Trees as a Habitat

There are often more insect species on native woody plants than on “new exotics” because plants and animals share a long history of co-evolution. The presence of many diverse insects affects the abundance of native songbirds feeding on the insects.  

Examples of native woody plants: Willows, birches, hornbeams, field maples, rowans, service/sorb trees, wild apple trees/crab apple trees, spindles, buckthorns, and hawthorns.   

Overall, deciduous trees are more richly inhabited than conifers.  

Be aware of breakage: If there is a danger of breaking branches or falling trunks, please intervene using pruning shears or saws to keep others safe!  

Only plants that can cope with dryness, limited light, nutrient deficiency, and withstand a tree’s heavy root pressure can survive in the shade of free-standing trees. These are primarily woodland perennials including lilies of the valley, ferns, wild garlic, and woodruff that have adapted to growing in these harsh conditions. In spring, for example, wood anemones or liverworts utilize the light filtering through the still bare deciduous trees to grow! These species also tolerate dryness better than others. The north side of a tree and directly around the trunk are particularly difficult locations because the area is particularly dark and dry. Cranesbill species, alchemilla, golden strawberries, and aster species, however, have been able to adapt to these conditions. Ivy is a very well-known shade plant that can also thrive in these conditions.   

The outer circle around the trunk gets a little more moist, where plants like hostas, bergenias, geums, astilbes,  heucherellas, and astrantias thrive. Some smaller woody plants like mahonia or boxwood and even some ornamental grasses can adapt to the root pressure.  

Those wishing to plant trees in their gardens should educate themselves about different root species. Trees can be divided into three different root systems: 

• Trees with Lateral Roots: Form a wide root system near to the ground’s surface. Only a few lateral roots grow vertically into the ground for better anchoring. Since the roots usually do not reach groundwater, these trees rely more heavily on rainwater, often extracting it from the undergrowth. Examples: Norway maples, spruces, poplars, and willows.  

• Trees with tap roots: Form deep main roots that grow vertically into the ground and rely on groundwater. Examples: Fruit trees like apples, cherries, plums, rowans, pines, and firs. 

• Trees with heart (oblique) roots: Form vertical and horizontal roots, creating a heart-shaped root system that ensures their water supply and anchoring. Examples: Norway maples, birches, limes, alders, and beeches.