Branch collar
Encyclopedia
A branch collar is the attachment structure in woody plants that connects a branch
to its parent branch or to the trunk
. The branch collar consists of overlapping wood fibers
.
During plant growth cycles, wood
on smaller branches forms first. Wood at the base of the branch extends slightly over the face of the trunk, forming the branch collar. Then, the wood of the parent branch forms over the top of the basal branch wood, usually forming a circular structure called the trunk collar. Together, the branch collar and trunk collar are simply referred to as the branch collar. Branch collars can also be flat or somewhat recessed into the trunk or parent branch, as in some conifers.
The accretion of layers of wood behind the branch collar is a conical
decay-resistant structure called the branch core. The knot found in lumber
is this branch core.
When woody plants naturally shed branches because they are nonproductive, usually from lack of light, these branches die back to the branch collar. Insects and fungi decompose the dead branch, and it eventually falls off, leaving the exposed branch core. The branch core resists the spread of decay organisms into the parent branch or trunk during the time it takes for the woundwoodhttp://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun014.htm, or callus, to seal over the wound.
Events such as storms or pruning
may damage the branch collar, thus defeating the naturally-occurring defense of the branch core and exposing the trunk to decay. Understanding the branch collar anatomy is important in tree
pruning. Pruning practices that mimic natural branch shedding avoid unnecessary damage to the plant's defensive anatomy.
Branch
A branch or tree branch is a woody structural member connected to but not part of the central trunk of a tree...
to its parent branch or to the 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...
. The branch collar consists of overlapping wood fibers
Wood fibre
Wood fibres are usually cellulosic elements that are extracted from trees, straw, bamboo, cotton seed, hemp, sugarcane and other sources.The end paper product dictates the species, or species blend, that is best suited to provide the desirable sheet characteristics, and also dictates the required...
.
During plant growth cycles, wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
on smaller branches forms first. Wood at the base of the branch extends slightly over the face of the trunk, forming the branch collar. Then, the wood of the parent branch forms over the top of the basal branch wood, usually forming a circular structure called the trunk collar. Together, the branch collar and trunk collar are simply referred to as the branch collar. Branch collars can also be flat or somewhat recessed into the trunk or parent branch, as in some conifers.
The accretion of layers of wood behind the branch collar is a conical
Cone (geometry)
A cone is an n-dimensional geometric shape that tapers smoothly from a base to a point called the apex or vertex. Formally, it is the solid figure formed by the locus of all straight line segments that join the apex to the base...
decay-resistant structure called the branch core. The knot found in lumber
Lumber
Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....
is this branch core.
When woody plants naturally shed branches because they are nonproductive, usually from lack of light, these branches die back to the branch collar. Insects and fungi decompose the dead branch, and it eventually falls off, leaving the exposed branch core. The branch core resists the spread of decay organisms into the parent branch or trunk during the time it takes for the woundwoodhttp://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun014.htm, or callus, to seal over the wound.
Events such as storms or 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...
may damage the branch collar, thus defeating the naturally-occurring defense of the branch core and exposing the trunk to decay. Understanding the branch collar anatomy is important in 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...
pruning. Pruning practices that mimic natural branch shedding avoid unnecessary damage to the plant's defensive anatomy.