in Thoreau’s Journal:

In warmer autumns, if I remember rightly, [the hickories at Poplar Hill] last several weeks later than this in some localities, one succeeding another with its splendid glow, an evidence of the genialness of the season.  In cool and moist places, in a genial year, some are preserved green after others have changed, and by their change and glow they prolong the season of autumnal tints very agreeably.