Even then, diagnosis may be difficult because the original stress may be obscure or no longer present. There are several symptoms that may indicate decline. As stress continues, foliage may appear small and pale in color. Water sprouts may grow from the branches and trunk. Thinning in the upper crown foliage becomes evident as twigs die back.
Larger branches die as the decline progresses.
Heavy seed formation may be another indication of decline. Affected trees may survive indefinitely while continuing to gradually decline, or death may occur in a year or two. Trees that have been declining gradually may appear to suddenly die. In addition, lime-induced iron deficiency is often associated with oak declines and girdling roots can contribute to maple decline. These problems are explained below.