if may 'suggest' try using a mixture of both hardwood branches (osage orange, mulberry, locust, ect) and PVC. stuff cement blocks with branches with all the cut ends together, the branches on 1 side going 1 way and opposite on the other and secure them with going around each side tied off and then going to the opposite diagional end and again tying off. these will go in shallow water. for deeper water use 5 gallon buckets with holes drilled at 90 degree angles at the bottom of each bucket and insert 3' pieces of PVC, this will help keep them upright. cement both the hard wood branches and PVC into them. finally in the deepest water use just PVC tubing . this creates a path for the fish to use all year long, shallow to deep... feel free to use cedar trees/ shrubs in place of the Christmas trees.