Terms and definitions Flashcards
For the purposes of this British Standard, the following terms and definitions apply
3.1 adaptive growth
process whereby the rate of wood formation in the cambial zone, as well as wood quality, responds to gravity and other forces acting on the cambium.
NOTE This helps to maintain a uniform distribution of mechanical stress.
3.2 adventitious bud/root/shoot
bud/root/shoot that forms other than through primary development
NOTE For example, shoots which develop other than from terminal or axillary buds, or roots which are initiated within the mature tissues of a stem or woody root. See also 3.15.
3.4 arisings
any parts of a tree, including stem, roots, branches (brushwood), bark, other woody material and foliage, derived from the tree during tree work operations
3.5 canker
area of dead cambium and overlying tissues killed by a pathogen
3.6 cavity
hole in a woody part of a tree caused by decay or damage
NOTE Cavities can hold water (wet cavity) or be dry
3.7 co-dominant stem/branch
upward growing stem/branch with a similar height and disposition as another stem/branch
NOTE Where such stems/branches arise from the same union, their stability or the integrity of the attachment of the stems/branches could be compromised. See also 3.17.
3.8 competent person
person who has training and experience relevant to the matter being addressed and an understanding of the requirements of the particular task being approached
NOTE A competent person is expected to understand the hazards pertinent to the task being carried out and the methods to be implemented to eliminate or reduce the risks that can arise. For example, when on site, a competent person is able to recognize at all times whether it is safe to proceed.
3.9 coppicing
cutting trees close to ground level with the intention of encouraging regrowth of multiple shoots
3.10 crotch
forked region formed by the junction of a branch and the stem, or by two branches
3.11 crown
main foliage-bearing part of a tree
3.12 crown lifting
removal of lower branches to achieve a stated vertical clearance above ground level or other surface
NOTE The vertical clearance will usually be stated in the work specification (4.1).
3.13 crown reduction
operation that results in an overall reduction in the height and/or spread of the crown of a tree by means of a general shortening of twigs and/or branches, whilst retaining the main framework of the crown
3.14 crown thinning
removal of a proportion of small, live branches from throughout the crown to achieve an even density of foliage around a well-spaced and balanced branch structure
3.15 epicormic branch/bud/shoot
branch/bud/shoot initiated on a mature woody stem or branch
NOTE Shoots can form in this way from dormant buds or be adventitious (see also 3.2)
3.16 heartwood
dead or predominantly dead central wood of tree species whose sapwood has a finite and pre-determined lifespan NOTE In some species heartwood is highly durable
because it contains pre-formed defensive substances. In certain others, it remains chemically reactive when exposed to air and/or fungal colonization. It is sharply delineated from the sapwood (3.24) because the sapwood–heartwood conversion involves the death of most of the sapwood cells at about the
same time (c.f. ripewood, 3.23). It can be harder than the sapwood and/or distinctly coloured
3.17 included bark
bark tissue lodged in the union between a branch and the parent stem, in the crotch of two branches, or between the bases of co-dominant stems, indicating potential weak attachment
3.18 knuckle
swelling that forms at a pollard point, especially after repeated cutting
3.19 lapsed coppice/lapsed pollard
tree that has been coppiced/pollarded but has not been maintained by cycles of cutting
NOTE See also 3.9 and 3.20
3.20 pollard
tree that has formed a crown consisting of numerous branches arising from the same height on a main stem or principal branches
NOTE This can be by natural process or by pollarding (3.21).
3.21 pollarding
cutting a tree so as to encourage formation of numerous branches arising from the same height on a main stem or principal branches
NOTE 1 This process is initially carried out on trees that have not yet reached maturity. The form of the tree can then be maintained by cycles of cutting. This is not the same as topping (3.28).
NOTE 2 The pollard heads collectively, and the framework of a pollarded tree, are both known as the bolling
3.22 retrenchment pruning
form of crown reduction (3.13), intended to encourage development of the lower crown, which emulates the natural process whereby the crown of an ageing tree retains its overall biomechanical integrity by becoming smaller through the progressive shedding of small branches
3.23 ripewood
older central wood of those tree species in which sapwood gradually ages without being converted to heartwood
NOTE Ripewood is usually not durable since it lacks both pre-formed defensive substances and an ability to react to wounding. It is not sharply delineated from the sapwood because the cells die gradually over many years. See also 3.16 and 3.24.
3.24 sapwood
outer, living, water-conducting part of the wood of a tree
NOTE See also heartwood (3.16) and ripewood (3.23).
3.25 stem
principal above-ground structural component of a tree that supports the branches
NOTE 1 This either extends throughout most of the height of the tree (primary stem), or is one of a number of such components (secondary stems) which divide from each other either near the ground or at a higher level.
NOTE 2 Trees comprising two or more stems arising from, or immediately above, ground level are commonly referred to as “twin-stemmed” or “multi-stemmed”.
NOTE 3 ”Stem” is synonymous with “trunk” for single-stemmed trees, particularly those of a large diameter.
3.26 stub
broken or severed short remaining section of a branch extending beyond a crotch
NOTE Also known as a “snag” or “noggin”.
