Ambient vibration of one green ash tree over six months

Tree movement was recorded on one green ash [Fraxinus pennsylvanica 'Sherwood Glen' (Oleaceae)] growing in an institutional landscape in Fort Collins, Colorado, USA. Using a triaxial accelerometer (AL100, Oregon Research Electronics, Tangent, Oregon, USA) attached to the stem 4.1 m above ground, ambient vibration was recorded continuously at 10 Hz within a range of +/- 2g between 4 April and 29 October 2022. Attached using two wood screws, the accelerometer's y- and z-axes were oriented tangential (east-west) and perpendicular (north-south), respectively, to the underlying trunk surface, and the x-axis was visually aligned parallel to the trunk's longitudinal axis (i.e., roughly vertical). The tree's trunk diameter at breast height, DBH (m), and height, H (m), was 0.18 m and 8.2 m, respectively. After measurement, the data were combined into four separate files (A_1 - A_4) containing datetimes (stored as date numbers) in the first column and acceleration (g) measured along the x-, y-, and z-axes in the second, third, and fourth columns, respectively. During the study, wind conditions were also monitored near the tree using a triaxial ultrasonic anemometer (81000, R.M. Young, Traverse City, Michigan, USA). The anemometer was mounted 8.3 m above ground on a guyed mast erected 8.2 m northwest of the ash. The sensor's x- and y-axes were oriented east-west and north-south, respectively, and the z-axis was visually aligned vertically. The wind speed measurements along each axis were continuously recorded at 20 Hz between 21 April and 2 October 2022. The data were similarly combined into four separate files (U_1 - U_4) containing datetimes in the first column and wind speed along the x-, y-, and z-axes in the second, third, and fourth columns, respectively.