Research

Research

Current Research

Bark Beetles

soil respiration
woody decomposition
soil sampling

Working with an interdisciplinary team of entomologists, biologists, and metagenomicists, we have established research sites in Mississippi, Arizona, and Honduras to experimentally quantify the contribution of a fungi-mediated interaction between bark beetles and subterranean termites to wood decomposition rates across coniferous forests (tropical, subtropical, and arid). We measure meteorological parameters (temperature, precipitation, throughfall, soil moisture), wood and soil heterotrophic respiration, and wood and soil carbon and nitrogen to isolate the role of biological interactions from exogenous climatic conditions on nutrient turnover dynamics. The link between two ecosystem engineers (bark beetles and termites) is likely a significant driver of carbon fluxes in many forest ecosystems, and therefore may have significant impact on the future conceptual frameworks employed to quantify and model wood decomposition rates.

Bark Water Storage

bark
measuring bark

Bark is a large reservoir for water storage in forest ecosystems. It is directly exposed to wetting during rainfall and reacts to changes in relative humidity via absorption or desorption of water vapor with the atmosphere. The proportion of rain water that can be absorbed and stored in bark compared to the amount that makes it to the forest floor and to the tree's roots depends on the species. In this way, bark influences the water cycle of individual trees and entire forests. Differences in bark structural traits such as density, porosity, hydrophobicity (external water repellency), and hydroscopicity (internal water retention) vary among directly influence the water storage capacity of a tree. This research spans forest types across continents to understand:

  1. How structural and physical differences of bark among species impact bark water storage.

  2. How these differences are manifested under varying rainfall and drying regimes.

  3. How these differences change along the tree trunk, across age classes, and across forest management regimes.

CRP Climate Change Mitigation

soil sampling
data logger

Southeastern forests exhibit high productivity and Conservation Reserve Program (CRP) tree plantings in the region have the potential to sequester significant amounts of carbon as well as providing co-benefits. In this project, we are evaluating CRP tree plantations across the Major Land Resource Areas in the southeastern US by collecting forest inventory data integrated with terrestrial LiDAR, high resolution point dendrometer recordings and allometric models to improve estimates of carbon sequestration in aboveground biomass. We are measuring belowground soil pools and soil greenhouse gas fluxes to calibrate key parameters in the DayCent model to estimate climate change mitigation benefits of this systems. We are also quantifying wildlife co-benefits of CRP tree plantings and develop improvements to the harvest wood products module in COMET-farm.

 

Mesophication

stemflow
fire

​​In eastern upland oak forests, anthropogenic suppression of natural fire has led to the establishment of shade-tolerant species (red maple, hickory, ash) which create damp and dark understory conditions. These species outcompete oaks (a process called mesophication), preventing oak regeneration and leading to dramatic change in forest composition across large swathes of the eastern US. In this project, we seek to understand:

  1. How water resource distribution by the forest canopy is impacted by difference physical and morphological structures of oaks vs. non-oaks and how this distribution impacts soil and fuel moisture.

  2. How soil biogeochemistry varies among oaks vs. non-oaks.

  3. How prescribed fire as a management tool impacts soil stability, erosion potential, and water quality.

Short Rotation Woody Crops

short rotation bioenergy crops
soil respiration

Short rotation woody crops such as eastern cottonwood (Populus deltoides), hybrid poplar (Populus spp.), black willow (Salix nigra), and American sycamore (Plantanus occidentalis) are fast growing, competitive species ideally suited for biomass plantations for bioenergy production. These systems can provide both ecosystem services and disservices through their fast growth and resource consumption that need to be evaluated along with their productivity and biomass quality. We seek to address these questions across a suite of experimental plantations throughout the southeast investigating:

  1. Soil carbon sequestration and storage potential

  2. Soil nutrient uptake and availabilty

  3. Soil respiration and other greenhouse gas emissions

  4. Agricultural runoff mitigation and water quality

  5. Rainwater partitioning