Koa pasture scarification, silvopasture, and plantation
August 17, 2009 ~ Kukaiau Ranch
Koa forests can be restored to upland pastures in Hawaii either by soil scarification to stimulate germination of buried seeds or by planting. Cattle may be able to graze in open koa stands in silvopasture systems, but cattle eat the tops of young koa and may damage roots and introduce diseases even in older trees. Most koa plantations have been damaged by livestock and have very low potential timber yield. Here we demonstrate different methods of soil scarification and herbicide use to regenerate koa. We also investigate timber yield and quality from a nearby 33-year-old koa plantation.
University of Hawai‘i at Manoa
College of Tropical Agriculture and Human Resources
- James Leary, Assistant Specialist, Invasive Plants, Department of Natural Resources and Environmental Management, UH Mānoa CTAHR (Kula, Maui), 808-352-8774, firstname.lastname@example.org, http://www.ctahr.hawaii.edu/LearyJ/
- J. B. Friday, Extension Forester, Cooperative Extension Service, NREM, UH Mānoa CTAHR (Hilo), 808-969-8254, email@example.com, http://www.ctahr.hawaii.edu/forestry/
- Travis Idol, Associate Professor of Forestry, Department of Natural Resources and Environmental Management, UH Mānoa CTAHR (Mānoa), 808-956-7508, firstname.lastname@example.org, http://www.ctahr.hawaii.edu/Idolt/
USDA Forest Service Institute of Pacific Islands Forestry
- Paul Scowcroft, Research Forester, USDA Forest Service Institute of Pacific Islands Forestry (Hilo), 808-933-8121 ext 127, email@example.com, http://www.fs.fed.us/psw/programs/ipif/
- Robert Sporleder, Kukaiau Ranch, firstname.lastname@example.org
USDA Natural Resource Conservation Service Conservation Innovation Grant, http://www.nrcs.usda.gov/programs/cig/, Hawaii contact: Mike Whitt, Resource Conservationist, USDA NRCS (Honolulu), 808-541-2600 ext. 153, email@example.com.
Video Virtual Field Days
- Establishing Silvopastures with Acacia koa: Video of scarification for koa establishment at Kukaiau Ranch
- Thinning, Fertilization and Herbicide Trials to improve Koa Production: Video of thinning, fertilization, and herbicide trials to improve koa production in a young koa stand at Umikoa Ranch
- Grass Suppression for Koa Regeneration: Dr. James Leary, UH-CTAHR, conducts herbicide trials at the Kona Hema Reserve to control grasses suppressing regrowth of koa seedlings (Acacia koa) using glyphosate (Roundup®), fluazifop-p-butyl (Fusilade®), and imazapyr (Habitat®). Dr. Leary also demonstrated use of a hands-free spraying system and evaluates the impacts of imazapyr on other native species (ohia, Metrosideros polymorpha)
- Herbicide Trials on kikuyu grass at Hawaii Volcanoes National Park: Dr. James Leary, CTAHR Invasive Weed Specialist, initiates herbicide field trials with staff from the National Park Service (NPS) on kikuyu grass (Pennisetum clandestinum) at Volcano National Park. Herbicides tested were: glyphosate and imazapyr. Two types of hands-free spraying systems are shown. Dr. Leary visits the site again and reports back on how the herbicides performed.
Herbicide application for grass suppression for koa establishment
Soil scarification for koa establishment [photos by J. B. Friday]
Experimental harvest of five koa trees in the 33-year-old “cornfield” plantation at Kukaiau Ranch [all photos are by J. B. Friday except for photo 9 by Jian Wang.]
Handouts from the field day (all files in pdf format )
Handout on koa scarification demonstration, 33-year-old “cornfield” koa plantation, and results of experimental thinning of koa stands at Umikoa ranch
- Handout on 21-year-results of soil scarification for koa establishment at Hakalau Forest National Wildlife Refuge