Definition of "dolorousness"

Taking old William and Benny with me, I was soon camped in a little hut on the west point of Frigate Bird, in a grove of tall puka trees where the wind moans with a pleasing dolorousness and a dozen species of sea birds squawk discordantly from their perches in the branches.

1929, Robert Dean Frisbee, The Book of Puka-Puka, Eland, published 2019, page 82