Forest health monitoring: 2001 national technical report

Damaging Agents and Tree’s Health Condition in an Urban Forest

“…The tree damage indicator protocol proposed by the Forest Inventory and Analysis Program and Conkling et al (2005) was implemented. Beforehand, the field crew integrated by three people (two Biologists and one Forest Engineer) was trained to identify the main symptoms and to calibrate some of the more subjective measures, like damage severity.…”

“…According to Conkling et al (2005), a damage severity index (DSI) score was determined for each damaged tree. The DSI score was determined based on three variables collected a priori in the field: 1) the location of the damage on the tree, 2) the nature of the damaging agent, and 3) the severity of the damage.…”

“…For several years, previous research has mentioned the variables that can be used to evaluate and characterize the current health condition of natural and urban forests (Ferretti, 1997); however, these variables must be scientifically valid and economically feasible to collect (Stone et al, 2003b); some of the most studied variables are foliar discoloring, defoliation percentage, crown density, leaf and needle size, and damaging agents (one or more types of damage) (Conkling et al, 2005;Coulston et al, 2005). Although identifying tree damaging agents could be a simple task, expressing the damage in numerical terms is a complicated assignment because of the lack of linkages and thresholds, and the difficulty in interpreting damage (Conkling et al, 2005). Not to mention the DSI or other indexes, which integrate information from multiple variables in a single value, for example, the RUSI index for urban landscapes (Scharenbroch et al, 2017).…”

“…Tree health assessment must be seen as a comprehensive process based on a visual and complete inspection of its organs (Alexander & Palmer, 1999;Stone et al, 2003b). Damaging agents that affect the root and stem have a greater potential to affect the overall physiology of the tree, hence their presence is considered more dangerous (Conkling et al, 2005). Under other conditions, damage caused to active growth organs (small branches and foliage) may be temporary, since the leaves, sprouts, and reproductive structures can be replaced in the short or medium term (Conkling et al, 2005, Winn et al, 2011.…”

“…Damaging agents that affect the root and stem have a greater potential to affect the overall physiology of the tree, hence their presence is considered more dangerous (Conkling et al, 2005). Under other conditions, damage caused to active growth organs (small branches and foliage) may be temporary, since the leaves, sprouts, and reproductive structures can be replaced in the short or medium term (Conkling et al, 2005, Winn et al, 2011. Finally, the aims of this study were to identify tree damaging agents, and to obtain a Damage Severity Index (DSI), in order to categorize tree health condition of the San Juan de Aragon Park.…”