This study clarified the suppression effects of Miscanthus (Miscanthus sinensis) - and deciduous-tree-dominated vegetation on sugi (Cryptomeria japonica) planted trees with reference to two aspects; limitation of light for photosynthesis and inhibition of crown development. The growth of sugi saplings during the three years after planting and branch volume of sugi in the fourth year were investigated in Miscanthus-dominated vegetation (Miscanthus type: M) and deciduous-broadleaved-dominated vegetation (deciduous broadleaved type: DB). The analyses using generalized linear mixed model demonstrated that the growth of sugi saplings under competitive status where the crown top was not suppressed was significantly lower in M compared to that in DB. The branch volume of sugi saplings at the 61-100 cm in height was also lower in M than in DB. These results suggested that the dense foliage of Miscanthus covering the large part of branches in lower crown of sugi limited light more severely than deciduous trees and/or shrubs. These results also suggested that the contact of Miscanthus foliage might have inhibit the development of sugi crown more strongly than deciduous trees and/or shrubs. We concluded that these suppression effects in M caused a more pronounced reduction in the growth of sugi saplings than DB, suggesting a need of taking into account the suppression on the lower crown and the inhibition of branch development when we consider to reduce the weeding frequency or period in the young plantation site dominated by Miscanthus.

To improve forest science education, we conducted a national survey of universities and colleges. It was conducted in 2021 and targeted university faculty members at 26 schools offering education in forest science: 25 schools had pre-existing forestry curriculums, and one school was a newcomer. Twenty-four schools answered it: 8 schools had a forest science special course in a department, 10 schools had a these course, and another 6 schools taught them as part of another course. As a result, the number of required subjects was 400: 200 subjects were related to forests, 65 were related to forest products, and the others were integrated subjects or practice. The number of elective subjects was 714: 434 were related to forests, and 177 were related to forest products. Both forest and forest products subjects were offered in 14 schools as required subjects. The educational contents of forest science were divided into 11 categories: tree physiology, ecology, silviculture and pedogenesis, insects and animals related to control, disaster prevention and hydrology, engineering, management, policy, contents involved in culture, land surveying, and wood science. The curricula were divided into three types by necessity of forest science contents: I) 12 schools offered more than half of the contents as required subjects, II) 10 schools offered more than half of them included in elective subjects, and III) the other 4 schools offered only several contents. In conclusion, each university or college offered various contents related to forest science, making it difficult to grasp the main educational elements.

Thematic maps, such as forest change and land cover change maps, are generally inaccurate. The assessment of accuracy, defined as the correctness of a map, is critical for understanding the quality and utility of thematic maps. This review shows the fundamental principles in area estimation and accuracy assessment for forest change maps based on three components: sampling design, response design, and analysis, and then reveals the criterion and recommended practices. Several special cases of accuracy assessment are also discussed. A probability sampling design is implemented in the statistically rigorous accuracy assessment to estimate accuracy based on the comparison of a map and reference data. Population error matrix is crucial in assessing the accuracy and estimating area. Further, the use of unbiased or consistent estimators that correspond to the sampling design is critical for deriving accuracy metrics and area estimates with associated uncertainty. Although the fundamental principles of accuracy assessment are well established, methods for addressing issues have also recently been developed. Practitioners are required to choose the optimal protocols to achieve their objectives of the accuracy assessment because no single protocol or approach can completely address all situations.