How to patch a tree wound

Tree Wounds | Tree Care Kit

Wayne K. Clatterbuck Associate Professor Forestry, Wildlife & Fisheries University of Tennessee

Tree wounds are common and the causes include: broken branches; impacts, abrasions and scrapes; animal damage; insect attack; fire; etc. Wounds usually break the bark and damage the food and water conducting tissues. Wounds also expose the inside of the tree to organisms, primarily bacteria and fungi that may infect and cause discoloration and decay of the wood. Decay can result in structurally weakened tree stems and can shorten the life of a tree. Decay cannot be cured. However, proper tree care can limit the progress of decay in an injured tree. This fact sheet discusses tree responses to wounding and what can be done after wounding to keep the tree healthy.

Tree Response to Wounding:

Trees respond to wounding or injury in two ways: compartmentalization and the development of barrier zones (Shigo 1986).


When a tree is wounded, the injured tissue is not repaired and does not heal. Trees do not heal; they seal. If you look at an old wound, you will notice that it does not “heal” from the inside out, but eventually the tree covers the opening by forming specialized “callus” tissue around the edges of the wound. After wounding, new wood growing around the wound forms a protective boundary preventing the infection or decay from spreading into the new tissue. Thus, the tree responds to the injury by “compartmentalizing” or isolating the older, injured tissue with the gradual growth of new, healthy tissue.

Barrier Zones

Not only do trees try to close the damaged tissue from the outside, they also make the existing wood surrounding the wound unsuitable for spread of decay organisms. Although these processes are not well understood, the tree tries to avoid further injury by setting chemical and physical boundaries around the infected cells, reacting to the pathogen and confining the damage.

If the tree is fast and effective with its boundary-setting mechanisms, the infection remains localized and does not spread. However, if the boundary-setting mechanisms are not effective, the infection will spread. Most vigorous or actively growing trees are fairly successful in coping with decay-spreading mechanisms.

Care for Tree Wounds:

Proper care of tree wounds encourages callus growth and wound closure.

Physical Repair

Tree wounds often appear ragged where the bark is torn during the injury. This is common during branch breakage and when the trunk of the tree has been scraped. To repair this type of damage, cut off any ragged bark edges with a sharp knife. Take care not to remove any healthy bark and expose more live tissue than necessary. If possible, the wound should be shaped like an elongated oval, with the long axis running vertically along the trunk or limb. All bark around the wound should be tight.

Wound Dressings

Research indicates that wound dressings (materials such as tar or paint) do not prevent decay and may even interfere with wound closure. Wound dressings can have the following detrimental effects:

  • Prevent drying and encourage fungal growth
  • Interfere with formation of wound wood or callus tissue
  • Inhibit compartmentalization
  • Possibly serve as a food source for pathogens

For these reasons, applying wound dressings is not recommended. Trees, like many organisms, have their own mechanisms to deter the spread of decay organisms, insects and disease.

Cavity Filling

Filling large holes or hollows in the tree is generally done for cosmetic reasons. There is little data to indicate that a filled tree has better mechanical stability. However, fillings may give the callus tissue a place to seat, thus stopping the in-roll (folding) of the callus (Shigo 1982). Almost any filling can be used as long as it does not abrade the inside of the tree.

Filling a tree cavity is generally expensive and not recommended. Filling does not stop decay and often during the cleaning of the cavity, the boundary that separates the sound wood or the callus growth from the decayed wood is ruptured. Thus, this cleaning for cavity filling can have more detrimental effects on the tree than if it were left alone. Care must be taken not to damage the new callus tissue that has formed in response to the tree damage and subsequent decay.

Pruning Wounds

Proper pruning should be used to remove dead, dying and broken branches; to remove low, crossing or hazardous branches; and to control the size of the tree. However, pruning of any kind places some stress on the tree by removing food-producing leaves (if the branch is alive), creating wounds that require energy to seal, and providing possible entry points for disease.

Pruning cuts should be made to maximize the tree’s ability to close its wound and defend itself from infection. When pruning, make clean, smooth cuts. Do not leave branch stubs. Leave a small collar of wood at the base of the branch. The branch collar is a slightly swollen area where the branch attaches to the trunk. Cutting the limb flush with the trunk will leave a larger area to callus over and a greater chance of decay organisms entering the wound. The optimal pruning time is in the winter (dormant season) when temperatures and infection rates are lower and when trees are not actively growing.

