Ponderosa pine growth response to soil strength in the volcanic ash soils of central Oregon.

Abstract

Mechanical harvesting and associated logging activities have the capacity to compact soil across large portions of harvest units. Two thinning treatments (felled only versus felled and skidded) in 70- to 80-year-old ponderosa pine stands were replicated at three sites with volcanic soils in central Oregon. Growth in diameter, height, and volume of residual trees were related to degree of soil compaction, measured as soil strength with a recording penetrometer. Felled and skidded plots had significantly higher soil strength values than felled-only plots (42 percent). Tree diameter, height, and volume periodic annual increment declined significantly as average soil strength values increased above undisturbed conditions.

Citation

Parker, R.T.; Maguire, D.A.; Marshall, D.D.; Cochran, P. 2007. Ponderosa pine growth response to soil strength in the volcanic ash soils of central Oregon. Western Journal of Applied Forestry. 22(2): 134-141