Douglass F. Jacobs

Director, Tropical Hardwood Tree Improvement and Regeneration Center (Tropical HTIRC)

Douglass F. Jacobs is the Fred M. van Eck Professor of Forest Biology in the Department of Forestry and Natural Resources at Purdue University and Affiliate Graduate Faculty in the Department of Natural Resources and Environmental Management at the University of Hawai‘i at Mānoa. He studies the ecology and physiology of forest regeneration. He began working in Hawai‘i in 2003, co-instructing a course on forestry nursery systems to Pacific Island managers, which led to the publication of the Tropical Nursery Manual (USDA Forest Service Agriculture Handbook 732). He was based in Hilo during 2016, where he was a Visiting Professor at University of Hawai‘i at Mānoa and the USDA Forest Service Institute of Pacific Islands Forestry. As Director of Tropical HTIRC, he leads an integrated research and extension program to promote the restoration of native Hawaiian forest tree species.

Tropical HTIRC Advisory / Steering Committee:

The role of the committee is to provide guidance on the strategic directions of the center, prioritization of research themes, and staffing. The committee is comprised of members representing diverse groups associated with ecology and management of Hawaii's forests. Many of the committee members are active collaborators on Tropical HTIRC research and extension projects.


Title, Institution

Steve Bergfeld
Hawai‘i Island Branch Manager, DLNR Division of Forestry and Wildlife
Kualiʻi Camara
Department of Hawaiian Home Lands
Phil Cannon
Forest Pathologist, USDA Forest Service, Pacific Southwest Region
Michael Constantinides
State Forester, USDA Natural Resources Conservation Service, Pacific Islands Area
Susan Cordell
Director, Institute of Pacific Islands Forestry, USDA Forest Service, Pacific Southwest Research Station
Nicklos Dudley
Forester and Maunawili Experiment Station Manager, Hawaiʻi Agriculture Research Center
J.B. Friday
Extension Forester, University of Hawaiʻi at Mānoa
Christian Giardina
Research Ecologist, USDA Forest Service, Pacific Southwest Research Station
Matthew Ginzel
Professor and HTIRC Director, Entomology and Forestry and Natural Resources, Purdue University
Jennifer Grimm
Forest Manager, DLNR Division of Forestry and Wildlife
Jesica Gurevitch
Department Head, Forestry and Natural Resources, Purdue University
Diane Haase
Western Forest Nursery Specialist, USDA Forest Service, Pacific Northwest Region
Neil Hannahs
Paniolo Tonewoods
Robert Hauff
Protection Manager, DLNR Division of Forestry and Wildlife
Travis Idol
Professor of Tropical Forestry and Agroforestry, University of Hawaiʻi Mānoa
Nicholas Koch
Paniolo Tonewoods
Creighton M. Litton
Professor of Ecosystem Ecologist, University of Hawai‘i
Robert K. Masuda
Forestry and Natural Resources, Purdue University
Irene Sprecher
Forest Solutions, Inc.
Aina Wieczorek
Interim Dean, College of Tropical Agriculture and Human Resources, University of Hawai‘i at Mānoa

Tropical HTIRC Graduate Students, Staff, and Affiliate Scientists

Erin Bell

Erin Bell is a PhD student with the Department of Forestry and Natural Resources at Purdue University. She earned her undergraduate degree in Biology from Carroll College in 2014 and her master’s degree from Miami University in 2020. Prior to enrollment at Purdue, she gained experience in ecological research in Idaho and Montana with the US Forest Service before moving to work in the diverse ecosystems of Hawai’i. Working with Maui Forest Bird Recovery Project and their partners since 2019, she developed a passion for native plants and the unique relationships they hold with Hawai’i’s forest birds. Erin is interested in pursuing research that explores forest restoration techniques that benefit native birds, land managers, and plant biodiversity to inform and influence management decisions.

Owen Burney

Owen is an Professor at New Mexico State University. He is leading projects related to thinning of juvenile stands of koa, grafting of koa, ‘iliahi restoration, and collaborating on other initiatives.

Solomon Champion

Solomon Champion is a PhD candidate in the Botany Department at the University of Hawai‘i at Mānoa, studying the genetics of native Hawaiian tree species. Solomon’s interests are in genomics, phylogenetics, and evolution. He is using population genetics to elucidate population structure within the Hawaiian sandalwoods as a whole and to identify hybrid individuals. Solomon is using physiological and genomic methods to characterize genotypic variation at the individual and population levels. He hopes this research helps answer practical questions about phenotypic plasticity, local adaptation and hybridization within ‘iliahi.

