Forestry Flashcards
Why are forests an important resource in terms of timber?
Timber
- wood is strong, high strength:weigh ratio, flexible, requires little processing for use
- mahogany and teak = tropical
- oak and beech = temperature deciduous
- conifer = northern coniferous forest
Uses: structural e.g. building, construction, telegraph poles, shuttering for concrete, furniture and tools
Why are forests an important resource in terms of fibres?
- most paper is made from flattened sheets of interwoven cellulose fibres from pulped wood
- cotton is made from the fibres that surround the seeds of the Cotten bush
- viscose(rayon) textiles are made by the chemical treatment of cellulose fibres extracted from wood
Why are forests an important resource in terms of fuel?
Fuelwood:
- before Industrial Revolution wood was the main energy source
- wood still provides energy for the greatest number of people mainly in LEDCs
Why are forests an important resource in terms of food?
- provide fodder for livestock and fruit and nuts for human food
- bushmeat in LEDCs
- agriculture for coffee, bananas, cacao, nuts and papayas
- pigs and chickens are originally forest animals
- CWRs
Why are forests an important resource in terms of medicine?
- trees produce many chemicals that have medicinal uses
- some are extracted from tree tissue
- e.g. willow bark = aspirin
How are forests involved in ecosystem services?
- balance of photosynthesis and respiration to regulate atmospheric CO2 and O2
- huge reservoir of carbon
- carbon sequestration
- total mass of carbon is double the mass in the atmosphere
How are forests involved in regulation of the hydrological cycle?
- transpiration rates from forests are greater than from any other terrestrial ecosystem and is important in increasing precipitation rates downwind
- interception by foliage increases evaporation rates but decreases infiltration
- forests help soil formation and reduce soil erosion so soil depth may be greater, soil will retain water after it has rained and moderate to the flow into rivers
- low albedo so the absorption of sunlight is increased
- forests radiate heat overnight reducing temperature extremes between day and night
How do forests create microclimates?
- canopy vegetation absorbs a lot of the solar insulation, especially red and blue, so plant living below the canopy have less access to to light so they must have special adaptations to absorb additional pigments or denser chlorophyll
- the lower wind velocity produced by the shelter if the trees means plants below the canopy rely on animals to help with pollination and seed dispersal
- high humidity means that animas such as amphibians can survive more easily as their skin does not dry out
How to forests creat habitat and provide wildlife refuge?
- forests are the most biodiverse terrestrial ecosystems, each species of tree supports its own unique community of species so forests with a greater variety of trees are likely to have a greater overall biodiversity
- lots of ecological niches and this is increased by stratification within the forest
- high primary productivity of forests provides a lot of energy to support high trophic levels, the energy is not always available to other organisms, as quickly, as much is stored in the wood which will be released when the trees dies and decomposes
How are forests involved in soil conservation?
- dead vegetation contributes humus and nutrients to the soil and the food energy for detritivores and decomposes
- prevent soil being washed or blown away by intercepting rainfall and reducing wind velocity
- living trees and leaf litter on the soil surface help to reduce wind velocity and the impact of raindrops
- tree roots hold soil together
How are forests involved in recreation and amenities?
Forests are important for recreational uses such as walking, orienteering, cycling and camping
What is traditional forest management?
The management of existing woodland areas to maximise yields of forests products, mixed species plantations and doesn’t tend to involve mass clearing
What are uses of different tree species?
Oak: timber-framed buildings, ship building
Beech: furniture, tool handles
Ash: furniture, roof timbers
Holly: mathematical instruments, walking sticks
Hazel: fencing panels, interwoven wall panels
What are standard trees?
- trees grown to maturity for the production of large timber for uses such as construction of buildings and ships
What is coppicing?
- cutting trees to ground level on a cycle of 1 to 20 years depending on the use of wood
What is pollarding?
- cut above ground level so the regrowing branches cannot be eaten by livestock
What is modern commercial forestry?
- uses of wood have changed and more wood is used for sheet construction material and plywood for concrete shuttering
- harvesting methods now in live large scale clear felling, reducing the biodiversity of the forest
- natural forests replaced with single species plantations
How can forests be managed through cultivation of non-indigenous species?