Conclusion. Healthy trees usually recover from wounding quickly. Try to keep wounded trees growing vigorously by watering them during droughts and providing proper fertilization. This will increase the rate of wound closure, enhance callus growth and improve the resistance to decay mechanisms.


Shigo, A.L. 1982. Tree health. Journal of Arboriculture 8(12):311-316.

Shigo, A.L. 1986. A New Tree Biology. Shigo Trees & Associates, Durham, NH. 595 p.

Tree Wounds and Healing | Purdue Extension Forestry & Natural Resources

Got Nature? Blog

Posted on September 29th, 2020 in Disease, Forestry, How To, Plants, Urban Forestry, Woodlands | No Comments »

Purdue Landscape Report: Trees are incredible survivors in spite of the challenges from pests of all kinds, including us! They are vulnerable to injuries such as mechanical wounds from lawn equipment, vehicles and ice. Pruning results in an intentional wound which is of importance to consider. Tree owners and managers need to prune trees to maintain aesthetic characteristics, remove infected limbs, reduce risk, or improve structural stability. Proper pruning practice and understanding tree wounds can minimize the impact of creating wounds on trees.

Wounds attract pests due to the phytochemicals dispersed from exposed tissue. When tree tissue is damaged or wounded, the newly uncovered tissue is exposed and that is when to expect an attack. Insect pests are drawn to trees in distress, feeding on the tissue and weakening the tree. Diseases affecting trees will introduce enzymes into the cells, digesting living tissue responsible for food and water translocation (phloem and xylem) or structural support resulting in unhealthy, unsightly, or unsafe trees.

Wound wood Formation
Trees attempt to close wounds by sealing or compartmentalizing the affected area, naturally.

Tree trunk damaged by construction equipment developing wound wood around the edges to eventually seal the wound.

Pruning cuts will develop callus tissue on the exposed tissue giving rise to wound wood.

Wounding of trees during the growing season results in the formation of callus tissue which develops over the wound surface or parts of it. This callus tissue is an unorganized group of important parenchyma cells. As the callus develops and grows, wound wood develops which hopefully will cover the exposed tissue quickly and efficiently.

Wound recovery rates vary widely for different tree species. The speed of recuperation is greatly affected by developmental environmental conditions, vigor and health of the tree. Some trees may never completely close their wounds due to their genetic capacity or perhaps inadequate resources to keep the tree vigorous. However, numerous studies reveal that faster wound closure results in fewer health issues for the tree. Quick healing is always better!

A healthy tree will seal wounds faster and the same for younger trees as well. Trees that are planted in well-drained, quality soils, with good texture, structure, and containing adequate nutrition levels, grow in a way that favors the healing process. Thus, when planting trees, homeowners should be aware of the effects of site selection, soil quality, and other site factors that may impact tree growth.

Wound dressings slow closure and can prevent healing.

Complete wound closure improves tree health and slows decay.

Faster closure
There are few ways wound closure can be hastened, or at least not inhibited. First, it is essential to avoid limiting oxygen availability to the wounded tissues. Oxygen is necessary for proper recovery. For example, painting a wound with any kind of material that interferes or impedes oxygen will slow or even prevent wound closure by poor callus formation. Wound treatment with petroleum-based products is not recommended. In fact, research indicates any type of wound dressing can slow the healing process. There is one exception for treating wounds. This is in areas where oak wilt disease occurs, wound paints may be useful in preventing insect spread of the oak wilt fungal pathogen.

Basically, the best way to help insure proper wound closure and quick and effective sealing of the tissue is a proper pruning cut and preventing damage whenever possible.

Find a professional
Be sure to always hire an insured, tree care professional, preferably and ISA Certified Arborist with the experience, expertise, and equipment to provide proper tree care. Require proof of liability insurance to protect yourself as well.

Another easy way to find a tree care service provider in your area is to use the “Locate Your Local Tree Care Industry Association Member Companies” program. For more information refer to the publication Trees and Utilities at the Purdue Education Store.

Find an ISA Certified Arborist in your area by visiting the Trees Are Good website.

