This is the 3136th most frequent Turkish word.
devrilen
"Devrilen" means "overturned" or "fallen over" in English.
Here, 'devrilen' is an adjective formed from the verb 'devrilmek' (to topple), used to describe the tree.
Devrilen ağaç yolu kapadı.
The fallen tree blocked the road.
'Devrilen' describes the wall that has been toppled, acting as a characterized noun adjunct.
Fırtına nedeniyle birçok ağaç devrilen duvarın üstüne düştü.
Due to the storm, many trees fell onto the toppled wall.
In this case, 'devrilen' describes the bus that has overturned, providing specificity to the subject being discussed.