Causes Of Decay Wood products used in gardening and landscape environments are susceptible to deterioration from insects and fungal attack. Decay organisms grow most rapidly at temperatures between 70 deg to 90 deg F, wood moisture content above 20 percent, and in the presence of oxygen. The protection requirements of wood products used in the garden or landscape depends to a large extent on end use. For example, wood used above ground is not exposed to the same level of decay organisms as wood used in-ground. It is most appropriate to use a level of treatment commensurate with the end use.
Wood is most vulnerable to decay at the ground-line.
Below ground-line there is insufficient oxygen to support fungal growth. Above the ground-line with proper care, wood moisture content will be too low to support fungal growth. The home gardener must also feel comfortable with issues associated with the safety of products chosen for use in the garden and landscape. Natural Decay Resistance Lumber or timbers containing natural preservatives can be used effectively in gardening and landscape applications. Certain lumber species naturally resist attack by decay organisms.