Forests under Threat
Our anthropogenic activities threaten the forests and trees of the planet, which are half the lungs of the planet (the other half being the oceans). Forests are under threat for anthropogenic activity from all sides. Economic activity such as agriculture and converting the land for other uses is exasperated by unsustainable logging practices and global warming, which can lead to draughts which can kill forests, turning carbon sinks into carbon sources.
Globally:
- 12-15 million hectares of forest are lost each year.
- Deforestation is responsible for 15% of all greenhouse gas emissions.
- Tropical forests, where deforestation is most prevalent, hold more than 210 gigatonnes of carbon.
- 87% of global deforestation occurs in just 10 countries, with Brazil and Indonesia accounting for 51% of emissions from forest loss.
Deforestation is caused by:
- Conversion of forests for other land uses including pulp, palm, and soy plantations, roads and other infrastructure
- Forest degradation from fires, illegal and unsustainable logging, fuelwood harvesting, and climate change.
(Source: WWF)
Figure 1: Global deforestration map
Greater Mekong Countries have lost 33% of their Forests in 40 Years
- Cambodia has lost 22% of its 1973 forest cover,
- Laos 24%
- Burma 24%
- Thailand 43%
- Vietnam 43%
Together, these 5 countries in the greater Mekong have lost nearly 40m hectares (ha) of forest cover since 1980 but have retained about 98m ha of natural forest, just over half of the region’s land area. The 2013 WWF report on ecosystems in the greater Mekong area warns that these countries risk losing more than one-third of their remaining forest cover within the next two decades if they fail to increase protection.
“The greater Mekong is at a crossroads,” said Peter Cutter, landscape conservation manager with WWF-Greater Mekong. “One path leads to further declines in biodiversity and livelihoods, but if natural resources are managed responsibly, this region can pursue a course that will secure a healthy and prosperous future for its people.”
Alarming fragmentation has been taking place in the past 30 years. Large connected areas of “core” forest – defined as areas of at least 3.2km sq of uninterrupted forest – have declined from over 70% in 1973 to about 20% in 2009. If current trends continue, WWF predicts that by 2030 only 14% of the greater Mekong’s remaining forest will consist of contiguous habitat capable of sustaining viable populations of many wildlife species.
(Source: Guardian)
Drought Induced Forest Die-Off from Global Warming
Assessing the potential for, and consequences of, extensive climate-induced forest dieback is fundamentally important because trees grow relatively slowly but can die quickly. A 100-year-old tree may be killed by severe drought within a few months to a few years. As a result, drought-triggered forest mortality can result in rapid ecosystem changes over huge areas, far more quickly than the gradual transitions that occur from tree regeneration and growth.
Land-use impacts such as anthropogenic burns and forest fragmentation, interacting with climate-induced forest stress, are likely to amplify forest dieback in some regions, for example the Amazon Basin (Nepstad et al., 2008). If current forest ecosystems are forced to adjust abruptly to new climate conditions through massive forest dieback, many pervasive and persistent ecological and social effects will result from the loss of forest products and ecosystem services – including sequestration of atmospheric carbon.
One consequence of substantial forest dieback is redistribution of within ecosystem carbon pools and rapid losses of carbon back to the atmosphere. For instance, climate-driven effects of forest dieback, insect and disease mortality and fire impacts have recently turned Canada’s temperate and boreal forests from a net carbon sink into a net carbon source (Kurz et al., 2008). Similarly, it is possible that “widespread forest collapse via drought” could transform the world’s tropical moist forests from a net carbon sink into a large net source during this century (Lewis, 2005).
Given the potential risks of climate-induced forest dieback, increased management attention to adaptation options for enhancing forest resistance and resilience to projected climate stress can be expected, for example thinning stand densities to reduce competition, selection for different genotypes (e.g. drought resistance) or translocation of species to match expected climate changes – Craig D Allen, Eminent Forestry Researcher
Figure 2a: Current vs future projected trends of forest die-off due to climate change (Source: Craig D Allen)
Figure 2b: Potential limits to vegetation Net Primary Production n based on fundamental physiological limits by vapor pressure deficit , water balance, and temperature (Source: Churkina & Running, 1998; Nemani et al., 2003; Running et al., 2004).
