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Forests are threatened by both biotic and a-biotic factors such as climatic hazards, diseases prompted by insects or pathogens, threats of a purely anthropogenic nature, fires, atmospheric pollution, deforastation, and the increase in social pressures.Â
But this classic division is a bit artificial, since man is partly responsible for all these threats.Â Indeed the mark of human actions is always present : it is however relatively moderate concerning climatic disorder despite the emissions of greenhouse gases, responsible for important destructions ; it is average in the sensitive growth of certain artificial forestry stands prone to parasitic attacks ; it is preponderant in the phenomena of atmospheic pollution or of deforestation. These aggressions will therefore be classed by groups but keeping an effort to maintain classification by growing order of mans implications, and therefore the possibility of theoretical intervention will also increase.
Agricultural purposes – Grazing cattle or planting crops. Poor farmers in developing countries chop down a small area of trees and burn them, which provide nutrients for the soil (know as the ‘Slash-and-Burn’ technique). This supply is quickly exhausted so the farmers move on to a fresh area, and the cycle starts again. This occurs on a much larger scale for intensive or modern agriculture e.g. large cattle pastures often replace rain forest to grow beef .
Commercial logging – the cutting down of trees for sale as timber or pulp. In the developed world, there are increasing demands for hardwoods such as mahogany and ebony. The rate at which trees are felled is increasing to meet these demands. People in third world countries need the timber for firewood, as it’s practically the only source of fuel available to people living there. The heavy machinery used (e.g. bulldozers) is just as damaging to a forest overall as the chainsaws are to individual trees.
Climatic hazards and natural catastrophes
Climatic hazards or natural catastrophes are pratically independent from the actions of the man. However, the worries concerning eventual future climatic changes, due to the consequences of green house gases from industrial pollution are going to grow. It is sufficient to study here not the ways of fighting these aggressions, but those measures to take before forestry stands are subjected to these events.Â
Forests are submitted more than any other terrestrial ecosystem to climatic hazards, due to the duration of their maturity, wich can take up to 200 years. In such a period the number of climatic hazards can be great.
Storms and win-blow
Storms have had an important destructive effect throughout this century, especially throughout the last twenty five years in Europe, destroying millions of m3 of wood, the following
– 1990, almost 110 million m3 destroyed throughout Europe.Â
– 1999, 140 million m3 in France.Â
These anarchic destructions greatly perturb cutting cycles and general forestry work. Delaying The development of the forest and disrupting the wood market. Against such freak winds forestry management has very little power. However, although foresters are unable to prevent such catastrophes, they have the power to limit the destruction of violent winds by favouring the development of stands that are more wind resistant, and by adopting a prudent and diverse outlook towards management.
Periods of drought
Water stress renders forestry stands very fragile. They can arise either by a change in the distribution of water throughout the seasons, for the same quantity of annual precipitation (the supply therefore being brought forward in relation to the demand of forest stands), or by a fall in the annual volume of precipitation. It has now been established that the numerous cases of dieback observed in forests stands throughout the world in the last ten years (which at the time were entirely blamed on atmospheric pollution) are due in part, to periodic water stress. In fact, those observations realised concern those forests in regions subjected to strong pollution fall out, but also forests of less affected regions. Â
Diseases and the attack of insects : brief overview of the situationÂ
Insects and fungi play an important part towards the causes of dieback in many forests of the world.Â
These biotic agents intervene, either as primary agressors, or most often as secondary agressors, often attacking already weakened stands. The examples of diseases and illnesses caused by pathogens are unfortunately numerous and only a few will be outlined. These illnesses develop, either as a result of native pathogenic activity, or by the invasion of the non-native agents in non-resistant stands. Robredo and Cadahia drew up a very complete table of the world situation concerning this problem during the tenth world forestry congress, from wich the following text is largely inspired (in COLLECTIF. – The forest, inheritance of the future – Acts of the tenth forestry congress . – French forestry revue. – Nancy, 1991.).
In North Africa, natural cedar stands are attacked by xylophitic insects , during periods of climatic stress.
