Outline of forestry

The following outline is provided as an overview of and guide to forestry:

Forestry – the art and science of managing forests, tree plantations, and related natural resources. Forest ecosystems have come to be seen as the most important component of the biosphere,[1] and forestry has emerged as a vital field of science, applied art, and technology. The main goal of forestry is to create and implement systems that allow forests to continue a sustainable continuation of environmental supplies and services. The challenge of forestry is to create systems that are socially accepted while sustaining the resource and any other resources that might be affected.[2]

Focus of forestry

  • Forest – defined as either a geographic area or delineated by the general composition of individuals;
  • Biome – ecologically defined by its forest structure, leaf types, tree spacing, and climate
General Forested Biomes
Boreal
Taiga
Temperate
Coniferous Broadleaf and mixed Mediterranean
Tropical/Subtropical
Coniferous Moist broadleaf Dry broadleaf
Wetlands
Mangroves Bogs Swamps
Other
Urban Riparian

Branches of forestry

Occupations in forestry

  • Log scaling – measurement of felled trees to determine the volume of wood going to the manufacturer
  • Log bucking – delimbing and partitioning of trees into logs
  • Log driving – transportation of logs on a river or lake downstream to the mill

Management focuses

Main article: Forest management
  • Tree breeding – method of genetically modifying/selecting forest stock for improved growth or vigor characteristics

Silvicultural methods

Main article: Silviculture

Site preparation

Planting

Intermediate treatments

Harvest rotations

  • Clearcutting – harvesting of all stems in a given area regardless of species and size
  • Coppicing – cutting vigorous juvenile trees near the ground, regeneration comes from new shoots coming up from the stump
  • Seed-tree – cutting of all trees save widely spaced residual trees, which will provide natural seedstock for the following generation and are later cut
  • Selection – harvesting of selected trees in a stand, removing either merchantable timber or to favor the growth of desirable individuals (a thinning)
  • Shelterwood – removal of merchantable trees in succession, establishing a multiaged stand
  • Variable retention – removal of trees of varying density across a landscape, in order to retain structural diversity
  • Salvage logging – harvesting of trees killed by natural disturbances in order to maximize economic returns that would otherwise be lost
  • Sanitation harvest – removal of individual trees affected by a pathogen in order to diminish the possibility the entire stand being affected
  • Biomass harvest – harvesting of small wood for energy purposes, either following a commercial harvest or for its own sake, such as in energy forestry
  • Underwater logging – harvesting of trees from underwater forests flooded during construction of artificial dams or reservoirs

Environmental issues pertaining to forests

Forest resource assessment

Main article: Forest inventory or Timber cruise

Timber metrics

  • Diameter at breast height (DBH) – measurement of a tree's diameter standardized at 1.3 meters (about 4.5 feet) above the ground
  • Basal area – defines the area of a given section of land that is occupied by the cross-section of tree trunks and stems at their base
  • Tree taper – the degree to which a tree's stem or bole decreases in diameter as a function of height above ground
  • Girard form class – an expression of tree taper calculated as the ratio of diameter inside the bark at 16 feet above ground to the to that outside bark at DBH, primary expression of tree form used in the United States
  • Quadratic mean diameter – diameter of the tree that coordinates to the stand's basal area
  • Leaf Area Index – the ratio of total upper leaf surface of the forest canopy divided by the surface area of the land on which the vegetation grows
  • Tools
  • Biltmore stick – utilizes ocular trigonometry to quickly measure diameter and height
  • Diameter tape – cloth or metal tape that is wrapped around the bole, scaled to diameter
  • Caliper – two prongs connected to a measuring tape are placed around the most average part of the bole to determine diameter
  • Relascope – multiple-use tool that is able to find tree height, basal area, and tree diameter anywhere along the bole
  • Clinometer – common tool used to measure changes in elevation and tree height
  • Cruising rod – similar to a caliper, calculates the number of pieces of lumber yielded by a given piece of timber by measuring its diameter
  • Hemispherical photography – estimates solar radiation and characterize plant canopy structure/density using photographs taken looking upward through an extreme wide-angle lens

Surveying techniques

  • Traversing – method of surveying used to establish sampling plots along a line or path of travel
  • Chain – equivalent to 66 feet, widely used distance in surveying practices in the United States and other countries influenced by imperial Great Britain
  • Line plot survey – plots taken at a regular predetermined distance along the traverse path
  • Tools
  • Pacing – quick method used to survey in the field, requiring calibration of one's "paces" (pair of footsteps) to a known distance (oftentimes a chain)
  • Hand compass – a compact magnetic compass with a sighting device used to determine the location of plots for a given bearing
  • Wedge prism – optical instrument typically made of glass ground at slight angles to refract light passing through it from the smaller width side of the prism to the thicker width side of the prism, calibrated to a desired plot size (basal area factor)
  • Angle gauge – similar in principle to a wedge prism, although it must be held a fixed distance from the eye
  • GPS – global satellite navigation systems used to determine the position of oneself and plots
  • GIS – an information system capable of integrating, storing, analyzing, and displaying forest geographic information collected in the field

