Climate and Temperate Forests in Equilibrium - Essay Example

Climate and Temperate Forests in Equilibrium Introduction Temperate forests comprise a large percentage of the world’s forest cover, roughly half according to Dudley (1992). Compared to tropical forests, which are being actively exploited to an alarming degree, temperate forests are generally preserved in its natural state. This may be because of the biodiversity present in such ecosystems. In New Zealand for example, consisting of merely 1% of total forest cover but the number of species teeming within it is disproportional. It is the purpose of this paper to assess if temperate forests are in fact in equilibrium with its climate by considering paleocological studies concerned with the effects of climate change to ancient forests as well as more recent studies of the ;problem of global warming and its effects on temperate forests. Do temperate forests exhibit stability in terms of cover, biodiversity and function in the carbon cycle? What is causing temperate forests to decline if it is indeed in equilibrium with climate? The Forest as a Carbon Pool The article “Forests and climate change” (FAO Corporate Document Repository) states that forests serve an important function in the environmental balance as a carbon pool. A carbon pool is the storage area where carbon dioxide is released or stored. The rate of exchange normally depends on the life cycle of the forest elements. Ideally, the forests are in a state of a perpetual carbon sink, which is defined as a system in which there is more carbon going in than out. Equally admirable is when the amount of carbon absorbed from the atmosphere is equal to the amount of carbon released back into the environment. Unfortunately, especially since the Industrial revolution, this balance has been upset to an increasing degree until the effects of the climate system imbalance has become too severe to be ignored. There have been several efforts in limiting, and hopefully eventually eradicating, this imbalance, with minimal success. One of the more seemingly ecologically correct notions is to implement forest management policies to preserve existing forests and to extend its area through afforestation. Dudley states the preservation of the old temperate forests would be of benefit to the ecology. However, he further implies that the establishment of newer, faster-growing but ecologically unfit forests would be detrimental to the cause of ecological salvaging. Characteristics and Types of Temperate Forests Temperate forests are found mainly in western and central Europe, the eastern side of North America and northeastern Asia. These are scattered all over the middle and high latitudes although very few of them are large. Of the global temperate forests, Dudley estimates that 41% of are to be found in Siberia, 31% in the US and Canada, and the remaining 27% in Australasia, Asia, Latin America and Europe. WWF (October 19, 2006) divides temperate forests into coniferous forests, mixed coniferous/broadleaved forests and broadleaved forests. Temperate rainforests, so called because of its excessive amount of rainfall, is mainly coniferous; deciduous forests where leaves are shed during winter, sport broadleaved trees which react easily to changes in temperature; Mediterranean scrublands feature small oak and pine trees. Temperate forests, according to the University of California Museum of Paleontology (1994-2007), thrive in temperatures ranging from -30° to 30° C with rainfall levels ranging from 75-150 cm spread evenly throughout the year. It is not as dense as tropical forests, allowing an appreciable amount of light to filter through and exhibits a diverse mix of fauna and flora. Biodiversity in Temperate Forests The preservation of biodiversity is one of the main concerns in the preservation of temperate forests. Although occupying a total land area less than that of tropical forests, the variety of species existing within temperate forests of equal size outstrip those found in its warmer counterparts. This is explained in part because of the climatic factors that prevail in the two ecosystems. Tropical forests exist in a more or less steady temperature, which dispenses a year-round supply of foodstuff for the inhabitants of the ecosystem. The flora and fauna tend to cluster within a discrete area within the biome. This eliminates the need for any of the inhabitants to migrate from their zone. Indeed, the method of plant fertilization relies on close contact rather than being airborne as the wind factor with a tropical forest is too low to depend on this type of propagation. Temperate forests, on the other hand, are characterized by a distinct winter period that may range from mild to severe. In many cases, the drop in temperature causes the food supply to taper off to a point where it becomes nonexistent. Some of the forest inhabitants, both flora and fauna alike, respond to the inhospitable climate by hibernating. Those able to find suitable alternative conditions elsewhere migrate, later to return. Some adapt characteristics that help them through the lean times, such as shedding their leaves to preserve moisture. Over time, small adaptations may become a springboard for a diversification in one member of a species which gradually evolves into yet another species better suited for a particular place at a particular season. Climatic Factors The relationship between forests in general and the climate depends mostly on its role in the carbon cycle. Carbon sequestration, as defined by