To assess ectomycorrhizal (ECM) fungal diversity in a suburban secondary forest, we surveyed sporocarps, ECM root tips, and sclerotia in a Quercus serrata dominated site in Ome Forest, Tokyo, Japan. Using line census and plot sampling, 766 samples (436 sporocarps, 327 ECM root tips, and 3 sclerotia) were collected. Based on a morphological classification and analysis of internal transcribed spacer (ITS) rDNA sequences, 159 molecular operational taxonomic units, 41 distinct fungal genera, and 23 fungal families were identified, most of which belonged to Amanita, Boletaceae, Lactarius, Russula, Sebacina, and Tomentella. While these fungal species were common and widely distributed in the forest, other genera, such as Rhizopogon and Suillus, were distributed locally in various parts of the census route and plots. Our results revealed abundant diverse ECM-fungal species in a suburban secondary forest subject to anthropogenic disturbance. Furthermore, hierarchical clustering analysis using species data obtained by plot sampling indicated that locally distributed fungal species characterized the community composition of each plot, although the plots share common groups occurring at high frequency. Differences in stand type, anthropogenic disturbance, and microtopography may have affected these community compositions.

The protection forest system has been playing an important role in the conservation of forests and forest land. This study aimed to clarify the operation of private protection forests and to analyze the relationship between private headwater conservation forests and forestry management in Hitachiota City, Ibaraki Prefecture. We conducted interviews and collected data from prefectural government officials and five forest owners. The main results are that the owners of private protection forests, which are managed for timber production income, generally own more than 100 ha of forest land, and the majority of such land has been designated as headwater conservation forests. A comparison of the average annual rates of forest clearcutting and thinning between protection forests and non-protection forests in Hitachiota in during the fiscal years from 2016 to 2020 showed that the rates of forest clearcutting and thinning were both higher for protection forests. The incentives for designating land as headwater conservation forest include exemption from property tax and deduction of inheritance tax assessments. We clarified that owners of headwater conservation forests are conducting timber production activities while trying to reduce their tax burden. The designation of headwater conservation forest is thought to contribute to the sustainable forestry management of private forests. However, since the tax incentives vary depending on the land designation, the area size of their forest holdings is the one of the factors that limited the number of forest owners who wish or need to have their land designated as protection forest.

Extending rotation age allows maintaining various types of artificial forests. Growth data for old forests are abundant for Cryptomeria japonica and Chamaecyparis obtusa, but not for Larix kaempferi. We examined the growth process and discussed the optimal rotation age of Larix kaempferi plantation in a heavy snowfall area within the Akita Prefecture in Japan. The plantation is composed of four study plots varying in thinning intensity and frequency in the early stage. At 120 years of age, stem density, mean DBH, and mean tree height were 160-240 stem･ha^-1, 45.8-56.0 cm, and 31.6-36.6 m, respectively. DBH increased vigorously in the last ten years, while tree height growth was suppressed due to snow damage. As a result, Larix kaempferi maintained periodic annual volume increment of 5.5-8.6 m³･ha^-1･yr^-1 in the last ten years. Thinning intensity and frequency did not influence the total stand volume including thinned volume (1,035-1,173 m³･ha^-1). Mean annual increment was maximal at around 60-90 of age, which suggests an optimal rotation age for this forest in terms of volume growth.