Science fiction: Book about a single person on a remote planet with a large forest that seem to collect knowledge of the universe

[Andrey Chursin]

Hi, I read a book some time ago(15+ years ago), trying to recall the name.

Genre: Science fiction. The book features a single person on a remote planet. Few things I remember about the book:

* The two main 'locations' of the book as far as I recall are some wreckage of an ancient ship with some strange creature(some kind of slug) that lives in it, and the forest of very high and large trees.

* There is diary of previous person who also visited the planet. That other person seem to gone insane, the diary for the most part just lists endless colors and other unconnected words. But every now and then there are clues about the planet. For example diary mentions that trees are antennas receiving knowledge from the universe. That knowledge is then collected in the seeds of the trees and stored for some purpose

* There is a moment in the book when one of those giant trees is cut, and it seem that there are some tiny creatures that live in those trees, that flee when the tree is dead.

Unfortunately this is all I recall, let me know if it rings the bell!