Forests Under threat

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Conservation of Threatened Forests

Conservation of Tropical Rainforests

The global average annual rate of deforestation is 130,000km^2. This number is very high, however, it doesn't mean that deforestation rates are increasing everywhere. Deforestation rates are decreasing in some countries (e.g. Costa Rica and Brazil) because:

Government policies are introduced that incentivise landowners to reforest areas.

International pressure encourages companies to reduce their impacts on the rainforests.

Monitoring systems help authorities act fast to prevent illegal logging.

The threats to rainforests don't just affect particular countries; they affect the whole world. Worldwide actions are needed to protect rainforest biodiversity.

Rates of deforestation are increasing in some countries (e.g. Borneo and Nigeria) because:

There are lots of subsistence farmers and high local demand for fuelwood because of population growth and poverty.

Exploiting rainforest resources helps poor countries pay off debt.

Governments are improving transport links to boost development, but this is exposing rainforest to logging, mining and agriculture.

REDD

The rules of REDD mean that it is possible to fell tropical rainforest, replace it with low biodiversity palm oil plantations and still receive rewards.

Advantages:

Tackles the direct effects of deforestation and root of climate change.

Protects biodiversity by protecting habitats.

Relatively inexpensive method of reducing emissions.

Disadvantages:

Deforestation may carry on elsewhere.

Local communities who depend on activities such as mining or agriculture may be affected by the restrictions.

The rules of REDD mean that it is possible to fell rainforest, replace it with low biodiversity palm oil plantations and still get rewards.

CITES

Advantages:

Controls trade globally and not just in a few countries.

Educates people on the threats to biodiversity and so raises awareness of the issues.

Disadvantages:

Species are protected but their habitats are not.

Not all of the rules are clear.

Not all countries have signed the agreement.

Sustainable Management of Tropical Rainforests

Sustainable management of rainforests involves using forests in ways that allow people to benefit from their resources now and in the future. Sustainable management strategies include selective logging (only removing certain target trees) and replanting (replacement of removed trees).

Social challenges

Conventional forestry provides more jobs than sustainable management.

Sustainable forestry may be incapable of meeting the demands for wood and land of continually growing populations.

Environmental challenges

Replanting trees does not necessarily restore the forest ecosystem.

Selective logging of target trees can damage other nearby trees.

Economic challenges

Poorer countries desperately need immediate income, but sustainable management only benefits economies in the [long]-term.

Convincing private companies to adopt sustainable methods can be hard because these methods are usually more costly.

The priorities of organisations that fund sustainable forestry schemes can shift quickly, resulting in loss of funding.

A preferred long-term option for protecting rainforests might be to promote alternative livelihoods, such as ecotourism (tourism that benefits locals and causes minimal environmental damage) and sustainable farming (farming that protects the soil and helps maintain long-term productivity):

Sustainable farming

Agroforestry involves growing trees and crops at the same time. This protects the soil because the tree roots bind with the soil and the tree leaves intercept heavy rain.

Green manure refers to nutrients that growing plants supply to the soil. This helps to maintain soil fertility.

Crop rotation involves moving crops between areas each year, with 1 area always remaining empty so that the soil can recover.

Ecotourism

The number of tourists allowed in a space or region at one time is very restricted.

Land and water contamination are reduced by making sure waste is properly disposed of.

Provides employment for locals, meaning that they don't have to log or farm to make a living.

Can help generate funds for rainforest conservation.

Conservation of Taiga forests

Conservation of taiga forests has traditionally been quite simple because they are both difficult to access and remote. But human activity is increasingly taking place in these areas and so conservation methods are becoming increasingly important. Such methods and their associated challenges include:

Creating wilderness areas

Wilderness areas are undisturbed by humans and are managed with the goal of landscape protection. Challenges include:

Difficult to police these vast and remote landscapes.

Companies who want to extract the natural resources placing economic pressure on governments.

Pressure from companies and tourists to improve access by building roads.

Sustainable forestry

Sustainable forestry is harvesting timber without preventing future generations from being able to do the same. Challenges include:

Enforcing restrictions can be difficult.

There are likely to be disagreements over the restrictions.

Creating national parks

National parks are mostly natural and are managed with the goals of biodiversity protection and recreation promotion. Challenges include:

Indigenous communities have needs that must be considered.

The ecosystem can be damaged by access roads, infrastructure and pollution from visitors.

People have different opinions on whether taiga forests should be protected or exploited. The arguments put forward by each group of people are outlined below:

Exploitation

Global demand for resources found in taiga forests continues to rise.

Many local people depend on forest industries for employment.

Approximately 25,000 people are employed in forestry and logging in Canada.

Exploiting taiga forest resources is very lucrative.

Sweden's forest industry generates US$15bn annually.

Protected

Deforestation will contribute to global warming because lots of carbon dioxide will be released into the atmosphere.