Tree Pruning Essentials, Publication & Video, The Education Store, Purdue Extension resource center
Tree Pruning: What Do Trees Think?, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store
Tree Installation Process and Practices, The Education Store
Tree Pruning for the Landscape, Webinar, Purdue Extension – Forestry and Natural Resources Youtube channel

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources

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How to close up a hollow in an apple tree, how to cover it up on a trunk so that it does not rot, how to cover up a fruit tree with polyurethane foam

A hollow is a very dangerous formation on a tree trunk, which is important to quickly heal and close up. The cause of its appearance is an open wound somehow obtained with damage to the cortex, and often the cambium. The wet layer of wood exposed as a result of an injury is completely defenseless against microorganisms and fungi that willingly settle here. They cause wood decay, penetrating deeper into the trunk. With a high intensity of the process, the apple tree dies.

If rotting is stopped, a dry hollow is formed. But even in this case, the tree becomes much weaker and more susceptible to other diseases. Due to purely mechanical reasons, the cavity increases with time, and the tree loses its strength. An apple tree can break from a strong gust of wind or even under the weight of its own branches. The yield of such a plant becomes noticeably lower.

If a hollow is found, the apple tree must be treated immediately by any appropriate means.


  • Reasons for the appearance of a hollow on an apple tree and other fruit trees
  • Why it is best to heal in the fall and not leave it in frosty weather
  • Step-by-step instructions: how to properly and competently close a hollow
    • Cleaning for treatment Disinfection: compositions of solutions:
    • How to treat if it is affected by a fungus
    • Filling the trunk with mounting foam
  • What to do if:
    • A hollow has formed in a seedling
    • Large hollow hollow, how to close
    • Procorous competent treatment: cover with cement
    • infected with ants and begins to rot
    • a lot of rotten wood
    • in the old apple tree
    • flowers Video
    • Conclusions

    Causes of a hollow on an apple tree and other fruit trees

    Any damage that causes cracking of the bark can lead to the appearance of a hollow. These include:

    • mechanical injuries - impacts, breakage of large branches, damage by rodents, etc., which at one time were not repaired with garden pitch. Find out what to do if the hares gnawed on the apple tree at the link.
    • injuries sustained by the tree or when pruned incorrectly. For example, when a branch is not removed “on the ring”, as required by the rules, but a stump is left;
    • frosts - severe colds lead to cracking of both the bark and the trunk itself. Therefore, in severe frosts, not only trees that are not resistant to cold are wrapped, but all apple trees;
    • lifting of the bark due to incorrect or careless cutting of branches. In order not to provoke injuries, the base of the branch is first sawn from below. Many gardeners, especially when removing thin branches, neglect this recommendation.

    The appearance of a hole in the middle of the trunk or hollow is the result of careless care. Read more about the proper cultivation of apple trees in this article. Any injuries to the tree should be immediately treated with a 3% solution of copper sulfate and covered with garden pitch so that there is no rot.

    If a cavity does appear, it must not be left. Over time, it increases and, in the end, will lead to the death of the apple tree.

    Why it is best to heal in autumn and not to leave it in frosty weather

    It is better to fill the resulting hollow in autumn - in October-November, or even at the beginning of winter, if the weather permits. At this time, sap flow slows down, the tree practically does not grow, and the filling has time to harden. In the spring, it is better not to carry out the procedure, as the apple tree begins to grow and the material does not have time to harden.

    Hollows of small size that have formed in fruit trees are clogged with a wooden cork and covered with garden pitch.

    If in spring open cracks with leaking juice are found on a tree - the result of frost, for example, or if cones are found under intact bark, treatment is started immediately, regardless of the time of year. Due to the growth of wood, the filling crumbles and the hollow “appears” again.

    Under no circumstances should the hole be left open for the winter. If the cavity is large, then it is better to make a filling earlier, in the summer, so that the material hardens.

    Step-by-step instructions: how to repair a hollow correctly and competently

    Hollowness is not a sign of tree age. Cavities can appear even in ten-year-old apple trees. So when it is found, you should not cut down the plant.

    The treatment is carried out according to the same scheme for any cavity size. However, the choice of material for the filling depends on the size of the hollow and its nature - it is affected by a fungus, dry.


