The Deciduous Woodlands: How seasonal change affects temperate forest life

By Ron Divelbiss, Metea County Park Naturalist

Most of Fox Island and Metea is woodlands. The changing seasons dominate deciduous woodlands. Woodland animals and plants live and breed in conditions that vary widely throughout the year. The key to their success is an ability to survive the winter and then take full advantage of the spring and summer. Deciduous woodland is the natural vegetation of much of temperate Europe and North America, and also occurs in the limited temperate lands of the Southern Hemisphere. But its water retentive soils make excellent farmland, and in many places woodlands have been replaced by agricultural development.

In the depths of winter there seems to be little life in a deciduous woodland. The trees are bare, snow may lie along the branches, and there is little bird song to be heard. Yet even so, there is activity. On the woodland floor shrews hunt for invertebrates such as woodlice and earthworms. Also active are resident birds like downy and hairy woodpeckers and blue jays. The blue jay survives the winter by eating the acorns it stored in the autumn. The hairy woodpecker changes diet, eating invertebrates in the warmer months and seeds in the winter.

Many species of birds - and a few bats - simply avoid the winter: they head for warmer climates after breeding. Mammals like the mouse and the skunk stay put but become less active, or hibernate.

As winter retreats, the days lengthen, the temperature rises and the snow melts; greenery and life return to the woods. First come the spring flowering plants, which expand their leaves and produce their flowers before the canopy closes over them and shades them from the Sun's light. Woodland trees - oak, hickory, maple, ash, beech and many others burst into leaf, and no sooner are their leaves expanded than they are being eaten by insects and their larvae.

Migrating birds such as warblers return in spring to build their nests and raise their broods. The plentiful harvest of insects provides breeding birds with a protein-rich diet for their young. Down on the woodland floor deer browse the vegetation, and in the dense understory mice are busy searching out seeds, buds and invertebrates.

All parts of the forest - from the woodland floor to the top of the canopy - have their predators. Hunting spiders chase small invertebrates across the woodland floor, and far above, superbly adapted woodland hawks hunt small birds among the branches.

By late summer the migratory birds have raised their young and begin to leave. Trees are preparing for the dormancy of winter by withdrawing the nutrients from their leaves and shedding them. The leaves turn brown, red and gold as they die, and the jays hunt once more for acorns. The cycle begins again.