Ancient Trees in Nihonmatsu
ancienttrees.app

Kohata no O Sugi (Kohata's Great Cedar)
Japanese Cedar (Cryptomeria japonica). roughly 780 to 800 years. Free, shrine grounds. Reached via the shrine's main approach (omote-sando) off route 117, a stone stairway from the first torii up Mt Kohata; parking (~10 cars) near the approach entrance and ~5 more near the second shrine office. This is a genuine climb, not a flat stroll, but no permission or ticket is needed.

Sugisawa no O Sugi (Sugisawa's Great Cedar)
Japanese Cedar (Cryptomeria japonica). roughly 1,000 years (city and prefecture both use this figure; one source gives a wider possible range). Free, public land (managed by the Sugisawa administrative district on national land). Bus: from Nihonmatsu Station take the Sugisawa bus to the 'Sugisawa Taigi' stop, then 5 min on foot. Car: about 30 min from Nihonmatsu Station or 35 min from Nihonmatsu IC (Tohoku Expressway).