Green infrastructure are foundational services that use natural elements such as vegetation or that are relatively environmentally friendly as compared to conventional infrastructure. This can be contrasted with "grey infrastructure" made with industrial materials such as concrete that has dominated in the past. Green infrastructure includes the simplest of infrastructure such as an urban forest and the most complex of infrastructure such as modern buildings with maintainable greenwalls. The following are common types of green infrastructure.

Bioengineering for stabilizing slopes and reducing soil erosion	Bioswales
Blue roofs	Community gardens
Composing	Constructed wetlands
Fish passages	Green alleys
Green railway tracks	Green roofs
Green school yards	Green walls
Greenways	Habitat corridors
Habitat restoration projects	Living shorelines
Pedestrian-friendly streets	Permeable pavement
Protected conservation areas	Rain barrels
Rain gardens	Rainwater harvesting
Reforestation & afforestation	Riparian buffers
Stream restoration	Terracing
Tree-lined streets	Urban forests
Urban parks	Urban wetlands
Water management infrastructure	Wildlife crossings

Below is an example of a green roof made with moss. This is lightweight and low maintenance but provides insulation and cooling effects. This would also be viewed as a blue roof because the moss will reduce and delay the flow of stormwater from the roof.

Summary

Green infrastructure are foundational structures and services that are literally green such that they are made with natural elements. This term is also used for infrastructure that is relatively environmentally friendly such as cycling infrastructure.