Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
(N/A)
Non Technical Summary
On September 26, 2024, Hurricane Helene made landfall as the strongest-ever hurricane observed in the Big Bend region of Florida. It caused significant damages, not only to homes and businesses, but also to the timber industry that occupies a large area in the region and is a main source of income in southeastern United States. However, aside from the immediate damage to the pine stands along the hurricane path, the hurricane could trigger other delayed effects, such as proliferation of disease. The trees suffer wind-related stress as well as wounding due to limb loss or damage from objects transported by high-speed winds. Identifying risks associated with extreme weather events, disease incidence, and other stress factors can provide landowners with valuable information to mitigate the impact of high winds and wind-induced disease outbreaks in pines.Pitch canker is a common disease in pines and one of the most damaging. It is caused by the fungusFusarium circinatum,which is already abundant in the area. The lesions caused by the hurricane and flying debris facilitate the entry of the fungus, which in turn may produce disease outbreaks several months after the hurricane. Knowing how this disease occurs and spreads in the months after a hurricane will help timber growers, private landowners, and conservation organizations to better predict potential losses, mitigate damage, conduct salvage operations in affected areas, and determine silviculture regimes to maximize survival in risk-prone areas. There are current models that estimate damage to timber stands after a hurricane, but it does not take into account the effects of disease months after hurricane landfall. The data obtained through this project would allow to add that feature into these models. In addition, wind damage can also cause physiological effects in trees, such as hydraulic dysfunction, which reduces the transport of water and nutrients through the tree, which could kill growing tips or branches.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
?The overall objective of this project is to understand how wind damage affects incidence and severity of pitch canker disease and predict the probability that stands will be damabed by disease outbreaks in loblolly and slash pines.We hypothesize that trees exposed to high winds will show significant differences in disease severity and hydraulic function. To test this hypothesis and fulfill the overall objective of this study, we propose the following specific aims:Aim 1: Determine the impact of wind speed on pitch canker incidence, hydraulic dysfunction, and disease severity in stakeholder plantings previously pre-screened for pitch canker. To accomplish this, we will 1.1)catalog and quantify the incidence of factors likewind damage, pitch canker disease, and hydraulic dysfunction in slash and loblolly pine stands at different distances from the path of Helene and compare with wind records obtained across these areas. 1.2) Identify differences of disease severity in families pre-screened for pitch canker and compare with previous controlled trials on those families. 1.3) Perform controlled experiments in wind tunnels to reveal the mechanisms of hydraulic dysfunction and asssess pitch canker symptoms in pines subjected to wind tunnel conditions.Aim 2: Develop hurricane pitch canker risk reporting systems for near-term (90 days) and long term (12-15 months) after hurricane landfall that could be integrated into current monitoring models.
Project Methods
The methods for each aim are the following:Aim 1: Determine the impact of wind speed on pitch canker incidence, hydraulic dysfunction, and disease severity in stakeholder plantings previously pre-screened for pitch canker.Aim 1.1. At each site, we will measure mortality (fallen trees) and disease symptoms at 6, 9, and 12 months after hurricane landfall, including branch dieback, resinosis, survival, crown health, and F. circinatum fruiting bodies (sporodochia), as well as other signs of stress or decay, like the presence of bark beetles or other opportunistic pathogens. This will allow to inform the public when to expect symptoms of the disease and prepare accordingly. During surveys, we will sample branches from assessed trees at each location, transport them to the laboratory in Gainesville, FL, and determine hydraulic dysfunction by measuring the percent loss of hydraulic conductivity. We will use multivariate analyses to analyze the complied data to develop and estimate correlations between wind speed, planting density, tree age, tree health, tree size, hydraulic dysfunction and pitch canker disease severity. Because the proposed stands have different ages, this variable will be included as covariate to adjust our analysis.Aim 1.2.For those sites where there is pedigree information, we will collect genetic data and compare with previous controlled trials (i.e. greenhouse trials)on those same families, where available. Using this genetic data, we will use linear mixed models to estimate family breeding values and rank them according to disease tolerance, as well as trait-trait and site-site genetic correlations to assess significant relationships between wind damage and pitch canker incidence.Aim 1.3.To reveal the mechanisms of hydraulic dysfunction and improve our field-based observations of wind-induced damages, we will expose pine saplings and excised pine branches from trees not exposed to hurricane Helene to controlled conditions replicating the wind-speed gradient of our field sites. These experiments will be conducted at the University of Florida's Self-configuring Boundary Layer Tunnel (BLWT), which is capable of replicating strom-force winds under controlled conditions.Afterwards, we will inoculate a subset of these with pitch canker and will measure others for hydraulic dysfunction (as in Task 1.1). Finally, we will assess disease symptoms on the pathogen-challenged subset and conduct X-ray MicroCT imaging of the intact plants, to determine the degree to which high wind speeds can induce irreversible hydraulic dysfunction in pines, to improve models of long-term hurricane impacts on growth.Aim 2: Develop hurricane pitch canker risk reporting systems for both the near-term (first 90-days) and long-term (upon project completion, up to 15 months after hurricane landfall) that could be integrated into current monitoring models.Aim 2.1.In the first 90 days of the project, we will work with FBRC cooperators and Georgia landowners to select additional sites outside of the current FBRC study sites to include in this study. After our initial field assessment and hydraulic dysfunction tests, we will produce a document detailing our observations that will be distributed directly to corporate land manager stakeholders, as well as a broader range of private landowners through the Florida Land Steward program (https://programs.ifas.ufl.edu/florida-land-steward/)at the University of Florida School of Forest, Fisheries and Geomatic Sciences and the ProForest group (https://proforesthealth.org/).Aim 2.2.. By the end of the project (15 months after hurricane landfall), we will have a complete assessment of the impact of Hurricane Helene on forest health and the effects of high winds on stem hydraulics. We anticipate producing an open-access research article with the results of this project.