For example, if you measure the space between the sets of bud scale scars on the twig of a woody plant, you can tell how much it has grown in recent years. It is a little tricky to know what is a normal rate of growth and whether lower than normal rates necessarily mean the plant is unhealthy. However, declining rates of growth over the past several years can be telling, and they can often even be traced to a particular event, such as installation of new sewer lines or a new driveway. Conversely, pointing out normal annual growth can also help allay fears that something major is wrong with the plant � for example, on maple when all that is found is some tarry spots on the leaves.