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Glossary of Farm Forestry Terms

Note Number: AG0795
Published:January 2002
Updated: August 2008

This Agriculture Note is a list of terms commonly used in farm forestry, along with their definitions.

Agroforestry

The integration of trees with other agricultural enterprises on a farm. Trees are typically planted as timberbelts, shelterbelts, alleys or woodlots amongst pastures or row crops.

Alley farming

A form of agroforestry where trees are arranged in belts with conventional agriculture in the alley between the trees.

Annuity value

A fixed annual return on an investment. For example, in some tree-growing joint ventures the returns normally expected to be received at the end of the venture are distributed as an annual return over the term of the venture. See also Internal rate of return.

BA (Basal area)

The cross sectional area (m2) of a tree at Breast Height (1.3 m). BA= 0.00007854 x dbh2. The sum of the basal area for all the trees in a unit area is used as a measure of stand density and is usually expressed in terms of m2/ha.

Backsawing

A term describing the method of sawing timber where trees growth rings are less than 45° to the face of the board, when the board is viewed in cross section.

Basket whorl

A particularly dense whorl (circular arrangement) of braches on a tree. Basket whorls are relevant to pine trees, and may contain over a dozen branches. If the whole whorl is removed at once, the trunk may break at that point or the tree may die.

Bole

The trunk or stem of a tree. Generally thought of as the merchantable part of the stem, the bottom part of the stem.

Breast height (BH)

1.3 m above the ground. The standard height at which tree diameter is measured. For increased inventory precision a 1.3m stick should be used for locating breast height.

Browsing

The action of animals (vermin, native animals, stock and insects) grazing on trees. Damage may be insignificant or, may cause the tree to die, or affect quality of final timber product.

Butt log

The lowest log cut from the tree (ie. the lowest part of the trunk or bole). Usually this is the only clearwood log and may represent the bulk of the timber value of a tree.

Butt sweep

A substantial curve in the trunk of a tree near the ground (also known as sweep). Butt sweep occurs when a tree is partially windthrown when young, but then stabilises its roots with further growth being straight. See also Windthrow.

CAI (Current annual increment)

The volume of wood grown by a stand of trees in the current 12-month period. Units are m3/ha. See also MAI.

Canopy

The mass of branches and leaves of a tree (also called Crown).

Canopy closure

The point at which the crown of the trees present on a site begin to contact each other. It is usually after this point that competition between the trees results in tree growth below the potential growth of that tree.

Carbon sequestration

The process where trees and other plants take up carbon dioxide (CO2) from the atmosphere and store it in their leaves, branches, stems and roots. Plants sequester CO2 as part of the growing process.

CDUB

Centre diameter under bark, measurement of diameter of a log in cm taken halfway along the length of the log.

Clearfelling (CF)

Often called clearfall, the final harvest of all the trees in an area at one time.

Clearwood

Wood free of knots. Clearwood is produced naturally after branch shedding and after pruning when the tree grows around (occludes) the branch stub.

Code of Practice for Timber Production

A set of rules designed to ensure that commercial timber growing and harvesting on public and private land is conducted in a manner compatible with the environmental values of a forest. Available from the DPI website: http://www.dpi.vic.gov.au/privateforestry

Commercial thinning

A forest operation that removes competing trees within a stand for a direct financial return for the products extracted during this operation.

Commodity crop

Timber produced for general use such as pulpwood and construction materials

Coppice

Regrowth that grows from dormant buds under the bark of tree stumps after the tree has been felled. Most eucalypts will coppice. It is very useful if trees are to be managed for firewood production.

Cubic metre (m3)

A measure of timber volume, usually described in terms of m3/ha of merchantable timber or as m3/log. A typical intensive pine plantation would yield around 600 m3/ha in a 35 year rotation.

Cuttings

Pieces of plant taken from a parent plant and made to take root or strike as new plants. They are genetically identical to the parent.

DBHOB (Diameter breast height over bark)

A common reference point when comparing trees. It is measured at 1.3 m above ground level. See also UB.

Defect

An imperfection in a tree or log that makes it undesirable or unsuitable for a specific purpose. A defect may be caused by a number of agents such as: borers, termites, fire (causing resin pockets and veins), branches, fungi etc.

Defect core

The central part of a log, containing heartwood and the stubs of branches that were pruned off or shed when the tree was young. The defect core is of little vale for sawing and its size should be minimised, by early pruning, to increase log value.

