The most well known series of disasters related to rain forest ecology are in the deforestation of rain forests. The cycle of full forest through to deforestation to desertification is a good way to explain the ecology of the rain forest in a way that will stay on the mind.
The canopy of the rain forest prevents jungle formation, as it shuts out light to all but the tallest trees. When the canopy is destroyed, either through disease, lack of rainfall or from man made disasters, the light reaches all of the dormant or stunted plants, which can now grow into a dense, impenetrable thicket.
When the dense, impenetrable thicket is removed, the soil is left. The soil is then vulnerable to the raindrops which are plentiful and which impact the rich humus at great force, first saturating the soil, then creating gullies and rills which further erode as the concentrated water gains more force. Or, the water flows in great sheets over the saturated soil, dragging the fertile soil with it and leaving sand and heaver particles.
The sand and heavier particles are no longer able to sustain plant life or hold together from root structures. The smaller particles of sand can be easily lifted and remain in suspension in the air for a long time, followed by heavier particles which can be carried for long distances, leaving earth that is without any ability to sustain plant life or to resist collapse of hillsides. Desertification, and the end of any hope of restoration without bringing in Superfund levels of riparian restoration is the final stage.
The microbes, fungi and animal life that was dependent upon the food and shelter of the canopy and of the plants of the ground now have to relocate to new grounds, if they can. But the new grounds are now crowded with animals which already need a certain amount of territory for the optimal survival of each pack or family or flock. The ensuing competition for living space can become deadly and destructive as the masses of displaced animals and birds must fight to establish themselves in new and unfamiliar surroundings which already may not have enough food and sustenance to support the established life forms and the newcomers as well.
As a result, the ecology of the temperate and tropical rainforests of the world can be easily known as we watch the progress of devastating and catastrophic deforestation. Where we see outstanding forest management, we see that trees, animals, ground plants, fungi, insects and birds all exist, but within the limits of a particular territorial ability to get enough light, get enough food, and to get enough shelter from the elements and from predators.
The earth is replenished with dead and decayed plant and tree material, making it rich and highly viable for sustaining plant life. The soil is held together and will not erode. The insects, molds and fungi break down the dead material. The beetles, flies and wasps eat the dead flesh so that dead animals do not rot for extended periods, leaving disease. The birds keep the seed and insect populations in balance. The larger animals keep the rodent population in check. The fish have healthy and safe waters for propagation and are wily enough to not be eaten into extinction.
Conversely, attempts by humans to manipulate one or the other factor of tropical and temperate rain forests may have unintended and unanticipated consequences, as the balance of life is changed. Some tropical and temperate rain forests are, for example, destined to die out and to evolve into grasslands. Others will develop life replenishing and flourishing jungles at their fringes. Attempts to prevent a natural process by killing or helping one or the other might cause problems that were never anticipated.
