Epicormic shoot
Encyclopedia
An epicormic shoot is a shoot
growing from an epicormic bud which lies underneath the bark
of a trunk
, stem
, or branch
of a plant
.
beneath the bark, their growth suppressed
by hormones from active shoots higher up the plant. Under certain conditions they develop into active shoots, such as when damage occurs to higher parts of the plant, or light levels are increased following removal of nearby plants. Epicormic buds and shoots occur in many woody species, but are absent from many others, such as most conifers.
practices that exploit epicormic growth rely on plants that have epicormic budding capabilities for regenerative
function in response to crown
damage, such as through wind
or fire
.
Epicormic shoots are the means by which trees regrow after coppicing
or pollarding
, where the tree's trunk or branches are cut back on a regular cycle. These forestry
techniques cannot be used on species which do not possess strong epicormic growth abilities.
Pruning
leads to growth of suppressed shoots below the cut – these may be from epicormic buds, but they may also be other growth, such as normal bud
s or small shoots which are only partly suppressed.
which would destroy most other plants, many Eucalypt
tree
s found widely throughout Australia
have extensive epicormic buds which sprout following a fire, allowing the vegetative
regeneration
of branches from their trunks. These epicormic buds are highly protected, set deeper beneath the thick bark than in other tree species, allowing both the buds and vascular cambium
to be insulated
from the intense heat. It should however be noted that not all eucalypt trees possess this means of vegetative recovery, and the ability of a tree to survive and re-sprout depends on many factors, such as fire intensity, scorch height, and tree height, species, age, and size. Jarrah trees, found in the south-west of Western Australia
, have epicormic buds which are activated after a bushfire or other extreme conditions.
The mediterranean Quercus suber (cork oak) resprouts from epicormic buds after fire.
Epicormic shoots sometimes appear on dogwood
trees dying from dogwood anthracnose (Discula destructiva
), a fungal
disease, which are susceptible to the infection.
Epicormic shoots can be used in mass propagation
of oak
trees.
The long-lived Pseudotsuga menziesii forms epicormic shoots not in response to damage but as a means of forming growth on existing branches. The epicormic branching pattern has been observed to six iterations.
Shoot
Shoots are new plant growth, they can include stems, flowering stems with flower buds, and leaves. The new growth from seed germination that grows upward is a shoot where leaves will develop...
growing from an epicormic bud which lies underneath the bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
of a trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...
, stem
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
, or branch
Branch
A branch or tree branch is a woody structural member connected to but not part of the central trunk of a tree...
of a plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
.
Epicormic buds
Epicormic buds lie dormantDormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
beneath the bark, their growth suppressed
Apical dominance
In plant physiology, apical dominance is the phenomenon whereby the main central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets....
by hormones from active shoots higher up the plant. Under certain conditions they develop into active shoots, such as when damage occurs to higher parts of the plant, or light levels are increased following removal of nearby plants. Epicormic buds and shoots occur in many woody species, but are absent from many others, such as most conifers.
Function
Human horticulturalHorticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
practices that exploit epicormic growth rely on plants that have epicormic budding capabilities for regenerative
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. At its most...
function in response to crown
Crown (botany)
The crown of a plant refers to the totality of the plant's aboveground parts, including stems, leaves, and reproductive structures. A plant canopy consists of one or more plant crowns growing in a given area....
damage, such as through wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
or fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
.
Epicormic shoots are the means by which trees regrow after coppicing
Coppicing
Coppicing is a traditional method of woodland management which takes advantage of the fact that many trees make new growth from the stump or roots if cut down. In a coppiced wood, young tree stems are repeatedly cut down to near ground level...
or pollarding
Pollarding
Pollarding is a pruning system in which the upper branches of a tree are removed, promoting a dense head of foliage and branches. It has been common in Great Britain and Europe since medieval times and is practiced today in urban areas worldwide, primarily to maintain trees at a predetermined...
, where the tree's trunk or branches are cut back on a regular cycle. These forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
techniques cannot be used on species which do not possess strong epicormic growth abilities.
