PART THREE: FORESTS AND GEOPHYSIOLOGY

If environmentalism is concerned with the beauty of Trees and Forests’ landscape values; if ecology is concerned with the naming of Trees and the inter-relationships between Trees and Wildlife; then geophysiology is concerned with Forests’ relationship with the climate. Ecology rarely concerns itself with the climate - except in so much as to take it for granted as a given which influences Trees’ evolution. This relationship is the domain of geophysiology, the science of the Earth’s life support system. This chapter looks at Forests’ influences on the Earth’s climate. It does this through the four main components of global warming: the Photosynthetic effect, the greenhouse effect, the albedo effect, and the heat effect. [1]

3.1: An Analysis of Forests’ Influences on the Climate.

This work is based on the assumption that global warming is composed of four different phenomena; the Photosynthetic effect, the greenhouse effect, the albedo effect, and the heat effect. [2] The Photosynthetic effect concerns Photosynthesizers’ absorption of Carbon from the atmosphere. This helps to determine the concentration of atmospheric Carbon. The greenhouse effect is the blanket of atmospheric gases which allows sunlight to reach the Earth's surface but blocks the escape back into space of heat radiated from these surfaces in the form of infra-red radiation. The albedo effect is the amount of sunlight reflected back into the atmosphere by a particular surface on the Earth. This phenomenon is distinct from the greenhouse effect. This becomes apparent from the fact that the effectiveness of the greenhouse effect in keeping the Earth warm varies with different albedo effects. For example, if the Earth’s surface was a perfect mirror reflecting sunlight straight back into the atmosphere, the greenhouse effect would be different than if the Earth’s surface was covered in tar reflecting little light back into the atmosphere. Finally, the heat effect is the amount of heat absorbed by a surface. The albedo effect and the heat effect are thus two sides of the same coin. Whilst the albedo effect is the amount of sunlight reflected back into the atmosphere by a particular surface, the heat affect is the amount of sunlight absorbed by that surface. The heat absorbed is then reradiated into the atmosphere in the form of infra-red radiation. It is this reradiated heat which is absorbed by greenhouse gases and which causes the greenhouse effect. From this analysis of the four components of global warming it should thus be clear that the greenhouse effect is not the same as global warming. The greenhouse effect is just a contributor to global warming. It is global warming that determines the Earth’s global average temperatures.

3.1.1: Forests and the Photosynthetic Effect.

When Forests extract Carbon and water from the atmosphere they moderate global warming. They are an important determinant of the concentration of atmospheric Carbon. The following sections explore Forests’ moderation of global warming through the Photosynthetic effect. The first sections explore Forests’ absorption of Carbon and later sections explore its absorption of water.

3.1.1.1: Carbon Absorption.

Forests extract Carbon from the atmosphere through Photosynthesis. However, there are three main ways by which Forests keep Carbon from returning to the atmosphere and thus reducing global warming. Firstly, Forests store Carbon. Secondly, they pump Carbon into the soil from where it leaches into the oceans. And, finally, as a result of Forest fires, they convert Carbon into Charcoal. The longer that Forests keep Carbon out of the atmosphere through one of these three means, the greater the moderation of the global warming.

3.1.1.1.1: Forests as Carbon Stores.

There are three main ways that Forests store Carbon absorbed from the atmosphere. They store Carbon in the form of Trees, in the form of soils, and in the form of Wildlife.

3.1.1.1.1.1: Forests Storing Carbon in Trees.

The first major way in which Forests store Carbon is, most obviously, in the form of Trees. Some of the Carbon absorbed through Photosynthesis is incorporated into Trees. This moderates the greenhouse effect by keeping Carbon out of the atmosphere. The greater the number of Trees, and the larger the size of the Trees, the greater the Carbon storage. And, the longer that Carbon remains in the form of Trees, the greater the Carbon storage. If a Forest remains intact for thousands of years then, in effect, the Forest has kept its Carbon out of the atmosphere where it would contribute to global warming. Forests have the ability to store vast quantities of Carbon. The more Carbon that is stored in Forests, the lower the concentration of atmospheric Carbon, the greater the global cooling, “Forests play an important role in the climate system. They are a major reservoir of carbon, containing some 80% of all the carbon stored in land vegetation, and about 40% of the carbon residing in soils.” [3]

3.1.1.1.1.2: Forests Storing Carbon in Soils.

Forests also store Carbon in the form of soils. Forests create soils through a number of different processes:-

* when leaves fall to the ground they are either broken up by decomposers or dragged into the soil by a vast range of Soil Fauna where they eventually decompose;

* Trees pump Carbon into the Soil through their roots;

* Animals browsing on leaves and other products deposit Manure on the ground where it is absorbed by micro-organisms or soaks into the soil.

Some types of Forest generate more Soil than others. [4] All Forests are rooted in soils - even tropical Rainforests stand in some soil. Soils did not suddenly appear on Earth out of nowhere. They were created through the decomposition of Photosynthesizing bacteria, Plants and, eventually, Trees. There is little point in trying to analytically separate soils from Forests because they are so interdependent upon one another. According to john gribbin, there is more Carbon in humus and soils than there is in Trees, “Undisturbed soil holds even more Carbon than there is in the form of Trees.” [5] Gregg marland argues, “So long as harvest does not occur, considerable Carbon accumulation continues to take place in litter, soil organic matter, and the below ground portion of Trees." [6] Marland has indicated the proportion of Carbon that ends up in the soil after being absorbed through Photosynthesis, “A hectare of Sycamore Trees in the u.s. soaks up from the atmosphere about 7.5 tonnes of Carbon per year, says marland. Of that, up to 5 tonnes may end up in soils rather than the Trees themselves.” [7] In other words, two-thirds of the Carbon absorbed by Trees ends up in soils - a substantial, and surprising, figure.

Given the right climatic conditions i.e. where there is an excess of Carbon in the atmosphere, Forests can continue to grow and create more and more soil. This could go on for any length of time. The longer that Forests are left untouched by oomans, the more soil that Forests create. Although the soils of Amazonia are currently shallow, in a few thousand years’ time they could be much deeper.

3.1.1.1.1.3: Forests Storing Carbon in the Form of Wildlife.

The third place in which Forests store Carbon is in the form of Wildlife. Imagine a Forest without Animals - which, in reality, would be a physical impossibility since Forests depend as much on Animals as Animals depend on Forests. There would be no Animals to:-

* prune branches;

* consume fruits;

* fertilise the Soil;

* disburse seeds;

* germinate seeds, etc.

Without Wildlife, Forests would find it difficult to grow - they might even find it difficult to survive.

Over the course of time, new Animal species emerge which survive by exploiting unused ecological niches. In turn, these new species create new niches for other species. Biodiversification is the process by which more and more Animals create more and more ecological niches which enable more and more species to survive and flourish. It is a process, like russian dolls, which packs more and more species into a particular habitat - especially those as palatial as Forests. As a consequence, the greater the concentration of Animals in a habitat, the more Carbon which ends up in the ground, creating even more Soil, enabling more Trees to flourish, creating more habitats to be exploited. In effect, Biodiversification packs more and more Carbon into Forests, boosting its Carbon density. [8] If there was no Biodiversity the amount of Carbon that could be stored in Forests would be far smaller. It is not true that, “Most managed forests teem with life.” [9] The more natural a Forest, the greater the biodiversity, the greater the storage of Carbon in that Forest. Tropical Rainforests are a good example of the extent to which Forests store large quantities of Carbon in the form of Animals. [10] Animals store considerable amounts of Carbon in their bodies but they also help Forests to store even more Carbon than would be possible in the absence of Animals. When oomans trample through Forests they frighten away Wildlife and reduce the Forests’ capacity for Carbon storage. Over time, as more and more oomans trample through the Forest they dramatically reduce the number of Animals in the Forest and reduce Animals’ Carbon storage role. They release Carbon into the atmosphere and prevent Forests from absorbing as much Carbon as they would have done in the absence of oomans.

