We often see mulch piled eight inches or more up the trunk of trees. A hot, steamy and moist environment is created for the cambium layer of the tree to support a new life system of molds and assorted fungi. Bio diversity is assured. In cold weather the mulch is an excellent home for small rodents and has a built in snack supply for the winter ( the bark and cambium layer of the tree). Many more life forms are supported with this method, so please do not be guilty of building mulch volcanoes – very bad for your tree.
Apart from looking aesthetically pleasing within the garden mulch is a great insulator through fall and winter. In summer, the mulch conserves soil moisture and keeps tree roots cool.
When using mulch though, it’s important to not exceed a 3 inch depth.