Diana Beresford-Kroeger.
She wrote, among others, a book called To Speak for the Trees, subtitled My Life's Journey from Ancient Celtic Wisdom to a Healing Vision of the Forest. It's another one of the very few books I think everyone needs to read, to the point where I'm seriously considering buying something like a dozen (more) copies and giving them away.
EDIT, 2022-03-18: Not just considering. Shortly after writing the above post, I did buy a bunch (10, I think) more copies and have been giving them away over the intervening two-plus years.