Flooded trees

Went to a backwater lake, the dock at the launch was almost completely submerged, guy at the launch said the dock was only partially submerged only yesterday-so when do fish start to use that structure? Does it vary by species? Thanks

Caught a few yesterday off the main channel within a couple feet of flooded trees in 5-6 ft of water.The branches were too low to proceed any closer or further into the trees but I would guess there were fish in them also.Their arrival in the trees is unknown to me since there has been enough water for fish to swim in the trees for at least a week where I have been fishing.

Close to a channel, what about when the water goes way up into a flat section? Thanks Matt