Experimental Setup - Kyloe Woods

Objectives

The objectives of the experiment in Kyloe Wood were:

• To measure wind profiles and turbulence within and above a forest stand with two canopy layers
• To measure the tree response to the wind
• To compare measurements with those obtained in the wind tunnel
• To use these data to parameterise equations for structured stands, that can be implemented in wind risk analysis tools such as ForestGALES
• To examine influence of thinning on the wind loading experiences by trees

Experimental setup

The experimental setup was similar to the one in Clocaenog Forest. Once more the goal was to measure the wind-tree interaction with a high temporal resolution. The wind profile was measured at two locations with eight cup anemometers (NRG#40, NRG Systems), that were mounted onto two 30M masts. Mast II, which was located in a location, where there was an understorey, carried in addition to the cup anemometers, two ultrasonic anemometer (USA-1, METEK GmbH) to measure atmospheric turbulence with a time resolution of 10 Hz, and two wind vanes.

The experienced turning moments of nine experimental trees were measured using strain transducers. Every experimental tree was equipped with two strain transducers, which were mounted perpendicularly into the stem at about breast height. The signal output of the strain transducers is linear to the change in distance between the two holes where the strain transducer is screwed into the tree. Every single strain transducer was calibrated by stepwise pulling while measuring the applied turning moment.

Data pool

For this experiment 5278 hours of data were collected during the time period from 11th of March 2006 until the 20th of November 2006. Unfortunately we missed some really strong gales in December 2006 and January 2007. But the equipment was needed for another experiment.

The figure below shows the frequency of hourly mean wind speeds measured at 30.8 m height.