3.1.1.1.1.4: Old Growth Forests’ are better for Carbon Storage than Tree Plantations.

Given excess atmospheric Carbon, Forests could continually absorb more and more Carbon because they can store it in the form of Trees, soils, and Animals. Forests could go on storing more and more Carbon not merely over the decades or the centuries but over the millenia. It is possible, where there is an excess of atmospheric Carbon, that they would never reach a stable climax state. Forests stop absorbing net amounts of Carbon only when the amount of Carbon in the atmosphere declines. These arguments lead to the conclusion that old growth Forests are better at Carbon storage than Tree plantations.

Ernst-Detlef Schulze, Christian Wirth, Martin Heimann.

“Important new scientific studies, including a recent SCIENCE article, highlight the importance of old-growth forest ecosystems as a mechanism to address climate change, and provide a powerful new argument for protecting ancient forests. New studies indicate that old-growth continues to remove carbon even when fully mature, and that old and wild forests are better than plantations at dependably removing carbon dioxide from the atmosphere. Huge amounts of carbon are sequestered for long periods in old-growth ecosystems—both in trees and perhaps more importantly in soils. Soils in undisturbed tropical rain forests and temperate woodlands contain enormous amounts of carbon derived from fallen leaves, twigs and buried roots that can bind to soil particles and remain in place for 1,000 years or more. When such forests are cut, the trees' roots decay and soil is disrupted, releasing the carbon dioxide. It would take centuries for newly planted trees to build up such an underground carbon reservoir.” [11] ; “The German study, together with other similar research, has produced a picture of mature forests that differs sharply from long-held notions in forestry, Dr. Schulze said. He said ageing forests were long perceived to be in a state of decay that releases as much carbon dioxide as it captures. But it turns out that the soils in undisturbed tropical rain forests, Siberian woods and some German national parks contain enormous amounts of carbon derived from fallen leaves, twigs and buried roots that can bind to soil particles and remain for 1,000 years or more. When such forests are cut, the trees' roots decay and soil is disrupted, releasing the carbon dioxide. Centuries would have to pass until newly planted trees built up such a reservoir underground.” [12] [13] [14]

Fast growing eucalyptus plantations may reach a 'climax state' in a matter of decades but this is of little consequence as far as Carbon storage is concerned because firstly, they contribute little to Soil formation; and, secondly, they do not provide a habitat for a wide range of Wildlife. The tragedy of logging the world’s Forests is not simply that the Carbon stored in Trees is dumped into the atmosphere but that Soil erosion, and the obliteration of Biodiversity, dumps even more Carbon into the atmosphere. For Forests to maximize the storage of Carbon they must remain unmolested by oomans. The best conditions for Forests to store Carbon would be where they have been declared off limits to bipeds.

3.1.1.1.2: Forests As Carbon Pumps.

The second way in which Forests prevent Carbon from returning to the atmosphere is by acting as Carbon pumps. Forests act as Carbon pumps by contributing to rock weathering (also referred to as chemical weathering). The following sections explain the complexities of rock weathering; Forests’ involvement in the process; the importance of Forests to rock weathering; and, finally, the importance of rock weathering to the climate and the stabilization of the climate.

3.1.1.1.2.1: The Nature of Rock Weathering.

The Creation of Acid Rain.

Rock weathering is the erosion of rocks by acidic solutions. Michael allaby describes the process in which acid rain soaks into the soil and dissolves basalt rocks creating a solution of calcium bicarbonate and silicic acid, “Carbon dioxide is only slightly soluble in water and, as with oxygen, its solubility decreases as the temperature rises. When it dissolves, some of the Carbon dioxide forms Carbonic acid (H₂CO₃), and the remainder bicarbonate (HCO₃) ions, and the reactions proceed in either direction so Carbonic acid and bicarbonate are constantly dissociating and reforming. When water containing Carbonic acid, and saturated with Carbon dioxide, comes into contact with rocks containing calcium, the two react to form calcium bicarbonate {Ca[HCO₃]₂), which is soluble. If the water then mixes with water containing little dissolved Carbon dioxide, or is exposed to the air, the calcium bicarbonate will dissociate, yielding Carbon dioxide, water and calcium Carbonate (CaCO₃) - which is insoluble and settles as a precipitate.” [15]

Carbon Leaching into the Oceans.

This solution seeps through soils into waterways, rivers, and eventually the oceans. In the seas, the bicarbonate is used by marine micro-organisms to make their shells. When these organisms die, they fall to the ocean floor. Over millions of years vast numbers of shells pile up on the ocean floor and are crushed, under their own weight and the weight of the water above them, into layers of sedimentary rock - such as the white cliffs of dover. This results in the permanent burial of Carbon thereby reducing the greenhouse effect.

3.1.1.1.2.2: Forests’ Double Contribution to Rock Weathering.

Forests make a twofold contribution to rock weathering.

Forests’ Indirect Contribution to Rock Weathering.

Forests release huge quantities of water vapour which dissolve Carbon dioxide in the atmosphere to form a weak solution of Carbonic acid. When this acid rain falls to the ground it soaks into soils and promotes rock weathering. These chemicals are leeched into waterways and are eventually washed into the sea. It has been noted earlier that, according to lovelock, Forests generate most of the rainfall that falls on the Earth’s continents so the scale of this indirect contribution to rock weathering is likely to be significant, “Rainfall on the continental land masses of the Earth is, to a considerable extent, a consequence of evapotranspiration; the pumping by Trees and large plants of water from the soil to their leaves where it evaporates.” [16]

Forests Pumping Carbon into the Soil.

The second way that Trees contribute to rock weathering is by extracting Carbon from the atmosphere through Photosynthesis and then pumping it through their trunks and roots into the soil where it dissolves in water to form Carbonic acid and promotes chemical reactions in exactly the same way as was outlined above. Lawrence e joseph describes the process, “When Plants die, their roots decay into the soil, and the organic Carbon reacts with the rocks in a process known as weathering. (Weathering also occurs while the Plants are alive, since some of the Carbon dioxide they absorb is not used but is conducted and deposited deep into the soil, initiating the same chain of chemical reactions). In a process catalyzed and hastened by bacteria, the Carbon and the oxygen of the Plant materials react with the calcium silicate, the substance of rock particles, releasing oxygen into the atmosphere and forming calcium Carbonate (limestone) and gelatinous silicic acid. Unlike their rock-solid silicate predecessors, limestone and silicic acid dissolve readily into the groundwater and are transported to local streams and rivers, which empty into the sea. Marine organisms filter the limestone from the water to form their shells, essentially reconstituting the land stones for use as their shelter.” [17]

3.1.1.1.2.3: The Major Role of Forests in Rock Weathering.

James Lovelock.

