For millennia, trees have fallen into lakes, and fish along with other aquatic organisms used them as habitat.
Trees in riparian areas emerge as seedling, they grow and mature dropping seed to establish future forest stands. When trees die, many fall into lakes creating fish habitat, leaving seedlings in their wake, to again mature and replace dying trees, thus continuing the cycle that links these shoreline areas to lakes and streams.
Fish use submerged trees in a variety of ways. Many species spawn on, adjacent to our under trees that provide cover which help some species protect their incubating brood. For example, smallmouth and largemouth bass preferentially build spawning nests near submerged trees, particularly large logs, while rock bass place them next to or under logs. Because the male bass and sunfish defend their eggs, and young in the nests, placing nests adjacent to or under submerged trees reduces the nest perimeter that they need to defend against predators. Once the young have left the nest, newly hatched smallmouth bass will oftern inhabit submerged trees. Declines in submerged tree habitats have been linked to reduced abundance of young smallmouth.
Yellow perch use submerged wood along with aquatic vegetation to lay eggs; long ribbon-like stands can often be seen draped on them in the early spring. Three studies found a decline in yellow perch abundance when trees were removed from lakes. Fathead minnows, an important food item of larger fish and fish-eating shorebirds, spawn on the underside of wood in cavities.
The young of many species of fish often disperse throughout the brances for protection, while predators, such as northern pike, muskies and largemouth bass use the same trees for ambush foraging. Shade from branches and bole provides daytime refuge for diurnal low-light species such as walleyes. Use of trees can be species-dependent, age-dependment and season dependent, and trees provide many diverse habitats that attract fish for different reasons.
Current research has found that the association between fish and trees clearly is related to the complexity of branches and location and position of the tree in the water. More fish and more different species of fish use trees that have more complez branching and in fact, individual, large, complex trees can host entire fish communities. In north temperature lakes, up to 15 species or more may inhabit a single tree at a time. Walleye and white suckers can be found beneath trees in deeper, darker water, adult smallmouth bass can be found in the bole, and many of the other species like minnows, bluegills. pumpkinseed, rock bass, muskes and more can be found throughout the complex web of branches.
Riparian trees are an amazing example of a renewable resource; valuable to us on land, then again in the water after they die while more trees are being regenrated on land...for free. We just need to understand and embrace this cycle as a long-term renewable source of habitat.
Isn't it ironic that on many lakes we have reduced or eliminated trees in riparian areas thus preventing them from becoming habitat in lakes, only to then build fish cribs made from trees at substantial cost and energy? Riparian trees and shrubs are a "free commodity" provided by nature at no cost. All we need to do is recognize their benefits and let nature provide free fish habitat to its full potential.
Michael A. Bozek
Read the entire article at http://dnr.wi.gov/topics/fishing/documents/outreach/TreesShoreline.pdf

The following fish species were found in one submerged white pine tree:
-Black crappie -Smallmouth bass -Largemouth bass -Walleye -Muskie -Rock bass -bluegill -pumpkinseed -mottled sculpin -Logperch -Johnny darter -Yellow perch -white sucker -minnows