Timber volume determination

  • Site index – a species specific measure of site productivity and management options, reported as the height of dominant and co-dominant trees (site trees)in a stand at a base age such as 25, 50 and 100 years
  • Stocking – a quantitative measure of the area occupied by trees relative to an optimum or desired level of density
  • Stand Density Index – a measure of the stocking of a stand of trees based on the number of trees per unit area and DBH of the tree of average basal area
  • Volume table – a chart based on volume equations that uses correlations between certain aspects of a tree to estimate the standing volume
  • Stand density management diagram – model that uses current stand density to project future stand composition
  • Units of measurement
  • Cord – very common measure, equivalent to 128 cubic feet (3.62 m3), corresponding to a pile of wood, bark, and air 4 feet wide by 4 feet high and 8 feet long
  • Stère – invented in France, equivalent to a cubic meter of cut wood with space for air
  • Board foot – specialized unit of measure for lumber in North America, equivalent to the volume of a one foot length of a board one foot wide and one inch thick

Stand growth assessment

  • Increment borer – specialized tool used to extract a section of wood tissue from a living tree with relatively minor injury to the tree, used often for tree growth analysis
  • Mean annual increment (MAI) – refers to the average growth per year a tree or stand of trees has exhibited at a specific age
  • Periodic annual increment (PAI) – describes the average annual change in tree diameter between the beginning and ending of a growth period, used more often than MAI for percental growth
  • Ecological yield -the amount of wood volume in any given year whose harvesting would be considered sustainable
  • Growth and yield modelling – entails the creation of models of prospective tree growth and harvest yield for management purposes
  • Stumpage – the price charged by a land owner to loggers for the right to harvest standing timber on that land
  • Optimal rotation age – the age at which the harvesting of stumpage will generate the maximum revenue or economic yield

Harvesting

Main article: Logging

Harvesting methods

  • High lead logging – a cable is anchored to a tree at the top of the hill:
  • Skyline logging – a carriage is used alongside the main cable to provide leverage

Harvesting tools

  • Axe – primitive tool used felling and splitting
  • Chainsaw – portable mechanized all-purpose saw, the most common tool used in hand-felling
  • Crosscut saw – saws that have teeth that are designed to cut wood at a right angle to the direction of the wood grain, used for felling and bucking
  • Bucksaw – a type of crosscut saw used by one or two people to buck felled trees into sawlogs
  • Feller buncher – vehicle with an attachment that can rapidly cut and gather several smaller trees before felling them
  • Harvester – first half of the CTL system, vehicle that cuts, delimbs, and bucks the logs "to length"
  • Peavey – a traditional tool consisting of a wooden lever handle with a movable metal hook with a sharp tip, used to spear the log for handling and moving
  • Cant Hook – tool with the same premise as the peavey but with blunt teeth-bearing tip
  • Yarder – in cable logging, a piece of equipment utilizing a pulley system of cables to pull or fly logs from the stump to the landing
  • Forwarder – second half of the CTL system, the vehicle that carries logs clear off the ground from the felling site to the roadside landing
  • Skidder – vehicle that drags logs along the ground from the felling site to the roadside landing
  • Michigan logging wheels – historical skidder, consisting of a specially designed large set of wooden wagon wheels and could be used in unfrozen soil conditions
  • Skid cone – a steel or plastic cone placed on the end of a log while being skidded, in order to ease its transportation or protect residual trees
  • Splash dam – a dam built to temporarily raise the water level of a river to float timber downstream
  • Flume – chutes specifically constructed to transport lumber and logs down mountainous terrain to a sawmill by using flowing water.
  • Timber slide – chutes constructed parallel to a river in order to avoid damage to timber rafts caused by rapids or waterfalls
  • Boom – barriers placed in a river, designed to collect and or contain floating logs felled from nearby forests

Forest products

Main article Forest product, or Wood processing

Primary forest products

Main article Wood

Main article Engineered wood

Secondary forest products

Main article: Wood fuel and Biomass
Main: Ecosystem services

History of forestry

Main article: History of forestry

Notable people

Lists

Allied sciences

See also

References

  1. ^ http://www.tutorvista.com/content/biology/biology-iv/ecosystem/ecosystem-definition.php ecosystem part of biosphere
  2. ^ "Forestry." Gale Encyclopedia of Science. Thomson Gale, 2001. NA. General OneFile. Gale. 12 Oct. 2009 <http://find.galegroup.com/gps/start.do?prodId=IPS>.

External links