a healthy tree in shock, especially if the removal doesn’t reduce the trees ability to reach light. Depending on pest pressure of a region or sight, it is possible that large wounds can leave a tree vulnerable to borers of other pests, but generally trees are well equipped to survive the removal of large limbs.

A scaffold branch needs to have enough room to have space for smaller branches to spread out from it along most of its length. All branches need to have enough room to hold the amount of smaller branches that their diameter warrants. It is often better to remove a large branch or even a scaffold branch than to try to remove too much small wood to keep enough space between 2 large branches. Sometimes it’s necessary to temporarily leave more open space than desired temporarily in order to remove an overly large branch- a hole in the canopy to fill later with smaller productive wood.

Scaffold branches should be trained in 3’s or 4’s. An open center tree and the first tier of a central leader tree is usually most efficiently served by having only 3 scaffold branches of approximately the same diameter, each occupying about 120 degrees of the circle of light they intercept. This provides adequate space for each scaffold to develop smaller branches.

Very spurry apple and pear types sometimes benefit from a 4 branch tier system, even from the first tier. This is because it can be hard to get the branches on such trees to spread out far enough to harvest the full circle of light- secondary branching is inadequately vigorous. Also, lanky fruit trees that are slow to produce secondary and tertiary branches may require extra scaffolds, at least when they’re young. The optimum amount of scaffold branches may be more in a young tree and become surplus as it ages thus requiring selective removal.

The goal of the pruner is to create a canopy that uses the least amount of wood to harvest the most light. This is accomplished when a tree has as high ratio of small wood to large wood with all the small wood getting ample light.

The leaves on a branch apparently nourishes the fruit they are closest to; This is why the largest and best tasting fruit is produced in the parts of the tree that get the most light. This is also why it is important to evenly distribute light throughout the tree so all fruit is well exposed to sunlight.

The dominant branches in a tree are those with greatest access to light. While this may seem obvious the reason is more than directly the result of better access to the sun. Exposure to sun and wind draws more water through the exposed leaves probably increasing access to nitrogen and other root derived nutrients.

This will mean that annual pruning will tend to be more aggressive in the top of the tree. This pruning will be almost completely in the form of thinning cuts where branches are cut back all the way to another branch or the trunk. In apple and pears maintained with a central leader only the first three branches are usually maintained indefinitely. Higher branches are periodically replaced when their diameter exceeds about 50 percent of the diameter of the branch underneath it. These replacements are made starting with a less vigorous shoot and take several years. This branch replacement is best done gradually.

Thinning Cuts Encourage Fruiting- Stubbing Encourages Vegetative Growth. Stub cuts effectively delays the maturity of any given branch while thinning cuts provide more light onto the older wood of remaining branches that tend to be more in the interior of the tree.

Sunscald on the scaffolds of old apple trees is not really “sunburn”; Stub cuts of water sprouts in the top of the tree are often made by well intentioned arborists to prevent “sun burn” on old apple trees. This excessively stimulates vegetative growth at the tip of the stubs depriving the rest of the tree of adequate light for best fruit production.

Exposure to the sun is only indirectly responsible for sun-scald in old trees. I believe that such scalding occurs in the spring just as the first leaves have formed and the bark is “slipping”. When an excessive amount of small branches are removed from a large branch there are not enough leaves to draw adequate sap through the cambium to cool this tissue at its most tender stage and under a very strong sun. Of course the exposure to light increases the temperature of the cambium as well but if there is adequate transpiration ahead of the exposed bark it won’t cook.

If an arborist wants to maximize floral display and/or fruit production and is concerned about excessive exposure there is a better strategy than “stubbing”. That is to leave some of the least vigorous annual shoots along the length of large branches to provide quick leaf formation in the spring to protect old wood in an aggressively pruned tree.


Pruning and Steering Tree Vigor

Regulating tree vigor through a combination of rootsock selection, nitrogen fertilization, irrigation, fertigation and branch spreading are widely covered in orchard management literature, but not pruning, except about how stub cuts and excessive pruning prolongs juvenility and often creates excessively vegetative growth.

Pruning books often start with the axiom that all pruning is dwarfing, even though stub cuts usually create a riot of new shoots at the point of such a cut in a well lit and especially in a
vertical branch, but overall size of the tree at the end of the season is supposed to be reduced based on how much wood is removed during pruning. .

