Gross primary productivity
Net Ecosystem Productivity
Tells whether a forest is a carbon source or sink
What’s more productive a tropical rain forest a a temperate forest or the open ocean? Tropical versus woodlands and grasslands?
Tropical rain forest is 50% more productive than a temperate forest but not as productive as the open ocean.
3-5x as productive as woodlands and grasslands
How much of the GPP of a rainforest is respirated?
Terrestrial ecosystem model
Uses five components
- carbon in veg
- carbon in soils and detritus
- N in veg
- N in soils and detritus
- available inorganic soil N
- soil texture
- veg type
What is a carbon sink?
More sequestration less respiration
Leaf area index (LAI)
The lead area above a square meter of forest floor.
High in the tropics
Water use efficiency
Ratio of water used in plant metabolism to water lost via transpiration
Diffuse radiation (solar dimming)
Increased light use efficiency due to increasing fraction of diffuse light (dust, aerosols)
May reduce c losses via photorespiration (temp stress)
Wet tropics benefit greatly
Disturbance recovery hypothesis
Lighter wooded species decline and heavier wooded species increases proportionately with succession
Resource availability hypothesis
No relationship between C stocks and wood density
Effects of deforestation on climate
Temperature increase in the tropics by 2 Celsius and drier air above tropics and drought in northwest America
Increased temp effects
Higher tree mortality
Theory of island biogeography
With time areas or islands will attain dynamic equilibrium
How is Chagas’ disease being effected by fragmentation
Lives in palm oil trees
More palms =more bugs that are infected = more people with the disease
How is soil formed?
P-parent material C-climate O-organisms R-topography T-time
Role of n and p in tropical soils
N is limiting in temperate and high latitude
P is limiting in lowland tropics
N constrains growth due to high P in montane tropical forests
Grazing and fire on North American vs South African Savannah
SA has more history with fire and grazing also larger herbivores affecting the grassland in different ways than that of a NA grassland
Net primary productivity