Timbered Wetlands (Green Tree Reservoirs)


Bottomland forests are an important wetland habitat type for many species of wildlife. Several million acres of bottomland hardwood timber once occurred in Missouri and throughout the lower Mississippi River valley. Today only a fraction of this unique wetland habitat remains.

The management plan for a bottomland forest should protect the health of the trees; therefore, do not flood during the growing season. It is easy to damage and kill the timber in these areas.

Flooding Timbered Wetlands

When To Flood

  • If there are leaves on the trees, do not flood the timber.
  • Do not look at just the overstory. 
  • Check the understory because the seedlings, which are the forest of the future, typically hold onto their leaves a little bit longer and should be evaluated prior to fall flood up.

In northern Missouri, keep in mind that thick ice can damage tree health. Timbered wetlands in northern Missouri usually can be flooded from November 1 to February 15. Timbered wetlands in southern Missouri should be flooded no earlier than November 15, and draining should start by February 1.

Flooding dates, depths, and duration should vary from year to year to maintain the productivity of the forest. The management schedule should include one year in every three or four years where there is no artificial flooding.

When to Drain

The water should be drained before the trees leaf out in the spring. A slow drawdown is better than a rapid one with the forested wetland because of the potential to produce moist-soil plants in these low, open areas. Open areas in the forest can be planted in Japanese millet or managed for natural foods.

If Natural Flooding Occurs During the Growing Season

Flood water that inundates the wetland unit during the growing season should be removed as quickly as possible. Flooding during the growing season can cause stress and, ultimately, tree mortality if not removed within a few days. Constant monitoring of water control structures is necessary to make sure that flood waters are being drained during the timber's growing season.

Timber Management

Practice good timber management. Acorn production, regeneration and reforestation all depend on a good forest management plan. Consult your local district forester to help with timber management.