Forest resource analysis of private forests in Toyama Prefecture, Japan, using National Forest Inventory plot data
2020
Nakajima, H.
Forest resource analysis of private forests in Toyama Prefecture, Japan, before (1999-2003) and after (2012-2015) an epidemic of Japanese oak wilt disease was conducted using data from 113 plots in the National Forest Inventory. After the epidemic, total volume (growing stock) of the study region was estimated as 45,519 ± 6,974 thousand cubic m (± 95% confidence interval) and composed of 54% plantation forests and 46% natural forests. Volume change rates between before and after the epidemic were estimated as 449 and 120 thousand cubic m/yr for plantation and natural forests, respectively. These estimated values were 115-128% of the values computed from forest registers ("Shinrin-bo"), suggesting that empirical yield tables of forest registers underestimate stand volume increments. Cryptomeria japonica occupied about 90% of the total volume of plantation forests. In natural forests, first, second, and third most dominant species were Quercus crispula, Fagus crenata, and Q. serrata, respectively, before the epidemic, while F. crenata, Q. serrata, and Q. crispula, respectively, after the epidemic; the total volume of Q. crispula decreased by 56% during the epidemic. Mean stand volumes were 478 cubic m/ha for plantation forests and 191 cubic m/ha for natural forests. Mean stand volume increments were 8.02 cubic m/ha/yr for C japonica plantation forests and 2.81 cubic m/ha/yr for Q. serrata natural forests. The estimated volume, vertical distribution, and frequency of appearance for each tree species appeared in this study were revealed as basic information of regional forest resources.
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