Since its breakthrough 2001 album, “Echo Echo,” Richmond's Carbon Leaf has steadily landed in a small sweet spot of professional comfort. Scoring the occasional radio hit, it may never sell out stadium-size arenas or top the charts for weeks on end, but its brand of alternative roots pop is immediately recognizable and consistent, generating gradual but increasing numbers to the group's already loyal fan base. Recently parting ways with longtime label Vanguard to pursue independent releases, and concentrating on more frequent output, Carbon Leaf's genre-mixing of Americana, Celtic, country, folk and other is hitting a rejuvenating stride. Following its recent EP “How the West Was One, Vol. 1” released earlier this year, the band has hit the holiday spirit with an album entitled “Christmas Child.” Carbon Leaf is scheduled to perform at the National on Saturday, Dec. 18, at 7 p.m. $18-$21.