Three dimensional point cloud images of trees were obtained by using LiDAR (Light Detection and Ranging). In this study, light weight portable lidar was used. An operator walks along the target area and the lidar scans point cloud images. Each image is co-registered and a three dimensional image can be constructed. Lidar-derived tree trunk diameter estimation and its directly measured value were compared and the errors were examined when the distance from the target tree was changed. It was shown that the distance from a target tree should be as close as possible. When the distance is more than 80 m, the image generated from the lidar data is too unclear to estimate the tree trunk diameter. Then, walking and cars were adopted as a platform of lidar. Relationship between their moving speed and accuracy of lidar-derived tree trunk diameter estimation was examined. Finally, a site with vegetation was measured by walking and using a car and their obtained images were compared. The advantage of on foot as a platform is high-accuracy and accessibility to uneven grounds. On the other hand, the strong point of a car is less labor working and less time for measurement. Therefore, both walking and using a car are available for the platform of lidar.
Process-based ecosystem models simulate carbon, nitrogen and water cycles connected to ecosystem services such as wood biomass provisioning service (WPS), carbon sequestration service (CSS) and flood control service (FCS) in forests. They are potentially applicable to the comprehensive assessment of forest ecosystem services and their changes under climate changes and/or a variety of forest management. In this study, thinning and self-thinning processes were implemented to modified Biome-BGC (Machimura et al., 2016) to calculate timber volume and stand density changes by forest management. Moreover, we adjusted model parameters to reproduce the timber volume and stand density recorded in the yield table for Chamaecyparis obtusa private plantation in Hyogo as a case study. The improved model and adjusted parameters could reproduce the timber volume and stand density of 1 to 80-year stand. We analyzed changes of WPS, CSS, FCS and timber volume growth (TVG) under climate change (RCP8.5) and several forest management cases in Hyogo. Among different rotation periods (60, 80 and 120 years), WPS by middle rotation period (80 years) was the largest and was best for woody biomass production. In contrast, the long rotation period (120 years) showed the largest FCS, the largest TVG and only 2% smaller WPS than middle rotation period, therefore this management practice was suitable for controlling flood and getting high-value timber. This example demonstrated that the improved model can analyze the tradeoff relationship between services and it is applicable to a comprehensive forest management considering ecosystem changes by climate change and practices.
Wasabi (Wasabia japonica Matsumura) was grown under photoautotrophic micropropagation conditions using nine temperature regimes by combining day temperatures of 10°C - 26°C with night temperatures of 10°C - 26°C. Temperature-related variations in relative growth rate (RGR) were analyzed by growth analysis. After 28 days of culture, maximum dry weight was measured at a constant air temperature of 18°C/18°C. This study showed that the relative contributions of leaf area ratio (LAR) and net assimilation rate (NAR) to RGR depended on the growth temperature. An increase in NAR was responsible for an increase in RGR in the low-temperature range of 10°C -18°C, whereas a decrease in RGR in the high-temperature range of 18°C - 26°C was attributable to a decrease in NAR and LAR. In the low-temperature range, variation in specific leaf area (SLA) accounted for the differences in LAR. In addition, although the contribution of leaf mass ratio to the differences in LAR was enhanced in the high-temperature range, temperature-induced decreases in LAR were largely because of decreases in SLA. The plasticity of growth responses of wasabi plantlets to temperature was very different across the two temperature ranges.