Soil Disturbance Recovery after Timber Harvests - Malheur

<p style='margin:0in; margin-bottom:.0001pt;'><p style='margin:0in;margin-bottom:.0001pt;
mso-add-space:auto;text-indent:.25in;line-height:150%'><span style='font-size:
12.0pt;line-height:150%;font-family:&quot;Times New Roman&quot;,serif'>Soil productivity
is essential to the sustained production of ecosystem goods and services and
monitoring the impacts of land management is critical for ensuring the
continuation of productive forests.<span style='mso-spacerun:yes'>  </span>The
National Forest Management Act of 1976 (NFMA) mandates monitoring soil property
changes following management practices at all national forests, so they “will
not produce substantial and permanent impairment of the land”.<span style='mso-spacerun:yes'>  </span>The Forest Soil Disturbance Monitoring
Protocol (FSDMP) was developed by the U.S. Department of Agriculture Forest
Service (USFS) to ensure a standard method for collecting pre- and post-harvest
soil monitoring data.<span style='mso-spacerun:yes'>  </span>Data collected
following the FSDMP provide temporal and spatial insights into soil recovery
rates and alteration of soil processes or hydrologic function following
disturbance.<span style='mso-spacerun:yes'>  </span>The objective of this study
was to 1) identify site factors and operational harvest impacts that alter
dynamic soil properties, and 2) outline best management practices that account
for these site and operational factors.</span></p>

<p style='margin:0in;margin-bottom:.0001pt;
mso-add-space:auto;text-indent:.25in;line-height:150%'><span style='font-size:
12.0pt;line-height:150%;font-family:&quot;Times New Roman&quot;,serif'>Prior harvested
stands on the Malheur National Forest in northeastern Oregon, USA were identified
to reflect a range of soil types, climatic conditions, past timber harvest
mechanisms and seasonal timing, as well as topographic position (slope,
aspect).<span style='mso-spacerun:yes'>  </span>Fifty-one stands were selected
within a project area approximately 31,000 hectares<span style='mso-spacerun:yes'>  </span>and monitored retrospectively to evaluate
soil disturbance and site characteristics that influence soil recovery from
timber harvests completed within the past 5, 10, 20, or 40 years ago.</span></p>

<p style='margin:0in;margin-bottom:.0001pt;
mso-add-space:auto;text-indent:.25in;line-height:150%'><span style='font-size:
12.0pt;line-height:150%;font-family:&quot;Times New Roman&quot;,serif'>We found that clay
and silt content, spring moisture deficit, fall mean maximum temperature as
well as interactions between clay x silt content, depth to restrictive layer x
coarse fragment content, and silt x depth to restrictive layer had the most influence
on soil disturbance.<span style='mso-spacerun:yes'>  </span>Important
management considerations are (1) harvest operations that occurred during
winter months resulted in less soil disturbance, (2) greater clay content (relative
to silt content) decreased the amount of soil disturbance, and (3) soils show a
trend toward recovery 10-years after harvest operations are complete.</span></p><br /></p>

Tags: malheur-national-forest, soil-disturbance, soil-land-resources, soil-recovery, soil-science, soils-monitoring, university-of-idaho
Organization: University of Idaho