Experimental Tropical Hardwood Plantation

Project Description

The plantation is located on a 3 acre parcel of land at the University of Hawaii at Hilo College of Agriculture's Farm in Panaewa on the Island of Hawaii.  The eight hardwood species used in this experiment are:

1) naio (Myoporum sandwicensis)

2) narra (Pterocarpus indicus)

3) kamani (Callophylum inophylum)

4) koa (Acacia koa)

5) milo (Thespesia populnea)

6) gmelinia (Gmelinia inophyllum)

7) rainbow eucalyptus (Eucalyptus deglupta)

8) kou (Cordia subcordata)

The experiment has a twofold purpose.  Primarily it is designed to test the benefits of growing hardwoods in association with NFTs (Nitrogen-fixing trees).  For this experiment, Acacia angustissima, was used as it is a fast-growing leguminous tree that can be extensively pruned every 3-6 months.  The trimmed branches and foliage are left in the plot as a source of nitrogen and organic matter.  The goal is to determine whether this supplies enough available nitrogen to the hardwoods to cause a measureable increase in growth, outweighing the effect of increased competition for space and light.

Additionally, it is hoped to identify high value hardwoods that thrive in Hawaii, specifically a species that can grow at low elevations on unimproved a'a lava substrate.

The land is divided into 6 main plots, with eight subplots (one for each species) arranged in a randomized block design within each main plot.  Three of the main plots are planted with NFTs and 3 without.