Glossary
Glossary on Pruning Techniques
Glossary on Site Work
Apical Meristems
Start in buds and continue in tips of twigs. Roots do not form buds. Apical meristems are active in tips of roots.
Apoplast
Is the network of connected dead cells and cell walls that act as the tough framework that holds the symplast in place. The apoplast holds water.
Bark
Is the protective covering of trees. Bark is made up of living and dead cells. Bark keeps moisture and gases in and resists attach by insects and micro-organisms.
Barrier Zone
Bolling
A term usually used to describe a pollard head (the original zone of primary pollarding). Sometimes the term also includes the main trunk of a pollard tree.
Branch
A branch may extend from either a limb or the main trunk, and it divides into branchlets and twigs which support the leaves.
Branchlet
A branchlet is a side shoot of a branch.
Branch Collar / Branch Bark Ridge
A feature associated with the base of a branch at its point of attachment to a parent stem or trunk where a thickening of tissues is present that indicates the separation between branch and stem.
Buds
Are organs made up of small preformed parts and an apical meristem. There are leaf buds, flower buds - male alone, female alone, male and female and mixed buds that have leaves and stems and flowers.
Calus
Is a soft, non-woody tissue that forms about the edges of fresh wounds. Atfer several woods to a few months, during the growing period, it is replaced by woundwood.
Cambium Zone
Is a cell generator that is between the wood and inner bark. The cambial zone produces cells on its outer side that mature to form phloem. The zone produces cells on its inner side that mature to form xylem. The cambial zone is sometimes called the vascular cambium. It is not green. It is rarely made up of a single layer of cells. The cambial zone is a meristem.
Canopy
This is a general term used to describe the crown area when it is in full leaf and the internal branch structure is obscured by the external canopy of leaves. When only the silhouette of the crown area is seen, because the leaves are obscuring the internal framework of branches that support them.
Cellulose
is a substance made up of long, twisting chains of glucose molecules.
Codit
A model used to describe the Compartmentalisation Of Decay In Trees, it describes four ìwallsî of defence that the tree uses to confine the spread of decay. These are: wall 1 ñ resistance to vertical spread; wall 2 ñ resistance to inward spread: wall 3 resistance to lateral or circumferential spread; and, wall 4 ñ separates infected wood from new healthy wood that continues to form around the wounded area.
Cortex
Is a tissue in the bark of young trees and in some old trees, that contains chlorophyll, the substance that can trap the energy of the sun in a process called photosynthesis.
Crown
That part of a tree where the greater mass of foliar bearing growth is present and is composed of limbs, branches and foliage. The crown area of a tree includes growth from the main branches out to the tips of the furthest twig. The main trunk is not part of the crown area.
Decay
The degradation of plant tissues, including wood, by an organic process over time, often accelerated by organisms such as fungi and bacteria. The decay process in a natural and integral part of the arboreal ecosystem.
Deciduous
Trees that loose their leaves in Autumn are known as deciduous. This process reduces their wind resistance over winter, when the weather is often most damaging.
Diomorphic
Dormant Season
Deciduous trees have a period of dormancy over the winter months when there is no available energy from photosynthesis and they become inactive.
Epicormic Growth or Shoot
Growth derived from a dormant or adventitious bud on a main stem or branch. Such growth within the crown of fully mature and veteran trees is valued for longevity and its protection and promotion is an important aspect of veteran tree management (see Retrenchment Pruning & Reiterative Growth).
Evergreen
Trees that retain living ( green ) leaves all year round. Evergreen trees are more susceptible to weather damage over winter when heavy snow fall and high winds can break branches.
Fibers
Are vertically aligned cells that have thick, tough walls. Most fiber cells live for less than a year. Dead fiber cells provide strong mechanical support for trees.
Growing Season
This is a collective term for the summer months when enough energy is available from photosynthesis to sustain growth throughout the tree.
Heartwood
Is a type of protection wood where protection substances form as a result of normal genetically controlled aging processes as cells die. The substances often, but not always, impart a colour to the wood darker than the sapwood..
Hemicelluloses
Are substances made up of twisting chains of glucose molecules, but are distinct from cellulose because they comprise shorter chains of sugars.