- better adapted to the environmental conditions and are less likely to suffer damage caused by pests or disease
- les likely to support indigenous wildlife
E.g.s: Uk = Sitka spruce and Douglas Fir
Central America = teak
East Africa = eucalyptus
How can forests be managed using single species plantations?
- growing a monoculture of one tree species can make management of a plantation easier
- planting, thinning and felling can be carried out over large areas at the same time
How can forests be managed by close planting?
- planting seedlings close together makes the trees compete with each other for light so they grow tall and straight
- low light levels at the ground inhibit growth of other plants that would be using water or nutrients
- reduces the wildlife diversity of the forest
How can forests be managed by simple age structure?
- planting trees at the same time makes management easy, they will all be of similar size and will all need similar management activities at the same time
What is deforestation?
- deliberate removal of forests to make space for another land use e.g. agriculture, urban development
- unsustainable exploitation/exploitation above the MSY
Why is agriculture a cause of forest loss?
- growth of local populations increase and so does demand for food so more land needs clearing for farming
- forest clearance for commercial cash crop agriculture where the produce may be taken to cities or exported
E.g. rainforest clearance in South America for sugar cane and soya beans or cattle
Why is mineral extraction a cause of forest loss?
Forest clearance for mining and the associated infrastructure affects a relatively small total area but can have local impacts
Why are reservoirs a cause of forest loss?
Reservoirs for public supply, irrigation or hydroelectric power can replace forests
- the expansion of HEP in South America has caused the loss of large areas of tropical rainforests
How is urbanisation a cause of forest loss?
Expansion of urban areas can cause the direct loss of forest
- also increases the demand for fuel and food which can cause further forest loss
How is transport infrastructure a cause of forest loss?
- road and railway creation can create barriers to the movement of wildlife, causing population fragmentation
- improved transport systems increase accessibility and makes removal of felled trees easier, making forest clearance easier
How is timber being unsustainably exploited?
- softwood e.g. pine and spruce produced by conifers is often produced sustainably with replanting to replace harvested areas
- hardwood species e.g. teak and mahogany grow more slowly sp it is more difficult to commercially manage
How is fuel being unsustainably exploited?
- wood is a heavily relied on fuel in LEDCs
- lots of energy from combustion is lost causing deforestation rates to increase
How is livestock fodder being unsustainably exploited?
- in LEDCs farmers may cut off branches of trees, to feed livestock, if this exceeds the growth of the trees then the forest may gradually be degraded and disappear
How is loss of forest resources and effect of deforestation?
Loss of timber, fuel, fibres and medicines
What ecological impacts are caused by deforestation?
- reduced biodiversity
- loss of species
- fragmentation of remaining forest areas
What changes to hydrology are caused by deforestation?
- reduced interception and transpiration
- increased run off
What impacts on soil are caused by deforestation?
- reduced soil formation
- less dead organic matter
- increased soil erosion
- less protection of soil by vegetation and leaf litter
- reduced soil organic matter
- reduced root binding
What climate impacts are caused by deforestation?
- increased albedo
- reduced carbon sequestration and carbon reservoir
- reduced rainfall downwind
How are harvesting rates a feature of a sustainably managed forest?
The rate of resource removal must be no greater than the Maximum Sustainable Yield
How are mixed species plantations a feature of a sustainably managed forest?
Wildlife biodiversity is increase by growing multiple species because there is an increase in food choices, inter-species relationships and niches
How are indigenous species a feature of a sustainably managed forest?
If indigeniuse species are cultivated it is more likely that other indigenous species will benefit e.g. birds and insects
How are mixed age structure a feature of a sustainably managed forest?
- greater diversity of abiotic factors such as light levels, temperatures and wind velocity
- increasing the biodiversity of other species living in the forest
How are selective logging a feature of a sustainably managed forest?
- different felling times
- more labour intensive and more expensive
- smaller impact on the survival of remaining wildlife populations
- wildlife that has lost its tree habitat will not have to more as far to find a new habitat