Lovelock believes that life speeds up rock weathering. Rock weathering would take place only slowly if there were no life on Earth, “All life forms, from micro-organisms to trees, from amoebae to elephants, in various ways increase the rate of rock weathering, which is the sink for the greenhouse gas, CO₂.” [18] However, given that Forests are the major form of terrestrial Vegetation, and that they harbour a high proportion of terrestrial life forms, then they are likely to make the biggest contribution to rock weathering, “If the soil of a well-vegetated region almost anywhere on Earth is examined, the Carbon dioxide content is between 10 and 40 times higher than the atmosphere. What is happening is that living organisms act like a giant pump. They continuously remove Carbon dioxide from the air and conduct it deep into the soil where it can react with rock particles and be removed. Consider a Tree. In its lifetime it deposits tons of Carbon gathered from the air into its roots, some carbon dioxide escapes by root respiration during its lifetime, and when the Tree dies the carbon of the roots is oxidized by consumers, releasing Carbon dioxide deep in the soil. In one way or another living organisms on the land are engaged in the business of pumping carbon dioxide from the air into the ground. There it comes into contact with, and reacts with, the calcium silicate of the rocks to form calcium carbonate and silicic acid. Were life not present, the carbon dioxide from the atmosphere would have to reach the calcium silicate of the rocks by slow inorganic processes like diffusion.” [19] ; “The dominant political philosophy of the market should make it easier to appreciate the value of Gaian services. If the algal ecosystems do make clouds, and if land plants do control rock weathering, then their value is as great as that of life itself, and is so far beyond price as to be inaccessible.” [20]

Lawrence E Joseph.

Without Forests, rock weathering would transport far less Carbon from the land to the sea .. “one type of vascular Plant ecosystem, angiosperm-deciduous Plants .. weathers the minerals in the rocks and the soil at a rate three to four times faster than the ecosystems comprised primarily of Conifers ...” [21]

Peter Bunyard.

Bunyard describes how the fungi surrounding Trees’ roots also contribute to rock weathering. The roots of trees .. “penetrate deep into the soil and subsoil. But they do not operate alone, and special fungi, called mycorrhizae, live in close symbiotic association with the root systems of healthy trees, as well as other plants. The fungi accelerate weathering around them and, helped by the mild acid solution of carbon dioxide, are able to mine the subsoil and even the bedrock for minerals. They then form bridges through which they pass on essential nutrients such as phosphorus, that they have made available.” [22]

Tyler Volk.

As far as helping to extract Carbon from the atmosphere is concerned, the roots of Trees are just as important as Trees’ leaves. Indeed, the bigger the Trees, the bigger the root system, the deeper that Carbon can be pumped into the soil. Tyler volk turns a common perception of Trees on its head , “Solid support for increased weathering by vegetation is coming from experiments .. We usually think of trees as defined by trunks, branches, and leaves. But as a recent biochemical guild (assemblage) of gaia, it may be tree roots that are most significant in altering the cycle of elements. In the largest taxonomy of the guilds, trees are photosynthesizers, big siblings to algae and cyanobacteria. But they occupy a unique slot as rooted photosynthesizers. Rooted photosynthesizers have worked distinctive effects on the cycles of carbon and other elements.” [23]

3.1.1.1.2.4: The Importance of Chemical Weathering to the Climate.

Lovelock believes that chemical weathering is the most important means for permanently burying Carbon on the sea floor and thus moderating global warming, "Chemical weathering of calcium and magnesium silicates in rocks is a much bigger Carbon sink, and one that absorbs Carbon at 4 times the rate it is buried as reduced organic Carbon. Chemical weathering acts as a sink for Carbon, locking it up in limestone." [24] He asks what .. "determines the level of Carbon dioxide in the atmosphere? In short, it is rock weathering - or, to be more precise, the rate of reaction of Carbon dioxide with calcium silicate rocks. Basalt rock, the solid dark exudate of volcanoes, is rich in calcium silicate, and when it is immersed in rainwater saturated with Carbon dioxide, it slowly dissolves. The products of this reaction are a water solution of calcium bicarbonate and silicic acid (which percolate through the soil into the sea and) end up on the ocean floor as sediments and eventually are buried, to form the source of limestone (calcium carbonate) rock strata." [25] He argues, "Calcium silicate rock .. is the only true sink for carbon dioxide." [26] And concludes, “The abundance of CO2 in the air depends on the balance between the amount being injected from beneath the crust through volcanoes and the amount lost from the air by chemical reaction at the Earth’s surface.” [27]

Lovelock also argues that, “The CO₂ in the Earth’s atmosphere today totals about 50,000 units .. It has an income of 11.7 units from volcanism, and a debit of 16.7 units for weathering on land. If there had been no life on Earth, the negative balance would be 5 units per year, and it would take only 10,000 years to use up all the CO₂ in the present atmosphere. We would all freeze. .. organic production takes a whopping 38.3 units from the atmosphere every year. (There has been climatic stability over the last 10,000 years because Carbon has been dumped into the atmosphere not merely by volcanoes but by other sources - ed). Part of the dead organisms decayed, producing CH₄ and other gases, and the oxidation of these would return 5 units to the atmosphere. That was not enough, the big share of the deficit of 38.3 units had to be supplied by the ocean. Where did the oceans get their Carbon from? From the land! When terrestrial organisms died, only a small part of its organic Carbon was stored in continental sediments, the rest went into the oceans.”; “The dominant political philosophy of the market should make it easier to appreciate the value of Gaian services. If the algal ecosystems do make clouds, and if land plants do control rock weathering, then their value is as great as that of life itself, and is so far beyond price as to be inaccessible” [28]

3.1.1.1.2.5: The Major Role of Rock Weathering in Stabilizing the Climate - the Major Role of Forests in Stabilizing the Climate.

James Lovelock.

Lovelock believes that rock weathering has a central role in stabilizing the Earth’s climate. Whilst ecologists mention the existence of rock weathering, it was lovelock who realized its climatic significance, “I had long thought that the observation that CO₂ in the soil throughout the world was concentrated between 10-30 times more than in the atmosphere was important evidence for gaia. Biogeochemists accepted the evidence and agreed that it was due to the metabolism of soil micro-organisms, but they failed to see its significance globally. I saw the high concentration of soil CO₂ linked with faster rock weathering and a greater removal of CO₂ from the air, which in turn leads to a cooler global climate. We proposed that the weathering of the rocks by carbon dioxide and rainwater was part of a self-regulating process, which involved the living organisms in the soil.” [29] What this implies is that since Forests have a major role in chemical weathering, and since chemical weathering plays a major role in stabilizing the climate, then Forests have a major role not merely in moderating global burning but in stabilizing the climate.

David Schwartzman and Tyler Volk.

When global temperatures rise, Forests release more water vapour and pump more Carbon through their roots into the soil. Both of these factors boost rock weathering which, eventually, reduces the greenhouse effect - a negative feedback effect stabilizing the climate. David schwartzman and tyler volk argue, "Chemical weathering acts as a sink for Carbon, locking it up in limestone. And the warmer the Earth is, the faster the weathering proceeds and the more CO₂ is taken from the atmosphere. Chemical weathering, transforming calcium silicates to carbonates, stabilizes the climate, removing more CO₂ when the climate is warmer and less when it is cooler." [30]

James Lovelock.

Lee r kump reinforces this view, “Most geochemists agree that Forests promote the chemical weathering of the crust, a process that removes carbon dioxide from the atmosphere and thus tends to reduce the greenhouse effect and global temperature. Organisms that influence the global environment, like .. trees, which promote weathering, all perform their vital functions for other reasons. .. trees create acidic soils to acquire mineral nutrients. The dms-climate feedback appears to be positive today so climatic stability probably relies on stabilizing factors such as the tree-weathering feedback.” [31]

3.1.1.1.2.6: The Major Role of Rock Weathering in the Earth’s Climate.

