Folk - yes; since the age of 14 (1975) with roots going back through Folk-Psychedelic-Pop since the age of 10 (it was the Strawbs who got me into dulcimers with Witchwood in 1971 touching on earlier native inspirations with Northumbrian Smallpipes & Highland Bagpipes - especially Piobaireachd, which isn't folk, though it is traditional) - although never exclusively: I have parallel passions for free-jazz, improv, electronica, Kraut, ethno, medieval, punk, metal, renaissance, post-punk, avant garde, prog, baroque, exotica, hip-hop, etc. etc.
Beard - yes; never been keen on shaving, bearded since 15 with a brief period shaven circa 1999-2002, aged 38-40.
Sandals - yes; and I wear them with boot socks in winter, regardless of the weather, but if things get too extreme I wear my Doc Martens, but never without my Barbour; an essential pairing - like I only drink tea with fish & chips.

The connection? An inner yearning for the primal wilderness.