Factors that influence Forest Growth
- The main abiotic controls of primary production (temperature, radiation, and water) interact to impose complex and varying limitations on vegetation activity in different parts of the world (Churkina & Running,
- 1998; Nemani et al., 2003; Running et al., 2004)
- Physiological responses to changes in climate are highly dependent on the limiting factors of a particular site to forest growth
- For example, increasing temperature may also increase vapor pressure deficit (VPD) of the air, and thereby increase transpiration rates, resulting in adverse effects on dryer sites, unless stomata close in response to other changes such as an increase in CO2, or if increases in night-time temperature exceed increases during the day (Kirschbaum, 2004)
- The figure above depicts the distribution of the limiting factors to primary production in terms of water, sunlight, and temperature on a global scale
- Very few forest types in this figure are solid colors, expressing variability in the dominance of limiting factors within a given year
- For example, the productivity of temperate forests of northwestern North America may be radiation and temperature limited in winter, temperature limited in spring and water limited by midsummer
- These controls depend on climate and are expressed as a mosaic of regionally varied impacts on forest systems
- Temperature (heat) controls the rate of plant metabolism, which in turn determines the amount of photosynthesis that can take place
- Most biological metabolic activity takes place within the range of 0–501 C (Hopkins & Hu¨ner, 2004); there is little activity above or below this range
- The optimal temperatures for productivity coincide with 15–25 1C; the optimal range of photosynthesis (Hopkins & Hu¨ner, 2004)
- Lethal levels are between 44 1C and 52 1C (Schulze et al.,2002)
- Photosynthesis depends on radiation, increasing with increasing irradiance
- Water is a principal requirement for photosynthesis and the main chemical component of most plant cells
- In dry regions, there is a linear increase in NPP with increased water availability (Loik et al., 2004)
(Source: Celine Boisvenue & Steven W. Running)
Figure 3: Localities with increased forest mortality related to climate stress from high temperature and draught (Source: Craig D Allen, 2009)
Forest Die-off by Continent
Click on each image to see more detailed image of die-off examples for each continent
Figure 4: Die-off by continent – Africa, Asia, Australia, Europe, North America, South America (Source: Craig D Allen, 2010)
Figure 2: Deforestration Infographic 1 (Source: Jonathan Krause)
Figure 3: Deforestration Infographic (Source: Jonathan Krause)
One way to mitigate the nearly 20 % GHG contribution by forestry is to channel billions of dollars per year into international forests conservation and management.
- Forests can be 25 percent of the climate solution through 2020 and payments can be up to $20 billion
- Forests could reduce carbon prices in developed nations by one-third through 2020
- Brazil and Indonesia are likely to be the largest forest carbon suppliers in the medium term and nations in the Amazon-Andes and Central America are well positioned to contribute to near-term supplies
- Public-sector investments are needed to build capacity and avoid shifting deforestation
Figure 4: Greenhouse Gas Contributions, 2007 (Source: UNEP 2012 Report: Keeping Track )
The Forest Carbon Index (FCI) compiles and displays global data relating to biological, economic, governance, investment, and market readiness conditions for every forest and country in the world, revealing the best places and countries for forest carbon investments. It estimates each nation’s potential to attract forest carbon investment based on profit potential and country-specific risk factors.
- Profit Potential. Raw profit potential is calculated by subtracting the expected cost of managing a piece of land for forest carbon from expected forest carbon revenues. The Profit Potential Index measures profit potential by looking at biological and economic factors.
- Risk. The Risk Index discounts raw profit potential by taking into account the institutional, technical, and political risks within a country, incorporating widely accepted data from the World Bank about governance conditions (including corruption) and ease of doing business.
To watch an html presentation, click here
1. Above Ground Carbon Stock
2. Opportunity Cost of Land
3. Accessibility to Human Activity
4. Local Forest Carbon Costs
5. Profit Potential
6. Risk
7. Best Places
8. Country Score
(Source: Forest Carbon Index)
Responsible Forestry Management
Another important way to protect forest is to buy wood from sustainably managed and harvested companies. The Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC), the two largest forest certification bodies worldwide with slightly different approaches to management and certification, certify socially and environmentally responsible forestry.
An impressive annual 20% growth rate of labeled forests indicates that both producers and consumers are actively influencing timber production. Nevertheless, in 2010 still only about 10% of the total forest extent was managed under FSC and PEFC practices.
The Global Canopy Programme is an alliance of scientific institutions around the world, applying their combined knowledge and skills to protect forests and the vital ecosystem services they provide to humanity. The GCP takes a multidisciplinary approaches to meet the complex challenges facing forests. They have successfully built up policy and business programmes to complement their science.
They have developed initiatives that have successfully targeted key threats to tropical forests:
The GCP Little Book Series
(Click on each book to download. All books link to the Global Canopy Programme website)
