Did you have a specific tag in mind?

1) Closest match but still a garden (i.e. will be rendered exactly like now).
https://wiki.openstreetmap.org/wiki/Tag:garden:type%3Darboretum

2) 
https://wiki.openstreetmap.org/wiki/Tag:natural%3Dwood

3) Like this one?
https://www.openstreetmap.org/way/22984028