The term 'Hazel Tree Relative' can be solved by the crossword solution 'ALDER' (5 letters). ALDER is a genus of trees and shrubs in the birch family, Betulaceae. It is native to temperate and subarctic regions of the Northern Hemisphere. ALDER trees are often found near streams, rivers, and wetlands, and they are known for their fast growth rate and ability to thrive in wet soils. ALDER is closely related to the hazel tree, and both species are used for medicinal purposes.