Borehole oleoresin production from slash pine

Abstract

A process is described for production of oleoresin from borehole wounds to the xylem in slash pine (Pinus elliottii Engelm. var. elliottii). Advantages of this process over conventional oleoresin production methods include higher labor productivity, improved product quality, reduced tree damage and stress, and reduced insect pest problems. In experiments conducted in Florida and Georgia from 1991 to 1994, oleoresin yields averaged 657 g (1.45 lb) per borehole, or nearly 1.7 kg (3.7 lb) per tree with multiple boreholes. Tests of other species used commercially for oleoresin production, including longleaf pine (Pinus palustris Mill.), produced substantially lower yields. Borehole oleoresin yields were very sensitive to tree stem size, reflecting the capacity of preformed oleoresin stored in the resin duct system. Yields were significantly affected by treatment manipulations of borehole diameter, depth, number, spacing, orientation, chemical stimulants, and collection container type. Oleoresin flow was highest during the midsummer period and continued over a period of several months. Oleoresin flow potential was related to the percentage of tree stem basal area tapped. For optimal treatments affecting 35 to 40% of tree basal area, predicted yields ranged from 1.52 to 3.10 kg (3.35 to 6.83 Ib) for trees 23 to 37 cm (9 to 14.5 in.) dbh, respectively. Tree growth rates were not measurably altered by borehole treatment. Comparisons with conventional bark-chipping oleoresin production systems in slash pine showed that the borehole system achieves a labor productivity two times greater than the best alternative, but sacrifices overall yields per tree. The borehole method offers new opportunities for utilization of the slash pine resource and an additional economic enterprise for forest lands.