Mark 8:22-26 is the story of Jesus healing the blind man at Bethsaida.
Jesus comes to Bethsaida and the people bring a blind man to him. Jesus spits on his eyes and puts his hands upon him. Spit was apparently defiling in Judaism. Then the blind man looks up and sees "men as trees, walking". This refers to Isaiah 61:3. Jesus reads from Isaiah 61 in Luke 4:16-21, this reading inaugurates the 10th and final Jubilee. So the blind man sees men walking around as righteous, glorifying the Lord, rebuilding old wastes, raising up former desolations, repairing the waste cities and the desolations of many generations (Isaiah 61:4). In Enoch the opening of blind eyes is linked to the overthrow of evil and releasing from bondage, both Jubilee themes. Luke 4:18 mentions recovery of sight to the blind as part of Jubilee. In Luke Jesus quotes from the Septuagint text of Isaiah 61 (the definition of the relevant Greek word) not our Old Testament/masoretic text if I'm reading everything correctly.
So basically all I really want to say is that the trees that are walking around refer to Isaiah 61:3 and this is all related to the Jubilee which Jesus has inaugurated and will be fulfilled in His renewing of the convenant at the Cross.