All too often trees are the forgotten giants of our garden areas. A shrub or ground cover plant is far closer to the human eye than a tree, and these plants usually get most of our attention because they are so easily seen. With trees it often seems to be "out of sight, out of mind".
Trees are in fact potentially far greater problems than shrubs. If a shrub blows over, it creates a bit of a mess and a gap in the garden bed. If a tree blows over, it can destroy half the garden, make a large hole in the roof of a house, or crush your new car. Trees, like people, can be hurt, they can get sick, and sooner or later they will die. They need to be fed and watered, and they do need "doctoring" if their life is to be extended to the fullest. Some trees, like some people, are hardier and never seem to become ill. In the same way, however, many trees have "medical" problems which no one seems to notice until it is too late!
Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.