Abstract
The influences of (1) a high fiber content, (2) the arrangement of fibers in fiber groups, and (3) a layered hierarchical composition of the bark of the giant sequoia (Sequoiadendron giganteum) on its energy dissipation capability are analyzed and discussed regarding the relevance for an application in bioinspired components in civil engineering. The giant sequoia is native to the Sierra Nevada (USA), a region with regular rockfalls. It is thus regularly exposed to high-energy impacts, with its bark playing a major protective role, as can be seen in the wild and has been proven in laboratory experiments. The authors quantify the fundamental biomechanical properties of the bark at various length scales, taking into account its hierarchical setup ranging from the integral level (whole bark) down to single bark fibers. Microtensile tests on single fibers and fiber pairs give insights into the properties of single fibers as well as the benefits of the strong longitudinal interconnection between single fibers arranged in pairs. Going beyond the level of single fibers or fiber pairs, towards the integral level, quasistatic compression tests and dynamic impact tests are performed on samples comprising the whole bark (inner and outer bark). These tests elucidate the deformation behavior under quasistatic compression and dynamic impact relevant for the high energy dissipation and impact-damping behavior of the bark. The remarkable energy dissipation capability of the bark at the abovementioned hierarchical levels are linked to the layered and fibrous structure of the bark structurally analyzed by thin sections and SEM and µCT scans.
Highlights
The bark, the total of all tissues outside of the vascular cambium, represents the outermost layer of stems of woody plants [1]
One example of a tree species possessing a bark with an outstanding insulation capability during forest fires is the giant sequoia (Sequoiadendron giganteum Lindl.)
The layered composition and the fibrous nature of the thick bark of S. giganteum is made up of a comparatively thin inner bark, which is surrounded by a thick outer bark (Figure 1)
Summary
The bark, the total of all tissues outside of the vascular cambium, represents the outermost layer of stems of woody plants [1]. The anatomical defense, on the other hand, is based on the mere mechanical resistance of the more or less thick bark, representing a protective barrier. The vascular cambium is located subjacent to the bark and is only a few cell layers thick As this sensitive tissue is crucial for the formation of secondary xylem (wood) and phloem (bast)—and the bark—it is essential for the survival of the whole tree. This highlights the protective function of the tree bark, since it represents the only layer surrounding the cambium. The inner and outer structure of the bark differs from species to species, resulting in differences concerning the protective potential
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