Diameter tape

A tape measure that directly measures trunk diameter over bark (in cm) when placed around the circumference of the tree.

Direct regime

A silvicultural regime aimed at producing the highest value timber in the shortest time period. A direct regime usually entails sacrificing returns from intermediate lower value products such as pulpwood by undertaking earlier noncommercial thinning in order to get to the final stocking as quickly as possible.

Discharge area

Area where the watertable rises to ground level, and discharged across the surface.

DOS

Diameter over stubs. In the centre of a log, the diameter of the area within the stem that includes all the branch stubs resulting from earlier pruning. The aim should be to have a relatively uniform DOS throughout the sawlog.

Double leader

The forked top of a tree caused by two shoots being equal or nearly equal in vigour. Double leaders are undesirable as they do not allow a single log to form, and this weakens the tree. One shoot should be removed as soon as the double leader is identified. See also Form pruning.

DSE (Dry sheep equivalent)

The term used to describe the livestock carrying capacity of land. One DSE is the amount of land required by a 45kg wether or non-pregnant, non-lactating ewe to maintain its weight.

Early wood

The paler coloured and less dense part of a growth ring, produced in spring and early summer.

Endemic species

Restricted to a (defined) geographic area.

Environmental services

A function provided that has a beneficial impact on the natural surroundings. This could include the sequestration of carbon, provision of habitat for wildlife, provision of a buffer along streamsides, lowering watertables or other activities.

Epicormic growth

The development of new shoots from an established part of the plant generally above the ground level. The development of epicormic shoots in older material is usually the result of severe defoliation or pruning. The growth of epicormic shoots may lead to the formation of branches and subsequent defects within a log.

Essential oils

Volatile plant oils, such as eucalyptus oil.

Exotic species

A species not native to a region. Reference to 'exotics' in Australia usually implies the species is from outside of Australia.

Falling or felling

Cutting down of trees.

Feller buncher

A logging machine that fells trees debranches cuts-to-length and groups them ready to be removed with a forwarder or skidder.

Farm forestry

Commercial tree production on farmland.

Fixed lift pruning

Pruning that removes branches of all the trees to the same height (irrespective of the amount of green crown left on the trees). See also Variable lift pruning.

Flitch

A log that has been 'squared up' in a sawmill.

Form

The shape of the tree trunk or stem and the nature of the branching. A tree with good form will have a straight trunk with minimal taper and swelling, and small diameter branches broadly angled to the stem.

Form pruning

Selective removal of branches or stems from a tree to ensure that the tree grows with a single, straight trunk. Form pruning, which mainly involves the removal of double leaders and ramicorns, can begin when seedlings are planted out and should continue until the straight trunk is the height of the desired log (usually 6 m).

Forwarder

Rubber-tyred tractor that loads felled logs on to a trailer to remove them from the forest.

Habitat

Home (shelter, breeding area and food) for wildlife.

Hardwood

Short-fibred wood from broad-leaved, flowering trees, for example, eucalypts. Harvester See Feller buncher

Harvesting

The felling of trees, either as a thinning or a clearfelling operation.

Heartwood

The non-conductive, darker-coloured deadwood in the core of the stem. It is often impenetrable by preservatives.

High pruning

See lift pruning

Integrated Pest Management

This is a program that considers both the environmental and economic aspects of undesirable organism control.

Internal rate of return (IRR)

The break-even discount rate of an investment ie. the rate at which net present value (NPV) equals zero. For NPV to be positive (ie. The investment worthwhile) the IRR must be greater than the investors discount rate.

Inventory

The process and product of a survey that assesses a resource. May also be termed forest inventory, stand inventory or plantation inventory.

Joint venture

An enterprise in which different partners provide different resources in order to achieve a common goal. In agroforestry it would be common for a farmer to provide the land and routine maintenance of a stand, while an investor or forest company would provide the trees, expertise and marketing opportunities.

Knot

A cross section of a branch embedded in sawn timber. Green knots (from living branches) are tight in the wood; loose knots (form dead branches) often fall out of sawn planks.

Knotty core

See Defect core

Late wood

Denser, darker part of a growth ring produced in autumn, at the end of the growing season. Also called summer-wood.

Leader

The highest shoot on a tree, the leading stem. To produce a good trunk, the leader should be straight and clearly dominant over all other shoots.

LED

Large end diameter, diameter of the large end of a log when it is cut.