When pruning mature apple, pear and European plum trees, throw that axiom out and know that sometimes trees need to be pruned in a manner to stimulate more vegetative growth when they lose adequate vigor to produce replacement wood.

Spur wood is dwarfing and older trees often are consumed by excessive spur wood in a last gasp measure to produce fruit for seeds, I guess. Even some young trees of certain varieties can be runted out this way- especially sports that are selected for early fruiting as is the most popular strain of Arkansas Black. Trees kept in pots can also have this occur as can almost any variety of dwarfing rootstock that has been mismanaged and allowed to fruit to heavily before reaching adequate size.

The solution along with supplementary N is to cut off a lot of that spur wood.


Thank you for your thorough pruning guide, as well as your many comments on other threads from which I’ve learned a great deal.
This past spring I planted a few apple whips in our backyard (southern PA). Mostly MM111 and a few on Bud9 rootstock. I am looking for pruning guidance after this first growing season as the scaffolds on several of the trees overcame or nearly matched the vigor of the leader. I guess this is due to the fact I did little to bend the branches down, though I initially spread them with toothpicks to open the crotch angle. Also several of the trees only had a couple buds form branches, so there was little selection of scaffolds, I just went with whatever the tree gave me.
Per the 1/3 ratio rule, these large scaffolds should be completely removed, but then I would basically be starting over with whips again next year. Is there any chance I can maintain these branches and with a combination of heading back and bending down, the scaffolds will be dwarfed sufficiently to allow the trunk and main leader to catch up and restore the proper 1/3 diameter balance over the course of a season or two? Or better to start over, remove them, and select new scaffolds next year?
I would love to hear what recommendations you would have or any others who have dealt with similar situations.
I will try to upload some photos to help illustrate.

Thank you!


I suggest you remove the small branches that are more that 50% the diameter of the trunk, at least on any free standing rootstock like M7 or 111. I know it’s painful but it’s more painful to start trees out without proper guidance. The trunk needs to be dominant for a couple of reasons. Early fruiting and strong, well supported branches. It is trunk tissue that surrounds the connection and if the branch is growing nearly as fast as the trunk, not enough tissue supports the union.


Thanks, that makes sense. As for the trees on bud9, I gather that I would either need to provide support to each scaffold branch to avoid breakage, or remove those branches and follow the 1/3- 1/2 ratio in training them while maintaining support on the trunk, or train to open center, supporting each scaffold. Would that be correct?

1 Like

I don’t do dwarfs besides a few espaliers. Mostly it’s about not over pruning or letting them bear too much fruit before they reach desired size, to my understanding. It also depends partly on the natural vigor of the scion.

1 Like

Just looking at the trees again this evening- I was planning on making the corrective cuts (removing branches > 1/2 the trunk dia) during the dormant season pruning, but I am curious- would there be any advantage to doing it now? The trees are growing quite vigorously now with the cooler weather and some of the side branches have now even overcome the leader in height and girth on several of the trees.
Or would pruning now set back the trees overall more than dormant pruning?

1 Like

For such young trees I think you are right. Let them serve their roots until they loose their leaves than prune them just before they come out of dormancy.


Here are some other guides to pruning that I found useful as a newbie to fruit trees:

training and pruning home orchard.pdf (4.8 MB) A very basic guide (14 pages). I liked this one because it has pictures for all the terminology I needed to learn (leader, sucker, water sprout, scaffold) and a short overview of different systems (open center, central leader, etc.).

Training and Pruning Apple Trees from VA extension (951.9 KB)- 9 page overview of physiology, the different types of cuts, timing and 1st-4th year for a tree.

Pruning Peach Trees from VA extension (3.8 MB) - 11 page overview of physiology, the different types of cuts, timing and 1st-4th year for a tree.

Two articles from “Good Fruit Grower” which talk about both the 3:1 ratio size rule and the 1-2-3 rule (both are things mentioned above):
ten apple pear tree pruning rules.pdf (1.4 MB)
has a picture about the 3:1 size ratio rule and a bunch of other tips.
pruning apple and pear 1-2-3.pdf (1.3 MB) more details about the 1-2-3 rule

physiology of pruning.pdf (936.3 KB) science! No “how to” in this article- just plant physiology and the effects of pruning

For older neglected trees these were my two favorites:
SP307-K-Pruning Neglected Fruit Trees.pdf (438.0 KB)
Uploading: restoring an apple tree.pdf…