    The first step in any tree treatment is the removal of dead, diseased or damaged tissue. Hollow is no exception. Remove all rotten wood with a chisel, garden knife, or other similar tool. It is important to get to healthy light tissue. Moreover, the first layer of healthy wood is also removed, since, most likely, it is already infected with a fungus. If the cavity is deep and complex, a bent tablespoon and a flashlight are used to remove it. In extreme cases, they cut out a passage to get to the walls. Then the cavity is thoroughly wiped, small debris is removed from it and allowed to dry. The edges are also cut to bare wood. Wood must be completely dry before fungicide treatment.

    Collect all rubbish and contaminated wood in a bag to keep it out of the soil. Thus, re-infection with the fungus is prevented.

    Sometimes an apple tree may look completely intact, but when tapped on the trunk, you can find a void. A closed cavity threatens to rot inside the apple tree. It is necessary to cut or drill an artificial passage and clean the inner hollow, as well as the open one.

    Disinfection: formulations of treatment solutions

    To stop wood decay, the cavity is treated with fungicides. The most common solutions are used:

    • 1-3% copper sulphate solution;
    • 5% iron sulfate solution;
    • potassium permanganate - a dark pink solution of potassium permanganate;
    • 3% carbolic acid solution.

    Solutions are applied by spraying. At the same time, they observe safety precautions: wear protective gloves, goggles, a mask.

    How to treat if affected by a fungus

    If a fungus was found during the cleaning of the hollow, then treatment with a solution of copper sulphate may not be enough. In such cases, the cavity is additionally sprayed with Bordeaux liquid, a solution of colloidal sulfur or special broad-spectrum fungicidal preparations.

    For small lesions, sorrel leaves and garden var are suitable for antiseptic treatment.

    Garden pitch is a soft and thick substance obtained by processing tree resin with auxiliary components.

    The treatment of a large hollow is carried out in several stages - 3–5 procedures for 2–3 weeks in a row. Only after that you can start filling.

    Filling the shaft with mounting foam

    There are several different methods of filling. The method determines the size of the hollow.

    If the cavity is small and shallow, it is plugged with a wooden plug. The cork is selected so that its upper edge is at the level of the edges of the hollow. Then the cork in the hole is sealed with garden pitch. You can use oil paint based on natural drying oil and even match it to the color of the bark.

    Larger and deeper cavities are sealed with thick cement mortar.

    Cement to sand ratio 1:3 or 1:4. Previously, a braided wire, fixed with nails, is placed in the hole. It is also recommended to coat the sealed cavity with oil paint.

    The method of sealing with the help of polyurethane foam has become very popular, the substance does not conduct air and moisture at all, that is, the wood is protected from moisture ingress. In this case, a very large cavity can be filled with material. The procedure is the following.

    1. The hole is cleaned and disinfected in the usual way.
    2. After treatment with copper sulphate solution, wait 3-4 hours for the wood to dry completely.
    3. The edges of the hole are treated with garden pitch.
    4. The hollow is blown out with polyurethane foam.
    5. Cut off excess foam after curing. Since the polymer filling is sensitive to ultraviolet radiation, it must be painted over with oil paint.

    For larger masses, the procedure becomes somewhat more difficult. It is impossible to simply fill the cavity with cement mortar, since the latter, without a solid foundation, will crumble as the tree grows. Proceed as follows to securely close the hole.

    1. The cavity is cleaned and treated with fungicide, if necessary, in several steps.
    2. After the wood has dried, small broken bricks or crushed stone are poured into the hollow. With a large volume of the cavity, reinforcement is used.
    3. Cement mortar is prepared in the ratio of cement to sand as 1:3. The consistency of the composition is like that of thick sour cream. Lastly, a tablespoon of drying oil is added to the solution and stirred well.
    4. Fill the hole with mortar. The filling should be flush with the edges of the hole, so that excess cement is removed immediately. The surface of the seal is smoothed with a trowel or a hand in a rubber glove.
    5. Cement filling dries within 6 days. After hardening, it is covered with oil paint in 2 layers.

    All work on filling the hollow must be carried out in appropriate protective clothing, goggles and a mask.

    Once a year, the edges of the hollow are cleaned to the cambium or cuts are made along the edge of the growing bark. This stimulates further overgrowth of the cavity.

    Caring for tree trunks

    What to do if:

    Hollows are not always found on time. In addition, hollow apple trees may end up on the acquired plot of the garden. Accordingly, the gardener has to deal with a variety of cases.

