SUSTAINABLE MANAGEMENT – RAINFORESTS

Due to the sheer speed and scale of deforestation in the world’s rainforests, sustainable management techniques have been put into place to reduce the impact. I will discuss these shortly.

It does make you wonder to what extent rainforests can regenerate naturally without human intervention. If small areas of rainforest are cleared at a small scale then left alone, the rainforest can regenerate. However, the large-scale deforestation breaks the natural nutrient cycle. This in turn affects the soils and leaves the soil subject to erosion where the land has been cleared. Then when the rains come, more nutrients are lost as they are washed away. In turn, the land becomes infertile with new tree roots being unable to establish themselves. The ecosystem dies and the land remains empty. The loss of trees in the area results in the global oxygen and carbon dioxide balance changing which is believed to contribute to global warming.

Sustainable management

Exploitation of the rainforests is causing severe global consequences. If this continues in an uncontrolled way, irreversible damage could be done to the rainforests. This is why sustainable forest management is needed.

Sustainable management can be seen in the Amazon rainforest. There are currently three main aims that have been put into place:

·         To protect the rainforest canopy and bio-diversity, preventing soil erosion

·         To maintain the operation of the nutrient cycle

·         To ensure the natural regeneration of the forest

These aims are accompanied by a range of strategies:

·         Agro-forestry – Growing trees in line with agricultural crops. Allows farmers to use the trees as a protective canopy for their crops and also have a supply of nutrients from decomposing plant matter.

·         Forest Reserves – Ensure areas of forests are completely protected from any type of human activity allowing growth of sustainable products such as plants for medicines and latex from rubber tapping.

·         Tree measuring – Trees should only be felled once they have reached a certain height which ensures younger trees have a chance of survival.

·         Afforestation – Planting new trees when mature trees have been felled in attempt to maintain the canopy.

·         Education – Ensuring those who use the rainforest know how to in a sustainable manner.

·         Selective logging – Ensuring trees are only felled once they have matured. This helps preserve the existing canopy, and helps the slower growing hardwoods such as mahogany (see previous post about hardwoods).

Students can use this link as a potential case study which shows a comparison of the Pacific ACP states rainforest’s: http://ec.europa.eu/development/body/publications/courier/courier193/en/en_030.pdf.

The S-cool revision website is a useful source when studying this area which covers other areas such as tourism and ecotourism in the tropical rainforests as well. See: http://www.s-cool.co.uk/a-level/geography/ecosystems/revise-it/managing-the-tropical-rainforest.

This is an article showing that despite sustainable management strategies being put into place, it is only occurring in small areas of rainforest and there is still much development needed. Despite the attempts to add protection to the forests making them areas of non-activity, it has been noted that only 3% of rainforests worldwide between 2005 and 2010 were protected. See the following article for more details: http://www.nature.com/news/2011/110608/full/news.2011.308.html.

This final link shows a video of rainforests in Indonesia and Costa Rica and the impact of destruction and sustainable management on them. Students will find this very beneficial to watch: http://www.bbc.co.uk/learningzone/clips/rainforest-destruction-kalimantan-indonesia-and-costa-rica/3096.html

 

Links:

http://www.aqua.org/explore/baltimore/exhibits-experiences/upland-tropical-rainforest

http://lornali.com/sustainable-rainforest-management

http://www.amazoncharitabletrust.org/en/index.asp

http://www.bbc.co.uk/schools/gcsebitesize/geography/ecosystems/human_uses_rainforest_rev5.shtml

HUMAN IMPACT ON THE RAINFOREST

Hundreds of years ago rainforests were not under threat human activities. Despite rainforests catering for small tribes of people, these tribes had very little effects on the ecosystem. However, today rainforests are under great threats as ‘our’ actions are destroying them – rapidly! The main problem is deforestation!

Deforestation is happening quickly! Too quickly! Trees are being felled at a much quicker rate than what they are growing at. It is feared that by 2030 the world’s rainforests may be gone. To put this into perspective, in the Amazon it is thought that 2.5 hectares of forest are cleared each minute! This is the equivalent of 5 football pitches! (I will make reference to the Amazon throughout this post to give an outline of the scale of the human activities listed below).