Lift pruning

The pruning of all branches on a tree up to a certain height. On any one pruning visit, each tree should be treated individually to an appropriate formula relating to the size of the tree (variable lift pruning) rather than all trees being pruned to the same height (fixed lift pruning - which disadvantages smaller trees by removing a greater proportion of their growing material). Pruning to the final clearwood height (usually 6 m) will generally be done in a number of "lifts". Three lifts are common, going from approximately 0-2 m to 2-4 m and 4-6 m at appropriate times.

Log

Usually a long section of a felled trees trunk or sometimes a limb. It is usually trimmed of branches but not further processed.

Log volume

The amount of timber contained within a section of felled tree. Log volume is usually expressed in m3.

Logging

Felling and removing logs from forest.

Low pruning

Removing lower branches up to about 2.0 - 2.5 m, often done for fire protection.

MAI

Mean annual increment, a measure of the average growth of merchantable timber over time. MAI is expressed in terms of m3/ha/yr at a certain age. Because of this, it is also used as a measure as to how well a site can grow timber. See also CAI.

Merchantable

A term used to describe timber suitable for processing into wood products, for which markets exist.

Mill door

The price paid for wood delivered to the mill including transport, logging cost and stumpage.

Mounding

The processes of raising a cultivated bed of soil for the planting of trees.

Multi-thinned

When trees are thinned on a number of occasions before being clearfelled.

Net present value (NPV)

The current value of a project after future cash flows are discounted back to present day values. A positive NPV indicates that the project is financially worthwhile.

Non-commercial thinning

Thinning of trees to waste; that is, the thinned trees are not sold or used after harvest but left where they fall, chopper-rolled or heaped and burned. Trees may also be poisoned and left standing.

Opportunity cost

The cost of production forgone to undertake a new enterprise eg. planting a tree crop may result in loss of sheep production.

Pathogen

An agent that causes disease within another organism.

Peeler logs

Logs of top quality. They must be straight, round, fairly large and have a small DOS, so they can be "peeled" for veneer timber.

Portable saw (sawmill)

A bandsaw, circular saw or chainsaw than can be easily transported to a log so that the log can be milled where it falls. Portable saws are either trailer mounted or easily assembled and disassembled for transport.

Plantation

A planted forest of either native or exotic species. Small plantations may be called blocks or woodlots.

Provenance

The place of origin of a species, subspecies or variety.

Pruning

The removal of selected shoots or branches from a tree to improve tree form or wood quality. Done with secateurs, pruning shears, or hand or power saws, depending on branch size, conditions, and to a certain extent preference. May also be termed stem pruning.

Pulp

Wood fibre processed to make paper. Pulp logs are processed into wood chips or pulp for wood based panels, paper and paper products.

Quartersawing

A method of sawing timber so that tree growth rings are at angles between 45° and 90° to the face of the board when the board is viewed in cross section. This process may produce more waste when milling however eucalypts are often quartersawn to produce a more stable timber.

Radial sawing

Sawing of logs so that each cut runs to the centre of the log as a round pie or cake would be cut. This results in boards with wedge-shaped cross sections, useful for special applications. The technique is effectively the ultimate in quartersawing and results in very stable boards in timber where other sawing methods may result in unacceptable warping. Radially sawn pieces may be recut to produce boards with a backsawn pattern.

Ramicorn

A vigorous branch that is steeply angled (usually less than 30° to the trunk). Such branches should be removed as early as possible because they are hard to prune later and can threaten the integrity of the single, straight trunk.

Recharge area

An area high in the landscape (usually) where rainfall infiltrates into the soil, adding to the ground water flow towards the valley bottom.

Recovery

The proportion of log milled into sawn timber, expressed as a percentage of the log volume. Good recovery from high-quality pine logs would be around 50-60 per cent.

Ringbarking

Removal of a ring of bark and sapwood all the way around a tree. Initially this results in the death of the roots and subsequent death of the crown.

Ripping

Disturbance of the soil by a vertical tine pulled by a tractor or bulldozer. Ripping before tree establishment can break up the subsoil and help the trees establish their root systems.

Rotation

The period of time from planting to clearfalling. Roundwood (pulpwood) Small diameter logs used for the manufacturing of paper or

particle board products.

Royalty

Money paid to a grower for timber on stump (usually as $/m3), at a rate determined by species, quality and distance to markets.

Sail area

A term used to describe how much wind a tree catches in areas where young trees are prone to windthrow. It is especially relevant to heavy-canopied trees such as Pinus radiata, and can be reduced by tip pruning.