Ferests Forever (2007) is the conversion of atmospheric CO2 into biomass such as wood and stored until it is released back at the end of its life cycle, either naturally or through human machination. This could take the form of decay or combustion. It should be noted, however, that the forest is not only composed of the flora and fauna, but the soil as well. In fact, more than half of the CO2 absorbed from the atmosphere ends up in the soil. Science Daily (2007) disclosed in a study headed by University of California – Davis geology professor Isabel Montanez that carbon dioxide (CO2) levels during the transition 300 million years ago from an ice age to long-term global warming fluctuated wildly, affecting the retreat (when CO2 were high, 2,000 parts per million) and expansion (when CO2 levels were low, comparable to present-day levels of 250 parts per million) of the southern ice sheets. Montanez and her team pointed out that this seemed to confirm that greenhouse gases caused the end of the Paleozoic era. Greenhouse gases are released when biomass such as wood or soil release their store of CO2 into the atmosphere in excessive amounts. These gases effectively prevent the heat from climbing away from the earth’s surface, thus creating the greenhouse effect. With the steady rising of temperature from accumulate heat, global warming results. Hardstaff (1997) defines the greenhouse effect as “The process whereby the suns warmth is trapped in the lower atmosphere of the earth by a number of gases (including carbon dioxide). These gases let solar radiation through but reflect back the warmth radiated from the earth.” This results in the warming of the earth, and the greatest source of these emissions is the burning of fossil fuels for human consumption, forest fires resulting from the increase in temperature and deforestation. During deforestation, the act of cutting down trees whether for fuel or other purposes not only depletes the carbon pool of viable storage units but also affects the ability of the soil to hold on to its CO2. This could lead to other ecological undesirables aside from greenhouse gases, such as acid rain. The merits of forest management, according to Forests Forever (2007), is that it provides guidelines for the efficacy of judicious clearcutting (such as in Canada) and fertilizing to maximize the role of the forests as carbon sinks. Some scientists believe that cutting down older trees ensures that more CO2 is absorbed. Global warming due to the greenhouse effect is one of the biggest environmental issues of the century mainly because its effects are perceived to be potentially catastrophic based on previous climatic upheavals. However, Montanez postulates that major climate change such as during the period described will likely occur when global warming happens drastically, not gradually. Moreover, the fear that the human species will face extinction at the end of this particular period of global warming is most probably unfounded. Paleoecological records indicate that while this present global warming is a cause for concern, it is not at the grand scale of disaster or extinction feared by many. Science Daily (October 15, 1998) culls a study of University of Arizona in Tucson geologist Judith Parrish, who goes even so far to state that perhaps global warming to a certain degree would be a good thing for the propagation of forests over an exdtended period of time. In her study, fossil remains were found in the polar ice caps dating from the mid-Cretaceous period, 100 million years ago. She found evidence that appear to indicate the existence of an ancient forest that flourished during this time before the ice took over. This was the middle of the period when dinosaurs lived, and the climate was much warmer. If global warming stays at a manageable level, low temperature areas where forests would not otherwise be able to thrive may find a foothold in a few years. But that is long-term planning indeed. In the meantime, the concern of the more immediate negative effects of global warming is serious enough to warrant consideration. Of the many movements that are geared towards preserving the present way of life, the planting of more trees is the most attractive. Aside from expanding the area of forests, it also serves an aesthetic purpose, improving the view and providing forest inhabitants more potential habitats. The growing clamour for cleaner fuels and alternative power sources is also admirable and has many advocates, but a workable solution is far from being a reality as of the present. The call for reforestation of denuded forests is also on the menu. All these initiatives have merit, but they only address the problem of global warning in the short-term. An Environment News Service article (December 12, 2006) discussed the probable effects of planting more trees for temperate forests based on the results of a 3-D climate carbon model developed by Université Montpellier II, Carnegie Institution and Lawrence Livermore National Laboratory scientists. According to the study, the trend is the planting of more trees in a particular area, or afforestation. It is an attempt to increase the area of forests that theoretically would curb the release of greenhouse gases in. However, the ENS study shows that such afforestations may not be the best solution for all areas. The model shows that conducting afforestation in the middle and high latitudes may cause more harm then good. Instead of contributing to reigning in the march to higher global termperatures, the opposite is true. Why