In Spain,Â Abies pinsapoÂ is subjected to combined attacks of theFungiÂ Fomes annosus, and xylophitic and cortical perforating insects.
In Europe, dieback can be observed amongst various oak species, most notably, the cork oak and evergreen oak (attacks ofÂ DiplodiaÂ andHypoxilon).
In Quebec, the pine shoot moth periodically attacks the annual shoots of (Abies balsamea and Picea glauca) as in the whole of the North East of North America. This indigenous insect reaches epidemic proportions roughly every thirty years. The last infestation (1938-1958) provoked the death of 60 % of Firs and 20 % of Spruces. At the end of 1975, an epidemic breakout covered 35 million ha of Quebec.
Fires:-Fire has always been an element present in many forestry ecosystems. Natural causes of fire exist such as lightening and volcanic eruptions. The area subjected to natural fires has been very important and can cover millions of hectares. However the lapse of time is generally long between successive fires, permitting the ecosystem to recover and reconstitute itself.Â
Large fires have always ravaged the surface of the earth. In the North of China, 1.33 million ha went up in flames in 1987 ; more than 3.5 million ha were burnt in Kalimantan (Borneo) between 1982 and 1983 ; in 1988, 400.000 ha were destroyed by fire in the United States in yellow stone national park. Recently in 1993, considerable damage was done by an enormous fire in Australia.
The importance of human factor
The main causes of contemporary fires and anthropogenic :
This is the case with the recurrent fires in the European Mediterranean zone, or those fires provoked in tropical humid zones, which have their goal the clearing of land for agriculture.
In dry tropical zones with mixed broadleaved forests and rich undergrowth, human populations have always used fire to make way for grazing and agriculture.
In Europe, figures gathered by the FAO permit one to establish the area of forest burnt annually between 1980 and 1988, i.e. some 585.000 ha. During the same period North America lost some 3.5 million hectares of forest to fires. That percentage attribued to human causes being around 97% in Europe, 91% in the United States and 66% in Canada.
Very little is known concerning the equivalent information for the entire world. The total wooded surface touched by fire annually is around 10 million hectares, which represents some 0.3% of the total world forested area. However the impact of these fires is more important than this small percentage suggests. In fact, in the zones where the frequence of fires is high, the destructive character of such fires is worsened by the fact that forest stands do not have the time to reconstitute themselves between the passage of two consecutive fires.Â
An Integrated policy for the prevention and fighting of fires
The methods of fighting fires must be adapted to the socio-cultural environment in which they are put into place.
- Developed countries
Developed countries possess the necessary materials to permit them to carry out a “No-fire” policy in order to satisfy public opinion, which is generally very sensitive to this form of threat to the natural environment. In this case, a perfect coordination between terrestrial and aerial fire fighting means must be provided, in addition to the active participation of the public and private forestry sectors, for example, in the participation of preventive operations and detective procedures.Â
- Developing countries
In developing countries or in natural regions wich are less densely populated, one must accept that a part of the wooded surface will be burnt. This practice is due to an agro-silvo-pastoral culture wich includes positive elements and is therefore difficult to condemn. Solutions can not be looked for without taking into account the subsistence requirements of those populations concerned.
3. BENEFITS OF AFORESTATION
Afforestation refers to the conversion of wasteland into a woodland or forest. It is essentially the transformation of land which has not been forested for a period of more than 40 year to woodland through seeding and planting. Afforestation is the best technique used to minimize the greenhouse effect. Therefore, there is constant necessity to develop afforestation programs in order to preserve and protect the forestry including the wasteland. A massive afforestation program is required to meet the increasing demand of fuel wood, timber and fodder. Here are the main benefits of afforestation.
1. Preserves wildlife
Afforestation is useful especially when it comes to protecting the wildlife. According to recent scientific studies, upland forest vegetation tends to affect the population of birds on neighboring unplanted moorlands. Planting of trees simply restores and maintains ecological balance of all systems in the environment.
2. Tourist attraction
Trees provide oxygen and also help to preserve ecological splendor of the landscape which in turn attracts tourists from all parts of the world.
