About This Project

Forests play a pivotal role in regulating the energy and mass exchange between terrestrial ecosystems and the atmosphere. However, invasive pathogens and insects have caused extensive tree mortality, which threatens the delivery of crucial ecological functions by forests. Over the past decade, disease and insect outbreaks occurred more frequently and severely in forest landscapes, which have contributed to the unprecedented extent of tree mortality in key biomes worldwide.

Ask the Scientists

What is the context of this research?

Sudden Oak Death is a representative example of emerging infectious disease that has received particular attention since being discovered in the mid-1990s. In California, SOD posed a substantial threat to forest health, killing millions of trees mainly in mixed oak woodland and redwood-tanoak. Widespread mortality of local oak and tanoak trees could reduce wildlife habitat and food resources, raise the risk of forest fires, increase water runoff and soil erosion, and alter the composition and structure of the natural plant, microbial, and aquatic communities. In the past decade, two major fires repeatedly occurred in California’s SOD-impacted forests, including the recent Soberanes Fire, costing $236 million (most expensive in U.S. history) to suppress.

What is the significance of this project?

This project:

• Is important because more research is needed to understand tree mortality caused by SOD and the evolution of the disease over time.
• The project will fill significant knowledge gaps. Tree mortality is observed to be induced by both drought and infestation in the traditionally SOD-infected areas. This research will give a timely and accurate approach to distinguishing between the two types of disturbances using efficient remote sensing technology.

• SOD has a high impact on the wildfire occurrence, where US federal and state governments spent a lot of money on. Best available science is needed to inform the best possible decisions.

After project completion, policy makers will have additional tools to make more informed decisions.

What are the goals of the project?

The goal of the study is to develop a forest disease mapping algorithm to produce disease infested extent maps capturing its heterogeneity in space over the decade. Firstly, we will analyze and process the field measurement data. Then we will integrate spectral, spatial and temporal properties from multi-source satellite and airborne images coupled with field data to develop a high-resolution (30m), long-term tree disease mapping technique for broad-scale forest management using SOD as a case study, because remote sensing technology supplies a relatively cheap and rapid method of acquiring up-to-date information over a large geographical area. Finally, an ecological niche model will be applied to eliminate the areas with low probability of infestation.