Mulching Trees

What is that?

What good is it?
mulch ring around newly planted tree
                                                    Mulch ring over the root zone of a newly planted tree

What problems can mulch cause? What is the best mulch to use? How do you put it on? Where can I get more information?

ISA, 2002.  "Proper Mulching Technique."  For other information, advice and help on this topic, call offices of your State Urban Forestry Coordinator or University Extension service, or visit urban forestry web sites.