I got a better recording of the strong winds on Saturday night blowing through the poplars. This time I managed to get section that didn't involve the bit where the wind was hitting the phone microphone. The peak this time is sharper and closer to 300Hz. This is only due to branches. I stood near the shrubs later and there was a different sound due to leaves rustling and hitting each other. I am also wondering whether the microphone range might be a factor but this suggests not. But I do have ideas about how to test this.