Abstract
There are many broad-leaved forests in Japan that were formerly managed for charcoal production, which have been abandoned for decades. Appropriate thinning can revitalize these forests if the cost balance of the management is positive. Two critical elements are the construction of spur roads to facilitate mechanized harvesting operations and management planning that considers stand properties such as the growing stock, species, and tree size distribution. We surveyed three abandoned former broad-leaved coppice stands; one coastal, one cool temperate and one warm temperate. The stock in all three stands exceeded 300 m3 ha-1, two- to three-fold the official forest registry data estimates. The dominant species in terms of tree numbers are Castanopsis sieboldii, Pieris japonica, and Quercus glauca. Medium-sized trees involve those well suited for firewood, i.e., Quercus acuta, Quercus glauca, Quercus serrata, etc. Each plot contained a few large trees that potentially have a high market value, e.g., Cinnamomum camphora, Zelkova serrata, Abies firma, etc. The average income from harvested trees was estimated to be 10200 JPY (Japanese Yen) m-3, whereas the thinning costs would be 3200 to 5400 JPY m-3, with the additional spur road construction costs. The management cost balance of a broad-leaved stand in a 60 year rotation was evaluated with both Net Present Value (NPV) (for interest rates of 1, 2, 3, and 4%) and Internal Rate of Return (IRR). This balance was compared with that of a typical plantation stand of Japanese cedar (Cryptomeria japonica) and of a fast-growing plantation stand of Chinese fir (Cunninghamia lanceolata). The estimated NPVs were largest for the fast-growing plantation stand, second largest for the typical plantation stand, and lowest for the broad-leaved stand with a NPV interest rate of 1 + %. However, the IRR of the broad-leaved stand was the highest, followed by that of the fast-growing plantation stand, while the IRR of the typical plantation stand was the lowest. This order was the same for NPVs assuming higher interest rates. 1 JPY=0.0086 € on April 29, 2019.
Highlights
Natural woodlands comprise 42% of Japan’s forest area and most consist predominately of broad-leaved species (Forestry Agency 2018)
Croat. j. for. eng. 40(2019)2 changed to fossil fuel, many broad-leaved forests were abandoned, and have remained unmanaged in the decades since
Problems such as oak disease and invasion of bamboo have occurred in these abandoned stands because management practices such as thinning were not applied
Summary
Natural woodlands comprise 42% of Japan’s forest area and most consist predominately of broad-leaved species (Forestry Agency 2018). These were historically managed for the provision of woody fuels such as firewood and materials for charcoal production. 40(2019) changed to fossil fuel, many broad-leaved forests were abandoned, and have remained unmanaged in the decades since. Problems such as oak disease and invasion of bamboo have occurred in these abandoned stands because management practices such as thinning were not applied. It is established that thinning can revitalize such abandoned woodlands and enhance CO2 sequestration (Kominami 2019). Yoshimura Assessment of Broad-Leaved Forest Stand Management: Stock Densities, Thinning ... Yoshimura Assessment of Broad-Leaved Forest Stand Management: Stock Densities, Thinning ... (365–375)
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