Publication Date


Document Type


First Advisor

Liu, Lichuan, 1945-

Degree Name

B.S. (Bachelor of Science)

Legacy Department

Department of Electrical Engineering


Trees play an essential role of providing oxygen and taking in the increasing carbon dioxide in the atmosphere. They can live thousands of years, but their lives can be cut short due to unexplained circumstances. The Morton Arboretum’s Center for Tree Science speculates that acoustic emissions (AE) can help resolve these mysteries by detailing and quantifying the stress waves inside a tree to better understand the health and well-being of trees. For this goal, an electrical circuit and accompanying mechanical housings were designed to support an AE sensor. The AE sensor system was tested in Northern Illinois University’s Digital Signal Processing Lab’s anechoic chamber. During testing, the system recorded three distinct responses from each mode of testing. While the device displayed an ability to serve as a platform to collect AE readings, improvements to the mechanical housing for eventual long-term deployment and expansions to the circuit to support more detailed data collection methods can be made.

Honors Capstone Final Report - Theresa Li.pdf (2036 kB)
Main article (1.989Mb)

Capstone Title, Approval Page & Abstract - Theresa Li.pdf (93 kB)
Submission Info (93.71Kb)


58 pages




Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Alt Title

Acoustic Emissions and Phenological Acoustics Monitoring System

Media Type