When to put in the time, money, and effort to save a tree using the ‘Visual Vitality Index’.
If a tree has experienced typical stressors such as drought, browsing, or soil compaction to name but a few, how do you know when to put the time, money, and effort to save the tree, or to manage the tree as it senesces, or remove it?
Using the ‘Urban Tree Visual Vitality Index’ for stand alone trees, or the ‘Visual Vitality Index for trees in groups, individual trees can be graded as having ‘high’ or ‘low’ vitality.
The method incorporates three individual scores for (1) crown size, (2) crown density, and (3) crown epicormic growth. Scores are totalled to give an estimate of the urban tree visual vitality of the tree and scores have a nominal range between 1 and 17.
Those with a score greater than 10 have high vitality and are good candidates for saving. Those with a low score, 10 or less, have little chance of long-term survival.
Figure 1: Urban Tree Visual Vitality Index taken from Sepulveda & Johnstone (2018).