Change in forest area

Transcription

1 Deforestation FOR414 January 2009 Change in forest area Frontier forests are the world's remaining large intact natural forest ecosystems - undisturbed & large enough to maintain all of their biodiversity. Reading: Sands Net change in global forest area million hectares per year km2 of forest per day 0.18 percent of remaining forest area each year NC = 12.6 million ha million hectares per year 0.22 percent per year Previous estimate = Uncertainty in FAO data 2.50 Sources of error National forest surveys (only 50% based on remote sensing) Projection from older (or newer) forest surveys Aggregation of plantations, open, and closed forest Forest area per capita Percent Forested Grainger, 2008, PNAS DEVELOPING ASIA & OCEANIA DEVELOPED ASIA & OCEANIA AFRICA WESTERN EUROPE FORMER WARSAW PACT UNITED STATES & CANADA LATIN AMERICA Source: FAO

2 -0.78 ANNUAL FOREST CHANGE RATE (FROM ) UNITED STATES & CANADA ASIA & OCEANIA DEVELOPED* WESTERN EUROPE FORMER WARSAW PACT ASIA & OCEANIA DEVELOPING LATIN AMERICA AFRICA PERCENTAGE PER YEAR** Source: FAO-FRA 2000 *This region includes Australia, New Zealand, Israel, South Korea, Singapore and Japan selected by GDP > USD 10,000 ** Percentage calculated from initial forest land data of O-FRA 2000 includes Australia, New Zealand, Israel, South Korea, Singapore and Japan selected by GDP > USD 10,000 e calculated from initial forest land data of 1990 ANNUAL FOREST CHANGE RATE (FROM ) PERCENTAGE PER YEAR** 78 UNITED STATES & CANADA ASIA & OCEANIA DEVELOPED* AFRICA WESTERN EUROPE FORMER WARSAW PACT LATIN AMERICA ASIA & OCEANIA DEVELOPING ASIA & OCEANIA DEVELOPING LATIN AMERICA AFRICA ANNUAL FOREST CHANGE RATE (FROM ) PERCENTAGE PER YEAR** Source: FAO-FRA 2000 *This region includes Australia, New Zealand, Israel, South Korea, Singapore and Japan selected by GDP > USD 10,000 ** Percentage calculated from initial forest land data of 1990 ASIA & OCEANIA DEVELOPED* 0.02 FORMER WARSAW PACT 0.03 UNITED STATES & CANADA 0.08 WESTERN EUROPE National income Gross Domestic Product: total money value of goods and services produced in a country in one year. GDP/capita is total divided by population. Absolute poverty: US$1/person/day Ghana: US$354/ person in 2003 Canada: $27,100/ person in 2003 Purchasing power parity (PPP) takes into account price differences (converted to US dollars using relative cost of same basket of goods and services, rather than official exchange rate) 2

3 China India USA Indonesia Brazil Japan Germany UK France Population (millions) From: Population Reference Bureau, World Bank GDP (millions US$) $1,409,852 $598,966 $10,881,609 $208,311 $492,338 $4,326,444 $2,400,655 $1,794,858 $1,747,973 GDP per capita in PPP $4,520 $2,650 $36,110 $3,070 $7,450 $27,380 $26,980 $26,580 $27,040 Historical Change in Forest Cover Forest transition US, Japan Forest Cover Exceptions: India China Development (GDP/capita) ANNUAL % CHANGE in FOREST COVER TOP SEVEN COUNTRIES (FROM ) Historical Change in Forest Cover China United States Forest transition US, Japan Forest Cover Russian Federation 0.02 Canada 0.00 Development (GDP/capita) Brazil Dem Rep of the Congo Indonesia Exceptions: Pre-1491 Americas PERCENTAGE FOREST CHANGE PER YEAR * Source: FAO-FRA 2000 * Percentage calculated from initial forest land data of

4 Sago Cultural forests Chicle Shifting Cultivation Also called: shifting agriculture slash and burn Sacred Groves 1. Fell trees, dry, burn 2. Nutrient pulse 3. Plant for 3 5 years 4. Regenerate Manioc Cassava Yucca Some traditional agriculture brings permanent change to landscape 4

5 Shifted agriculture Colonization projects; migration Increasing population density grow crops until no longer productive convert to pasture graze until no longer supports livestock abandon forest regeneration? Agents of deforestation? Small farmers Fuelwood Logging Large landowners: Ranches & plantations Why care about tropical deforestation? Value of forests lost >>> Value of alternative use Deforestation is net loss Explaining tropical deforestation Three models Small Small farmer as example of agent of deforestation i.e., the person who decides whether to cut trees Use graphs to represent one subsistence farmer s decision, or many farmers decisions combined Von Thunen Kuznet s (variation on the forest transition ) Supplemental reading: Sills & Pattanayak (2005) Available from References section of website 5

6 $ 0% MNB A MNB F 100% Defining costs and benefits Depends on assumptions about alternatives Costs are equivalent to diminished benefits Net benefits = benefits costs Consider Net benefits of converting a hectare to ag crops (MNBa) Net benefits of maintaining a hectare in forest (MNBf) Benefits and costs in the future weigh less in the farmer s decisions that benefits and costs today Consider: would you rather have $10 today or $15 in 5 years? If you choose $10, then your discount rate is at least 8% per year why? Inflation, opportunity cost, impatience Costs Benefits time 6

7 Example from Indonesia Discount rate: factor used to compare costs and benefits that occur at different points in time and to calculate their present value Compare to an interest rate - a bank s discount rate Source: CIFOR Net benefits of agriculture Immediate: cost to clear and plant, revenues from timber and first large harvest of crops Future: annual labor and harvests Net benefits of forest Small but consistent flow of environmental services, non-timber forest products, timber revenues from occasional harvests $ 0% MNB A MNB F 100% 7

8 $ Benefits and costs are measured in terms of quantity * value For products that are purchased or sold, value = price When supply increases, price? Each unit of a scarce good is more valuable than each unit of an abundant good When there is lots of forest and little agriculture, each hectare of ag gained is far more valuable than each hectare of forest lost (and vice versa) P* 0% MNB A D -1 D P * D +1 MNB F 100% What do the lines represent? Why does agriculture decline from the left? Why does forest decline from the right? Why is agriculture above forest for most of the graph? What does the point of intersection represent? Thursday Meet in computer lab on 5 th floor of Jordan Review assignments Annotated website (due Jan 20) Memo (due Jan 27) Research assistance & practice from NRL 8