3. Minimizes soil erosion
Soil erosion is significantly reduced as tree plantations prevent run off after heavy rains. In addition, trees bring soils together which prevents soil erosion.
4. Provides forest products
With an increase in demand for forest and timber products, afforestation is very valuable due to the explosion of livestock and human population. For that reason, construction of infrastructure has led to the demand of forest products.
5. Stabilizes the climate
Planting of trees in semi-arid areas attracts rainfall. This way, agricultural practices such as irrigation are carried out efficiently. In addition, afforestation acts as a catchment for water and soil conservation.(5)
4 .EFFECT OF DEFORESTATION
When forests are killed, nature basically requires people to renew the forest. Reforestation is one concept that is in the opposite direction as deforestation, but is proven to be a much harder effort than deforestation.
So the rate of deforestation has not been offset by the rate of reforestation. Thus, the world is now in a troubled state when it comes to issues concerning the environment.
When an area of rainforest is either cut down or destroyed, there are various climate changes that happen as a result. The following is a list of the various climate changes with a brief description of why they come about.
Desication of previously moist forest soil
What happens is because of the exposure to the sun, the soil gets baked and the lack of canopy leaves nothing to prevent the moisture from quickly evaporating into the atmosphere. Thus, previously moist soil becomes dry and cracked.
Dramatic Increase in Temperature Extremes
Trees provide shade and the shaded area has a moderated temperature. With shade, the temperature may be 98 degrees Farenheit during the day and 60 degrees at night. With out the shade, temperatures would be much colder during the night and around 130 degrees during the day.
Moist Humid Region Changes to Desert
This is related to the desicaiton of previously moist forest soil. Primarily because of the lack of moisture and the inability to keep moisture, soil that is exposed to the sun will dry and turn into desert sand. Even before that happens, when the soil becomes dry, dust storms become more frequent. At that point, the soil becomes usesless.
No Recycling of Water
Moisture from the oceans fall as rain on adjacent coastal regions. The moisture is soon sent up to the atmosphere through the transpiration of foliage to fall again on inland forest areas. This cycle repeats several times to rain on all forest regions.
Less Carbon Dioxide and Nitrogen Exchange
The rainforests are important in the carbon dioxide exchange process. They are second only to oceans as the most important “sink” for atmospheric carbon dioxide. The most recent survey on deforestaiton and greenhouse gas emisions reports that deforestation may account for as much as 10% of current greenhouse gas emmisions. Greenhouse gases are gases in the atmosphere that literally trap heat. There is a theory that as more greenhouse gasses are released into the atmosphere, more heat gets trapped. Thus, there is a global warming trend in which the average temperature becomes progressivily higher.
The ozone layer is a mass of oxygen or O3 atoms that serves as shield in the atmosphere against the harmful ultraviolet rays from the sun. Because ozone is made up of oxygen atoms, oxygen react with carbon monoxide. Such reaction would use up oxygen It follows that when there are more carbon monoxide atoms going to the atmosphere, the volume of oxygen would decline. Such is the case of ozone depletion.
According to the United Nations Enviromental Programme (UNEP) in 1977, deforestation is an important factor contributing to desertificaiton. What is unclear is how fast deserts are expanding is controversial. According to UNEP, between 1958 and 1975, the Saharen Desert expanded southward by about 100km. In 1980 UNEP estimated that desertification threatened 35 per cent of the world’s land surface and 20 per cent of the world’s population. Recently, groups challenged those conclusions. Some scientists claim that the conclusion were based on insufficient data. Nevertheless, desertification still threatens more and more drylands.
7. (Soil Erosion Soil ErosionÂ – The trees and shrubs in a forest cover the ground and protect the soil from the rain. Tree leaves intercept the rain fall, and shrubs and leaf litter protects the soil from water dripping off the leaves. With this protection removed, the rain falls directly onto the bare soil and erodes it. The rain also leaches the soil of important nutrients, making it less fertile.
