This study simulates changes in the patterns of specialization that maximize total GDP in trade areas when Japan, the US, and China simultaneously implement targeted reductions in intermediate demand for electricity. The following conclusions are drawn from the simulation results. As the reduction rate of intermediate demand for electricity in Japan decreases (i.e., as the degree of Japanese targeted reduction increases), 1) the comparative disadvantage of the Japanese forestry sector changes to a comparative advantage; 2) the weak comparative advantage of the US forestry sector changes to a comparative disadvantage; 3) US agriculture never loses its comparative advantage; 4) the comparative advantages of Japanese metal products and transportation equipment sectors change to comparative disadvantages; and 5) corresponding to the change in item 4, the comparative disadvantages of US metal products and transportation equipment sectors change to comparative advantages. These results hold not only in the case in which only Japan imposes restrictions but also in the case in which the US and China also impose restrictions simultaneously. Moreover, these results hold within wide ranges of reduction rates in the US and China.
This study examined the effects of a new subsidy system, stand conditions, and forest road network on annual supply potentials and available amounts of timber and logging residues. Excepting a few municipalities, available amounts of logging residues with the new subsidy system were smaller than those with the old subsidy system because the subsidy in the new system was received for the thinning operations with more than 5 ha operation site areas and more than 10 m³/ha extracted volumes. Therefore, available amounts are expected to increase as a result of adapting forestry operation site areas and operation systems to the new subsidy system. According to stand conditions, final felling operations with Japanese cypress, larger supply potentials, gentle terrains, road sides, and shorter transporting distances led to a higher ratio of profitable sub-compartments. Larger areas are expected to have an increased ratio of profitable sub-compartments. However, almost all profitable sub-compartments were less than 4 ha because forwarding distances were estimated as average distances from the landings to all grids within the sub-compartments in this study, and larger areas tended to have longer forwarding distances and subsequently, higher forwarding costs. Since forest road networks were relatively well established in Tochigi prefecture, 73% of supply potentials and almost all available amounts of logging residues were within 100 m from existing roads.
The objective of this study was to develop a new method for modeling the site index using the spatial distribution of canopy height derived from digital stereo aerial photos. The study area was Shimanoto District, Kochi Prefecture, Shikoku Island, Japan, and the target species was sugi (Cryptomeria japonica). A data set of a digital canopy height model (DCHM), which was treated as dominant tree height, and tree age were prepared at 50-m resolution. DCHM was derived as the difference between digital surface height model (DSM) and digital elevation model (DEM). Topographic factors derived from digital terrain analysis using 50-m resolution DEM were incorporated into the data set. A model combining the site index and height curve was developed for predicting site index for a specific site using topographic factors and dominant tree height for specific ages at the site. Using the data set, the proposed combined model was parameterized by Bayesian calibration. Markov chain Monte Carlo sampling did not converge, and the goodness-of-fit of the developed model was poor, although the predicted height growth pattern and site index using estimated parameters were reasonable.
The effect of spacing shape is one of the major problems of tree growth modeling. Nelder (1962) proposed an area fixed, shape change plot design (design Ib) to solve the spacing-shape problem. We analyzed periodically measured data from a design Ib type plot of Picea glehnii planted in the Hitsujigaoka experimental forest at the Hokkaido Research Center of the Forestry and Forest Products Research Institute. As a preliminary result, spacing shape affected growth in both DBH and height.
In regions of heavy snow, Japanese cedar shows “basal sweep” due to snow pressure damage and experiences irregular growth. We reconstruct the shape of basal sweep of Japanese cedar for the first time by applying a motion capture system for three-dimensional (3D) visualization. Based on the reconstructed shape, we discuss the eccentric growth and volume variation involved in the basal sweep of Japanese cedar. The location coordinates of the basal sweep stem and ground surface were measured using a magnetic digitizer and the annual ring coordinates of the disks were converted using a translation and rotation matrix. The coordinates of the annual rings were converted into corresponding locations in the stem with a custom software program. This method afforded a view of the relationship among the annual ring width, shape of the trunk, and standing tree condition. Three patterns of eccentric radial growth were observed in the basal sweeps of young trees, and these patterns were distinct depending on the stem height. The tree volume of young trees was over 27 times that of old trees, but the basal sweep volume showed only a six-fold difference. The mean ratio of the basal sweep volume to total volume was 68.8% for young trees and 25.3% for old trees.
A central assumption in classical optimization is that all the input data of a problem are exact. However, in many real-world problems, the input data are subject to uncertainty. In such situations, neglecting uncertainty may lead to nominally optimal solutions that are actually suboptimal or even infeasible. Robust optimization offers a remedy for optimization under uncertainty by considering only the subset of solutions protected against the data deviations. In this paper, we provide an overview of the main theoretical results of multiband robustness, a new robust optimization model that extends and refines the classical theory introduced by Bertsimas and Sim. After introducing some new results for the special case of pure binary programs, we focus on the harvest scheduling problem and show how multiband robustness can be adopted to tackle the uncertainty affecting the volume of produced timber and grant a reduction in the price of robustness.