Presentation on theme: "The Fate of a Renewable Resource"— Presentation transcript:
1The Fate of a Renewable Resource Global DeforestationThe Fate of a Renewable Resource
2DeforestationDeforestation is the net reduction of forested area on our planetOne of the greatest forces of global environmental change (mainly over the past 200 years)Reduced forest cover by human action has a huge impact on global biodiversity
3Why We Deforestaion occurs Forests are cleared, degraded and fragmented by:Timber harvestConversion to AgricultureRemoval for heating and cooking firesRoad buildingHuman caused fireUrban development
4How Much Forest Do We Have Originally, almost half of the United States, three- quarters of Canada, almost all of Europe, the plains of the Levant, and much of the rest of the world were forestedCurrently about34 million Km2 offorest remains
5What’s Left? About ½ of our original forests are gone Each year another million hectares are removed (approximately the size of Panama)22% of the world’s old growth forest remainsAbout ¼ of the world’s land area is still forestedSeven countries including: Russia, Brazil, USA, Canada, China, Indonesia, Dem.Rep. Congo, account for 60% of the world’s forested land
6Frontier Forests of the World Red = Frontier Forests, 8,000 years ago Green = Frontier Forests Today Pink = Current non-frontier forests
7How Fast is it Disappearing? Most developed Countries currently have close to zero net deforestationDeforestation in Europe was largely completed before the end of the 1800sMost current deforestation currently occurs in the tropic and most severely in poor countriesIn Latin America and Asia deforestation rates are about 2% per yearAt this rate by 2080 we will have only ¼ our current forested area
8Key DefinitionsDeforestation: The conversion of forest to another land use or the long-term reduction of the tree canopy cover below a 10 percent threshold. Deforestation implies the long-term or permanent loss of forest cover and its transformation into another land use.Primary forest: is a forest that has never been logged and has developed following natural disturbances and under natural processes, regardless of its age.Secondary forests: are forests regenerating largely through natural processes after significant human or natural disturbance, and which differ from primary forests in forest composition and/or canopy structure.Disturbed forests: Any forest type that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.Frontier forests: large, ecologically intact, and relatively undisturbed forests that support the natural range of species and forest functions (WRI definition).Forest plantation is one established by planting or/and seeding in the process of afforestation or reforestation. It consists of introduced species or, in some cases, indigenous species.
9Types of ForestryClear Cutting: removal of ALL trees in a particular area. Includes commercial harvest and slash and burn practices.Most economically viable.Potentially most ecologically destructiveMay result in accelerated soil erosion, irreversible nutrient loss and alteration of hydrologic cycleIn some circumstances may be most ecologically responsible forestry technique (CPRS/Mosaic)
10Types of ForestryShelterwood: mature trees are removed in 2-3 cuts over yearsThis method allows regeneration of medium to low shade tolerant species because a “shelter” was left to protect themWorks well for hardwoods that produce seedlings capable of establishing in low light conditions (oak, hickory, cherry)Seedlings develop quickly once final mature trees removed
11Types of ForestrySelective Cutting: Individual trees of high economic value are removed from a forest with as little disturbance to the surrounding forest as possibleSurrounding trees now have less competition for sun and nutrients and grow more quicklyEntire stand can be selectively cut over years with little change in forest compositionMay require elevated disturbance due to road/trail constructionSome operations work seasonally or with traditional equipment (horses) to limit ecological disturbance
12Importance of Forests Forest Products In many poor areas wood is still commonly used for cooking.Building materialsFurniturePulp and paper products (including cardboard and cellulose)Source of numerous non-wood products, including bark, dyes, fibers, gums, incense, latexes, oils, resins, shellac, tanning compounds & waxes. Fruits, nuts and berries are harvested as food. Maple syrup is an example of a unique non-wood product from the sap of the maple tree.