Logging



Economic exploitation

Logging – there is a high demand for hardwoods such as mahogany and rosewood from the rainforests. Consumers in MEDCs will pay a lot of money for furniture made by these woods. However for every tree cut down it is believed that 30 others may be damaged or destroyed in the process. Five million hectares of forest are lost in the Amazon as a result.  

Mining



Mining – Some rainforests have developed above mineral rich resources. One of the main minerals found in Amazon rainforest is iron ore, also known as haematite. This is mined and exported to steel making countries. However this mining process is destroying huge areas of forest in the process. Iron ore is not the only mineral found in the rainforest, other metal ores such as gold, platinum, copper, lead, and bauxite can be found.



Cattle ranching



Cattle ranching – Another reason for the clearing of land is so farmers can rear their cattle. Since 1950, it is estimated that two-thirds of the Amazon’s lowland forest has been turned into pasture for grazing. Due to overgrazing, the nutrients in the soil decline making the quality of the grass poorer. This has resulted in ranches expanding their land for better quality soil and grasses.



Peasant farming – This is at a much smaller scale, but due to over-crowding in cities (particularly in Brazil) citizens have been pushed into the rainforest with permission to clear land for farming, however due to infertile soils, this has not been entirely successful.

 

I have found a useful link that provides a work sheet used in a school for Year 10. I think it would be effective for students working at GCSE level to take a look at it. It can be found on: http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=10&sqi=2&ved=0CHIQFjAJ&url=http%3A%2F%2Fwww.geography.learnontheinternet.co.uk%2Fvgd%2Fresources%2Fyear10%2Fecosystems%2Fwhatistheimpactofhumansinthetropicalrainforest.doc&ei=b7I3ULWJEuLS0QWZyYGQDg&usg=AFQjCNGrViY4d25e6KOBISE41rFxgNqoXA&sig2=IKoRFTq7ku4yfic84BEM7Q

 The National Geographic has provided lesson ideas and activities that can be used within the classroom with high school students. Some of the activities are very time consuming however may provide inspiration when developing personal lesson activities. See: http://www.nationalgeographic.com/xpeditions/lessons/14/g912/fayhuman.html

 

Links:

http://www.rain-tree.com/facts.htm

http://biology.clc.uc.edu/courses/bio303/human%20interactions.htm

RAINFOREST STRUCTURE

Rainforests have four distinct layers. These layers have formed based on the light available to plants which they need for photosynthesis.

These layers are:

·         The emergent layer - these trees (emergents) have broken through the canopy layer, growing taller than most trees in the battle for light. These trees can reach 50-60m in height and have trunk circumferences that can measure up to 5m. These trunks are usually supported by buttress roots, which also help protect the trees from strong winds. These trees are exposed to greater climatic and weather conditions than the other layers due to their exposure and therefore their leaves tend to be thick and waxy and hold water. Being above the other layers allows the trees to make good use of the wind to disperse seeds and fruits. This layer supports wildlife such as eagles, monkeys, butterflies, bats and snakes.

·         The canopy - also known as the primary layer. Emergents grow up to 45m. This layer can block 80% of the light reaching the under-layers of the rainforest creating high competition among many plant species. However the canopy also acts as a shield, blocking heaving rain from destroying the plants below. Thick, woody vines can be found in this layer, known as lianas, which grow up trees in the search for sunlight. In the canopy animals such as monkeys, sloths, bats, treefrogs, ants, beetles, parrots and other bird species can be found here.

·         The under canopy – also can be referred to as the ‘under-story’. This layer only receives around 2-5% of the sunlight available to the canopy. The plants that grow in this layer have adapted to make use of the little light they receive by having dark green leaves that take in more light than lighter leaves, in other words they are ‘solar collecting’ leaves. These plants also refrain from growing flowers to conserve more energy. Plant pollination is much harder on this layer due to the lack of air movement. Animals such as snakes, parakeets, leopards, jaguars and a range of insects can be found here.

Rainforest structure

·        The shrub layer – this is the forest floor and very few plants grow on this layer due to it only receiving between 0-2% of the sunlight and has 100% humidity. This layer hosts rapid decomposition of vegetation and other organisms that are broken down into nutrients that are recycled back into the rainforest. Insects, cockroaches, beetles, centipedes, millipedes and earthworms can be found here among mosses, herbs and fungi.