    A hollow has formed near a seedling

    Quite a rare case, but it also happens. In the seedling, it is enough to cover the hole with garden pitch and cover it with electrical tape or thin polyethylene on top. A young tree in the active growth stage, as a rule, successfully copes with the healing of cavities.

    Large cavity, how to close it

    The main task of the filling is to prevent the penetration of air and moisture into the closed cavity. If the latter is large or, worse, deep, it is necessary to act in an unusual way.

    1. First, the cavity is cleaned. If the hollow is not only large, but also old, it is very difficult to remove the wood manually. In such cases, use a drill with a nozzle in the form of a metal brush. When carrying out this procedure, be sure to wear protective goggles.
    2. Then the hollow is disinfected, and it is desirable to repeat the procedure at least three times.
    3. An extensive cavity is filled with crushed stone or broken brick in several stages - from 3 to 6. Each layer is carefully tamped and poured with a thick cement mortar with the addition of lime. After the previous layer has dried, the second layer is laid, and so on until the cavity is completely filled.
    4. The filling is covered with oil paint or garden varnish.

    A deep hollow is very difficult to clean and repair. In such cases, an artificial passage is cut out. This increases the area of ​​the open part of the cavity, but allows you to make a quality seal.

    You can speed up the process of overgrowing the hollow by grafting with a bridge. It is best to use the shoots of the tree itself for this. The grafting is standard: the cuttings are inserted into the T-shaped cuts above and below the hollow, covered with pitch and covered with a film.

    Competent root treatment: cover with cement

    A hollow formed in the lower part of the trunk, especially a through one, is very dangerous. At the same time, the tree becomes flimsy, which means that it threatens others. If the trunk is fragile and we are talking about an old apple tree, it is better to cut down the tree and leave a stump. With a well-developed root system, it will start new shoots.

    If the cavity is small and the plant is young, you can try patching the hole.

    A filling in the root cavity should not only block the access of air to the wood, but return the mechanical strength to the tree. Such cavities are always reinforced before pouring.

    • If the hollow is relatively small - less than 25 cm in diameter, it is filled with brick chips or small pebbles and poured with a liquid cement-sand mortar. So that it does not flow out of the hole, it is temporarily covered with a board. After the composition hardens, a layer of thick cement mortar is applied on top.
    • If the hole is larger than 25 cm, then the hollow is first reinforced. For this, a metal mesh with a thickness of 2–3 mm and a mesh size of 70–80 mm is used. You can use wire: it is installed in the cavity across or diagonally and secured with studs. Then the hollow is filled with stone chips and poured with cement, as in the previous case.

    Infested with ants and beginning to rot.

    Ants are pests that quickly colonize plant cavities. By themselves, they do not cause much harm, but are carriers of fungi.

    Anteater is used at low application rates: 1 ml is enough to treat about 5 - 10 anthills.

    If ants have settled in the apple tree, then you need to get rid of them. To do this, rotten wood, which is cleaned from the cavity, together with insects, is folded into a bucket and poured with boiling water. The hollow is treated with insecticides - Diazonin, Anteater. If necessary, then spray the cavity with fungicidal preparations.

    Also, drugs against ants are applied to the near-stem circle - when digging in an apple tree.

    A lot of rotten wood

    Here the decision is determined by the size of the hollow. If the cavity is large and there is a lot of rotten wood, then it is easier to cut the stalk and graft it onto a wild game, and cut down the affected tree. If the cavity is deep, but relatively small, then the apple tree is reanimated in the usual way: the hollow is cleaned, treated with fungicides and poured with cement mortar.

    There is another method: the hollow is filled with a mixture of ash and charcoal, and the top is closed with a wooden cork. The repaired damage is covered with polyethylene, rubber tape to prevent moisture from getting inside.

    At the old apple tree

    The choice depends on the general condition of the tree. If the apple tree bears fruit well, then the plant is still strong enough. In such cases, the cavity is closed up using one of the methods listed above and the apple tree is carefully looked after: watering and fertilizing are carried out as for a young tree. You can read more about feeding apple trees in spring here.

    If the apple tree is already really old and the yield is low, but at the same time it belongs to good varieties, then its stalk is grafted onto wild or Antonovka, since the latter has a very high adaptive ability. Dwarf and semi-dwarf rootstocks are not used. You can read more about dwarf apple trees here.