8. The Greenhouse EffectÂ – During photosynthesis, carbon dioxide is taken in and oxygen is given out. Deforestation removes the carbon ‘sinks’, and coupled with the carbon dioxide emitted from the burning of fossil, the levels of carbon dioxide in the atmosphere increase. The carbon dioxide forms a blanket around the earth and traps heat from solar radiation. This is called the greenhouse effect, and causes the average temperature of the earth to rise. If this continues, the polar ice caps could melt and cause flooding.
9. Disruption of the Hydrological CycleÂ – Deforestation can effect the local climate of an area by reducing the evaporative cooling that takes place from the soil and plants. Because the amount of evapotranspiration has been reduced, the formation of clouds and therefore precipitation is also reduced. This threatens the existence of the remaining plants in the forest. Deforestation can also cause flooding. In forested areas, flood water is absorbed into the soil and taken up by the tree roots. The water is then transpired through aerial parts of the plant and into the atmosphere, where it forms clouds. In deforested areas, the flood water runs across the area and is not stopped by vegetation. The top layer of soil is eroded in this process and gets transported into rivers where it causes the level of silt to rise. This rise in the river level causes floods to occur more frequently. Less evaporation also means that more of the sun’s energy is used to warm the surface and consequently the air above, leading to a rise in temperatures.
10. Spreading of DiseaseÂ – the mosquito, anopheles darlingi, which spreads malaria parasites, breeds in pools of water that are created in deforested land and on eroded land. Deforestation therefore favours a population explosion of this species.
11. Flooding. Deforestation can result to watersheds that are no longer able to sustain and regulate water flows from rivers and streams. Trees are highly effective in absorbing water quantities, keeping the amount of water in watersheds to a manageable level. The forest also serves as a cover against erosion. Once they are gone, too much water can result to downstream flooding, many of which have caused disasters in many parts of the world.
As fertile topsoil is eroded and flooded into the lower regions, many coastal fisheries and coral reefs suffer from the sedimentation brought by the flooding. This results to negative effects in the economic viability of many businesses and fatalities in wildlife population.
12. Other Effects
(a) Demand for land for cultivation.
This has been seen both in Kenya and other parts of the world especially countries that have Agriculture as the backbone of their economy. Trees have been cut down to obtain land for cultivation of both subsistence and cash crops, both by governments and individuals.
b) Need for firewood
People, especially those who live in rural areas where electricity and gas are unavailable, resort to use of firewood as a source of heat. Here, wood is cut down and burnt.
c) Need for land to build industries
Industries require a lot of land and while industrialization is important for every country, it is the bane of large tracts of forest. People need jobs in order to provide for their daily needs.
d) Need for land to build houses
With the worldwide increase in population, land to build houses for people to live in is very much required.
e) Need for wood for furniture, pencils, paper etc)
There many rewards such as clean air and clean water, perhaps the two most important, that forests provide. Rainforests also provide many aesthetic, recreational and cultural rewards. If the rainforests are destroyed, then these rewards dissappear. This has major social repercusions for the entire world.
Effect to biodiversity
- Destruction of animal habitats:
Apart from domesticated animals and marine and fresh water animals, all other animals need forests as their habitats. These forests do not only provide a place for the animals to roam day but also provide their food and act as a source of protection from predators through camouflage. Destruction of the animals’ habitats literally kills the animals.
- Medicinal Plants:
Some trees are used as herbs. Trees such as the Cinchona have been used as treatment against Malaria since time immemorial. Destruction of these forests leads to destruction of medicinal plants that could be used as treatment for various ailments.
Forests are natural habitats to many types of animals and organisms. That is why, when there is deforestation, many animals are left without shelters. Those that manage to go through the flat lands and residential sites are then killed by people.
Through the years, it is estimated that there are millions of plant and extinct animal species that have been wiped out because they have been deprived of home. Thus, biodiversity is significantly lowered because of the savage deforestation practices of some people.
Wildlife advocates have been constantly reminding that several wild animals left in the world could still be saved if deforested forests would only be reforested and the practice of slash and burn of forests would be totally abandoned.
