Sidney Laham,

Sponsor or Client: 

Title:

Ponderosa Pine Dwarf Mistletoe Responses in the Midst of a Prolonged Drought on Mogollon Rim, AZ

Abstract:

Southwestern dwarf mistletoe (Arceuthobium vaginatum subsp. cryptopodum) is a pathogen that has been present in Ponderosa pine (Pinus ponderosa) forests in the southwestern region for centuries. Until recently, this pathogen has been seen as a threat to forest health but also has positive impacts on wildlife species as a source of food and cover. I surveyed 84 plots on the Mogollon Rim in northern Arizona to examine changes in dwarf mistletoe infection rates in ponderosa pine dominated plots. I examined changes in mistletoe infection rating and spread, evaluated different environmental variables such as slope, aspect, tree height, tree density, and forest composition, and determined their influence on dwarf mistletoe infection. I found an increased spread of dwarf mistletoe across the study sites and a total higher mistletoe infection rates across the landscape. Many of the trees that were previously uninfected or had a low dwarf mistletoe rating now show new infections or have a higher dwarf mistletoe rating. These results have implications for forest health and management and will help on the ground decision-making with managing dwarf mistletoe infection rates within a range of natural variability in similar climatic areas.