This data publication contains regeneration data collected at the Holt Research Forest (HRF) in Maine between 1984 and 2010. The study area is comprised of 40 hectares divided into 1 hectare blocks (4-0.25 hectare quadrats), the western half where forest management (group selection harvest in 1987/1988 on 10 of 20 hectares) is practiced and the eastern half where no manipulations are allowed. There are three different types of regeneration plots inventoried periodically to evaluate the status of regeneration from seedling to sapling size over a large portion of the study area. Four square meter (4 m²) subplots are designed to assess tree regeneration at the scale of seedlings and saplings < 1.5 centimeters diameter at breast height (DBH). The number found in various height classes by species are provided for 1984, 1992, 1997, 2004, and 2009. The 25 square meter (25 m²) plots are designed to assess tree regeneration in response to forest canopy gaps (harvest, ledge, and tree gaps) versus intact canopy. These data include the number of saplings counted in size classes (0.5 meters tall to 9.49 centimeters DBH) by species, along with an assessment of damage in 1997, 2002, and 2010. Thirdly, the 200 square meter (200 m²) plots are designed to assess tree regeneration at the scale of saplings 1.5-9.49 centimeters DBH. For these plots the number of saplings counted in 1 centimeter DBH classes by species are provided along with an assessment of condition (not all years) in 1984, 1992, 1997, 2004, and 2009.