Tyler Volk.

In the geological past rock weathering by Forests has had a huge impact on the Earth’s climate. Volk believes the emergence of Trees hundreds of millions of years ago led to an increase in rock weathering .. “the third and probably most powerful factor in Earth’s temperature history: life. Land life enhances the chemical weathering of life. Best estimates currently put the boost to weathering that accompanied the evolution of deeply rooted terrestrial ecosystems - trees at a factor of seven (with a probable range from 3-10).” [32] ; “When land life cools the planet by a new advance in weathering enhancement (e.g. Trees), all life in the ocean is affected.” [33] To give an example of how powerful rock weathering has been in the Earth’s past, “At just about the same time trees were reaching skyscraper status, an unusual series of marine events took place. (Episodes of black shales in shallow water sites). Black shales usually indicate anoxic conditions in water. Did a continental flux of nutrients from tree-enhanced chemical weathering create permanent algal blooms along the shorelines that overwhelmed the water’s oxygen.” [34]

Kj Hsu.

Hsu has suggested that, “The rise of the angiosperms may have also contributed to global cooling during the last 100 million years. Volk suggested that the spread of angiosperm-deciduous ecosystems had caused a higher rate of global weathering, and thus increased fluxes of calcium and magnesium ions from continental silicates contributed to the increasing importance of calcareous Plankton. The Plankton precipitation in turn depleted the atmospheric Carbon dioxide.” [35]

3.1.1.1.3: Forests Burying Carbon in the Form of Charcoal.

The third way in which Forests keep Carbon out of the atmosphere is, ironically enough, through Forest fires. Forest fires clearly contribute to the greenhouse effect and yet, at the same time, they also create charcoal which permanently removes Carbon from the atmosphere because it is a highly inert substance. Charcoal does not decompose, and cannot be consumed and recycled by micro-organisms, so it does not release its Carbon back into the atmosphere, “Fires would lead to the burial of much more Carbon because charcoal is entirely resistant to biological degradation.” [36] Bunyard points out that only some Trees create charcoal when they are burnt, “When a tree, such as an oak, burns incompletely and charcoal is formed, the burial of carbon results. However, not all trees burn this way: a resinous piece of pinewood, or a piece of eucalyptus, will practically explode into flames, leaving next to nothing but the gases of combustion.” [37]

Recent research suggests Forests’ creation of charcoal is far more important than has previously been assumed, "For years, everyone has assumed that plankton and other marine organisms play a key role in regulating the amount of carbon dioxide in the Earth's atmosphere. But they may have been given more credit than they deserve, according to a new study which suggests that half of the carbon found in ocean sediments may not have been removed from the atmosphere by marine life but in fact came from forests. David Verardo, a geologist at the University of Virginia in Charlottesville, was addressing this question by studying organic matter in sections of a core of sediment drilled from the bottom of the Atlantic. Amazingly, about half of all the carbon in the core turned out to be charcoal .. In some sections, charcoal accounted for as much as 90% of the carbon. His explanation is that high winds, generated by the large temperature gradients which huge ice sheets created, transported an unusual amount of debris and charcoal dust from fires far out to sea." [38]

The implication of this view is that as global temperatures are rising, natural Forest fires around the Earth are nothing to worry about. They may be boosting the greenhouse effect but they are also contributing to the burial of Carbon. Thus fire fighters shouldn’t be wasting their time trying to stop Forest fires but should allow them to burn themselves out. Massive amounts of Carbon would be dumped into the atmosphere but the burnt out Forests would soon recover and start extracting the Carbon from the atmosphere. If america wants to reduce its Carbon emissions it shouldn’t attempt to strangulate Forest fires but should concentrate upon reducing anthropocentric emissions.

3.1.1.1.4: Conclusions.

Forests extract huge quantities of Carbon from the atmosphere through Photosynthesis. Some is released back into the atmosphere through respiration (Carbon pollution); some ends up becoming a part of a Tree or being absorbed in the Soil or being incorporated by Wildlife (Carbon storage); some is pumped into the soil where it either contributes to soil formation or becomes involved in the rock weathering process; and, finally, some is turned into charcoal by Forest fires (Carbon burial). Lovelock believes that rock weathering is one of the major means of permanently burying Carbon on the ocean floor but this is possible only because Forests extract Carbon from the atmosphere through Photosynthesis and then pump it down to their roots and into the soil. There are large numbers of greens who dismiss Reforestation as a means of combating global burning because, they allege, Forests do not help to extract Carbon from the atmosphere. This erroneous. Firstly, Forests store vast amounts of Carbon not merely in the form of Trees, but in the form of soils and Wildlife. If greens were to measure the Carbon stored in all three phenomena they might take Forests much more seriously. Secondly, Forests play a major role in burying Carbon through Forest fires that create charcoal. Thirdly, and perhaps most importantly of all, Forests play a major role in extracting vast quantities of Carbon from the atmosphere and then pumping it into the soils where it becomes involved in rock weathering and eventually ends up being buried on the ocean floor. This is the cardinal error made by most greens. They simply do not take into account the amount of Carbon that Forests contribute to rock weathering. It has to be suggested that of the two functions, Forests’ ability to pump Carbon underground is probably much more important than their ability to store Carbon above ground. What does it matter that a Tree manages to store the equivalent of only two bags of sugar a year when it is doing so much more to pump Carbon into soils and then the seas? If greens were to pay more attention to the variety of ways that Forests’ are able to keep Carbon out of the atmosphere they would not so casually dismiss the policy of Reforestation as a means of combating global burning.

The amount of Carbon stored in natural Forests is so great that should they be burnt or logged and replaced by Tree plantations there is little hope of the Tree plantation ever absorbing the amount of Carbon released into the atmosphere, “Over the past 20 years, scientists have turned increasing attention to the vast amounts of carbon that is stored in trees. For any tree that had been storing carbon for, say, 700 years, a lot of carbon is set loose when any such tree is toppled by the saw. Knowing this, some scientists have said that deforestation has potential to loose more carbon dioxide into the atmosphere than we liberate in our burning of fossil fuels.” [39]

3.1.1.2: Water Absorption.

3.1.1.2.1: The Extraction of Water from the Atmosphere.

The previous sections explored Photosynthesis’s absorption of Carbon dioxide. This section explores the absorption of water. Just as was the case with Carbon, the absorption of water from the atmosphere reduces the greenhouse effect.

3.1.1.2.2: Forests may play a Role in Storing Water during Global Burning.

Although considerable amounts of water vapour are absorbed by Forests it is commonly believed this does not reduce the Earth’s greenhouse effect to the same extent as the absorption of Carbon because proportion of water absorbed in comparison to the total quantity of water vapour in the atmosphere is far smaller than the proportion of Carbon absorbed in comparison to the quantity of atmospheric Carbon. However, Forests play a major role in storing water from the atmosphere because of the huge quantities of water trapped by Forests. In other words, the total water stored by Forests consists of the water absorbed through Photosynthesis and the water trapped by Forests.

The majority of commentators believe that Forests will release water back into the atmosphere as global burning increases but others suggest the reverse may occur, “According to results published yesterday, Plants may respond to extra Carbon dioxide in the atmosphere by conserving water. This would create a drier world, with fewer clouds and less rainfall, scientists said yesterday. Although the rainfall cycle depends on evaporation of seas and lakes, huge quantities of water are transpired through the leaves of plants. (In experimental, Carbon rich, atmospheres there was a reduction in) the transpiration of water by 9%. The implication is that there would be less water for cloud formation and a reduction of rainfall by 6%. This was the reverse of computer models, which suggested a warmer, wetter world.” [40]

3.1.1.3: Aerosols.

