Decline of Casuarina equisetifolia: A Loss to Pacific Island Agroforestry

Project Overview

Project Type: Research and Education
Funds awarded in 2008: $140,680.00
Projected End Date: 12/31/2013
Region: Western
State: Guam
Principal Investigator:
Roger Brown, Jr.
University of Guam
Dr. Robert Schlub
University of Guam

Annual Reports


  • Additional Plants: trees, ornamentals


  • Crop Production: windbreaks
  • Education and Training: technical assistance, decision support system, extension, focus group, on-farm/ranch research, participatory research
  • Pest Management: disease vectors, field monitoring/scouting, genetic resistance, integrated pest management, prevention, sanitation
  • Sustainable Communities: public participation, sustainability measures


    Ironwood trees (Casuarina equisetifolia) on the island of Guam began dying in 2002. By 2005, Ironwood tree decline (IWTD) was widespread and undiagnosed. With funding from Western SARE (Sustainable Agriculture Research and Education) in 2008, a research program commenced with preparations for a five-day IWTD conference in 2009. Research of conference attendees and others since then established that a complex of abiotic and biotic factors are involved in IWTD. Abiotic factors include host genetics, site environment and management practices. Biotic factors include Ganoderma wood rot, termites and xylem-residing bacteria Ralstonia solanacearum, Klebsiella oxytoca and K. variicola.

    Project objectives:

    Objective 1: Develop a diagnostic key for all known injury, signs and symptoms that occur on Ironwood worldwide. Consultation: Five day meeting on Guam to finalize survey procedures and diagnostic key.

    Objective 2: Determine the amount of change in Guam’s Ironwood population from 2002 to the present.

    Objective 3: Categorize tree damage according to injury, signs and symptoms and record percent of each occurrence.

    Objective 4: To inform the public of the survey finding and to form an Ironwood Tree Decline Committee.

    Objective 5: Identify a source of seeds from superior Ironwood trees that the Guam Department of Agriculture can use in their give-away program.

    Objective 6: Based an analysis of the data collected in Objectives 1-3 a conclusion will be drawn as to the cause or causes for ironwood decline.

    Objective 7: Drawing from the results of objective 6 and the knowledge and expertise of others, the Ironwood Tree Decline Committee will develop management strategies for Ironwood decline and host a three half-day Ironwood tree workshops: one for government agency employees and two for farmers and the general public.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.