Social effects of deforestation
Deforestation is hardly hitting the living conditions of indigenous people who consider forests as their primary habitats. Imagine how they are rendered homeless when forests are depleted. These natives would be forced to live elsewhere, and are usually left to becoming mendicants in rural and urban areas.
water sinks in deeper to the ground, and eventually replenishing the supply of water in the water table. Now, imagine what happens when there is not enough forests anymore. Water from rain would simply flow through the soil surface and not be retained by the soil.
Overall, effects of deforestation cannot be offset by the contribution of the practice to development. While it is logical that progress is very much needed by mankind, it must also be noted that nature knows no defeat. Destruct it and it would certainly retaliate, one way or another.
Pollution is rapidly growing along with population. Forests are greatly helping reduce the amount of pollutants in the air. So, the depletion of these groups of trees is greatly increasing the risk that carbon monoxide would reach the atmosphere and result in the depletion of the ozone layer, which in turn results to global warming.
5. SOLUTION OF DEFORESTATION
ReforestingÂ – this is especially popular in Vietnam, where most of their forests were destroyed during the war. Now, every pupil has to plant a tree and look after it.
BansÂ – generally, people want a ban on the logging of ‘ancient-growth’ forests and possibly compensating companies for not logging certain areas.
Sustainable ForestsÂ – using forest and the animals and plants that live in them in ways that do not permanently damage them. This could mean taking only as much timber or other products as the forests can support so that they will continue to be productive in future years.
RecyclingÂ – an option for the wealthier countries in the world to cut down on their consumption of forest products in general.
Protected AreasÂ – environmental organisations like WWF and Friend of the Earth can offer legal protection for certain areas by campaigning and informing governments over the necessity to protect a proportion of the world forests from destruction.
ProduceÂ – an increase in demand for products which have their origin in tropical rainforests e.g. body creams, bath oils, sweets, fruits and nuts, would make the forests more secure, as a large number of trees are needed to produce a large yield.
False Solutions:Â 1. “Sustainable” Commercial Logging On a governmental level, attempted solutions to deforestation caused by the timber industry have emphasised the necessity of supporting sustainable timber extraction. Such approaches assume, without supporting evidence, that rainforests can be used as an industrial resource base for timber on a sustainable basis. This has resulted in more rather than less deforestation. The International Tropical Timber Organisation (ITTO) has had to acknowledge that serious attempts at sustainable management of tropical rainforests for timber production are on a world scale, “negligible”.
As well as the technical obstacles to sustainability, the industry has shown itself to be unable to operate free from corruption. The only systematic attempt to disclose such corruption has been in Papua New Guinea, where a recent inquire concluded that “there can be no doubt that the timber industry, by its very nature, is conducive to acts of a criminal nature and acts contrary to law and proper government administration.
The Tropical Forestry Action Plan (TFAP), the first major international initiative to tackle tropical deforestation, was launched in 1985 by the UN’s Food and Agriculture Organisation (FAO), The World Resources Institute, the World Bank and the United Nations Development Programme. It claimed to offer a cure for tropical deforestation and its supposed causes, but its flaws were apparent from the outset. It was based on the assumption that poverty and overpopulation are the main underlying causes of tropical deforestation and failed to recognise the role of the developed countries. It paid lip service to the role of’ landlessness and destructive development, but made no real attempt to deal with them. The TFAP regarded deforestation as a result of too little government control and called for all rainforests to eventually come under government jurisdiction. Rather than calling for reforms to inequitable land ownership, the TFAP often requires annexation of traditional lands for government forestry estates.Â
Donor countries are becoming unwilling to fund TFAP projects. Peru, Colombia, Panama and Argentina have received less than 10% of the funding required for their national TFAP projects. The US Senate is now refusing to fund the TFAP at all, and Britain has said it will withdraw from the Plan entirely unless coordination of the TFAP is moved out of the FAO.