Photosynthesis does not absorb aerosols in the same way that it absorb water and Carbon. However, Forests trap aerosols in the same way they trap water and to the extent that aerosols contain nutrients this is beneficial to Forest growth. Sometimes it is nutrients from Forest fires which end up fertilizing the growth of other Forests, “Dust deposition also has benefits, however. Since many dusts are nutrient rich, their contribution is important to ecosystems, particularly in the oceans but also on land. Saharan dust contributes key nutrients to the Amazon rainforest (yet more evidence that it is not a mature Forest).” [41]

3.1.1.4: Tropospheric Ozone.

Forests extract Carbon and water vapour through Photosynthesis. They also absorb, in other ways, a number of gases and aerosols from the atmosphere. Forests also absorb tropospheric ozone, a greenhouse gas. This moderates the greenhouse effect. Once Forests have gone they no longer play this moderating role, "Forests remove ozone, and the amazon Rainforest is a major sink, especially in the wet season. The destruction of the Forest has the effect of increasing tropospheric ozone, and hence of warming the lower atmosphere." [42]

3.1.2: Forests and the Greenhouse Effect.

Forests boost the greenhouse effect through the release of Carbon and water vapour.

3.1.2.1: Carbon Emissions.

There are a number of ways in which Forests release their store of Carbon into the atmosphere and thereby boost the greenhouse effect.

3.1.2.1.1: Forest Burning.

Carbon Dioxide.

If Forests are set ablaze by lightning, or are razed by oomans, various Carbon compounds are released into the atmosphere which boost the greenhouse effect - the most important of which is Carbon dioxide. The razing of Forests was until relatively recently the most important source of atmospheric Carbon, “Until the mid 20thC, temperate deforestation and the loss of organic matter from soils was a more important contributor to atmospheric CO₂ than was the burning of fossil fuels.” [43]

Carbon Monoxide.

One of the greenhouse gases released by Forest fires is Carbon monoxide. Its contribution to the greenhouse effect is marginal because it survives only a short time in the atmosphere. It reacts rapidly with hydroxyl radicals which oxidise complex Carbon compounds in the atmosphere. When Carbon monoxide neutralizes hydroxyl radicals this prevents the hydroxyl radicals from neutralizing bigger Carbon molecules which have a greater global warming potential than Carbon monoxide, “Forests are important cleansers of the atmosphere. And concentrations of the hydroxyl radical - a highly reactive molecular fragment, largely responsible for holding down the atmospheric percentages of trace gases such as sulphur dioxide, nitrogen oxides and chlorofluorocarbons - might fall significantly because of Carbon monoxide coming from Forest burnings.” [44]

Nitrous Oxide.

Another greenhouse gas released by Forest fires is nitrous oxide. Trees store nitrogen and when they are burnt they release various nitrogen oxide compounds into the atmosphere - one of which is nitrous oxide, “The nitrogen is returned to the atmosphere through the action of bacteria in the soil as dead trees and other plants decay .. But when the Trees are destroyed by fire, the return of the nitrogen is speeded up. Large amounts of nitrous oxide and nitric oxide are emitted. Nitrous oxide is a much more effective greenhouse gas than carbon dioxide. Nitric oxide is not a greenhouse gas but is .. active in forming nitric acid, one of the main components of acid rain.” [45]

3.1.2.1.2: Respiration.

Trees use the Carbohydrates they have obtained from Photosynthesis to carry out their metabolic processes. In the process of respiration they release both Carbon and water vapour, “About half of the energy converted into chemical form (through Photosynthesis) is used in the metabolic processes of the Photosynthesizing Plants themselves. It is made available through the process of respiration, which involves the uptake of oxygen and the release into the atmosphere, or into the surrounding water, of about half of the CO₂ and water initially taken up in Photosynthetic process.” [46]

3.1.2.1.3: Tree Decomposition.

When Trees decay they slowly release some of the Carbon they have accumulated, “Part of the Carbon emitted into the atmosphere as a result of deforestation is discharged through burning, but the majority is released through decay.” [47] .. “wood decay fungi are instrumental in releasing around 85 billion tonnes of Carbon (as CO₂) into the atmosphere each year.” [48]

3.1.2.1.4: The Release of Terpenes.

It is not known how terpenes (hydrocarbons) released by Trees contribute to global warming.

3.1.2.2: Water Vapour.

The general relationships between Forests and the water cycle have been highlighted above. Water vapour is a greenhouse gas. When Forests release water vapour into the atmosphere this boosts the greenhouse effect. Trees release water vapour into the atmosphere in a number of ways.

3.1.2.2.1: Respiration.

According to gordon wells, "In a dense area of moisture-saturated, multi-tiered Rainforest, leaf surfaces may respire water vapour in amounts greater than can be evaporated from nearby open surface water." [49]

3.1.2.2.2: Transpiration.

Trees release water vapour through transpiration .. "plants consume water and expel water vapour through their leaves. This floral sigh, called transpiration, adds moisture and latent energy to the air, for making clouds and driving ‘wanton winds’.” [50] ; Forests .. “also transpire at a far greater rate than (than grasses), pushing back into the atmosphere between half and three quarters of the rain that falls over it - amounting, in the case of the amazon Rainforest, to some 12 million million tonnes of water.” [51] ; “Plants also affect the weather. They evaporate water from their leaves by opening or closing tiny sphincter-like pores called stomata. This loss of water is called transpiration and it keeps the plant cool and draws up liquids and salt through the plant. But the quantities of water are staggering. An acre of grass between may and july transpires over 500 tons of water.” [52]

3.1.2.2.3: Evaporation.

The evaporation of water which has collected on Tree surfaces boosts the greenhouse effect.

3.1.2.2.4: Evapotranspiration.

Evapotranspiration is a combination of evaporation and transpiration, “One factor which affects the rate at which moisture enters the air from land and which is of global importance is the presence of Plants, particularly Trees. Plants lose water from their leaves by a process known as transpiration. The total loss of water vapour from Plants and soil is called evapotranspiration.” [53] ; “In practice it is difficult to separate water evaporated from the soil, intercepted moisture remaining on Vegetation surfaces after precipitation and subsequently evaporated, and transpiration. For this reason .. as a general term for all of these .. the composite term evapotranspiration may be used.” [54] Peter bunyard estimates, “In a healthy rainforest, transpiration, by which vegetation pumps water through its stomata into the atmosphere, accounts for 60% of the humidity in the air over central amazonia and evaporation from the leaves and stems of vegetation for the remaining 40%.” [55]

The amount of water vapour released by Forests through evapotranspiration is colossal, “Although only a small fraction of a leaf surface bears the pores through which moisture evaporates, the potential rate of water loss from a many leaved canopy of leaves can approach that of loss from the same area of an open water surface.” [56] ; “This transpiration (of Trees) is a very effective mechanism, and a square kilometre of moist, ‘steamy’ tropical Rainforest can push more water vapour into the atmosphere than a square kilometre of ocean.” [57] A square kilometre of Forest has a far larger total surface area than a square kilometre of ocean. The scale of evapotranspiration is so extensive it contributes to cloud formation.

3.1.3: Forests and the Albedo Effect.