Aziz Ebrahimi

Aziz Embrahimi is a post-doctoral fellow at Purdue University, studying forest growth-climate interactions and molecular physiology and genes related to cold tolerance in koa and also phylogenomic of Juglans species. Aziz’s interests are in landscape genomics, phylogeny, and the evolution of tree species. Aziz is using genetics, genomics, and bioinformatics tools to address two critical steps for increasing the success of koa restoration at high elevation: characterization of koa genetic diversity across an elevational gradient, and the identification and characterization of genes influencing seedling cold tolerance.

Kelly French

Kelly French is a PhD student at Purdue University, Department of Forestry and Natural Resources. Kelly earned her BA in Biology from Colgate University in 2015 and worked for four years in human genetics while spending most weekends working on her family’s 450-acre Tree Farm in Maine. This drove her to return to school to study forestry, and in 2021 she graduated with her MS in Forest Resources from the University of Maine where she studied tree ecophysiology. During her PhD, Kelly is especially interested in investigating tree water and carbon relations in ‘iliahi and various host species, while developing adaptive management strategies to minimize drought stress. She plans to use physiological parameters to inform longer-term species growth responses, and is interested in how macroclimate, microclimate, and elevation influence these responses.

Simon Landhäusser

Simon Landhäusser is a Professor at University of Alberta. He is collaborating in projects on ‘iliahi physiology and host plant interactions, koa propagation and planting, and the role of carbon reserves for disease resistance in ʻōhiʻa

Quinn Moon

Quinn Moon is a senior Global Environmental Science and biology student at the University of Hawai‘i at Mānoa. For the past few years, he has helped on a number of research projects including the early establishment of ‘iliahi with endemic host species and studying the symbiotic nutrient transfer between koa and ‘iliahi. In 2022, Quinn traveled to Hawai‘i Island to assist Emily Thyroff in both greenhouse and field experiments. Quinn is planning to begin a PhD studying the ecology and evolution of plant-fungal interactions.

Rebekah Ohara

Rebekah Ohara is a PhD candidate in the Forestry and Natural Resources Department at Purdue University focusing on the pathways and opportunities for community-managed forests in Hawai‘i. She is the CEO for the Akaka Foundation for Tropical Forests, a nonprofit organization with a vision of vibrant forest communities alive with the voices of Hawai‘i from one generation to the next. Rebekah received her B.A. in Anthropology in 2009 from Humboldt State University (HSU), and in 2013 she completed her M.A. in Social Science at HSU’s Environment and Community Program, focusing on the social and ecological considerations of tropical forest conservation in Ecuador. Rebekah previously served as a Teacher’s Assistant and Field Guide for HSU’s Primate Field School at the Organization for Tropical Studies in Costa Rica.

Kylle Roy

Kylle Roy is a PhD candidate at Purdue University in the Department of Forestry and Natural Resources. She is both an Alfred P. Sloan Scholar as well as a Purdue Doctoral Scholar. Kylle is studying the chemical ecology of beetles, fungi, and ʻōhiʻa trees in association with Rapid ʻŌhiʻa Death (ROD). She hopes to develop management strategies for controlling the spread of ROD. Born and raised in Hawaiʻi, Kylle has a general interest in conservation of Hawaiian forests, especially in relation to entomology, disease, and molecular tools. Kylle has a MSc in Tropical Conservation Biology and Environmental Science from the University of Hawaiʻi at Hilo and a BS in Biological Sciences and a minor in Environmental Science from Chapman University in Orange, CA. Kylle recently accepted an Entomologist position for Hawai’i and the U.S.-affiliated Pacific Islands with the Forest Service Forest Health Protection stationed in Hilo, HI to begin in January 2023.

Tawn Speetjens

Tawn Speetjens is a PhD student at Purdue University in the Department of Forestry and Natural Resources (FNR) starting in spring 2023. He was born and raised on the Big island of Hawaiʻi, and graduated from the University of Hawaiʻi, Hilo in 2009 with a BS in Biology, and recently graduated from Purdue University in December 2022 with a MS from the Department of Forestry and Natural Resources. He has worked extensively throughout Hawai`i’s diverse ecosystems with highlights which include working for the USFWS on Laysan Island in the northwestern Hawaiian Islands, banding forest birds at the Hakalau National Wildlife refuge, and conducting watershed management with the Kohala Watershed Partnership. Prior to his enrollment at Purdue University, he worked as a forester and nursery manager for the Hāloa `Āina Reforestation Project where he was introduced to the unique challenges of growing Hawaiian sandalwood species (`iliahi). Tawn has a passion for growing Hawaii’s native plants and is interested in the development of propagation techniques for `iliahi and other Hawaiian native plant species. His masters research examined; 1) the effects of controlled release fertilizers, chelated iron treatments, and pot hosts on S. paniculatum seedling quality in the nursery, and 2) the effects of nursery fertilization, pot host, and established field hosts on S. paniculatum field planting performance. For his PhD program, he will continue his research with S. paniculatum while addressing the mechanisms underlying the haustoria-host connection and a broad host species suitability assessment.

