Biological resources are divided into plants and animals. Relationship between the biomass of animals and plants shown in the pie chart.
Plant resources are wild and cultivated plants. Cultivated plants in the world is much smaller than the wild. This map shows the eight centers of origin of cultivated plants, isolated and studied by Academician NI Vavilov. For each center are examples of cultivated plants whose origin is connected with this territory.
wild plants are concentrated mostly in forests, making forest resources. Forests on the globe form two zones:
North - forests of temperate and subtropical climates, with coniferous trees;
south - subequatorial forests and the equatorial belt of deciduous trees.
countries outside the boundaries of forest belts, suffer from a lack of forest resources.
Indicators of forest area is forest cover (the ratio between the area of forests and the total area in percentage), and timber reserves. The average forest cover of the globe is 30%. In South America, this figure reaches 52%, and in North Africa and the Gulf of 1-5%.
largest forests are concentrated in Russia, Canada, Brazil, the United States.
forest area of the northern belt of the middle of the XIX century. not significantly decreased, but the southern belt of the forest are rapidly disappearing. Causes depletion of "green lungs" of the planet are shifting cultivation, increasing exports of wood and use it as fuel.