Pruning
Pruning
Pruning is a horticultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping , improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for...
leads to growth of suppressed shoots below the cut – these may be from epicormic buds, but they may also be other growth, such as normal bud
Bud
In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of the stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be specialized to develop flowers or short shoots, or may have...
s or small shoots which are only partly suppressed.
Examples
As one of their responses to frequent bushfiresBushfires in Australia
Bushfires in Australia are frequently occurring events during the hotter months of the year due to Australia's mostly hot, dry climate. Large areas of land are ravaged every year by bushfires, which also cause property damage and loss of life....
which would destroy most other plants, many Eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s found widely throughout Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
have extensive epicormic buds which sprout following a fire, allowing the vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
regeneration
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. At its most...
of branches from their trunks. These epicormic buds are highly protected, set deeper beneath the thick bark than in other tree species, allowing both the buds and vascular cambium
Vascular cambium
The vascular cambium is a part of the morphology of plants. It consists of cells that are partly specialized, for the tissues that transport water solutions, but have not reached any of the final forms that occur in their branch of the specialization graph...
to be insulated
Insulation
Insulation means:* Building insulation, added to buildings for comfort and energy efficiency* Soundproofing, also known as acoustic insulation, any means of reducing the intensity of sound...
from the intense heat. It should however be noted that not all eucalypt trees possess this means of vegetative recovery, and the ability of a tree to survive and re-sprout depends on many factors, such as fire intensity, scorch height, and tree height, species, age, and size. Jarrah trees, found in the south-west of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, have epicormic buds which are activated after a bushfire or other extreme conditions.
The mediterranean Quercus suber (cork oak) resprouts from epicormic buds after fire.
Epicormic shoots sometimes appear on dogwood
Dogwood
The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
trees dying from dogwood anthracnose (Discula destructiva
Discula destructiva
Discula destructiva is a fungus in the family Valsaceae which causes dogwood anthracnose, affecting populations of dogwood trees native to North America....
), a fungal
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
disease, which are susceptible to the infection.
Epicormic shoots can be used in mass propagation
Plant propagation
Plant propagation is the process of creating new plants from a variety of sources: seeds, cuttings, bulbs and other plant parts. Plant propagation can also refer to the artificial or natural dispersal of plants.-Sexual propagation :...
of oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
trees.
The long-lived Pseudotsuga menziesii forms epicormic shoots not in response to damage but as a means of forming growth on existing branches. The epicormic branching pattern has been observed to six iterations.
See also
- Adventitiousness
- Apical dominanceApical dominanceIn plant physiology, apical dominance is the phenomenon whereby the main central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets....
- CoppicingCoppicingCoppicing is a traditional method of woodland management which takes advantage of the fact that many trees make new growth from the stump or roots if cut down. In a coppiced wood, young tree stems are repeatedly cut down to near ground level...
- Crown sproutingCrown sproutingCrown sprouting is the ability of a plant to regenerate its shoot system after destruction by activating dormant vegetative structures to produce regrowth from the root crown . These dormant structures take the form of lignotubers or basal epicormic buds...
- Cutting (plant)
- LignotuberLignotuberA lignotuber is a starchy swelling of the root crown possessed by some plants as a protection against destruction of the plant stem by fire. The crown contains buds from which new stems may sprout, and a sufficient store of nutrients to support a period of growth in the absence of...
- Plant hormonePlant hormonePlant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
- PollardingPollardingPollarding is a pruning system in which the upper branches of a tree are removed, promoting a dense head of foliage and branches. It has been common in Great Britain and Europe since medieval times and is practiced today in urban areas worldwide, primarily to maintain trees at a predetermined...
- ResprouterResprouterResprouters are plant species that are able to survive fire by the activation of dormant vegetative buds to produce regrowth.Plants may resprout by means of lignotubers at the base or epicormic buds on the trunk or major branches....
- Witch's broomWitch's broomA Witch's broom is a disease or deformity in a woody plant, typically a tree, where the natural structure of the plant is changed. A dense mass of shoots grows from a single point, with the resulting structure resembling a broom or a bird's nest....