Researchers are looking into the development of a system to predict yield of Acacia mangium, one of the common plantation tree species in Asia. Mr. Richmund Palma of the Misamis Oriental State College of Agriculture and Technology with Ms. Delia Catacutan and Ms. Charmaigne Pailagao of the World Agroforestry Center conducted a study to provide growth and yield information on Acacia mangium plantations to be able to predict the most profitable time of harvesting trees.

Acacia mangium is known for its good wood quality and adaptability to a wide range of soil types and hydrogen concentration (pH).
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The researchers used 51 temporary plots within the municipality of Claveria, Misamis Oriental in developing the yield model and the validation test. The yield prediction model consisted of site index guide equation and stand volume equation based on stand age, site quality, and spacing.

Yield tables for trees ages 3-18 years, 12-25 m in height and planted at the following spacing: 2m X 2m, 1m X 4m, 2m X 3m, 1m X 6m, 2m X 4m, 3m X 3m, 3m X 4m, 2m x 6m, and 2m X 8m, were constructed based on the derived model.

Using the yield prediction model, a plantation manager can predict with reliability the yield of an Acacia mangium plantation based on its age, spacing, and site quality. However, the model may not be applicable to other places and still has to be validated or modified.

The use of the equation in plantations beyond 18 years, 24.44 m and 2m X 8 m requires care. Validation test should be conducted before using the model outside the ranges of the data gathered and also the locality.

In a report to PCARRD, the researchers suggested that in order to further improve the equation, the model should consider other methods and variables; the number of plots should be increased to include other ages and varying site qualities; the effect of soil properties should be looked into; and the formulation of bark thickness, taper equation, and basal area equation be considered. (Leila C. America, S & T Media Service)