3. The Limits of Reserve Strategies
A significant proportion of tropical biodiversity would already be lost if nature reserves, often initiated by private conservation organisations, had not been established. However, all too often indigenous peoples, living harmoniously with their environment, have been expelled from protected areas or subjected to controls that have led to the disintegration of their cultures. It is a misconception to believe that nature reserves can conserve the greater proportion of the genetic diversity of tropical rainforests, where the number of individuals of each species per unit area tends to be low, but the total number of species can be enormous. On average, ten hectares of lowland tropical rainforest in South East Asia will contain more tree species than the whole of North America. It is therefore inevitable that any large-scale projects which destroy rainforests will lead to the extinction of hundreds of species.
Only by providing the widest possible protection for the remaining primary rainforests will it be possible to save the greater part of the Earth’s biological diversity from extinction. Strictly protected nature reserves can only be a supportive measure in an overall programme for the protection of rainforest ecosystems. The creation of nature reserves must not be used as justification for the destructive exploitation of unprotected rainforest areas.Â
4. The International Biodiversity Programme
The World Bank is pursuing the goal of a global “Biodiversity Action Programme”. Like the TEAP, this plan fails to confront underlying causes of biodiversity loss, and is likely to worsen the problem it is supposed to solve. Loss of biodiversity in tropical regions is due to the trend towards replacement of traditional species-rich agriculture and forestry with monocultures. Yet under the Biodiversity Programme, monocultures would be encouraged. The Programme sees the setting aside of reserves as the solution to the problem, but the minimum size required for viable areas of tropical forest is unknown. Worse, the setting aside of reserves is likely to be used as an excuse for the unrestricted exploitation of unprotected areas. The Programme would also increase the control of biodiversity by the North at the expense of the South.
TOWARDS REALISTIC SOLUTIONS:
Alternatives to destructive exploitation of tropical forests are to be found in small-scale initiatives coming from the grass roots in tropical countries, not from ill-conceived large-scale prestige projects such as the TFAP
1. Recognising the Rights of Traditional Owners.
The Australian Rainforest Memorandum, produced by the Rainforest Information Centre and endorsed by over 40 non-governmental organisations, asserts that: “The right to cultural survival for all tribal peoples is inviolable. All possible efforts should be made to support and safeguard their rights and those of other forest dwellers, in particular the right to security of land tenure.”Â About one thousand rainforest cultures still exist. Nearly all of them are in conflict with the development strategies of the dominant social classes and international development agencies that have taken control of their lands and who consistently ignore their basic rights and often even their very existence.
It is significant that the most successful projects to save rainforests are those which have been carried out in cooperation with the traditional owners of the forests. In Papua New Guinea and Ecuador, the Rainforest Information Centre and other organisations have been involved in schemes which support the legitimate development aspirations of traditional landowners with small-scale autonomous projects. In 1990, the Colombian Government gave back half its Amazonian territory to its rightful Indian owners, acknowledging that they were the best guardians of the forest. In Malaysia, Indonesia and the many other countries where the rights of traditional owners have been ignored, attempts to save rainforests have been uniformly unsuccessful.
2. Non-Timber Values
The economic value of keeping rainforests is often overlooked. Rainforests provide essential and renewable sources of fruits, starches, oils, medicines, firewood, animal products, building materials and other projects when extraction is well-managed. However, the value of rainforest goods and services to local human populations is usually ignored in the economic analyses upon which development decisions are based because these societies often operate with little involvement in the cash economy.
In many tropical countries, major sections of the population depend directly on intact rainforests for their daily needs. The people of Papua New Guinea, for instance, obtain 58% of their animal protein from rainforest areas.
In large regions of West Africa, people until recently met 65% of their animal protein needs from rainforests. This situation changed as the forests were destroyed by the establishment of export plantations and the timber industry.
Although the careful management of non-timber forest products has considerable national and international; potential, these resources are being lost through the destruction of the tropical forests. In the Amazon, over two million people depend on rubber, Brazil nuts and other “minor” forest products without damaging the biological integrity of the rainforest. Recent studies have shown that the value of non-timber forest products often far exceeds the value of timber in tropical forests. A study in the rainforests of Peru showed that the economic value of the minor forest products, including fruits, resins and medicines which were actually being marketed, exceeded the value of use the forest for timber by nine to one.
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