The 3 problems with planting trees in areas prone to waterlogging

Selecting the right trees for your site can be a daunting process, especially if you have the added issue of contending with difficult site conditions, as well as satisfying your tastes and styles. Selection of tree species to plant in areas prone to water logging or damp conditions is fairly limited, as there are only a number of trees that will tolerate this adverse condition.

Here are the 3 main reasons behind the limited tree species that will cope with water logged conditions:

1. Waterlogged conditions reduces the supply of oxygen to tree roots and thus inhibits the ability of the roots to support the tree, as ultimately all (or most) of the root function is reduced as the roots are ‘drowned’ by the water and begin to decay.

2. Carbon dioxide (a product of respiration) is prevented from diffusing away from the roots and this also reduces the root function.

3. Lack of function in a trees root system, particularly in the summer months when a tree is growing vigorously, prevents the movement of water and essential nutrient into and out of the plant and ultimately means that the leaves and stem of the tree become starved causing the failure of the tree.

Despite painting a grim picture of the fate of a tree that is placed in inappropriately waterlogged conditions, there are species that are well adapted to the anaerobic root conditions inflicted by wet soils. These species have specially adapted roots that enable them to continue to thrive even when oxygen is lacking.  This tends to coincide with trees being extremely vigorous, using the additional water to fuel rapid growth and development, rather than acting as a hindrance.

There are few trees that will tolerate prolonged periods of water-logging, however some will tolerate extremely moist soils. If your soil is prone to water-logging for long periods of time you should consider additional pit preparation prior to planting in order to aid drainage.

For trees that are tolerant of wet conditions, please see the expanded list on the right hand side.