Destruction of taiga forest habitats could put some highly specialised species at risk of extinction.

Taiga forests are central to the traditional way of life of many indigenous groups.

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Threats to Forests

Threats to Taiga Forests

Taiga forests are becoming increasingly exploited for their resources as global demand for goods and energy rises worldwide. Examples of the direct and indirect threats facing taiga forests as a result are:

Indirect - exploiting fossil fuels

Trees are felled so that oil and gas can be extracted from the ground.

Indirect - hydroelectric power (HEP) potential

To access the HEP potential in taiga forests, dams are built.

These dams can cause large areas of the forests to flood.

Direct - pulp and paper production

Trees are felled, crushed into a pulp and used in the paper-making process.

Direct - logging for softwood

Trees are felled so that their softwood can be used for making houses, furniture and matches.

Indirect - exploitation of minerals

Minerals such as iron ore, gold and copper can often be found in large quantities in taiga forests.

To exploit these minerals, mines and access roads need to be built, which requires trees to be felled.

Acid precipitation, forest fires, pests and diseases are all contributing to a loss of biodiversity in taiga forest ecosystems.

Pests and diseases

Pests and diseases harm organisms.

Because of the low biodiversity in taiga forests, it can be easy for a pest or disease to spread between members of the same species and cause a lot of damage.

Global warming is resulting in new pests and diseases being able to survive in taiga forests.

Forest fires

Wildfires are natural and beneficial elements of ecosystems.

But climate change is causing forest fires to happen more frequently and increasing the length of the fire season, which is changing wildfires from a positive to a negative force.

Acid precipitation

The combustion of fossil fuels releases sulfur dioxide and nitrogen oxides, which dissolve in atmospheric moisture to form acids. These acids then fall as acid precipitation, which has the following consequences:

Damages the leaves of plants.

Makes plants less able to cope with cold weather.

Soils become too acidic to nurture growth.

Kills organisms in water habitats

Threats to Tropical Rainforests

Deforestation is the removal of trees from forests. The reasons why deforestation is happening at such a rapid rate are:

Electricity (HEP)

Large areas of forest can be flooded when dams that generate hydroelectric power (HEP) are built.

Commercial and subsistence agriculture

Commercial - forest is often sacrificed to make room for cattle grazing as well as palm oil and soya plantations.

Subsistence - on a small scale, individual farmers will often clear forest so that they can grow food for their family.

Local demand for fuel wood

Local people fell trees so that they can use them as fuel.

Mineral extraction

Mining and selling minerals is a very profitable industry.

Demand for biofuels

Trees are often cut down to make space to grow the crops that are used to make biofuels.

Commercial hardwood logging

Timber can be sold for profit.

Additionally, trees must be felled to build roads that allow loggers access into the dense forest.

As well as the direct threats to tropical rainforests, such as deforestation, there are indirect threats, such as climate change.

Drought

Increasing temperatures and decreasing rainfall are leading to drought in some areas.

Consequences of drought

Drought can lead to ecosystem stress because the species are adapted to damp or moist conditions.

If droughts last for long periods of time, species can become extinct.

Forest fires, which can ruin large patches of forest, are also caused by drought.

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Types of Threatened Forests

Overview of Tropical Rainforests

Tropical rainforests are highly interdependent. This means that all the different parts depend on one another, and so a change to a particular part of the ecosystem will have knock-on effects for all the other parts.

Plants and animals

Animals gain nutrients from plants when they eat them.

Because the vegetation is so dense, there is enough food at the base of the food chains to support large animal populations.

Climate and soil

Decomposition happens quickly due to the warm and wet climate.

This means that the surface of the soil is nutrient-rich, and so plants can grow rapidly.

The knock-on effects of deforestation

When people reduce tree cover through deforestation, the whole ecosystem is affected.

E.g. less carbon dioxide is absorbed from the atmosphere for photosynthesis, and so the greenhouse effect increases.

E.g. less water is intercepted and so soil erosion increases.

Plants in tropical rainforests have adaptations to help them cope with the physical conditions of high rainfall and high temperature, as well as the intense competition for light.

Gradual and consistent dropping of leaves

This allows plants to continue growing year-round.

Smooth, thin bark

Thick bark isn't necessary as trees aren't exposed to cold temperatures.

Smooth, thin bark helps water run-off

Climbing plants

Climbing plants (e.g. lianas) use the tree trunks to drag themselves up towards the light.

Adapted to a particular layer

Tropical rainforests are split into 4 distinct layers (stratified structure), each with their own special adaptations:

E.g. in the highest layer, plants only have branches at their crown, where they are exposed to the most sunlight.

E.g. in the lowest layer, leaves have large surface areas so that they can absorb as much of the light that makes it through to them.

Buttress roots

Buttress roots are big roots that support the trunks of tall trees.

Thick, waxy leaves with drip tips

Having a waxy coating helps the leaves repel rain.

