Landels-Hill Big Creek Reserve

26 Oct, 09 AM - 30 Oct, 02 AM

Impacts of SOD mortality on fire severity in the Big Sur ecoregion, California Ross Meentemeyer, University of North Carolina-Charlotte David Rizzo, University of California, Davis Introduction: Coastal California forests have experienced high mortality since the mid-1990s from Phytophthora ramorum, an emergent generalist pathogen that causes sudden oak death (SOD). Our current research (EF-0622770) examines the environmental and biological circumstances that led to the current emergence of P. ramorum. A major goal of this work is to examine the changes in the forest environment that might result in positive or negative feedback between the pathogen, its various hosts and the physical environment. Within this framework we have established a number of different field- and lab-based projects. One of these projects was the establishment of 280 intensive long-term monitoring plots in the Big Sur area of California (Figure 1) that was also linked to a detailed mapping study of tree mortality based on aerial imagery (Meentemeyer et al., in press). Since late June 2008, a large wildfire fire (expected to reach ~ 40,000 ha) has greatly impacted the Big Sur region. Anecdotal evidence from firefighters on the ground has suggested that areas with SOD burned hotter and were more difficult to control than forest areas without SOD. Many media reports have mentioned the danger firefighters were placed in when working in SOD-infested forests. The current Big Sur wildfire presents a unique opportunity to assess the possible feedbacks between changes to forest structure caused by SOD mortality and fire dynamics across the landscape. We are requesting supplemental funding to collect time-sensitive data on the fire severity to conduct a cross-scale analysis of these compounded disturbances. At the local scale, we propose to examine whether SOD-caused tree mortality increased fire severity in infected plots by increasing fuel loads. At larger scales we will examine whether landscape heterogeneity of SOD tree mortality affected spatial patterns of fire severity. There are very few examples in the literature of post-fire ecological effects at the landscape scale that are based on both pre- and post-fire data; most studies are based solely on post-fire examination of the landscape with no previous data. Even rarer is the opportunity to examine the interaction of a wildfire with an emergent pathogen at the landscape. A new study focused on the Big Sur fire and SOD fits well within the scope of our original proposal. However, we had not anticipated the need to sample a fire of this magnitude. Proposed Research: The impacts of SOD on fire severity will be addressed at multiple spatial scales using our existing data on pre-fire forest structure and landscape heterogeneity and the following proposed measures of fire severity to be collected with supplementary funding. 1. Local-scale: Did SOD-caused tree mortality impact fire severity by increasing fuel loads (more standing dead trees or downed logs) in plots infected by P. ramorum? We have 280 plots in the Big Sur ecoregion with ~90 plots within the fire perimeter (Figure 1). In each 500-m2 plot we have quantified disease incidence, levels of tree mortality, coarse woody debris, canopy cover and regeneration. The plots within the fire perimeter are in both mixed-evergreen and redwood forest types and encompass a range of SOD mortality. Plots that were infected with P. ramorum had higher levels of standing dead host trees and downed logs than plots without SOD impacts. Our short-term objective is to determine fire severity in each plot and how variation in SOD mortality levels influenced this severity. In a field assessment immediately following the fire we propose to visit all plots within the burn perimeter and measure the burn intensity based on standard BAER assessments (e.g., soil hydrophobicity, ash content, etc.). These measures examine fire impacts on soil characteristics and functioning and incorporate the effects of fire heat, residence time, and fuel consumption. We also propose to classify the impact of the fire on forest cover, through potential damage to both understory and overstory vegetation. We will measure canopy cover in each plot to compare with our pre-fire measurements to determine whether the fire impacted the mainly the forest understory or caused more severe damage to tree crowns. 2. Landscape-scale hypothesis: Did landscape heterogeneity of Sudden Oak Death tree mortality affect spatial patterns of fire severity? Previously developed maps of pre-fire oak mortality ? number and basal area of dead trees; landscape-scale heterogeneity in mortality; heterogeneity in forest types, etc. (Meentemeyer et al., in press). In a collection of imagery immediately following the fire we propose to: ? Imagery of fire patterns: perimeter, spectral info on burn severity ? spatial distribution, spread. Broader Impacts: In addition to the basic research questions that will be answered by this project, there are a number of very important applied questions that will be addressed. Management of millions of dead trees caused by SOD has become a key question in these fire-prone ecosystems. We have received many inquiries from land managers, policy makers and the media about how our pre-fire dataset can be used to learn from this experience. As part of the outreach component of our grant, we had scheduled a large community meeting in Big Sur for July 8 to discuss many of these issues. That meeting was canceled (the fire was burning right up to the building we had reserved!) but there is much interest in a re-scheduled meeting. Managers in other areas of the state with large numbers of dead trees (Marin and Sonoma counties) have also contacted us. Overall, this fire is seen as an important learning opportunity.

Visit #16162 @Landels-Hill Big Creek Reserve

Approved

Under Project # 5891 | Research

SOD Impact Assessment, Monitoring and Evaluation

faculty - University of North Carolina

Reservation Members(s)

Group of 3 Graduate Student Oct 26 - 30, 2008 (5 days)
Group of 2 Faculty Oct 26 - 30, 2008 (5 days)
Group of 2 Research Scientist/Post Doc Oct 26 - 30, 2008 (5 days)

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Whale Point Researcher Cabin 7 Oct 26 - 30, 2008