Impacts of Tree Plantation Harvesting on Soil Density and Porosity in CARAGA Region, Mindanao, Philippines

Abstract

Tree farming is a common livelihood for people in the CARAGA
region. About 2.5 million Filipinos are employed in the tree
plantation industry. Harvesting is normally seen in the region on
a daily basis, where its impacts are unaccounted for. This
research was conducted to study the effects of harvesting on soil
bulk density and porosity at the CARAGA region.

An experiment following a Randomized Complete Block Design
(RCBD) with three treatments: control, landing site, skid trail,
and three replications were set-up. Thirty soil samples were
gathered from each replicate and processed in the laboratory.

Results showed that mean bulk density was1.29±0.08g cm-3 for
the no harvesting site, 1.41±0.10g cm-3 for the landing site and
1.54±0.11 g cm-3 for the skid trail. There was a 19% increase in
bulk density for the skid trail as compared to the control site.
These values exceed the growth limiting value of 1.45-1.5 g cm-3.
Mean porosity values were 51±3% for the no harvesting site,
47±4% for the landing site and 42±4% for the skid trail. A
significant decrease of 22% in porosity for the skid trail
compared to the control was observed.

It is recommended that tillage be practiced to enhance aeration
and decrease compaction in the site. The use of slash treatments
to minimize the adverse effects of felling and skidding is also
suggested.