Internal Shoot Growth
Internal epicormic growth from adventitious shoots or dormant buds.
Lignified
See xylem.
Lignin
Is a complex three-dimensional substance that is like a natural ëcement', which bonds cells together, and gives wood some of it's structural strength.
Limbs
The major components of the framework forming the tree's crown. A limb could be described as; a large branch or small trunk, which supports a section of the trees crown area. A limb could extend from the main trunk up to a fork or dividing point where it separates into smaller branches.
Madulary Rays
See parenchyma.
Main Branch Frame
This is a general term used to describe the internal framework of limbs and main branches, which support the canopy of leaves.
Main Trunk
The trunk is the thickest woody stem visible above ground and it extends from the surface of the soil up into the crown where it divides into a number of limbs.
Meristems
Are groups of cells that have the ability to divide and produce more cells that eventually differentiate or mature to form all parts of the tree. Apical meristems increase the length of stems and roots, and produce flowers. The vascular meristem, or cambium zone, increases the girth or circomference of the tree.
Monolith
A standing dead tree usually with truncated limbs and height, managed for long-term retention.
Outer Bark
Or periderm is mostly dead cells lined with a fatty substance called suberin or cork.
Parenchyma
Are thin walled cells that contain living substances for a few to many years ñ over 150 years in some trees. Parenchyma cells may be axial ñ aligned vertically, or radial ñ aligned in radial ray-like arrangements. Radial parenchyma make up structures called rays.
Phloem
Is inner bark, is a transport tissue. It transports energy- containing substances made in leaves towards non-woody absorbing roots.
Photosynthosis
This is an energy trapping process which uses light energy from the sun to produce glucose out of carbon dioxide and water. This glucose it then used to provide the energy for cell production and growth around the tree.
Poll (=Pole)
Pollard stem/s originating from the bole.
Pollard (N)
A tree that in the past has been subject to the removal of principal crown limbs to near the top of the main trunk (bole).
Protection Wood
Is wood that no longer has any living cells, and has been altered to a state what is more protective than the sapewood. When wounded, sapwood has a dynamic response because of living cells. When protection wood is wounded, chemically altered substances in the cells and cell walls resist the spread of infectionss.
Reaction Wood
Reaction Zone
Re-iterative Growth
A shoot growth developing from internal upper surface of branches (arising from dormant or cambial growth). In ancient trees this anatomical feature may develop into a structural component capable of independent functional linkage to the root system.
Ripe Wood
Sap Wood
Is wood that contains living cells or a symplast.
Symplast
Is the network of connected living axial and radial parenchyma cells in sapwood and inner bark. The symplast stores energy reserves.
Snag or Stub
A short section of a branch extending beyond the branch-bark collar. This may be naturally occurring or the result of previous prunings.
Sucker
A shoot arising from a root system below or just at ground level (the term usually refers to unwanted growth from the rootstock often of a grafted or budded plant).
Stem
Stem is a general term used to describe a growing plant structure which increased in length and width to support; leaves, twigs, branches, etc. Both trunks and limbs can be described as stems, and a stem may attach fruit or flowers to a twig.
Tracheids
Are dead, single-celled transport ìpipesî for liquids in xylem. Tracheids are found in Gymnosperms ñ plants that have naked or uncovered seeds such as conifers.
Trunk
The main stem of the tree, which supports the crown.
Twig
A twig is a small woody stem of shoot of less than 10mm in diametre.
Tylocies
Vessels
Are vertically aligned tubes of 'pipes' up of many dead cells that transport liquids in xylem. Vessels are found in Angiosperms ñ plants that have covered seeds such as oaks and maples.
Wet Wood
Woundwood
Is a very tough, woody tissue that grows behind callus and replaces it in that position. When woundwood closes wounds, then normal wood continues to form.
Wood
Is a highly ordered arrangement of living, dying and dead cells that have walls of cellulose, hemicelluloses and lignin.
Xylem
is a transport tissue. It transports free water and substances dissolved in it, from absorbing non-woody roots to leaves. When xylem is lignified it is then correctly called wood. Lignification means that high amounts of the natural 'cement' called lignin is deposited within the cellulose strands in the cell walls. This makes the cell walls very trough. Having tough, lignified cell walls is a unique feature of trees.
