Stump harvesting

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In plantation forests in parts of Europe, the tree stumps left after felling are now sometimes pulled out of the ground to supply wood fuel for biomass power stations. The stump is the base of the trunk and the attached woody roots. Tree stumps and roots are extracted using a hydraulic head on a tracked excavator or with a mechanical head equipped by a special tool for tractors. Stump harvesting is expected to provide an increasing component of the woody material required by the woody biomass power sector in Europe.

Contents

A vertical stump grinder in use. Rotor stump grinder at work.jpg
A vertical stump grinder in use.

Sustainability

Stump harvesting is unsuitable on many soils where the removal leads to long term reduction in nutrition or an unacceptable loss of soil carbon. [1] Also, it is necessary that care is taken to avoid areas with archaeology, ecologically sensitive areas, steep slopes, and areas close to streams and rivers. In many situations removal of stumps leads to a further loss of wood with a resulting loss of the potential biodiversity that depends on wood. [2]

History

Uprooted tree stumps Baumstumpf ausgegraben.JPG
Uprooted tree stumps

Stump harvesting is not a new process. Records of tree stumps being dug out of the ground for wood fuel go back hundreds of years in Europe. It was practiced in the 1970s in Swedish forests before declining in popularity, but is being considered again there now that there is a greater need for fuel wood. In Britain, stumps are removed in some forests for disease control, especially in south-east England. Additionally, they are extracted where restoring plantation forest areas to peat bog for conservation reasons. Recently small scale commercial stump harvesting has started in parts of Scotland to provide fuel for biomass power stations. In Finland, stumps were at one time used to produce tar and charcoal. In the 1970s, a number of trials were set up in Finland to examine the viability of stump harvesting for woody biomass, but it is only in recent years that it has developed into a large scale commercial operation.

Related Research Articles

Forest Dense collection of trees covering a relatively large area

A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 metres (16 ft) and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban use." Using this definition, Global Forest Resources Assessment 2020 found that forests covered 4.06 billion hectares, or approximately 31 percent of the world's land area in 2020.

Logging Process of cutting, processing, and moving trees

Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars.

Slash-and-burn Farming method in which trees are cut and burnt to clear land

Slash-and-burn agriculture is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area. The downed vegetation, or "slash", is then left to dry, usually right before the rainiest part of the year. Then, the biomass is burned, resulting in a nutrient-rich layer of ash which makes the soil fertile, as well as temporarily eliminating weed and pest species. After about three to five years, the plot's productivity decreases due to depletion of nutrients along with weed and pest invasion, causing the farmers to abandon the field and move over to a new area. The time it takes for a swidden to recover depends on the location and can be as little as five years to more than twenty years, after which the plot can be slashed and burned again, repeating the cycle. In Bangladesh and India, the practice is known as jhum or jhoom.

Wood fuel Wood used as fuel for combustion

Wood fuel is a fuel such as firewood, charcoal, chips, sheets, pellets, and sawdust. The particular form used depends upon factors such as source, quantity, quality and application. In many areas, wood is the most easily available form of fuel, requiring no tools in the case of picking up dead wood, or few tools, although as in any industry, specialized tools, such as skidders and hydraulic wood splitters, have been developed to mechanize production. Sawmill waste and construction industry by-products also include various forms of lumber tailings.

Silviculture is the practice of controlling the growth, composition/structure, and quality of forests to meet values and needs, specifically timber production.

Old-growth forest Forest that has attained great age without significant disturbance

An old-growth forest – also termed primary forest, virgin forest, late seral forest or primeval forest – is a forest that has attained great age without significant disturbance and thereby exhibits unique ecological features and might be classified as a climax community. The Food and Agriculture Organization of the United Nations defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. More than one-third of the world’s forests are primary forests. Old-growth features include diverse tree-related structures that provide diverse wildlife habitat that increases the biodiversity of the forested ecosystem. Virgin forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.

Clearcutting Forestry/logging practice in which most or all trees in an area are uniformly cut down

Clearcutting, clearfelling or clearcut logging is a forestry/logging practice in which most or all trees in an area are uniformly cut down. Along with shelterwood and seed tree harvests, it is used by foresters to create certain types of forest ecosystems and to promote select species that require an abundance of sunlight or grow in large, even-age stands. Logging companies and forest-worker unions in some countries support the practice for scientific, safety and economic reasons, while detractors consider it a form of deforestation that destroys natural habitats and contributes to climate change.

Bioenergy Energy made from biomass or biofuel

Bioenergy is energy made from biomass or biofuel. Biomass is any organic material which has absorbed sunlight and stored it in the form of chemical energy. Examples are wood, energy crops and waste from forests, yards, or farms. Since biomass technically can be used as a fuel directly, some people use the terms biomass and biofuel interchangeably. More often than not, the word biomass simply denotes the biological raw material the fuel is made of. The word biofuel is usually reserved for liquid or gaseous fuels, used for transportation. The U.S. Energy Information Administration (EIA) follows this naming practice.

This article is the index of forestry topics.

Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.

Tree stump

After a tree has been cut and felled, the stump or tree stump is usually a small remaining portion of the trunk with the roots still in the ground. Stumps may show the age-defining rings of a tree. The study of these rings is known as dendrochronology.

Energy crop

Energy crops are low-cost and low-maintenance crops grown solely for energy production by combustion. The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to generate electrical power or heat.

Biomass Biological material used as a renewable energy source

Biomass is plant or animal material used as fuel to produce electricity or heat. Examples are wood, energy crops and waste from forests, yards, or farms. Since biomass technically can be used as a fuel directly, some people use the terms biomass and biofuel interchangeably. More often than not, the word biomass simply denotes the biological raw material the fuel is made of. The word biofuel is usually reserved for liquid or gaseous fuels, used for transportation. The U.S. Energy Information Administration (EIA) follows this naming practice.

<i>Miscanthus × giganteus</i> Species of grass

Miscanthus × giganteus, also known as the giant miscanthus, is a sterile hybrid of Miscanthus sinensis and Miscanthus sacchariflorus. It is a perennial grass with bamboo-like stems that can grow to heights of 3–4 metres (13 ft) in one season. Just like Pennisetum purpureum, Arundo donax and Saccharum ravennae, it is also called elephant grass.

Short rotation coppice

Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading countries in area planted for energy generation are Sweden and the UK.

Short Rotation Forestry (SRF) is grown as an energy crop for use in power stations, alone or in combination with other fuels such as coal. It is similar to historic fuelwood coppice systems.

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

Biomass heating system

Biomass heating systems generate heat from biomass.
The systems fall under the categories of:

Woodchips Small pieces of wood made when shredding larger pieces of wood

Woodchips are small- to medium-sized pieces of wood formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste.

The wood industry or lumber industry is the industry concerned with forestry, logging, timber trade, and the production of primary forest products and wood products and secondary products like wood pulp for the pulp and paper industry. Some of the largest producers are also among the biggest owners of timberland. The wood industry has historically been and continues to be an important sector in many economies.

References

  1. Staaf, H. and Olsson, B.A.: Effects of slash removal and stump harvesting on soil water chemistry in a clearcutting in SW Sweden., 336 pages. Scandinavian Journal of Forest Research 9(4):305-310 2004.
  2. "Forest: Deadwood — European Environment Agency".