I was watching a documentary about abandoned soviet structures and cities. At the beginning of the documentary a piece of drone footage is shown featuring the abandoned flats of pripyat from above. While watching it i noticed something very peculiar, there were several fullgrown shrubs and even a tree growing on top of the roofs of the flats.
The red arrow points at a berch tree that's apparently growing on top of the rooftop as well. How is such a large plant able to grow there? I've seen plants grow in strange places in my own city Groningen as well. Here's an example of small shrubs that managed to grow out of asphalt.
Here are a couple of pictures of 2 seedlings that are growing out of a hole of a rotten piece of wood. The hole does not go all the way through the wood, so the roots are not in contact with the soil.
According to ChatGPT one explanation could be that over time, organic debris like leaves, bird droppings, and dead insects can accumulate on surfaces. This can decompose and form a thin layer of organic matter that serves as a growing medium for plants. But I can't believe that a tree such as the birch tree in the first video still could grow so large using only organic matter that deposited on the rooftop.
So how does this work? Can trees and shrubs use different materials like asphalt or roofpanels to extract nutrients from when there is little to no soil available? If so, how do they do it?