Many thanks
@IinaLohi for your reply.
I agree that the 3-30-300 Rule is a great rule of thumb, and that Urban Landcare can potentially help to implement it at the neighbourhood scale. However, a lot of work and support would be needed, with the 2014 graphic below showing that Australia's two largest cities were well below 30% tree canopy cover.
You also make the very good point that tree canopy cover isn't going to be a relevant measure for some native vegetation types. For example native grasslands, which are a common pre-European vegetation type in and around Melbourne and Canberra. For vegetation types such as grasslands, grassy woodlands, wetlands etc. a better measure might be 30% of land area in reserves rather than 30% tree canopy cover. This 30% figure would align with the findings of
CSIRO's work in grazed landscapes. Achieving this 30% figure would require large reserves, but it's possible. An example is the 770 hectare
Saihantala Ecological Park, a grassland and wetland reserve
located in Baotou, a city with a similar population as Brisbane. Australia unfortunately has a mixed history in regard to urban grassland conservation. Canberra has a
grassland conservation strategy which includes several substantial grassland reserves, however, grassland conservation efforts in Melbourne are being
heavily criticised.
Urban greening can also be achieved in even the
highest density locations through the utilisation of rooftops and balconies.