DEFORESTATION

Presentation prepared student 11-A Yevmentsev Dmitry

Deforestation - the process of converting forested land in occupied land without trees such as pastures, vacant lots, farmland, cities and more.

Reasons deforestation: deforestation without sufficient landing

new trees fire hurricanes flood acid rain change in the hydrological regime reduced resistance to phyto disease other

The effects of deforestation: loss of biodiversity enhancement of the greenhouse effect depletion of timber landslide

Active deforestation in Ukraine began in the 30s of the XVIII century, due to the resource needs of the military, construction, and production in the Russian Empire.

According to the archives of the Central State Military Archives of the USSR at this time every year only on the gums floated up to 200 thousand logs of wood. In Western Ukraine at that time cut down the forest Izyaslav and Volyn provinces.

During the XIX and early XX centuries forest-Ukraine has decreased by 30.5%. Particularly intensive operation took place forest ecosystems in the postwar years. Thus, due to the mass of solid Ruban destroyed three-quarters of woodland on the slopes of the Carpathians.

During the period of 1946-1970 years in the Ukrainian Carpathians cut down more than 120 million m3 of high quality industrial wood and cutting the main use exceeded the calculated allowable cut in 2,5-4,0 times. Since 1960, the area of forests in Ukraine is gradually increased by planting forests in areas malolisystyh south.

Earlier forest cover area in the world was 80 million km ², it is now reduced to 30 million km ², is destroyed by two-thirds. Over the past 200 years, forest area decreased at least 2 times.

Only for 15 years (1990-2005 pp.) Lost planet more than 125 million hectares of forest, is about 8 million hectares lost annually. At present, the Earth is destroyed 14 million hectares. forest each year. Of these, 130 000 km ² (0,8 - 2%) of tropical forests, which are the "lungs" of the planet. Historic logging is 5 billion m ³.

The annual volume of timber harvesting in the world greater than the annual increase of 20-24%. With 80% of the wood logs get low-quality wood and only 20% of the area - industrial wood quality.

The largest area of forest preserved in Eurasia. This is about 40% of the world's forests and almost 42% of the wood stock, including 2/3 of the volume of wood most precious species. Least forest cover is Australia.

In most developing countries, cutting is performed by the use of wood as fuel, as forests are destroyed to obtain arable land. Reduced and degraded by atmospheric pollution and forest soils in developed countries. There is a massive shrinkage of the treetops, resulting acid rain damage.

Scientists found that after logging infiltration properties of the soil are reduced by 3.5 times, and the intensity of water erosion is increased by 15 times

This situation could not go unnoticed. The most advanced and at the same time treeless country are conducting in the life of the program for the conservation and expansion of forests. For example, in Japan and Australia as well as in some Western European countries, the area under forests remain stable.

Methods of dealing with deforestation areas are banning logging, unions play assistance to poor countries in the fertility of their lands, the development of fertilizer industry, food aid.

Take care forest!!!