Transcript Sustainability

Sustainable Management
and Conservation
Learning objectives
• Explain how the management of an
ecosystem can provide resources in a
sustainable way, with reference to
timber production in a temperate
country
The Principle
As the population continues to grow,
humans need to take more care over
maintaining their resources by means of
sustainable management.
• ensures maintenance of
biodiversity
• allows companies to
profit by providing a
supply of wood which is
• continuous
• regular
•of similar quantity
Why are trees called a
biological resource?
• Biological
– trees are living organisms ;
– renewable ;
– growing ;
• Resource
– timber is of use to human beings
Sustainable production
• harvested at levels which leave sufficient
organisms ;
• to grow / reproduce and replenish what
has been harvested ;
• Through coppicing / replanting /
afforestation ;
• can be carried on indefinitely
Small Scale Timber
production
Coppicing
Trees are cut at the base so that
several shoots grow up.
The timber can then be
harvested after a number of
years regularly, without the tree
dying
Some large trees are
left and they are called
STANDARDS
Rotational coppicing
• A woodland can be divided into sections,
one of which can be cut each year.
• Increases light intensity
• Increases biodiversity – why?
• Woodland will have a range of habitats at
different stages of succession, each of
which favours different species
Benefit of having mix of
standards and coppiced trees
• Standards produce large planks of wood for
building/large furniture
• Coppiced wood with small diameter for
wood/fencing/hurdles/garden furniture
/charcoal/firewood/matches;
• Coppicing provides continuous source of
– timber/income;
– recreational use/nature reserve
Pollarding
This is similar to
coppicing but the
tree is cut higher
up so that the
shoots don’t get
eaten by livestock
Large scale
timber
production
Large scale clear felling
- must be avoided - WHY?
This can lead to soil erosion, loss of soil
fertility, water pollution , serious loss of
biodiversity and disruption of the water cycle.
Why?
Trees
• maintain the water cycle
(absorption from soil,
transpiration, precipitation
• Stop soil being washed
away
• Maintain cycling of
carbon, nitrogen, etc.
The best management practice:
• Selective felling
– only the oldest and most economically
valuable trees are harvested.
– maximises biodiversity and leaves habitat
largely unaffected
• Strip felling
– Leaving clearing/glades in woodland
The best management practice
• Improving productivity by
• controlling pests and pathogens
• reducing competition (spacing trees)
– less trees can be grown but they will be more productive
•
•
•
•
growing suitable (native) species
Supporting young trees to prevent damage from grazing
Growing fast growing trees (softwood/conifers)
Fire control
• Strategies to increase biodiversity
• deciduous broadleaved species around edges for aesthetic
reasons
– Creates different habitats
• Leaving fallen trees to rot
Traditional sustainable forestry
• Leaving sections of woodland to mature
• But it usually takes 50 to 100 years for
woodland to mature!
• Not cost-effective
Modern sustainable forestry
• Replacing each harvested tree
– Could be through grants for planting forests
• E.g. Awarded to countries with rainforests from
countries with large carbon footprints
– Could involve afforestation
• Planting of trees in areas that have not previously held
forests
• Maintaining the forest’ ecological function
(biodiversity, climate, mineral and water cycles)
• Allowing local people to benefit from the forest
A difficult balance
There will always be tensions between those
who wish to maximise the profit available
from a piece of woodland and those who
want to conserve it.
One theory is that, the more wood we get
from each tree, the fewer trees we need to
harvest.
Comparing the two approaches
Complete the following table
Small – scale
DIFFERENCES
Size of timber
Harvesting method
Extent of habitat destruction?
Soil quality reduced?
Planting new trees involved?
SIMILARITIES
Strategies
Large-scale
Comparing the two approaches
DIFFERENCES
Small – scale
Large-scale
Size of timber
Small
Large
Harvesting method
Coppicing
Felling
Extent of habitat destruction?
less
More
Soil quality reduced?
No
Yes
Planting new trees involved?
No
yes
SIMILARITIES
Selective cutting
Strategies
Growing standards