 Tree was deeply contented in his home life, his 63-year marriage and his passionate interests in gardening, natural history, ecology, history and the career of his renowned grandfather.He died at the Queen Elizabeth II Hospital in Welwyn Garden City three-and-a-half months after his 94th birthday, leaving his wife, Mary, daughters Belinda, Gay and Vicken, and son James.Another daughter, Susie, died in 1989.