    There is a large nest: cure with garden pitch

    In this case, all treatments for the tree are postponed until the chicks grow up and fly away.

    In some cases growers prefer to leave the nest. But, since an untreated hollow can easily turn into a focus of the disease, proceed as follows. In autumn, when the birds have flown away, the nest is taken out, the cavity is cleaned and sprayed with a fungicide. After drying, the hollow is treated with garden pitch. Then return the nest to its place.

    Juice is flowing

    If juice appears on a crack or in a hollow, this indicates a secondary disease. Measures are taken depending on the cause.

    • If the tree is affected by insect pests - sapwood, bark beetle, apple tree, injections are made with a special preparation - "Aktellik", diluted in a proportion of 2 ml / l of water. Injections are made with a regular syringe with a thick needle. The specified dose is enough for 1 sq.m. wood.

    The following year, after flowering, the tree is sprayed with Fufanon at the rate of 10 ml of the drug per bucket of water.

    • Incorrect processing of the hollow, for example, covering it with a mixture of manure and clay, further decay of the wood and the appearance of juice is also possible. In this case, the affected area is re-cleaned to healthy wood, disinfected and after 30 minutes treated with a composition of equal parts of Rannet paste and garden pitch.

    Do not use a mixture of clay, mullein, or the like to seal hollows. These materials perfectly pass water, and, therefore, provoke rotting of the wood under the seal.


    This video will tell you how to quickly close up a hollow in an apple tree.


    1. The hollow is a serious danger to the fruit tree. Exposed wood is easily attacked by bacteria and fungi. The apple tree is weakening, sick, the harvest is noticeably reduced. In addition, the plant loses its mechanical strength, begins to rot and becomes flimsy.
    2. Causes of the appearance of a cavity are most often mechanical injuries of a tree - wounds after breaking branches, frostbite in a frosty year, sunburn, and even incorrect, illiterate pruning. Read about the correct pruning of an apple tree in the fall in this material.
    3. The best way to prevent the appearance of hollows is to immediately close up (heal, cure) all cracks and abrasions that have appeared on the bark with garden pitch. You need to remove the branches "on the ring".
    4. Treatment depends on the size of the cavity. In any case, it includes cleaning the hollow, treating with fungicides and filling.
    5. Filling material and filling method are determined by the age of the apple tree, the depth of the cavity, the presence or absence of secondary diseases.
    6. It is best to fill the hollow in the fall, when the sap flow stops. However, with the sudden appearance of a cavity - after winter frosts, for example, treatment is started immediately.

    How to repair a hollow in a tree with your own hands - photo | Do -it -yourself

    Content ✓

    • ✓ Causes of the appearance of a hollow
    • ✓ The danger of wounds
    • ✓ How hollow appears in a tree
    • ✓ Time for treatment
    • ✓ Cleaning and disinfection
    • ✓ Filling out the breath

    Carrying out timely treatment of hollows prolongs the life of trees and protects them from death.

    Causes of the appearance of a hollow

    These include all types of mechanical damage that occurs during the life of the tree, especially those that have not been painted over or smeared with pitch. These can be, for example, tree fractures resulting from the departure of skeletal branches at an acute angle; injuries after improper pruning (if a branch is cut off leaving a stump), as a result of damage, bark scuffing, frost cracks.


    Danger of Wounds

    The appearance of open wounds on the trunk and skeletal branches of fruit crops weakens the tree. If they are not isolated in a timely manner, various fungi and bacteria begin to parasitize on the surface of the wounds, causing irreversible processes of wood decay. This is what causes the appearance of hollows on the trunk.

    How a hollow appears in a tree

    As the upper layer of wound cells dies off, access to the wood opens up. Under the influence of moisture, it soaks and serves as a good substrate for the reproduction of microorganisms involved in the further destruction of deeper layers.

    The hollow is a real disease of fruit trees. Hollow trees are characterized by weak growth and fruiting, lose strength and can break under the weight of the crop or from strong winds.

    To prevent the appearance of hollows on trees, it is necessary to create conditions for their rapid healing in a timely manner. But it should be remembered that the speed of wound healing is affected by their size. If the wound is small, then it will heal quickly, but if the wound is large, then it will take a longer period to heal.