should this be? Apparently, more trees than naturally occurs in the higher, drier latitudes produce canopies that are dark. This bounces back less of the sunlight and absorbs more of the accompanying heat in the lower portion of the atmosphere. The foliage produced by the newly-planted trees thus serves as the “greenhouse gas” in this instance. This is because it basically prevents the heat from escaping, much like greenhouse gase3s such as carbon dioxide does. Thus, it produces higher net temperatures, not lower. The study concludes that even if carbon absorption increases, the inability of the heat to escape back into the higher atmosphere due to obstruction by the excessive forest coverage cancels out any cooling effects produced by the additional trees. In fact, in one simulation where trees were planted in a temperate region where it did not naturally occur, it was projected that the increase in ambient temperature would be 10% more by 2100 in some areas than it would have been had the forest not been there. This is not true in the case of tropical rainforests, the study further states. The cooling effect of denser, more humid tropical forests is only one positive side of afforestation. The increased heat that permeates the forest causes increased water evaporation, ultimately lowering the earth’s global temperature. The Kyoto Protocol, developed during the UN Convention on Climate Change as a concerted effort to find a globally viable system to halt global warming, espouses afforestation and reforestation as desirable activities. However, it failed to take into account the carbon-climate interaction described above that makes any attempt of afforestation in temperate areas a mistake. The Decline of Temperate Forests Despite the many roots and causes of climate change, its effect on temperate forests appears to be just one of the factors that may be contributing to the decimation of trees. Dudley indicates that human actions have an equal or even greater effect on the health of temperate forces today, specifically air pollution. The factors that contribute greatly to this problem are electrical generation, exhaust from vehicles and manufacturing industries. Trees are subjected to such emissions as sulphur dioxide and nitrogen oxides, resulting in lower average lifespan as well as a decline in the quality of the wood. There is also an effect on the other types of flora such as moss and lichen. This in turn affects the more mobile inhabitants of the forest since a decrease in quality and quantity of the lowest stage of the food chain will inevitably affect those higher up the chain. Analysis Temperate forests have long been the subject of speculation and wonder because of its very diversity. Huge Douglas firs many hundreds of years old excite the imagination, and picturesque evergreen forests as well as delicate broadleaved trees provide silent testimony to the history of their environment. However, this state of balance is being threatened, as evidenced by a perceived decline in the composition and number of thriving forests in temperate areas. It was found that while global warming has an impact on all forests in general, this is not the main reason for the decline in temperate forests. Based on the available research, it appears that temperate forests have actually settled into a state of equilibrium with the current climate conditions. Where conditions permit, the flora grows in populations and to heights that go with the flow of fluctuations of temperature and precipitation. Leaves broaden or change form, as in the case of conifers, depending on the height of the location, its proximity to available water and extremities of temperature throughout the year. Seasonal changes dictate the availability of nutrients, and this likewise dictates the behaviour of inhabitants of the forest. However, the stresses is being created by man-made structures and machines that impregnate the air and environment with pollutants that the ecosystem cannot possibly cope with in the long term or at unrestrained levels. The situation is better in some areas, but the effect of human existence is all-pervading. Dudley reveals that to address these concerns, there is a study of the amount of pollution is absorbable for various types of ecosystems that short of permanent damage. These so-called critical loads will serve as guidelines for developing pollution-control policies in different affected countries. As long as humans understand that temperate forests are self-limiting with regards to climate, and seek to preserve the balance of nature within the ecosystem, the temperate forests need very little intervention to continue functioning efficiently its role in the carbon cycle. Climate concerns regarding the survival and propagation of temperate forests are valid but not to a great degree. However, the effect of air pollution seems to merit more concern. Synthetic emissions from man-made structures and production cycles go beyond the ecological capability of these ecosystems to breakdown and incorporate naturally. The result of this pollution, if left unchecked, would be the loss of many species from the face of the earth. It is important that the effect of air pollution be controlled so that both humans and forests can live out their expected life spans and be productive members of the biosphere. 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Chapter 4 in The primary source: Tropical forests and our future viewed January 7, 2007, < http://www.ciesin.org/docs/002-109/002-109.html> Read More