In ecology, sustainability is the capacity for a biological system to remain diverse and productive indefinitely

• A sustainable yield is the amount of a natural resource that can be taken from an ecosystem without reducing the base stock (it is replaced as rapidly as it is harvested)
  

Resource Harvesting

Softwood timber (e.g. hoop pine) is sustainably harvested at many plantation sites within Australia

• Selective felling of trees ensures there are gaps in the canopy to promote regrowth and minimises soil erosion
  

• Trees may be selected according to age to ensure there are enough trees remaining to flower and produce seeds
  

• Replanting and regeneration policies and practices ensure that logging does not outpace new growth 
  

• Ground measurement techniques and spatial modelling may be used to monitor and evaluate forest cover

Marine fish (e.g. bluefin tuna) are sustainably harvested from the oceans surrounding Australia

• Catch sizes are limited to prevent population decline (maximum sustainable yield should be half the carrying capacity of the species)
  

• Fishing vessels must be registered and certain oceanic regions are cordoned off for biological conservation
  

• Mesh net size restrictions prevent younger fish that are smaller in size from being captures (maintains potential for future reproduction)
  

• Closed seasons may be declared to allow for uninterrupted breeding periods during which fish can repopulate
  

• Fish farms may be used instead of open water fishing to allow for a level of control over the age at which fish are harvested