The BBC Learning zone website provides a video and teaching tips
when covering the rinforest structure in the classroom. See:
ttp://www.bbc.co.uk/learningzone/clips/rainforest-structure-layering/3092.html

Links:

http://library.thinkquest.org/27257/structure.html http://www.srl.caltech.edu/personnel/krubal/rainforest/Edit560s6/www/whlayers.html
http://www.geography.learnontheinternet.co.uk/topics/rainforest.html

TROPICAL RAINFORESTS

I remember studying in depth tropical rainforests for my GCSE’s. It was definitely an area that captured my interest more than others. However, just like everything I have studied feel I would not be able to talk about these in great depth without some revising first.

I am particularly excited to write a few posts on this area as I had the privilege of visiting the Amazon rainforest earlier this year and feel I can strongly relate to it.



Rainforest locations



Tropical rainforests are located in the tropics where the climate is hot and wet all year. They currently cover 6% of the Earth’s which has significantly decreased over the past 200 years where they used to cover twice as much.



Tropical rainforests are considered the most ecologically bio-diverse ecosystems on the planet:

-          They are home to 50% of all life-forms on the planet

-          They produce 40% of the worlds oxygen

-          The vegetation is dense with trees growing up to 50m in height.

The climate

Tropical rainforests do not tend to have distinct seasons, if any seasons at all. The day to day climate is usually the same all year round. The weather tends to be either hot and dry or hot and wet with occasional thunder storms. The average daily temperature is around 28°C which can reach 35°C and will never fall below 20°C and on average will receive around 2000mm of rain per year, creating a ‘sticky atmosphere’. I can agree that the rainforest was all of these... hot, muggy, humid, damp... Not the easiest conditions to live in to say the least!



Soil and nutrient cycle



The rainforest can be quite deceptive with its dense vegetation and range of exotic wildlife. It may be a lush paradise but in reality they have fragile ecosystems with poor soils. There tends to only be a thin layer of fertile soil on the grounds surface with the deeper soils being ‘iron-rich laterites’ which are not good for vegetation growth. The majority (80%) of the nutrients available in the forest actually come from the vegetation itself, when plant matter falls to the ground and decomposes rather quickly due to the hot wet climate. This allows the nutrients to be recycled back into the forest (see diagram).

Students may find the diagram useful to sketch to help remember the cycle.  



Links:

http://www.rain-tree.com/facts.htm

http://www.aqua.org/explore/baltimore/exhibits-experiences/upland-tropical-rainforest

http://www.bbc.co.uk/schools/gcsebitesize/geography/ecosystems/tropical_rainforests_video.shtml  

HUMAN IMPACT ON THE SAVANNA

Humans can have negative impacts on the savanna if their activities are not controlled. These can lead to areas of the savanna becoming deserted.

These activities include:

·         Man-made fires – These are made to burn areas of grassland to help aid the better growth of young grass in subsequent seasons. The use of fire however, destroys particular plant species who cannot withstand the fire, leaving areas to only accommodate pyrophytic plants species such as the baobab and acacia tree. Also fires can damage the soils making it harder for vegetation to grow in certain areas.

·         Grazing – Cattle grazing results in certain plants being killed leaving behind the so-called animal repellent plants behind such as thorny bushes, shrubbery and acacia trees. Also areas are cleared for farmland which in some extremes can lead to desertification of the area when the soil becomes infertile.

·         Hunting – Some animals in the savanna are hunted for their valuable body parts e.g. elephants for their tusks, lions for their fur and bison for their meat. Many animals have been hunted to the point they are verging on extinction. Despite certain measure being put into place, only 1% of grasslands are protected by the Government.

Here’s another video from BBC Bitesize to help students: http://www.bbc.co.uk/schools/gcsebitesize/geography/ecosystems/savannah_grassland_video.shtml. I am not keen on the video as I do not think it gets the point across effectively due to it being so brief, however I am currently struggling to find a more useful video.

And so it has taken me 15 posts to establish how to get a video onto the blog, it feels quite an achievement to say the least as I am no computer expert. This second video shows an African savanna, it shows what a savanna looks like, how it accommodates particular animal species and how the species are playing a role in shaping the savanna.  