Emily Thyroff

Emily Thyroff is a a post-doctoral fellow at Purdue University, studying tropical dry forest restoration with regeneration of endemic Santalum species, known as ‘iliahi or Hawaiian sandalwood. She earned a BS in biology from James Madison University, a MS in forest biology from Purdue University, and a PhD in natural resources and environmental management from the University of Hawai‘i at Mānoa.

Aaron Wehrman

Aaron Wehrman is a first year MEM (Masters in Environmental Management) student at the University of Hawai‘i at Mānoa. He was born and raised on Oahu and graduated from the University of Hawai‘i at Hilo with a BS in Environmental Science in 2022. In his undergraduate, Aaron started his work in Marine Science but has since made his transition to applied terrestrial ecology. He is currently working with Dr. JB Friday, Dr. Travis Idol, and the DHHL on an Acacia koa reforestation project on Mauna Kea. He is specifically interested in looking at the temperature differentiation caused by Ulex europaeus (gorse), an invasive species that covers the region, to see if it can protect koa seedlings from frost damage. Aaron is extremely grateful to the Hau’oli Mau Loa foundation for funding his education and research.

Pandu Wirabuana

Pandu Wirabuana is a PhD student at the University of Hawai‘i at Mānoa. He earned a BS in silviculture from Universitas Gadjah Mada and a MS in forest conservation from similar institution. He spent 8 years of his career working on reforestation in Indonesian tropical forest. He has worked in several types of ecosystems, like mangrove, lowland forest, and upland forest. Pandu previously worked as a junior staff in the Faculty of Forestry, Universitas Gadjah Mada. Since 2022, he had been working with Dr. Travis Idol as his advisor to develop a research project studying the interaction between neighborhood trees and hemiparasitic species in Hawaiian tropical dry forests.

Tropical HTIRC Graduate Student Alumni and Past Staff

Achyut Adhikari

Achyut is a MS student at the University of Hawai‘i, studying biology of koa reproduction and vegetative propagation, to help overcome koa wilt.

Lilian Ayala

Lilian was an MS student at Purdue University, studying genetic variation in cold tolerance, survival, and growth of high-elevation koa.

Gaoussou Diarra

Gaoussou completed his Ph.D. at the University of Hawai‘i in 2015, studying seedling nutrition.

Erin Hickey

Erin completed her M.S. at the University of Hawai‘i in 2016, studying vegetative propagation.

Faith Inman

Faith was Tropical HTIRC project coordinator and Research / Extension Faculty with University of Hawai‘i from 2013-2016.

Bradley Kaufmann

Bradley completed his M.S. at the University of Hawai‘i in 2016, studying nursery systems. He was then Tropical HTIRC project coordinator and propagation specialist until 2018.

Oriana Krauss

Oriana completed her M.S. at Purdue University of Hawai‘i in 2014, studying tree improvement. She was a Tropical HTIRC research associate and University of Hawai‘i Junior Extension Agent until 2016.

Shaneka Lawson

Shaneka is a Research Plant Physiologist with the USDA Forest Service, Northern Research Station, studying genetic variation among koa populations and genes regulating the formation of figured wood.

Bob Masuda

Bob was a Tropical HTIRC senior advisor from 2010-2017.

Charles Michler

Charles was a USDA Forest Service Northern Research Station Project Leader and the first Tropical HTIRC director.

Juan Oliet

Juan was a visiting professor with Tropical HTIRC during 2014-2015, studying ecophysiology of forest restoration. He is a Professor at the Technological University of Madrid, Spain.

Indira Paudel

Indira is a post-doctoral scientist at Purdue University, studying adaptiveness of koa populations to resource availability.

Kyle Rose

Kyle completed his Ph.D. at Purdue University in 2017, studying the adaptive role of heteroblasty in koa.

Anna Sugiyama

Anna was a post-doctoral scientist at Purdue University, studying use of intraspecific variation to predict seedling performance in koa.

Adel Youkhana

Adel is a post-doctoral scientist at the University of Hawai‘i, studying clonal propagation of koa.