Chapter 18 Lesson 3 Land resources

Vocabulary deforestation: the cutting of large areas of forests for human activities ore: a deposit of minerals that is large enough to be mined for a profit

Land as a Resource Natural resource: Something from Earth that living things use to meet their needs Living space: natural habitats and land with buildings, sidewalks, parking lots, & streets

Land as a Resource (continued) Cities make up only a small % of land use in the U.S.; most land’s used for agriculture, grasslands, and forests.

Forests and Agriculture Forests have regrown since 1920, but the new trees are not as tall as the original trees.

Forests and Agriculture Forests are cut down to get wood for fuel, paper products, and wood products and to clear land for development and agriculture.

Forests and Agriculture a. The amount of land used for agriculture has decreased in recent years. b. Crop production has increased in some parts of the country due to advances in farming techniques.

Forests and Agriculture Certain minerals are mined to make products that people use every day. a. Deposits of minerals that are large enough to be mined for a profit are called ores. b. Ores such as bauxite and hematite are called metallic mineral resources and are used to make metal products. c. Nonmetallic mineral resources include sand, gravel, gypsum, halite, sulfur, and fluorite.

Advantages and Disadvantages of Using Land Resources One advantage of using land resources is that they are widely available and easy to access. Another advantage of using land resources is that crops and trees are renewable—they can be replanted and grown in a relatively short amount of time.

Advantages and Disadvantages of Using Land Resources (continued) Disadvantages of using land resources include the following: minerals are nonrenewable and using land resources can result in deforestation and pollution. a. The cutting of large areas of forests for human activities is called deforestation. b. Deforestation can lead to soil erosion and loss of animal habitats.

Advantages and Disadvantages of Using Land Resources (continued) c. Deforestation can affect global climates because trees remove carbon dioxide from the atmosphere during photosynthesis. d. Runoff that contains chemicals from mineral mines can pollute soil and water. e. Chemical fertilizers in runoff from farms can pollute rivers, soil, and underground water supplies.

Managing Land Resources There is competition for space because the amount of land is limited. On preserved land, logging and development is banned or strictly controlled. According to government regulations, public and private mined lands must be restored.

Managing Land Resources (continued) Land used for farming and grazing can be managed to conserve soil and improve crop yield. Organic farming techniques do not use synthetic fertilizers. By recycling yard waste and vegetable scraps, you can help conserve land resources.

Where do aluminum and iron come from and what are they used for? Aluminum comes from the ore bauxite and is used for products like cars and appliances. Iron comes from the ore hematite and is used for products like nails and faucets.