Project Title: DESIGN OF AN AGROFORESTRY SYSTEM WITH STRUCTURED TREE CLUSTERS

Principal Investigators: Zeide, B.; Francis, P.; Kluender, R.

Grant Number: 97-35108-5126

Specific Aims

1. Implement a study to determine the best spatial configuration of two-species tree clusters and rows in the framework of an improved agro-silvicultural system and an agro-silvo-pastoral system.

2. Initiate monitoring of the economics and ecological impacts of these agroforestry systems to be continued over the life cycle of system (the 25-year timber component is the longest).

3. Use the results of monitoring in adaptive management and modify the original designs on the basis of that feedback.

Results

The study has been established on a 30-acre field of located at the Southwest Research and Extension Center of the Arkansas Agricultural Experiment Station in Hope, AR. 27 acres are used for the main study. This area is divided into two equal portions, one for hay and another for beef production. Three replications have been established in each portion. The area for each treatment block is 27/(2 x 3) = 4.5 acres. The remaining 3 acres are used for comparative studies.

Establishment of the study involved the following operations.

Ground preparation

(1) layout and flagging the plots (September-October 1997); (2) spraying Roundup to suppress competing vegetation (October 1997); (3) broadcasting clover (October 1997); (4) flagging tree clusters for planting (January 1998, Figure 1); (5) flagging the competition study (January 1998); (6) putting out T-posts to mark and protect tree clusters (April 1998).

Tree planting

(1) planting shortleaf pine (Pinus echinata L., February 1998); (2) planting loblolly pine (Pinus taeda L., February 1998); (3) replacing shortleaf pine that died (March-April 1998);

Vegetation control

(1) spraying Oust (2 oz per acre) and Velpar (1 qt per acre) to control competing vegetation within tree clusters (March 1998); (2) spraying tree clusters with Poast Plus (0.5 lbs/acre, August 1998).

Hay harvesting and fertilization

(1) first cutting, raking, baling, and weighing of hay (31,000 lb, May 1998); (2) applying 350 lbs/acre of 17-17-17 (May 1998); (3) second cutting, raking, baling, and weighing of hay (48,850

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lb, July 1998); (4) third cutting, raking, baling, and weighing of hay (27,900 lb, July 1998).

Unexpected Problems

Due to the severe drought, this was the worst year in history to plant tree seedlings. Despite great care, about 35% of the loblolly pine seedlings and 45% of the shortleaf seedlings died.

Plans for the Coming Year

In addition to the planned activities (measuring trees, cutting, raking, baling, and weighing of hay, fertilizing forage alleys), we will replant missing trees in February 1999.

Other products

An original frame to precisely plant two species of trees was designed by Bob Colvin, who was leader of the team that established this study (Figures 2 and 3).

Publications

Zeide, B. 1998. Design of an agroforestry system with structured tree clusters. In Proceedings of the VII International Congress of Ecology, p. 475. Edited by A. Farina, J. Kennedy, and V. Bossu. Alitalia, Florence, Italy. 480 p.

Zeide, B. 1999. Long-term study of agroforestry systems based on structured tree clusters. To be presented at Long term Observations and Experiments in Forestry. IUFRO International Symposium, CATIE, Costa Rica, February 23-26, 1999.