In this study, I investigated whether the sorting method of combining density adjustment and classification by height could produce Japanese cedar (Cryptomeria japonica) seedlings with a low H/D ratio (shoot height/basal diameter) and a low T/R ratio (shoot dry weight/root dry weight) after 1 year and if this could improve the yield rate (percentage of seedlings with shoot height ≥ 30 cm and basal diameter ≥ 3.5 mm to the number of cells used). Additionally, I examined the effects of sorting on the relationships between basal diameter and root dry weight, and the effects of topdressing applied to seedlings that were classified as short. I sowed in April 2019 and sorted the seedlings in August and September 2019, reducing the density according to the sorting classification. I measured the shoot height and basal diameter in November 2019, and measured shoot dry weight and root dry weight from March to June 2020. The sorting decreased both H/D and T/R ratios. The basal diameter could predict the root dry weight, but the predicted formulas differed depending on whether sorting was performed or not. During the seedling growth, sorting at least once improved the yield rate and sorting twice improved the percentage of seedlings yield and had a T/R ratio ＞ 100. The topdressing increased the T/R ratio but not the H/D ratio, and promoted shoot growth and let to an increased yield rate. These results confirmed the effectiveness of the sorting method in seedling production.
The seeds of Toxicodendron vernicifluum are considered to be in a state of combinational dormancy, which is a combination of physical and physiological dormancy. To improve the germination rate of T. vernicifluum seeds, the methods reported to be effective in promoting seed germination were evaluated separately for breaking physical and physiological seed dormancy. The most effective methods for breaking physical dormancy of T. vernicifluum seeds were soaking in concentrated sulfuric acid (H2SO4) for 60 to 120 min or partial removal of the endocarp. Water absorption was observed to begin at two locations on the seed after soaking in H2SO4 for 90 min. Cold stratification for 4 to 12 weeks was effective in breaking physiological dormancy of the seeds after soaking in H2SO4. However, seeds treated with cold stratification after partial removal of endocarp did not germinate. The germination rate of seeds soaked in H2SO4 for 90 min followed by 8 weeks of cold stratification (73.2±2.7％)was significantly higher than that of seeds soaked in H2SO4 or cold stratification alone (0.8±1.0％ and 0.4±0.9％, respectively) or no treatment (0.0±0.0), indicating that the combined treatment would be effective for improving T. vernicifluum germination.
The purpose of this study is to examine the content of forest science required in university education based on an analysis of the content of the examination for the professional engineer (forest disciplines), a highly specialized qualification. The target of the analysis was the contents of the professional engineer examinations (three subjects: specialized subject, required subject, and optional subject). The contents of the examinations were organized and classified by referring to the table of contents of the book “Essentials of Forest and Forestry Practice” and the presentation sections of the Japanese Society of Forest Science. As a result, the contents of the special subjects and required subjects were based on almost all the 26 chapters in the table of contents of the book and almost all the presentation sections of the society except for the education section. Particularly, some fields such as erosion control, forest engineering, and forest policy were more important than others because they tended to appear more frequently each year. There are three elective subjects: forest civil engineering, forest environment, and forestry and forest products. Many of the questions were related to erosion control and forest engineering, ecology and forest policy, and non-wood forest products and silviculture. Therefore, the content of forest science required for university education by the qualification examination for professional engineer (forest disciplines) is broad, including the field of forest products science. It is necessary to review the minimum commonality and academic system of forest science in university education.
Vocational education has been changing with the times. We worked on restructuring educational contents about management of the subject “Forest management” in vocational high schools in line with revised Education Ministry Guidelines (2017). Based on analysis of previous educational reforms and school textbook contents, forest management was revised. Previous textbook contents were categorized with nine details (fundamentals, sustainable forest management, forestry operation, planning, forest utilization planning, organizations, production control and financial management, forest information system, and multiple-use forest management). Analysis showed five central issues for restructuring: 1) organizing fundamentals of forests and forestry; 2) reconstructing contents by emphasizing practice; 3) understanding the relationship with other fields in agriculture; 4) understanding the whole of forests and forestry, environmental protection, management, and service industries; 5) sustainable forest management. Restructured forest management objectives and organization particularly emphasized sustainable forest management. The restructured contents included in three parts: 1) Definition of forest management: sustainable forest management in harmony with utilization and conservation; 2) Organization: administrative organization and forestry enterprise that involve various forestry occupations; and 3) Planning: forest planning systems, specific survey items, geographic information system and various types of forest utilization and management. Forest and forestry education has high potential for environmental education, so, revision of entire educational contents of forest and forestry education would be necessary.
In recent years, range expansion of bamboo stands has become a problem in Japan. In order to plan an appropriate management for bamboo stands, it is necessary to understand the topographical conditions controlling their establishment. Although previous studies have evaluated the topographical conditions in a limited area, no studies have been evaluated topographical conditions of bamboo stands under their climatic potential habitat in wide range. The purpose of this study was to obtain detailed information on the distributions of bamboo stands in Nagano Prefecture by using aerial photographs and field surveys, to evaluate the topographical conditions of bamboo stands in comparison with that of potential habitats. As a result, 55.7 percent of all bamboo stands in Nagano Prefecture (10,523 sites, total area of 1,449.0 ha) were located on gentle slopes with slope aspects of 5-20 degrees, and 53.5 percent were located on slopes facing southeast, south, and southwest, whereas potential habitat of bamboo stands in Nagano Prefecture has two peaks at around 0° and 30°, and is distributed in all directions. Moreover, these topographical conditions of bamboo stands were common among the five regions of the prefecture. These results imply that bamboo stands in Nagano Prefecture tended to locate mostly on gentle south-facing slopes and suggesting that local residents have been planted and remain in the present topographical conditions from the viewpoint of land use and bamboo forest management.
This study aimed to review the historical transition of forest engineer appointments in the prefectural administration of non-national forests since the Meiji era in Japan. First, using historical materials, the overview of the nationwide history of the transition was clarified from this era, when forest engineers with modern forestry education were first employed in prefectural non-national forests, up to now. The appointments of forest engineers in the prefectural administrations of non-national forests were responses to post-flood diseases that occurred in the 1890s and gradually spread to each prefecture. The number of prefectural forest engineers increased rapidly in the late 1930s to secure personnel for establishing forest product inspection agencies, the first of which was for charcoal. After the war, there were a total of 11,000 prefectural forest engineers, and they supported the administration of non-national forest policy under the Forest Law of 1951; however, that number has rapidly declined during the 21st century. Second, who was appointed and when in each prefecture, which can be said to be the beginning of modernization, was discovered using historical materials. Furthermore, the characteristics of the forest engineer appointments during the introduction period were clarified. All prefectures accepted these engineers over a period of 18 years, from 1895 to 1912; in addition, the number of graduates in 1890 was particularly outstanding.