Conservation - the maintenance of biodiversity, including diversity between species, genetic diversity within species and maintenance of a variety of habitat and ecosystems.
NOTE: Conservation does not mean leaving areas of land alone but managing them in order to get the best from the area.
Preservation - Protected areas of land, as yet unused by humans in their unprotected form. Maintaining the species that are present in their current diversity.
Ecosystems are static not dynamic as they change over time.
Reasons for conservation - Economic
1. To harvest a product
- Wood for making charcoal, burning or to make fences (see woodland management).
- Fish for food; if fishing is controlled then over-fishing will not take place.
2. Jobs for the economy
- Tourist trade Africa or Galapagos (see later section)
- Jobs for fishermen
3. Source of genes; natural populations of organisms contain a source of genetic material that we could use for interbreeding or genetic engineering to improve the production of farm plants and animals.
4. Source of drugs; many plants supply us with drugs e.g. aspirin in willow bark. The more plants that are destroyed the less access we have to a source of new drugs.
Reasons for conservation - Social and Ethical
1. Use them for our leisure pursuits e.g. Addington Hills fitness trail.
2. Ecotourism produces books, films which all provide a source of income.
3. To maintain life support systems e.g. soil regeneration and protection, recycling of nutrients and cleansing of water, on which humans depend.
1. Ethically, we should preserve as many species as possible.
- Species conservation in zoos, botanic gardens or seed banks.
- Habitat conservation e.g. coppiced woodland
- Keep them as areas of Special Scientific Interest because they contain rare plants/animals.
Sustainable woodland management
What is the meaning of sustainable in this context? - The woodland ecosystem is maintained same diversity, same population and a product is provided/produced which in this case is wood.
Coppicing is the cutting down of the tree layer to ground level. This technique is for broadleaved trees (dicot trees not conifers). The stump (or stool) send out shoots (or osiers) from which an indefinite number of poles can be cut at set intervals of years.
Intially, after cutting down the tree there is a lot of light on the forest floor and this encourages species to grow that would not normally grow under the tree canopy e.g. bluebells.
- Encourages species diversity in the plant population, which in turn will give you animal species diversity. Plants give different food sources, nesting sites, camoflague areas etc.
- This provides a source of straight wood, which can be, used for: furniture, handles for tools, fuel in a power station, charcoal.
Short rotation coppicing (every 2 to 5 years) - the coppiced wood is use directly as a fuel or to make charcoal.
Other species e.g. Sweet Chessnut are coppiced every 15 to 20 years and the wood is used for poles, fencing and maybe furniture.
A coppiced woodland requires little if any herbicides and pesticides. A coppiced woodland also requires very little fertilisers.
This wood could then be burnt to produce electricity.
It is thought that the trees will absorb as much CO2 as the power stations emit, thus not increasing the greenhouse effect, CO2 concentration. The wood does not give out high levels of SO2 and thus does not significantly affect/increase the amount of acid rain.
The ash from combustion can be used as a fertiliser.
In coppiced woodland some trees are allowed to grow to full size. They are called standards. When felled the timber is used in houses for floorboards etc. The trees regenerate from seed.
Pollarding and Clear Felling
Here are two examples of pollarding. Instead of the trees being cut down to the bottom the trunks are left about 0.5-1 metres high. New shoots form from the cut stumps as in coppicing. The wood removed can be used in the same way as coppiced wood.
- It stops the trees coming into contact with overhead cables.
- Stops the trees being eaten by herbivores (e.g. Rabbit).
This is the cutting down of all the trees in the area
- Conifer (softwood, pine) trees because they do not regrow shoots when coppiced.
- Trees left to grow for a considerable number of years to mature, 50-100 years
This removes only the largest and most valuable trees.
It is particularly effective on a slope. Generally it maintains the diversity and protects the minerals and water in the soil.
Good forestry practices include:
- Any tree is cut down is replanted with another tree
- Matching the tree species to be grown to the climate, topography (landscape, sloping woodland) and soil type. E.g. willow will only grow in a damp soil whilst oak likes a drier soil.
- Planting trees at the best distance apart for growth. If they are planted too close together then they might compete for light, water and nutrients and so grow tall and thin.
- Control pests and pathogens so the trees grow well and give a good quality of timber.