13Ecosystem ServicesInfluences climate: captures carbon, reduces atmospheric CO2, involved with hydrologic cycleWhere forests are cut increased erosion and flooding may be issues and may result in ultimately a drier climateProtection of soil and nutrientsFoster biodiversity (loss of potentially valuable species for medicine or agriculture)
14Tropical Deforestation about 100,000 km2 are deforested each year, and another 100,000 km2 are degradedEstimates are constantly improving, based on satellite imageryCauses of deforestation in the AmazonCattle ranches 65-70%Small-scale, subsistence agriculture 20-25%Large-scale, commercial agriculture 5-10%Logging, legal and illegal 2-3%Fires, mining, urbanization, road construction, dams 1-2%
15The State of Tropical Forests In many countries the rate of deforestation is accelerating.For example, most of the forested areas of Bangladesh, India, the Philippines, Sri Lanka and parts of Brazil's rain forest could be gone by the end of the century.Brazil contains about 3.5 million km2 of tropical forest. This is equivalent to 30% of the world's total
16Biodiversity and the Amazon Amazonia has been characterized as the "single richest region of the tropical biome."A single hectare of rain forest near Manaus yielded 235 tree species over 5 cm in diameter and 179 species over 15 cm in diameter.There are 2000 known species of fish in the waters of the Amazon Basin. This is eight times the number found in the Mississippi River system and 10 times the number found in all of Europe.
17The Impact of RoadsRoads usually accompany timber harvest, in order to move logs to sawmills and markets. Even when tree harvest is highly selective, and much of the forest remains, it has been found that the roads themselves have numerous adverse side-effectsAs forests become more open through thinning, they become drier, and more susceptible to fireIn wet areas roads become pathways for surface runoff, and carry sediments into streams, destroying aquatic lifeCulverts installed where roads cross rivers often block fish passageroads allow hunters and poachers much greater access, resulting in the large and very serious bushmeat trade
18Forest fragmentation by roads in Central Africa Forest fragmentation by roads in Central Africa. This study shows that 42% of forest area in the six countries is within 10 km of a road and more than 90% is within 50 km of a road
19Forest Management and Recovery Rotation Harvest: the goal typically is to maximize annual harvest while ensuring that the area harvested is consistent with forest regrowth rates and total area under management Results in a second harvest of the same forest plot after some years. The length of time between successive harvests of a forest is called the rotation length
20Forest Management and Recovery Multiple Use: Forests on federal and state lands are usually managed according to multiple use principles This means that in addition to forest harvest, the land is available for recreation and maintains a healthy forest ecosystem Managing to protect biodiversity and to restore pre- settlement conditions are relatively recent goals
21Forest Management and Recovery Indigenous Use:Forests may be used by indigenous people for:subsistence huntingforest harvestas a place to live
22Forest Management and Recovery If left to nature forests will re-establish themselvesThis process is called Succession and typically takes from years depending on tree growth rateTropical forest are very vulnerable as they are difficult to rehabilitate. Soil is quick to be leached of nutrients and may be lost through erosion
23Restoration Vs Rehabilitation Forest restoration may seek to restore the system to a near-natural or completely natural state, or to restore many aspects of the structure and function of an undisturbed forestThe latter is usually referred to as rehabilitation, to emphasize that the desired endpoint is not necessarily that of pre-settlement conditions
24Forest Management and Fire Fire is suppressed in many forest ecosystems to:Protect valuable commercial woodProtect human homes in or adjacent to forestProtect old growth ecosystemsIn many cases fire is positive to a forest ecosystemSome trees require fire to reproduce (jack pine)Other trees require thinning of the understory to repopulate (Oak)Fire suppression created a build up of dry fuelThis increases the intensity of a forest fire and may cause greater ecosystem damage
25Activism vs Ecoterrorism Some of the most contentious environmental issues in North America have often been associated with protecting forestsWhen the government (fedral, prov/state, local) is perceived as not responsibly protecting forests often Environmental Activists will stand up to logging companies and law enforcement to fight for their beleifsOrganizations like Greenpeace are consistently pushing the boundaries of what environmental “activism” means.
26Activism vs Ecoterrorism Sometimes the methods used to draw attention to issues or to fight back against irresponsible industry blur the lines between action and unlawful “terrorism”Most actions involve “peaceful protest” as a means of bringing attention to the issue
27Activism vs Ecoterrorism However some groups have been know to use arson, explosives or other targeted sabotage methods to inflict damage on specific organizationsFrom a forestry perspective the Earth Liberation Front (ELF) is a classic example of activism over the edge
28Where is the line?If “Justice” is not being looked after by the judicial system what degree of protest is appropriate?How should people be held accountable to damage to property or personal injury in the name of environmental protection?Do these extreme actions do anything to help the situation or does it make things worse?TIME FOR A MINI DEBATE!