Links:

http://www.ecologyandsociety.org/vol7/iss1/art9/des_human_influence.html

http://www.sln.org.uk/geography/schools/blythebridge/gcseecosystemsavanna.htm

VEGETATION IN THE SAVANNA



Elephant grass



The savanna hosts a range of vegetation, these plants however have adapted to survive in this varying wet and dry humid climate.

In the wetter areas, tall coarse grasses known as elephant grass can be found among many deciduous trees (these trees lose their leaves in the dry season). This is known as the tree savanna. In the drier areas, shorter tufts of grass grow known as tussock grass. This grass is usually accompanied by two types of drought resistant trees, the baobab and the acacia.

Tussock grass

The baobab tree – Also known as the ‘upside-down tree’ has a thick spongy trunk, long tap roots and bears leaves for only a few weeks.

The acacia tree – These have a crown structure, often flattened by the trade winds. These trees lose their leaves in the dry season.

These trees are pyrophytic meaning they can withstand fire mainly due to their insulating bark. They also have leathery leaves to reduce transpiration losses. Other plants are microphyllous, meaning they are small leaved to also reduce transpiration losses. 



Acacia tree



In the tree savanna a so-called ‘parkland’ exists. The trees crown shaped tops shade the root areas and help prevent soil moisture evaporation. These trees show xerophytic characteristics meaning they have adapted to survive in dry environments that lack water. These characteristics include:



-          Dense cell fluids

-          Hard waxy leaves

-          Thorns

-          A protected stomata

Baobab tree

These all help reduce water loss. 

Outside the tree savanna is the grassland savanna where the grasses between the trees become shorter and sparser. The grass tends to die back in the dry season and regrow from root nodules when it rains. Beyond the grassland savanna, is the shrub (scrub) savanna. Here you can find short tufted grasses, acacia trees and thorn bushes. In the shrub savanna, vegetation compete for water and have the ability to turn their blades away from the sun to reduce water loss.

For a better understanding students can watch the savanna grassland video on BBC Bitesize: http://www.bbc.co.uk/schools/gcsebitesize/geography/ecosystems/savannah_grassland_video.shtml



Links:

http://www.blueplanetbiomes.org/savanna_plant_page.htm

http://www.pupilvision.com/uppersixth/savanna2.htm

https://php.radford.edu/~swoodwar/biomes/?page_id=105

THE SAVANNA

Now I have studied the savanna at GCSE level and believe it to be another extreme landscape. Yet again, this is another area I do not remember in much detail due to studying it so long ago.

So, what is a savanna?

Now a savanna is not a desert. A savanna is a large area/space of grassland that comprises of widely spaced trees. Savannas can occur in several types of biomes and consist of a range of flora and fauna. They are enormous plains that are found between moisture equator forests and tropical deserts, and consist of various layers.

Savannas have a wet season (summer) and a dry season (winter) so only certain vegetation can grow there, however the conditions are suitable for a range of animal types. In the wet season savannas can receive on average between 15 and 25 inches of rainfall, however only around 4 inches of rainfall is received in the dry season.



African savanna



Savannas can be found in areas of Africa, in South America (mainly Brazil) and Northern Australia with the largest being found in Africa. It is Africa’s savannas that boast the most wildlife species and it is these savannas we often refer to. In Eastern African savannas such as the Serengeti Plains of Tanzania, lions, zebras, elephants, giraffe and many types of ungulates (which I have learnt today means  animals with hooves) inhabit the area. These animals migrate in the dry season to areas where more rainfall occurs due to the lack of vegetation available to graze on in the dryer areas.




Savanna transect

 

The type and density of the vegetation changes with latitude. Closer to the equator is the ‘closed’ savanna, with just a short drought season and therefore there is a greater amount of trees. Closer to desert areas, it is known as the ‘open’ savanna. This has a much longer drought season, little can grow here so shrubs and clumps of grass dominate these areas. Students may find the transect (see diagram)useful to understand how the types vegetation can vary across a savanna.

I think it is important for students to know this diagram and how the land and vegetation changes as you move away from the equator. It is particularly important as I have already covered the desert, I am currently covering the savanna and I will be posting about tropical rainforests shortly. Therefore this diagram is useful to use and refer back to.

Links:

http://www.worldstory.net/en/savana/the_savana.html

http://www.blueplanetbiomes.org/savanna.htm

http://www.geography.learnontheinternet.co.uk/topics/savanna.html