Adaptive growth – this is an increase in wood production in certain areas of the tree in response to a decrease in overall wood strength or external loads with the aim of evenly distributing the forces acting upon the tree across the overall structure.
Annual growth ring – this is the sleeve of wood under the bark on both stem and branches that is put on each season over the previous year’s wood.
Arboriculture – this is the cultivation of trees in order to produce individual speciments of ornamental or amenity value, for shelter or any other primary purpose other than timber production.
Bark – this is the protective layer that covers the outside of stems and branches. Brak is made up of a number of different tissues including dead cork cells on the outside and living cork cells on the inside.
Beat up – this is the process of replacing failutes in a new tree planting scheme, within a few years of planting.
Bracing – this is the installation of cables, ropes or belts to stabilise the structure of the tree to mitigate failure (pictured right). Bracing is usually used if parts of a tree’s structure have been weakened or in newly planted specimens.
Branch bark ridge and collar – this is the point where a branch joins the trunk or another branch. It is a natural feature that is usually distinguished by a ridge or rippled bark.
Broad-leaf – this is a tree which has broad, often laminar leaves as opposed to needles. The species classification is based upon its botanical characteristics, mainly that of its flowers and seeds, but can also include foliage. Not all broad-leaved species have broad leaves or hard wood. In the UK, most are deciduous.
Callus – this is a growing mass of cells that cover a plant wound.
Cambium – this is the layer of living cells just under the bark from which new growth develops.
Canker – this is a disease-damaged area usually caused by fungi or bacteria.
Cavity – this is a void within the structure of a tree caused by decay. It is advisable not to drain a cavity that is filled with water, only the soft, decomposing tissue at the edges should be removed if required in order to assess the extent of the void.
Co-dominant stems – this is where two or more stems compete with each other for dominance. They are usually upright and of equal size. It is important to assess the structural integrity of co-dominant stems regularly.
Coppicing– the act of regularly cutting down a tree within 300 millimetres of ground level. This technique is often applied to very particular species such as hazel.
Crown – this is the upper aprt of the tree including the stem, branches and foliage.
Deciduous – these are trees that shed all of their foliage for the duration of the annual dormant season. They are the opposite of evergreen.
Deadwood – these are branches or stems that are no longer living due to the natural aging process, or external influences. Deadwood forms an esential part of the local ecosystem and so as much should be left in the tree as possible. It is advisable to shorten or remove only those branches that pose a risk.
Decline – this is when a tree shows reduced signs of vitality for example: leaf colour, leaf size and the density of leaves in the crown.
Dieback – this is when the tips of the branches show no sign of life due to the natural aging process, or external factors. It is important to monitor dieback closely as it can either progress, stabilise or reverse as the tree adapts to its surroundings.
Dormant – this is the period of time when a tree is at its most inactive, typically between mid-October and March, although this does vary from species to species. There is limited growth during dormancy and deciduous trees will tend to shed their leaves.
Drop crotching – this is the process of shortening branches by pruning the ends back to a lateral limb which is at least one-third of the diameter of the portion of branch being removed.
Epicormic growth – this is new growth that arises from dormant or new buds, directly from the main branches, stem or trunk.
Evergreen – these are trees that retain their leaves all year round and usually for several years, even during dormancy. They are the opposite of deciduous and whilst the most recognised are spruces or pines, evergreen trees include a wide variety of speciments such as eucalyptus, ferns, cycads and palms.
Fertilising – this is the application of a chemical or natural substance to the tree’s root area with the aim of making the area more fertile where a deficiency has been confirmed. Fertilisation can help boost plant growth, or reduce the effects of decline.
Formative pruning – this is the minor pruning and removal of branches and/or stems of young broad-leaved trees to ensure that the tree grows with a single stem and light branching. It is practiced between three and 10 years after platning, and can be used to correct any defects that may impact on the tree’s structure as it grows.
Fungi – this is a spore-producing organism that feeds on organic matter and may colonise the living or dead tissues of a tree. It is important that a fungal colony is investigated by a specialist in order to determine the potential health and structural implications it may have for the tree.
Growth flush – this is a spurt of growth that a tree undergoes typically during spring.
Leader – this is the main vertical shoot in the crown of a tree.
Lopping and topping – these are outdated techniques that are no longer considered best practice. Lopping refers to the removal of large, side branches by making big vertical cuts. Topping refers to the removal of a large portion of the crown with big, horizontal cuts through the main stems.
Painting or sealing – this is the act of covering pruning wounds with bitumen-based paint. It is thought to be potentially harmful to the tree and should be avoided.
Pollard – these is the method of cutting trees above the browsing height of large animals and allowing them to regrow with a multi-stemmed crown. Pollarding is also used to reduce the size of urban and young trees and encouraging multi-stemmed growth from that point. Once started, the process of pollarding should be repeated on a cyclical basis always retaining the initial pollarding point.
Retrenchment pruning – this is a reduction technique that aims to encourage the development of the lower shoots and replicates the natural tree aging process.
Root pruning – this is the pruning back of a tree’s roots, commonly used before planting or relocation projects. The technique can affect a tree’s stability so we recommend seeking professional advice prior to undertaking any work.
Spot weeding – this is the process of weeding around individual trees once planted.
Veteran tree – this is a tree that is of special interest biologically, culturally or aesthetically due to its size, age, or condition.
Vitality – a tree’s capacity to live, grow, develop and importantly, thrive.