Salinity (dryland)

Dryland salinity results when rising watertables bring soluble salts to the surface. Watertables may rise when native vegetation is replaced by crops and pastures that use less water.

Sapwood

The generally lighter coloured band or wood under the bark that conducts water from the roots.

Sawlog

A log that can be converted to sawn timber. The value of sawlogs varies greatly with species, size, form and whether or not the tree was pruned on time.

Seasoning

The drying of green sawn timber either in the open air or in kilns.

SED

Small end diameter, diameter of small end of a cut log.

Selection ratio

The ratio of initial planting density to the final density. A higher initial planting density allows poor trees to be culled, leaving the selected better trees to grow on for the final harvest (eg. a 3:1 selection ratio allows one tree to be selected for final harvest out of the three planted).

Selective logging

Only selected trees are removed from a forest area. A range of tree sizes is removed, leaving a forest with trees of different sizes and different ages. This selection of trees may maintain a balance of different sized trees but may restrict opportunities for regeneration of species intolerant of shade.

Selective pruning

Pruning to remove only certain types of branches. Branches over a certain diameter or that are steeply angled to the stem are often targeted.

Shelterbelt

Belt of trees or shrubs planted to provide shelter to stock, crops or pasture.

Silviculture

The theory and practice of managing stands of trees for a variety of outcomes.

Skidder

A rubber-tyred tractor for dragging felled logs to a loading area.

Slash

Branches and leaves left lying on the ground after pruning or logging.

Snigging

The method of removing logs from site after felling operations, by dragging.

Softwood

Timber of coniferous trees, for example, pines and cypresses. Softwoods are long-fibred whereas hardwoods are shortfibred.

SPH (stems per hectare)

The stocking rate of trees or number of trees per hectare.

Stand

A group of trees, generally of the same age and species, that are managed as a unit.

Stand density

A measurement of the degree to which a site is being occupied by trees. Stand density may be measured in stems per hectare or in basal area (m3) per hectare.

Stocking

Refers to the number of trees per hectare usually expressed in terms of sph (stems per hectare) or tph (trees per hectare).

Stumpage

The net price paid to a private grower (expressed in $ per cubic metre or tonne) after all harvesting and transport costs have been deducted.

Taper

The rate of change of diameter over a specified length of tree or log. See also Form

Thinning

The process of removing trees from a stand so that the remaining trees can continue to grow as well by reducing the competition for resources present on the site. Usually those trees with less vigour and poor form are removed.

Timber

The general term used to describe sawn wood suitable for building and other purposes.

Timberbelt

A linear planting of trees (and sometimes shrubs) designed to give shelter and grow timber simultaneously. The number of rows varies from 1 to 6 and different trees are generally used to provide timber and low shelter. Selected rows of timber trees may be pruned for clearwood.

Tip pruning

Pruning of the ends of branches rather than the whole branch.

Tree form

The taper and general shape of a tree, particularly its trunk.

Understorey

Shrubs and groundcover plants that grow under forest trees.

UB

Under bark measurement.

Value adding

Processing done to increase the sale value of a product; for example, a tree may be sawn on the farm then sold at a higher price than if it were sold as a log.

Veneer

A thin sheet of timber rotary-peeled or sliced from a log.

Veneer logs

Logs of quality suitable for peeling or slicing to produce veneer timber.

Whorl

A group of branches radiating from the trunk like the spokes of a wheel. Typical of conifers.

Widespaced

A agroforestry arrangement in which trees are spaced more or less evenly in both directions across a paddock. This is the contrast with linear and group arrangements.

Windthrow

Trees blowing over, either partially or completely, early partial windthrow may still leave a good tree with butt sweep. Trees windthrown once the main stem has grown have little or no value, even if they survive. Where whole stands are windthrown they may be salvage-logged. Windthrow may be induced by late thinning, which may result in an unstable stand.

Winged ripper

A metal implement that is drawn through the soil, usually by a bulldozer. A winged ripper assists in the fracturing of heavy soils to permit easier plant root growth and allow increased water and chemical infiltration into the soil profile.

Woodlot

A small area of planted softwood or hardwood forest managed for the production of forest products.

Contact Services Available from DPI

Farm Forestry Notes on DPI Private Forestry Website:

www.dpi.vic.gov.au/privateforestry

Acknowledgements

This Information Note was written by Karen Johnson, Farm Services Victoria in January 2002 and was reviewed August 2008.