    Related link: Treatment of trees in spring - cracks, frost holes and hollows

    Time for treatment

    Treatment of the hollow includes cleaning of dead wood, treating the inner surface with a fungicide, filling with broken bricks and filling with cement mortar. It is better to start it from mid-autumn in warm, dry times, because it is during this period that metabolic processes decrease in fruit trees.

    Filling trees with cement is carried out in mid-autumn, not later, so that the filling has time to dry well. It is undesirable to do this in the spring: insufficiently hardened materials may crumble due to wood growth. However, in case of urgent need, you should not wait until autumn.


    Deep hollows of small diameter can be plugged with wood cork and topped with garden putty.

    It is important to timely prevent moisture from entering the hollow and reduce the decay of wood. The treatment of the hollow in this case can be carried out in 2 stages. Clean the cavity of the hollow from dead wood, disinfect with fungicide

    and isolate the hollow from atmospheric precipitation, for example, using a plastic film or roofing material. And the filling and sealing should be postponed until the fall.

    Cleaning and disinfection

    After a hollow has appeared, it must be repaired immediately. In no case should the hollows that have arisen on the tree be left open for the winter.

    Fillings are made to prevent moisture from getting into them.

    The found hollow is cleaned of rotten wood by cleaning the walls. Pay special attention to the fact that after cleaning from rotten wood, the inner walls of the hollow are dry (photo 1). If they are wet, then within a few days the hollow must be ventilated and dried.

    After the site has been prepared, it is disinfected with a 3% solution of copper sulfate (300 g: 1 bucket of water) or a 5% solution of ferrous sulfate (500 g: 1 bucket of water). After that, it is dried a little again and then sealed.

    Hollow Filling

    The cheapest and most popular filling method is to fill the hollow with small gravel or broken bricks, followed by filling with a mixture of sand, cement and lime (6:1:1) (photo 2).

    After cleaning and disinfection, small holes can be plugged with a dry, strong hardwood cork. The top end of the cork should be at the level of the edges of the hollow. It must be covered with garden pitch or paint.

    If the hollows are very large, then filling with the indicated mixture is carried out in layers, as they are filled with crushed stone or broken bricks.

    The outer part is painted over with oil paint or poured with a thick mortar of cement and sand in order to block access to air and moisture to the wood (photo 3).

    See also: Do-it-yourself birdhouse (photo)

    Wound healing

    For better wound healing, you can use a black film polyethylene bandage. It is cut into ribbons 5-8 cm wide and spirally wound tightly from the bottom up,. on the hollow The upper end of the film is tightly tied with twine.

    In the spring, as soon as the active division of the cambium begins, the bandage is untied along the boundaries of the hollow, the bast is removed with a sharp knife, a strip of live cambium is opened and bandaged again. Under dark conditions, the cambium actively deposits cells of new tissues towards the hollow.

    Please tell me how to prolong the life of an apple tree. On it along the entire trunk there is a deep and long hollow (from the root to the beginning of the fruit branches). The bark and part of the wood inside the tree is missing. But an apple tree in such a deplorable state bears fruit. Not sure how the nutrients pass? Maybe you need to make some kind of gypsum and cover it up in order to stop further decay?

    Dmitry Larin

    Questions: “How to cure an apple tree, how to save an apple tree…” constantly arise. I must say that in the case of a large hollow, it is not about treatment, but about prolonging the life of the tree, it is unrealistic to cure it! Such a tree can be compared with a sick and badly neglected tooth. Doctors no longer treat him, but remove him.

    Strictly speaking, the diseased, dilapidated apple tree should also be removed from the orchard. A weakened plant “attracts” diseases, and then spreads infections in the form of fungal spores to other trees. But gardeners are not ready to give up the apple tree, especially when it continues to bear fruit.

    To describe the process of “treatment” of an apple tree, let us again turn to comparison. Imagine that you are a doctor and you need to fill a tooth.

    The first thing to do is thoroughly clean out any rotten fabric. The doctor has a drill for this. Gardeners have adapted to use a drill. A round metal brush is attached to it, which allows you to quickly clean dead tissue. This is much faster and more efficient than scraping out rot with different knives, spatulas and other tools.

    Naturally, not everywhere you can get a drill, it only speeds up the process if the hollow is large. In narrow places, you will have to work with other improvised means, for example, a wire bent in the form of a hook helps. It is advisable to remove all rotten, loose wood to a healthy tissue.

