Epicormic shoot
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An epicormic shoot is a shoot growing from an epicormic bud, which lies underneath the
bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...
of a
trunk Trunk may refer to: Biology * Trunk (anatomy), synonym for torso * Trunk (botany), a tree's central superstructure * Trunk of corpus callosum, in neuroanatomy * Elephant trunk, the proboscis of an elephant Computing * Trunk (software), in rev ...
,
stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...
, or
branch A branch, sometimes called a ramus in botany, is a woody structural member connected to the central trunk of a tree (or sometimes a shrub). Large branches are known as boughs and small branches are known as twigs. The term '' twig'' usuall ...
of a
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
. Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up the plant. Under certain conditions, they grow 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
conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ext ...
s.


Function

Human
horticultural Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...
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 Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ...
or
fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. At a certain point in the combustion reaction, called the ignition point, flames ...
. Epicormic shoots are the means by which trees regrow after coppicing or
pollarding Pollarding is a pruning system involving the removal of the upper branches of a tree, which promotes the growth of a dense head of foliage and branches. In ancient Rome, Propertius mentioned pollarding during the 1st century BCE. The practice ...
, where the tree's trunk or branches are cut back on a regular cycle. These
forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests, woodlands, and associated resources for human and environmental benefits. Forestry is practiced in plantations and natural stands. ...
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 buds or small shoots which are only partly suppressed.


Examples

Epicormic resprouting is typical of some tree species from fire-prone ecosystems. As one of their responses to frequent bushfires which would destroy most other plants, many Eucalypt
tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s found widely throughout
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
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 The vascular cambium is the main growth tissue in the stems and roots of many plants, specifically in dicots such as buttercups and oak trees, gymnosperms such as pine trees, as well as in certain other vascular plants. It produces secondary xy ...
to be insulated from the intense heat. 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 ''Eucalyptus marginata'', commonly known as jarrah, djarraly in Noongar language and historically as Swan River mahogany, is a plant in the myrtle family, Myrtaceae and is endemic to the south-west of Western Australia. It is a tree with r ...
trees, found in the south-west of
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...
, 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.
Dogwood ''Cornus'' is a genus of about 30–60 species of woody plants in the family Cornaceae, commonly known as dogwoods, which can generally be distinguished by their blossoms, berries, and distinctive bark. Most are deciduous trees or ...
trees which are susceptible to a fungal infection known as dogwood
anthracnose A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...
('' Discula destructiva'') will sometimes send out epicormic shoots when they are dying from the disease. Similarly, ash trees may develop epicormic shoots when infested by the emerald ash borer. Epicormic shoots can be used in mass
propagation Propagation can refer to: *Chain propagation in a chemical reaction mechanism *Crack propagation, the growth of a crack during the fracture of materials * Propaganda, non-objective information used to further an agenda * Reproduction, and other for ...
of oak trees. The long-lived '' Pseudotsuga macrocarpa'' ( Bigcone Douglas fir) 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.''Crown development of long-lived trees''
University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seatt ...


See also

*
Adventitiousness Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant a ...
* Apical dominance * Coppicing *
Crown sprouting Crown sprouting is the ability of a plant to regenerate its shoot system after destruction (usually by fire) by activating dormant vegetative structures to produce regrowth from the root crown (the junction between the root and shoot portions of ...
* Cutting (plant) * Lignotuber *
Plant hormone Plant hormone (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pat ...
*
Pollarding Pollarding is a pruning system involving the removal of the upper branches of a tree, which promotes the growth of a dense head of foliage and branches. In ancient Rome, Propertius mentioned pollarding during the 1st century BCE. The practice ...
* Resprouter * Witch's broom


References


External links


Epicormic roots on a Norway Maple videoEpicormic shoots on oak, alder and larch
{{DEFAULTSORT:Epicormic Shoot Horticulture