3.1.3.1: Introduction.

Sunlight impinging on the Earth’s surface is either absorbed or reflected back into the atmosphere. [58] The first phenomena is the heat effect whilst the latter phenomena is the albedo effect. The solar energy absorbed by a surface is eventually re-radiated back into the atmosphere and is counted as part of the heat effect. If it is re-radiated back to the surface by greenhouse gases in the atmosphere this is counted as being part of the greenhouse effect. The heat effect is explored in the next section. The sunlight reflected from a surface on Earth is regarded as belonging to the albedo effect. As far as the albedo effect is concerned, it has been argued that, “Until recently, global reflectivity has been largely ignored by environmentalists because it seemed impossible to influence the planet’s color or gloss, one way or the other.” [59]

Forests create four albedo effects: they have their own albedo effect; they create a second through releasing water vapour which forms clouds; they create a third by releasing aerosols; and, finally, they release a greenhouse gas which forms stratospheric ice crystals which have an albedo effect.

The following analysis of Forests’ albedo effect is divided into three sections. The first explores the albedo effect of static Forests i.e. Forests which are neither declining or growing in size. The second explores the changes to Forests’ albedo effect as a result of deforestation whilst the third section explores the changes in Forests’ albedo effect as a result of Reforestation.

3.1.3.2: The Albedo Effect of Static Forests.

3.1.3.2.1: Forests’ Albedo Effect.

3.1.3.2.1.1: Comparing the Albedo Effects of Various Forests.

All Forests have an albedo effect, “By colouring the land, Plants increase the local intake of solar energy.” [60] The albedo effect of each Forest is different. (Black surfaces absorb sunlight and have an albedo effect of 0 or 0% whereas white surfaces reflect sunlight and have an albedo effect of 1 or 100%).

Deciduous Forests.

“Deciduous Forests, of the kind that grow naturally in temperate regions with seasonal climates, have an albedo of 0.15 to 0.18.” [61]

Coniferous Forest - The Taiga/Boreal.

“Coniferous Forest is darker (than deciduous Forests), with an albedo of 0.09 to 0.15 ..” [62] ; "Boreal Forests warm the subarctic zone by providing a dark mass that absorbs heat from the sun." [63] ; “Through their dark colour and capacity to shed snow, conifer Forests may lessen the length of winter in near arctic regions." [64]

Tropical Rainforests.

.. “tropical Rainforest is a little darker still (than Coniferous Forests). Its albedo is between 0.07 and 0.15.” [65]

3.1.3.2.1.2: Comparisons between the Albedo Effects of Forests and other Photosynthesizers.

Overall, Forests have a lower albedo effect than other types of Phytomass. They reflect less sunlight than Grasslands .. "a Forest reflects 12-15% of the sunlight which falls on it, whereas grassland will reflect about 20% and desert sands up to 40%. [66] Forests absorb considerable amounts of sunlight.

3.1.3.2.2: The Albedo Effect of the Clouds created by Forests.

Forests create a second albedo effect when they help to forms clouds as a result of by releasing water vapour and cloud condensation nuclei - remembering that water vapour by itself creates neither rain nor clouds. Some types of Forest create denser clouds than others. Clouds have a far higher albedo effect than Forests and thus a cooling effect.

3.1.3.2.2.1: The Influence of Forests on the Formation of Clouds.

University of crete researchers have suggested that Trees release hydrocarbons which act as cloud condensation nuclei, “Land based vegetation can promote the formation of cloud-forming aerosols, according to researchers at the university of crete. Their measurements, taken above a forest in portugal, show that hydrocarbon gases emitted by trees can form organic aerosols in the atmosphere. As these aerosols are important ‘condensation nuclei’ on which clouds can form, this study adds further weight to the hypothesis that trees contribute to the regulation of the climate.” [67] The contribution that evapotranspiration from Forests makes to the formation of clouds, and thus rainfall around the world, is significant, “Rainfall on the continental land masses of the Earth is, to a considerable extent, a consequence of evapotranspiration; the pumping by Trees and large plants of water from the soil to their leaves where it evaporates.” [68] ; “There is a close relationship between Trees and rainfall. Without a quantum of Trees there is less than a quantum of rainfall. Examples can be seen in the eastern mediterranean, along the coast of north africa and in arizona.” [69] Most of the rainfall over the amazon does not come from oceanic evaporation but from the Forests themselves. the worldwide fund for nature point out, “Each year approximately 70% of the precipitation which occurs in the (amazon) tropical Forests returns to the atmosphere due to the Forests own contribution to the process of evaporation.” [70] Stephen drury argues, “Today vegetation has major influence on humidity in continental interiors. Moreover, inessential compounds dissolved in transpired water enter the atmosphere as dust-sized crystals that encourage the nucleation of raindrops. Land vegetation helps create the conditions for its own survival, and thereby transforms otherwise purely inorganic processes that shape landscapes.” [71]

3.1.3.2.2.2: The Complexities of the Albedo Effect of Clouds.

The albedo effect of clouds is a complex issue.

* Firstly, clouds have a double-sided albedo effect. On the one hand they reflect sunlight back into space whilst, on the other, they reflect back to the Earth’s surface, the sunlight reflected from the Earth’s surface.

* Secondly, they also reflect infra-red radiation emanating from the surface.

* Thirdly, clouds’ albedo effect varies according to their height, “In general for low clouds the reflectivity effect wins so they tend to cool the Earth-atmosphere system; for high clouds, by contrast, the blanketing effect is dominant and they tend to warm the system.” [72]

* Fourthly, clouds’ albedo effect also varies according to the time of day, “Cloud is a cooling influence during the day-time, but a warming influence at night when it acts like a blanket.” [73]

* Finally, clouds’ colouration also makes a difference to their albedo effect .. “clouds play a critical role in the heat balance of the Earth, simultaneously reflecting solar energy back into space and, conversely, trapping solar energy as heat. How much they do of each of these depends on the nature of the clouds: the whiter they are, the higher their albedo and the more solar radiation they reflect: the thicker and darker they are, the more they serve as a heat blanket.” [74]

3.1.3.2.2.3: The Double Albedo Effect of Clouds.

As regards the double-sided albedo effect of clouds: the topsides reflect sunlight back into space thereby cooling the Earth whilst the undersides reflect sunlight back to Earth thereby warming the Planet. It is believed the net result is cooling, "The net overall effect is that clouds cool the Planet by 10-15C in contrast to a hypothetical Earth without clouds.." [75] So, whilst water vapour is a greenhouse gas which boosts global temperatures, the double-sided albedo effect of water vapour in the form of clouds cools the Earth .. "water vapour is a greenhouse gas, but once the vapour condenses to form clouds it has a cooling effect." [76]

3.1.3.2.2.4: The Cooling Effect of Amazonian Clouds.

The amazon Rainforest generates a vast cloud cover across large parts of the south american continent. It contains huge quantities of water which are constantly in the process of evaporating and condensing, “The Amazonian basin as a whole retains some two thirds of the world's non-polar fresh water supply.” [77] The albedo effect of this vast blanket of clouds plays a considerable role in cooling the Earth. Lovelock believes the main role of the amazon Rainforest is as an air conditioner controlling the Earth's temperature, "Amazonia may not be worth much as a source of oxygen, or by the same calculation, as a sink for Carbon dioxide, but it is a magnificent air-conditioner, not only for itself but also for the world through its ability to offset, to some extent, the consequences of greenhouse gas warming." [78]

Lovelock seems a little unfair in dismissing the amazon Rainforest as a Carbon sink. If it was set ablaze its role as a sink might become all too obvious. Nevertheless the point he makes is true - the amazon Rainforest’s main impact on the global climate is not the Carbon it extracts from, or releases into, the atmosphere but the albedo effect of the clouds it creates, the continent-wide clouds cooling the Earth. Even if it is true that, geophysiologically, the greenhouse effect is more important than the albedo effect of clouds, as far as the amazon Rainforest is concerned the reverse is true.