    After a thorough cleaning, the surface inside the hollow is treated with fungicides. Use a 5% solution of ferrous sulfate or the same solution of copper sulfate (Bordeaux mixture). The solution can be applied with a brush, and inside the trunk, especially in narrow places, it is better through a sprayer on a long boom. The solution should cover the surface very abundantly in order to destroy the fungus as much as possible.

    It is also recommended to use a special RanNet paste, where copper sulphate has already been added. For convenience, it is diluted thinner so that it can be applied with a brush.

    The problem with the apple tree is that we can't see the entire cavity of the hollow and can't clean out all the rot completely. The infection remains and continues to corrode the tree from the inside even after treatment with fungicides.

    The next step is to close the hollow from moisture with cement mortar (photo 2). This is a long-standing method, now polyurethane foam is also used. At the same time, the cement mortar strengthens the trunk if the hollow is too large.

    In the case told by Dmitry Larin (hollow in the form of a wide gap, along the entire trunk from bottom to top), before pouring cement, the trunk must be wrapped with a cloth so that the mortar does not spill out. If the cavity is too large, pebbles, broken bricks and even small plastic bottles are placed in the hollow to save cement.

    Stones and cement are laid in layers, making sure that the mortar fills the volume of the hollow as much as possible and displaces the air.

    When the cement hardens, proceed to the final stage - the hollow with cement mortar is covered with oil paint (preferably to match the tree trunk). This is necessary not only for aesthetic perception. The paint fills microcracks and protects against moisture. Periodically, the paint must be renewed.

    Depending on the size of the hollow and how carefully you have done the treatment, the life of the tree is extended by 3-5 years. During this time, a young seedling will grow up, which you will plant this spring to replace a sick apple tree.

    And, finally, the main thing. Trees need to be monitored, pruned correctly and on time, and the hollow will not have to be treated, it simply does not form!

    Treating a hollow in a tree. We put a filling.

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    It was a hollow, but already overgrown

    A hollow is a very dangerous formation on a tree trunk, which is important to cure quickly. The cause of its occurrence is the resulting open wound with damage to the cortex.

    The exposed wet layer of wood is completely defenseless against microorganisms and fungi. A hollow appears in the case of the death of the upper layer of the bark. This is a real disease that leads to a weakening of the tree, a decrease in yield and can even cause its death. Therefore, I advise you to carefully inspect your garden, so as not to let even the smallest wound.


    The resulting hollow is best treated in the fall - in October-November, or even at the beginning of winter, if the weather allows. At this time, sap flow slows down, the tree practically grows, and the filling, without interfering with physiological processes, has time to harden. But in the spring it is better not to carry out the procedure: juices will not allow the material to gain the necessary strength.

    Let's start the treatment of the hollow

    The treatment is carried out according to the same scheme, only the materials differ. The first step is to remove all rotten wood with a chisel, garden knife, or other cutting tool. It is important for us to get to the light fabric. First layer

    We also remove healthy wood, as there is a danger that it is already infected with a fungus. Then you need to remove small debris from the cavity and allow the wound to dry. The edges are also cut to bare wood.

    For disinfection, you can use a solution of vitriol - copper (300 g per bucket of water) or iron (500 g for the same volume). Before treating wood with fungicides, it must be completely dry!

    Fillings - not just for teeth

    If the hollow is small, then there will be no special problems with it, dry hardwood corks have proven themselves well here. They are hammered into the hollow, and then you need to carefully cut off the excess and close it with a layer of garden pitch.

    Difficulties may arise if the hollow in the tree is already large enough. To seal such a hole, it is necessary to prepare a solution of 1 part of lime, the same amount of cement and 6 parts of river sand. When hardening, the cement forms a reliable cork that prevents moisture and harmful microorganisms from entering the wood.

    After filling the hollow, the trunk at the treatment site must be bandaged, any materials can be used: cloth, parchment or plastic wrap. And then tightly tie everything from above with twine, twine, insulating tape or thin wire. This will be the tree band.


    Sometimes an apple tree looks completely intact, but when tapping on the trunk, you can find a void. A closed cavity threatens to rot inside the tree. It is necessary to cut or drill an artificial passage and clean the inner hollow in the same way as the open one.

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