Vegetation on artificial embankment slopes of the expressways approximate 50 years after construction in two expressways: Kyushu and Chuo Expressway

• Published in: Journal of the Japanese society of revegetation technology Vol. 48; no. 3; pp. 507 - 515
• Main Authors: OYAKE, Yui, MIMAKI, Riku, ODA, Kimisato
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Japan Science and Technology Agency 28.02.2023
• Subjects: Bamboo; Cluster analysis; Deciduous trees; Embankments; Evaluation; Highway construction; Highways; Revegetation; Slopes; Soil environment; Surveys; Vegetation
• ISSN: 0916-7439; 0916-7439
• DOI: 10.7211/jjsrt.48.507

While slope revegetation cases focusing on forest creation is increasing, there are no evaluation criteria for long-term vegetation assessment, and there is a lack of knowledge to evaluation about the long-term transition in artificial embankment slope vegetation. In this study, we surveyed the vegetation on eight slopes revegetated by sowing of two expressways constructed approximately 50 years ago and grasped the surrounding forest using aerial photo interpretation. In the Kyushu Expressway, almost all survey slopes were dominated by bamboo species, and much of bamboo forest surrounded slopes were observed. Thus, it suggested a higher tendency of recruitment and establishment of bamboo more other expressways. In the Chuo Expressway, many slopes were dominated by deciduous broad-leaved trees, on the other hand, in some cases adult (H ≧ 1.3 m) Pinus densiflora was observed, therefore maintenance of light and soil environment in which P. densiflora can establish was suggested. The vegetation observed on the two expressway routes was classified by cluster analysis and divided into two major patterns: deciduous broadleaf tree communities and communities in which the main species was Pleioblastus simonii; which was similar to the trend in previous studies. The approximate vegetation transition on the three expressway embankment slopes was equivalent. On the other hand, it was suggested that the influence of regional differences, such as temperature or surrounding vegetation, in the transition of slope vegetation was confirmed, and there is a need for follow-up surveys in different regions to evaluate slope vegetation.