Land Clearing Problems

Land clearing across the world is creating local, regional and global problems, threatening environments and challenging the way in which we manage our environment in many varied ways.

These are just some of the many considerations:

Deforestation

Tropical forests are being destroyed at an ever increasing rate. The estimates of the losses vary, but at least one half of the tropical forests of the world have already been lost. If the trend continues, the remaining tropical forests will disappear within the next three decades. This is an incalculable loss, because these forests provide habitat for an estimated half of the plant and animal species of the world. In addition, these forests provide water and fuel for a large portion of the world’s population. They also have a large influence on the local and global climatic systems. Such forests are also potentially a treasure house full of previously unknown chemicals, foods, pharmaceuticals, spices and more.

Most of the deforestation is caused by commercial logging, land clearance for agriculture, ranching and fuel. Solutions to these problems include:

• The development of alternative wood supplies for fuel and timber, achieved by planting and maintaining timber and fuel wood plantations.
• Developing alternative energy sources for cooking and heating to replace wood used as fuel (e.g. solar).
• The regulation of logging.
• A consensus on the value of forest conservation over commercial development.
• More efficient use of harvested wood products.

As with tropical forests, temperate zone forests are also under threat, although in some areas such forests have actually increased in extent. Acid rain is the greatest threat to these forests in the Northern Hemisphere. This is caused by acidic pollution from factories mixing with water vapour in the atmosphere and falling to the ground as rain. The conifer forest regions of Europe and North America are the currently most severely affected by acid rain.

Loss of Agricultural Land

Because of excessive increases in the worlds human population coupled with the construction of buildings and roads, the land available for food production is steadily decreasing. In much of the remaining land topsoil is lost by erosion and production decreased due to increasing salinisation problems. Due to erosion, large scale agriculture can result in severe and unsustainable rates of soil loss. Overgrazing and the collection of firewood can cause land to become arid, eventually resulting in the spread of deserts and semi-deserts. The problem is particularly severe in developing countries, where difficulties are caused by unsound and ineffective agricultural policies.

The Loss of Biological Diversity

A major conservation concern is the ever-increasing loss of fauna and flora species. The loss of habitat, especially in the tropical forests, is the greatest threat. Some species, such as whales and rhinoceros are threatened by over exploitation.

The Convention on Trade in Endangered Species of Flora and Fauna (CITES) has worked well to control trade in many threatened species. However, this is not enough. A more fundamental solution must be set up. This solution must be the establishment of a global network of areas to protect and conserve representative samples of the ecosystems of the world. Substantial progress has already been made towards the achievement of this goal, and most countries now have protected areas.

A secondary solution is maintaining animals and plants in zoos, botanical gardens, or even gene banks can be considered. A gene bank may work well for some species, although, when kept in storage, even the seeds of domesticated plants and their wild relatives lose genetic vigour.

The efforts described above are very limited in relation to the size of the problem.

Endangered Water Supplies

Water supplies worldwide are threatened with depletion and pollution. The major problem is the loss of watersheds through denudation of vegetation. The solution to this problem must come from the better use of land and the protection of crucial vegetation in the watershed areas.

The Exhaustion of Non-renewable Resources

The primary consideration here is the exhaustion of fossil fuels. The solution to this problem lies in the better use of the available fuel supplies, by increasing the efficiency of combustion, or by using alternative energy sources, such as wind or solar power or the use of all the above.

Environmental Weeds

Many garden plants escape into areas of natural vegetation, where they can compete or even completely take over from the native vegetation. The stability or balance of natural systems can be upset, causing radical changes, and as a result habitats for native fauna can be severely damaged. Environmental weeds can greatly reduce the variety of species present, and also may reduce access and recreational use, by creating impenetrable barriers of twining plants, or dense thickets.

Foreign plants will flourish without the pests and diseases that kept them in check in their original country, if suitable pollinators and seed dispersing animals are present, all at the expense of the native plants. A European broom for example, could replace a native wattle. Plants may spread by being dumped (common along railway lines, and in natural areas adjacent to residential areas) or by seed, often carried by birds. Another problem is that garden plants can sometimes cross pollinate with the local native (called indigenous) plants. This interbreeding results in hybrids which interfere with the natural evolution of the indigenous plants.

In the middle of suburbia, growing these types of plants is not generally as great a problem, but if a garden is near an area of native bush, there is a strong chance of garden plants escaping. Many road and rail reserves, foreshores and national parks are now infested with environmental weeds. The situation can be so bad that all weed control methods may be needed   including hand, chemical and biological control. The loss of natural ecosystems is a great cost to the community, in lost educational and recreational opportunities, the loss of indigenous plants and animals, as well as the public funds used (or not used) to control the problem.