3.1.3.2.2.5: The Cooling Effect of the Taiga.

The taiga Forest also releases water vapour but it does not produce the same spectacular scale of clouds as tropical Rainforests. To the extent that it produces clouds these too provide a cooling effect.

3.1.3.2.2.6: The Planetary Importance of the Albedo Effect of Clouds.

The albedo effect of clouds is an important factor in determining the Earth's average temperature.

James Lovelock.

“Through their capacity to evaporate vast volumes of water vapour through the surface of their leaves, Trees may serve to keep the ecosystems of the humid tropics and the Planet cool by providing a sunshade of white reflecting clouds. Their replacement by cropland could precipitate a regional disaster.” [79] ; “The evaporation of water from Forests is part of Gaia's cooling system.” [80]

William James Burroughs.

“Clouds are almost always more reflective than the ocean surface and the land except where there is snow. So when clouds are present they reflect more solar energy into space than do areas which have clear skies. Overall their effect is approximately to double the albedo of the Planet from what it would be in the absence of clouds to a value of about 30%.” [81]

Michael Allaby.

“The most dramatic variation in reflectivity is caused by clouds. Their presence or absence has a profound effect on the temperature at the surface. In extreme cases, big cumulonimbus storm clouds block almost all the solar radiation, turning day into night.” [82] The albedo effect of the Earth without clouds is 15%; with clouds it is 30%.

3.1.3.2.2.7: The Relationship between Forests’ Albedo Effect and Clouds.

The relationship between Forests own albedo effect and that of the albedo effect of the clouds they create varies according to the type of Forest. The taiga Forest has a bigger impact on the climate through its own albedo effect than through the albedo effect of the clouds it creates. The reverse is true for the tropical Rainforests - the albedo effect of tropical Rainforests seems to be less important climatically than the albedo effect of the clouds generated by these Forests. This is because tropical Forests produce dense clouds which reflect a lot of sunlight back into space whilst the taiga Forests generate fewer clouds and thus absorb far more heat.

3.1.3.2.2.8: A Comparison between the Albedo Effect of Clouds and the Greenhouse Effect.

One commentator believes the albedo effect of clouds has a far greater impact on the climate than the greenhouse effect, "Both the cooling and heating effects of clouds are huge, comparable to the effect of a massive, many fold increase in CO₂." [83] ; "The greenhouse effect of clouds is many times the effect that would be given by doubling the CO₂ of the air. The cooling effect of clouds is even greater, 10 times as large as their greenhouse warming." [84]

John houghton, one of the leading figures on the scientific working party of the intergovernmental panel on climate change (ipcc), believes the greenhouse effect is more powerful than clouds’ albedo effect. A commonly quoted estimate is that the greenhouse effect keeps the Earth 33C warmer than it would otherwise be. It is alleged that without the greenhouse effect the Earth’s average temperature would be -18C rather than its current average of 15C. Houghton questions the usefulness of one of the assumptions used in this estimate, “This calculation is often carried out using a figure of 30% for the average reflectivity of the Earth and atmosphere rather than the 16% assumed here; .. The higher figure of 30% for the Earth’s average reflectivity is applicable where clouds are also included, in which case the average of -18C is not applicable to the Earth’s surface but to some appropriate level in the atmosphere. For the purposes of illustrating the effect of greenhouse gases it is more correct to omit the clouds from this initial calculation.” [85] Houghton suggests that if the greenhouse effect did not exist then the temperature, at the surface of the Earth, would be -6C. This implies the greenhouse effect increases the Earth's average temperature from -6C to 15C i.e. a temperature difference of 21C. If the albedo effect of clouds is taken into consideration the Earth's albedo increases from 16% to 30% and, correspondingly, the Earth's average temperature decreases from -6C to -18C. This means the reduction in the Earth's temperature caused by clouds is 12C. If this interpretation of houghton's calculations is correct then the greenhouse effect has a more powerful influence on the Earth's average temperatures than the albedo effect of clouds. The greenhouse effect increases global temperatures by 21C whilst the albedo effect of clouds reduces temperatures by 12C. Whilst it is a fairly easy matter to imagine the dramatic cooling effect of clouds on the Earth's temperatures, as anyone could testify when clouds draw across a blazing hot sun, it is far more difficult to imagine that an invisible gas has a more dramatic impact on the Earth's temperatures than clouds. It also runs against everyday experience to accept that the warmth that people feel from the sun does not come directly from the sun itself but is the product of the greenhouse effect keeping the Earth as a whole much warmer than it should be. Perhaps the only people on Earth who can directly appreciate the role of the greenhouse effect are those who live high up in mountains in the tropics. The people living at the base of mount kilamanjaro experience the dramatic heat of the equatorial sun and yet if they start to ascend the mountain, getting closer and closer to the sun, they find that temperatures do not rise but decline dramatically until they meet almost polar conditions. The reason this tropical mountain is cloaked in ice is because whilst it is closer to the sun it is above the Earth’s blanket of heat provided by the greenhouse effect. Under such conditions the warmth from the sun does little to compensate for the arctic conditions.

3.1.3.2.3: Forests and the Albedo Effect of Aerosols.

Forests create a third series of albedo effects through the release of aerosols into, and the extraction of aerosols from, the atmosphere.

3.1.3.2.3.1: The Role of Forests in Extracting Aerosols from the Atmosphere.

Forests act like a giant sieve extracting a wide range of pollutants and dust from the atmosphere. This decreases the Earth’s albedo effect.

3.1.3.2.3.2: The Role of Forests in Dumping Aerosols into the Atmosphere.

Forests release aerosols into the atmosphere. Forest fires dump aerosols into the atmosphere. which boost the Earth’s albedo effect and thus cool the Earth.

3.1.3.2.4: The Albedo Effect of the Stratospheric Ice Crystals created by Forests.

Forests’ fourth albedo effect is caused by stratospheric ice crystals. Forests release methane into the atmosphere as a result of Tree decomposition. Methane drifts through the atmosphere and into the stratosphere where it contributes to the formation of stratospheric ice crystals. In the past, the release of methane did not cause such a phenomena because the stratosphere was not cold enough. The increase in global burning and the depletion of the stratospheric ozone has caused a drop in the temperature of the stratosphere which is sufficient to freeze water. In other words, this is a clear example of the way that global burning is itself triggering off further contributions to global burning. However, since Forests’ main contribution to the formation of stratospheric ice crystals is brought about by deforestation it is explored in the next section.

3.1.3.2.5: Conclusion.