Drip tips help run-off by channelling the water to a point. This means:

The weight of the water doesn't harm the plant.

Fungi and bacteria can't grow as there's no standing water.

Animals in tropical rainforests, like all other animals, are adapted to find food and escape predators.

Nocturnal (active at night)

Many animals (e.g. sloths) save energy by feeding at night when it's cooler.

Flaps of skin

Some animals (e.g. flying squirrels) have flaps of skin that allow them to glide between trees.

Sharp sense of smell and hearing

Some animals (e.g. anteaters) have adapted to the low light levels on the rainforest floor by developing sharp smelling and hearing.

Strong limbs

Many animals (e.g. howler monkeys) avoid predation by living in the canopy.

These animals have strong limbs so they can climb around all day.

Camouflage

E.g. leaf-tailed geckos avoid predation by looking like leaves.

Short, pointy wings

Some birds (e.g. the harpy eagle) have short, pointy wings which allow them to navigate through the dense vegetation.

Nutrients Cycling

Nutrient Cycling in Tropical Rainforests

The nutrient cycle describes how nutrients are transferred or move between 3 stores (biomass, litter and soil) in ecosystems.

In rainforests, the majority of nutrients are stored as biomass. The movement of nutrients between different stores is quick.

The majority of nutrients in tropical rainforest ecosystems are stored as biomass and the movement of nutrients between the different stores is quick. The reasons for these characteristics are:

Evergreen trees

Because the trees are evergreen, leaves are dropped gradually and consistently throughout the year.

Warm, moist climate

Decomposers rapidly break down the dead organic matter dropped by the evergreen trees because the climate is warm and moist.

The nutrients released by this process of decomposition dissolve in water. The soil then soaks them up.

Dense vegetation

Because the vegetation in tropical rainforest is so dense, plants rapidly take up nutrients from the soil via their roots.

Biodiversity of Tropical Rainforests

The biodiversity of an ecosystem is the sum of the variety of organisms living within it. Below are some facts and issues relating to biodiversity in tropical rainforests:

Very high biodiversity

Rainforests are home to half of all the plant, animal and insect species that have been discovered.

Stable and productive environments

The consistent climate of rainforests means that:

Rainforest ecosystems are stable because organisms don't have to cope with changing conditions.

Rainforest ecosystems are productive because there's always lots of food.

Highly adapted

Many species have become highly adapted to a specific habitat and food source.

Food chains illustrate what eats what in an ecosystem. Food webs show how different food chains within an ecosystem overlap with one another. In tropical rainforests, food webs are complicated.

Food chains

All food chains begin with producers, who produce their own food by photosynthesising.

Producers are consumed by primary consumers, who are consumed by secondary consumers, who are consumed by tertiary consumers, etc.

When organisms die, they are decomposed by decomposers.

Food webs show how different food chains in an ecosystem overlap.

Complexity of rainforest food webs

There are lots of links because there is such a huge number of species.

Some animals are primary as well as secondary consumers.

Overview of Taiga Forests

Taiga forests are made up of 6 main components: soils, water, climate, animals, plants and people. Taiga ecosystems are highly interdependent, and so a change to any of these components will affect all the others. For example:

The knock-on effects of deforestation

When people reduce tree cover through deforestation, the whole ecosystem is affected.

For example, deforestation leads to permafrost melting. Melting permafrost can lead to flooding and trapped greenhouse gases being released into the atmosphere.

Plants, herbivores and carnivores

If a herbivore relies on a certain type of plant for survival, they need to migrate to areas where that plant is available.

Carnivores will naturally follow this migration pattern if their main food source is the herbivore.

Trees, permafrost and plants

The trees provide valuable shade in the summer, which stops the permafrost from thawing.

This is good for plants because permafrost provides them with water.

Soil, plants and animals

The soil provides plants with nutrients.

Plants then provide these same nutrients to the animals that consume them.

Animals spread the seeds of the plants they eat, which helps the plants to reproduce.

Some examples of how plants have adapted to the cold, dry climate of taiga forests are:

Simple structure

The structure of taiga forests is lots of tall trees close together and that's about it.

This is because the soils are poor and only small amounts of light penetrate through the dense canopy to the forest floor, and not many plants can survive in these conditions.

Evergreen trees

Always ready to grow and so make good use of the light that's available.

Their cone shape means that heavy snowfall glides off branches without snapping them.

Having needles as opposed to flat leaves reduces the surface area, which means the plants lose less water.

Some examples of how animals have adapted to the cold, dry climate of taiga forests are:

White winter coats

Some animals (e.g. snowshoe hares) have white winter coats which make them camouflaged in the snowy conditions.

Migratory

Large mammals (e.g. caribou) migrate long distances in search of food.

Hibernation

Hibernation helps animals such as brown bears conserve energy for the long winters.

Good insulation

Good insulation is important given the freezing winter temperatures.