Based on the field survey and review of past studies, we summarized nest and roost tree characteristics of the Black Woodpecker (Dryocopus martius L.) in Honshu, Japan. We obtained quantitative information on ten nest trees and three roost trees of the Black Woodpecker in the Shirakami Mountains, on Mt Minami-Hakkouda, Aomori Prefecture, and on Mt Moriyoshi, Akita Prefecture. We established a 0.25-ha (50 × 50 m) plot around each of four nest sites. All trees with girth at breast height (GBH) ≥ 15 cm were identified, mapped, and tagged, and their GBH was measured. In addition to this, we reviewed past studies and summarized knowledge of Black Woodpecker nest and roost tree characteristics in Honshu, Japan. All nest and roost trees were live beeches located in pure beech stands. The mean diameter at breast height (DBH) of the nest trees in Honshu was 68 cm (SD: ±9.8 cm). 92% of nest trees ranged from 50 to 80 cm in DBH. The roost trees also fell within this range (mean: 66 cm, SD: ±6.2 cm). Cavity entrances were not oriented towards a single direction, but were mostly oriented in accordance and significantly correlated with the slope direction. 69% of nest trees were used continuously for more than 2 years by the Black Woodpecker.

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Natural regeneration and growth of Betula maximowicziana was investigated in a Larix kaempferi plantation containing B. maximowicziana seed trees after intensive thinning in which about 50% (in number) of L. kaempferi trees were felled. Clearing of subcanopy broad-leaved trees and undergrowth vegetation was also carried out. In part, slash removal was carried out by a wheel tractor, which unexpectedly caused ground surface disturbance by removing litter layer in a considerable area. Fourteen years after the thinning, regenerating trees of B. maximowicziana, Quercus crispuia, Magnolia hypoleuca, Morus australis, Padus grayana, etc. formed under layer of the double-layered forest. Betula maximowicziana was the most dominant species within the under layer, around 10 m in height, reaching up to the top of the crown of the under layer through vigorous growths, although almost regenerating trees were located beneath the canopy and some were overtopped by the crown of L. kaempferi. They were found all over the experimental area with density of 166 ha^-1, but their density was significantly higher in the part where the slash removal had been performed by the tractor, compared with the part where it had not been performed. The ground surface disturbance by the tractor seems consequentially to have brought effects of scarification which facilitate the emergence and establishment of B. maximowicziana seedlings. Intensive thinning accompanied by ground surface disturbance is likely to be effective in regeneration of B. maximowicziana in L. kaempferi plantations containing B. maximowicziana seed trees.

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