Research
The main focus of my research is quantifying how natural and anthropogenic disturbances shape forest ecosystems, emphasizing changes in structure and applications of quantitative modeling. To date, I’ve addressed this theme through studies of neighborhood effects in tropical plantations, natural variability in frequent-fire ecosystems, spatial patterns of ponderosa pine regeneration, forest restoration, course woody debris dynamics, and dendrochronology.
I also dabble in open-source electronics, remote sensing, artificial intelligence, and software development to further blur my roles as scientist, artist, ecologist, and hobbyist. Examples of my current research interests include:
Long-term Vegetation Changes in Ponderosa Pine-Bunchgrass Ecosystems – also known as the Woolsey Project – While most ecological research is done over short temporal scales, results may differ substantially over longer time frames. In a project collaborating with Northern Arizona University, Washington State University, and US Forest Service, I continue to examine long-term overstory tree and herbaceous understory vegetation dynamics of ponderosa pine (Pinus ponderosa) forests in the southwestern U.S. Using our unique dataset (>100,000 records), spanning almost a century, we are afforded unparalleled opportunities to model spatial and temporal dynamics and to provide guidance to ecological restoration in the region. We were recently awarded a second USDA NRI grant (bringing the funding total to just under $1,000,000). Collaborators on this project include Dr. Margaret Moore, Dr. Jon Bakker, (soon to be Dr.) Daniel Laughlin, myself, and Susan D. Olberding.
Effects of Spatial Pattern and Land-Use Legacies on Stand Dynamics – Forested stands are manipulated to achieve a range of management objectives, through various silvicultural treatments. These treatments affect the spatial pattern of individual trees and greatly affect observed stand dynamics and ecosystem processes (regeneration establishment, nutrient cycling, snag recruitment, etc). The primary goals of this study, which is an continuation of my dissertation research, were to determine how did disturbance influences the spatial and temporal patterns tree recruitment and How spatial pattern information, particularly with respect to patch characteristics, might inform current restoration and management practices.
Heterogeneity of Tree Size and Neighborhood Effects in Eucalyptus Plantations – Tree growth across a plantation is thought to be uniform, yet it can vary greatly in response to changes in microsite fertility, variations in precise silvicultural treatments, and neighboring. As part of an ongoing study with University of São Paulo, North Carolina State, Colorado State University, Aracruz Cellulose, and the Forest Nutrition Cooperative, I am please to be involved in a study examining the variability in tree size within three eucalyptus clonal plantations. This project is a cooperation between Dr. José Stape, Dr. Dan Binkley, and me.
Coarse Woody Debris and Recovery of Pinyon-Juniper Woodlands After Severe Fire – This project seeks to address questions related to post-fire recovery patterns in pinyon pine (Pinus edulis, P. monophylla) and juniper (Juniperus spp.), or “pinyon-juniper” ecosystems of northern Arizona. In particular, Dr. Dave Huffman and I are studying spatial arrangement of coarse woody debris, shrubs, and tree regeneration. It is our goal to evaluate relative importance of coarse woody debris and shrubs as nurse structures for both pinyon and juniper tree establishment. In addition, since sample plots were placed in wildfires of different ages, we’re looking at additional questions related to the length of time, or the period in woodland development, during which coarse woody debris is an effective facilitator of tree regeneration.
Biomass Assessment Techniques and Estimation of Biofuel Feedstocks – Tree biomass is defined as the total amount of living organic matter in trees and is typically expressed as oven-dry biomass per unit area (usually in tons/acre). More often than not, biomass is used to quantitatively describe changes in yield, growth, productivity, and structure; quantify or elucidate nutrient cycling; determine energy fixation in forest ecosystems; and (with increasing frequency) provide estimates of the carbon content in forest. My day-to-day job, and therefore a research interest, involves the utilization of biomass information within my agency. Suffice it to say, I’m currently involved in collaborative projects to assess methods to efficiently and accurately collect biomass information, validation of estimation equations and model forms at a national scale, facilitation of the utilization of biomass products as a source of biofuels.
Applications of Computer Science in Forest Ecology and Management – Computer Science is the systematic study of algorithmic processes that describe and transform information; basically, ‘What can be efficiently automated?’ This is an enduring theme of mine, beginning with my Masters work examining the effectiveness of artificial neural networks as a growth and yield modeling framework in longleaf pine ecosystems and progressing to my current infatuation with the application of structure from motion technology to tree allometrics and biomass estimation.
