Terms and definitions

Question 1

3.1 adaptive growth

Answer 1

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.

Question 2

3.2 adventitious bud/root/shoot

Answer 2

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.

Question 3

3.4 arisings

Answer 3

any parts of a tree, including stem, roots, branches (brushwood), bark, other woody material and foliage, derived from the tree during tree work operations

Question 4

3.5 canker

Answer 4

area of dead cambium and overlying tissues killed by a pathogen

Question 5

3.6 cavity

Answer 5

hole in a woody part of a tree caused by decay or damage

NOTE Cavities can hold water (wet cavity) or be dry

Question 6

3.7 co-dominant stem/branch

Answer 6

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.

Question 7

3.8 competent person

Answer 7

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.

Question 8

3.9 coppicing

Answer 8

cutting trees close to ground level with the intention of encouraging regrowth of multiple shoots

Question 9

3.10 crotch

Answer 9

forked region formed by the junction of a branch and the stem, or by two branches

Question 10

3.11 crown

Answer 10

main foliage-bearing part of a tree

Question 11

3.12 crown lifting

Answer 11

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).

Question 12

3.13 crown reduction

Answer 12

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

Question 13

3.14 crown thinning

Answer 13

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

Question 14

3.15 epicormic branch/bud/shoot

Answer 14

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)

Question 15

3.16 heartwood

Answer 15

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

Question 16

3.17 included bark

Answer 16

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

Question 17

3.18 knuckle

Answer 17

swelling that forms at a pollard point, especially after repeated cutting

Question 18

3.19 lapsed coppice/lapsed pollard

Answer 18

tree that has been coppiced/pollarded but has not been maintained by cycles of cutting

NOTE See also 3.9 and 3.20

Question 19

3.20 pollard

Answer 19

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).

Question 20

3.21 pollarding

Answer 20

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

Question 21

3.22 retrenchment pruning

Answer 21

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

Question 22

3.23 ripewood

Answer 22

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.

Question 23

3.24 sapwood

Answer 23

outer, living, water-conducting part of the wood of a tree

NOTE See also heartwood (3.16) and ripewood (3.23).

Question 24

3.25 stem

Answer 24

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.

Question 25

3.26 stub

Answer 25

broken or severed short remaining section of a branch extending beyond a crotch

NOTE Also known as a “snag” or “noggin”.