Untitled Flashcards Set

Deforestation & Forestry

• Woods renewability depends on how you are cutting them down and at what rate 

• Forestry - the science or skill of growing and taking care of trees in forests, especially to obtain wood

• 4 ways of Forestry

  • Clear Cutting

    • Least expensive

    • Biggest environmental impact

    • Causes soil erosion 

    • Higher soil & water temperatures

    • Biodiversity negatively impacted

  • Shelterwood

    • Cut every so often trees

    • Little more costly 

  • Selective Harvest

  • Mixed Age management

    • Always make sure that there is young trees and trees of all ages

Fire

• Fires in ecosystems can be harmful or beneficial

• Fires are inevitable in some regions (periodically dry, but lots of growth)

• High fuel load

  • In NC: Sandhills (Longleaf pine), south-facing slopes of piedmont & mountains (shortleaf pine)

    • South-facing things get more sun and therefore get drier

• Crown Fire: fire that gets up to the tops of the trees

  • Destructive, hard to stop, long time for recovery

• Ground Fire: sweeps across the base of the forest

  • Easily stopped (wetter areas, creek, road)

  • Makes crown fire less likely

  • Increased growth on the forest floor

  • Makes tres widely spaced

• Prescribed Fire/Controlled Burn: intentional ground fire with setup fire breaks (fuel removed)

• Ponderosa Pine

  • Looses lower branches when it grows to not allow crown fires

  • Insulating bark

Aquatic Ecosystem

• Abiotic Factors

  • Depth

  • Light

  • Temperature

  • Salinity

  • Tubidity (“cloudiness” due to suspended solids) 

  • Nutrients (Especially Nitrogen & Phosphorus)

• Benthic environment - Seafloor/lakebed

• Pelagic environments - Open water

• Nekton -  Organisms that have the ability to swim against currents

• Plankton - Free-floating organisms that cannot swim against currents 

• Primary Productivity

  • Primary Producers

    • Phytoplankton

    • Macroalgae

    • Seagrass

  • All depend on light

  • Coral - animal that produces a hard shell and lives symbiotically with phytoplankton attached to its body

• Depth & Light

  • Photic Zone - depth at which photosynthesis can take place. Varies, but in open ocean it averages 200 meters

  • Primary production in the photic zone supports deepwater food webs, because dead organisms sink below the photic zone 

• Turbidity & Light

  • Highly turbid waters limit light penetration

  • May be caused by suspended sediment ( silt,clay) from rivers, or phytoplankton in high-nutrient waters (also frequently caused by rivers)

  • Coral reefs are very intolerant of turbid waters. Seagrass and macroalgae are also limited by turbidity. Vulnerable to sediment and nutrient pollution

• Estuary

  • Where freshwater streams and rivers enter the ocean

  • Brackish salinity - salinity intermediate between ocean and freshwater

  • Importance

    • They are the nursery of the ocean

    • Nutrient-rich and very productive 

• Salt Marsh

  • Most common ecosystem in estuaries in areas of cold winters

  • Grasses are dominant

    • Roots hold the marsh mud together

• Mangroves

  • Located in very warm areas with mild winters

  • Have trees that can handle brackish salinity

  • Tree dwelling animals like primates and parrots share the ecosystem with aquatic animals and wading birds

  • Store 3-5x more carbon than tropical rainforests

• Fisheries

  • Located over shelf waters, where nutrients are abundant or where light hits the seafloor, including estuaries

  • Where there is upwellings