logging forests chapter 3.10. logging forests forests regulate climate by recycling water and carbon...

LOGGING FORESTS

Chapter 3.10

Logging Forests

• Forests regulate climate by recycling water and carbon dioxide.

• On hot days a large tree may absorb 5.5 tons of water from the soil and release it into the atmosphere through its leaves in a process called transpirationtranspiration.

FORESTRY PRACTICES

• Forests are logged by two different methods:

• CLEAR CUTTINGCLEAR CUTTING – every tree is cut down whether it has value or not and the unnecessary trees are left

• SELECTIVE CUTTINGSELECTIVE CUTTING – only certain trees are cut down depending on what they are needed for ( firewood, paper, furniture or lumber)

EVALUATING A CLEAR-CUT

• Company’s point of ViewCompany’s point of View

• 1. Less expensive – provide timber or pulp at a more competitive price

• 2. safer for workers

• 3. Company can choose which trees to plant – get better price for when the area is logged again in the future.

EVALUATING A CLEAR-CUT

• Ecological Point of ViewEcological Point of View• 1. Soil erosion and runoff into local streams

increases – increasing growth of algae• 2. Eroded soil forms sediment in streams,

affecting spawning areas of fish.• 3.Removal of vegetation on the ground exposes

the soil, increasing the warming of the area in summer and cooling in winter

• Exposure also increases water loss from the soil.

EVALUATING A CLEAR-CUT

• Clear-cut creates completely different abiotic and biotic conditions in the area.

• Ecosystem must change – therefore the community must change.

• Loss in forest plants – loss of forest animals

• Ecotones are also created between the remaining forest and the newly cut area.

DEFORESTATION

• Is any removal of trees from the area of land.

• Deforestation affects the environment in many ways:

• 1. Erosion – tree roots hold soil in place during heavy rains

• 2. Nutrient Loss – nutrients are washed away with the rain instead of being absorbed by the trees

DEFORESTATION

• 3. Temperature Change – the ground will absorb more energy (albedo effect?) and affect organism functions

• 4. Carbon Cycle Change - no trees to take in CO2 and to make O2

• 5. Food Web Changes – less producers at the beginning of food chains

• 6. Habitat loss – nesting areas and ground cover disappears

HANDOUT

• Read the handout “The Forests of the Temagami Region”

• Answer the questions at the bottom.