Lovelock believes the albedo effect of the taiga is one of the Earth’s main climate stabilizing factors, “How much is the Earth like daisyworld? We can speculate that the blankets of white marine stratus clouds reflecting sunlight back to space above the algal blooms of the ocean, are the white daisies, and the dark conifer Forests of the northern temperate regions are the black daisies.” [86] What is surprising about this quote is that he pairs off the taiga with oceanic Algal blooms rather than the tropical Rainforests which are similarly covered in clouds which reflect sunlight back into space. Does this mean he doesn’t believe the Earth’s two major Forests are important stabilizing influences on the climate - one warming up the Earth when it is cold and the other cooling the Earth when it is hot? The potential for the two types of Forest to play a stabilizing role exists because of their massive scale, “The northern and southern temperate Forests cover about 10% of the land area. The tropical Forests also used to cover about 10% of the land." [87] It is possible, however, that he doesn’t regard them as stabilizing influences, despite their symmetry, their similarity in size, and their close conformity to his daisyworld model of black and white daisies, because the more important factor about these two Forests is that they change size according to the level of the Earth’s oceans and ice age on the northern continents rather than global temperatures. For instance: if the size of the Forests depended solely upon global temperatures then, when it is hot, the amazon would increase in size whilst the taiga would decrease in size; and, when it is cool, the amazon would decrease in size and the taiga would increase in size. However, given the rise and fall of the oceans, when the climate is getting hotter the amazon decreases in size whilst the taiga increases in size; whereas, when the climate is cooling, the amazon Rainforest increases in size and the taiga decreases in size.

3.1.4: Forests and the Heat Effect.

The heat effect and the albedo effect are two sides of the same coin. Some of the sunlight hitting the surface of the Earth is reflected back into the atmosphere whilst the rest is absorbed by that surface. The previous section explored the albedo effect of Forests whilst this section looks at the absorption of solar energy by Forests i.e. the heat effect. Forests absorb huge amounts of sunlight and this energy is eventually released back into the atmosphere either as infra-red radiation or in the form of water vapour. All the above sections have mentioned water, or water vapour, and are thus connected to this section on Forests’ heat effect.

3.1.4.1: Forests’ Heat Exchanges.

3.1.4.1.1: Trees’ Absorption of Solar Energy.

Forests absorb energy directly from the sun. The water stored on the surface of Trees also absorbs solar energy. This energy is released back into the atmosphere either as infra-red radiation or as water vapour.

3.1.4.1.2: Trees Absorb Solar Energy through Photosynthesis.

Photosynthesis involves the absorption of heat. 

3.1.4.1.3: Trees Sucking Cool Water from Underground through Transpiration.

When the sun shines, Forests release water into the atmosphere and this sucks up huge quantities of underground water which has the effect of cooling the Forests, “Plants also affect the weather. They evaporate water from their leaves by opening or closing tiny sphincter-like pores called stomata. This loss of water is called transpiration and it keeps the plant cool and draws up liquids and salt through the plant. But the quantities of water are staggering. An acre of grass between may and july transpires over 500 tons of water.” [88] ; “Most of the humidifying vapours arise from the ocean. The soil’s surface supplies a third of what lifts from the land. The other two-thirds passes skyward through the leaves of plants.” [89]

3.1.4.1.4: Evapotranspiration and Respiration.

Forests release water vapour either as a result of solar energy causing evaporation of water from Forest surfaces or through respiration. The release of water vapour from Forests has a complicated series of impacts on global temperatures. Firstly, water vapour boosts the greenhouse effect. Secondly, when water vapour condenses into clouds it releases an enormous amount of energy which warms the atmosphere. Thirdly, the creation of clouds boosts the Earth’s albedo effect thereby causing global cooling.

3.1.4.2: The Heat Effect of Static Forests.

This section explores the heat effect of Forests - later sections explore the heat effects produced by deforestation and Reforestation.

3.1.4.2.1: The Heat Effect of Tropical Forests.

Forests release vast quantities of water vapour which, when it condenses, releases correspondingly huge amounts of heat. The quantity of heat released can be gauged from the fact that Forests create continent-wide cloud cover. The amount of solar energy absorbed by tropical Forests is so substantial it helps to create equatorial storm clouds which distribute heat around the Earth, "The sun's heat is absorbed mainly at the equator and then transported by the atmosphere and oceans towards the poles. The first stage of this process is the formation of giant storm clouds, vast packets of the sun's energy. This happens at three areas along the equator: the western Pacific, and the Amazon and Congo rainforest regions." [90] ; "Vegetation is crucial to the global air conditioning system. Plants transpire water and in so doing they transfer energy into the air. The transfer of heat is so large that it is an important contribution to the energy driving the global air circulation." [91] ; “In addition to controlling the flow of water, the processes of evaporation and condensation represent a system of temperature regulation. The water that evaporates in the amazon region absorbs heat that is returned to the atmosphere during the condensation process. On the one hand, this permits the tropical areas of the amazon region to cool down, and, on the other, it permits heat to reach the upper strata of the atmosphere. As the atmosphere circulates it carries these upper layers as far as the polar regions.” [92] ; Forests .. “also transpire at a far greater rate than (Grasses), pushing back into the atmosphere between half and three quarters of the rain that falls over it - amounting, in the case of the amazon Rainforest, to some 12 million million tonnes of water. The amazon basin, with its Forest intact, actually sends away more than 40 times all the energy currently consumed in all human activities across the globe. Much of that energy falls as rain over north america and europe, where its warmth is imparted to the atmosphere.” [93]

3.1.4.2.2: The Heat Effect of the Taiga.

The taiga Forest absorbs considerable quantities of heat, and thus boosts global temperatures, even during the winter months when they are covered in snow, “The snow-covered Forests of the northern hemisphere can absorb more sunlight during the winter months than the adjacent Treeless snowy areas and are therefore warmer. Not only do the exposed surfaces of the Trees absorb heat, but this heat also accelerates the melting of the snow that settles on them.” [94]

The scale of the heat absorbed by the taiga Forest is considerable given the colossal area of land it covers, “The boreal Forests (taiga) .. cover one-thirteenth of the Earth’s land surface. They are estimated to cover 4.3 million square miles, equivalent to three europes. Some 70% are in siberia and 22% in canada and alaska, most of the rest being in scandinavia. Siberia’s sector is three times as large as the brazilian amazonia.” [95]

3.1.4.2.3: The Importance of the Tropical Rainforest in comparison to the Taiga.

Although both the taiga Forests and tropical Rainforests release vast quantities of water vapour into the atmosphere, the former does not absorb anything like the same degree of heat as tropical Forests and is not involved in creating storm clouds on the same scale as tropical storm clouds. Tropical storm clouds are far more important for driving the Earth’s air circulation system, “Tropical Forests may have an even bigger effect (than Boreal Forests). They may help to drive the general circulatory systems of the atmosphere, influence precipitation patterns, and distribute heat to temperate zones." [96]

3.1.5: The Overall Impact of Forests on the Climate.

In conclusion, Forests play a vital role in influencing the Earth’s climate. Through Photosynthesis they continuously absorb huge quantities of Carbon which is either stored in the form of Trees, soils, or Wildlife; or it is pumped into the oceans through rock weathering where it has a considerable influence over the level of Photosynthetic activity in the oceans. It is even believed that Forests may be just as important as marine Algae in permanently disposing of Carbon in as much as Forest fires create Charcoal. Forests also release huge quantities of water vapour which not merely boosts the greenhouse effect but distributes heat around the Earth’s atmosphere. The water vapour released by Forests creates continent wide cloud cover whose albedo effect plays a major role in cooling the Earth.

There is no other phenomena which has such a wide range of impacts on the climate. However, these are merely influences on the climate. Is it possible that Forests have a more dynamic climatic role, one which helps them to stabilize the Earth’s climate? Before looking at Forests’ dynamic role in stabilizing/destabilizing the climate it is necessary to try and understand the main features of the history of the Earth’s climate.