Hydrologic response to conifer removal and upslope harvest in a montane meadow

Transcription

1 Hydrologic response to conifer removal and upslope harvest in a montane meadow Dr. Chris Surfleet, PhD, Associate Professor Watershed Management and Hydrology, csurflee@calpoly.edu Graduate Research Assistant, Noël Fie, nfie@calpoly.edu

2 OutlineOutline of Discussion Background information on conifer encroachment and montane meadows Research objectives Methodology Preliminary Results Questions

3 What is a montane meadow A groundwater-dependent ecosystem type dominated by herbaceous plant species where woody vegetation may be present, which supports plants that use surface water and or shallow groundwater at some point during the growing season Found at elevations higher than 500 meters

4 Why restore meadows? Small, isolated openings create habitat and provide water for species Soils of high-elevation meadows have high carbon (C) and nitrogen (N) densities which are important for storing water, retaining potential pollutants, and sustaining stream flows. Act as a sink

5 Meadow Hydrology Inputs: snowmelt, surface flow entering via stream, and direct precipitation Outputs: overland runoff, streamflow, and evapotranspiration Climate warming diminishes meadow hydrology and meadow plant life

6 Literature Review of Forest Management on Water Yield Hibbert (1967) reviewed results from 39 catchment experiments throughout the world, made the following generalizations: 1. Reduction of forest cover increases water yield 2. Establishment of forest cover on sparsely vegetated land decreases water yield. 3. Response to treatment is highly variable, and, for the most part, unpredictable.

7 Conifer Encroachment into Meadows Pinus contorta invasion 60% of Sequoia Kings Canyon National Park and 42% of Lake Tahoe Basin meadows contain Pinus contorta seedlings Marian Meadow in Chester, CA (left) and 2014 (right)

8 Causes of Conifer Encroachment Not one single event cause Soil moisture and composition often favor the establishment of Pinus contorta ssp. contorta In the Western Cascade and Coast Ranges of Oregon- meadow loss as much as 50% since the mid1940 s

9 Research Objectives and Goals 1. Quantify the meadow hydrology following removal of encroached conifers by measuring and analyzing soil moisture, groundwater table elevation, and various climatic variables. 2. Quantify the influences of upslope forest tree removal on a meadow s hydrology. 3. Determine if a natural restoration or manual restoration (re-vegetation treatments) is required for meadow species plant growth post conifer removal.

10 Study Area Marian Meadow, Plumas County By: Noël Fie Forest harvest thinning in Marian Meadow in summer of 2015 by Collin s Pine. Adjacent upslope harvest occurred in 2016.

11 The Control Control Meadow, Tehama County By: Noël Fie No Forest harvest thinning occurred. Control for climatic variables.

12 Methodology- Instruments Installed soil moisture probes and water level loggers and blank wells 1 weather station in Control meadow

13 Instrument Locations Location of instruments Spatially balanced random sampling approach

14 Methodology ERT to calculate water table depth (ft) during drought periods. Water Balance was used to construct weekly water budget : P + snowmelt = ET + S + G

15 Methodology Plots established in three different sites on Marian meadow in April Three different techniques: seeds dispersed onto bare soil, seeds dispersed onto bare soil with woody debris on top, and seeds dispersed onto existing vegetation. Vegetation data documented in August

16 Preliminary Results: Water Budget Change in storage indicates a change due to restoration Greater change in storage in Marian Meadow in the restoration year (2016). Marian Meadow Control Meadow Water Year and Meadow Annual Water Surplus or Deficit (-)(m) Annual Change in Storage (m)

17 Preliminary Groundwater Results Groundwater Table Elevation Feet Below Ground Conifer Removal Average Control (ft.) Upland Harvest Project Average Marian (ft.)

18 Statistical Analysis 12.5% decrease in average water table depths post restoration Indicative of supporting meadow plant species. Resulting in a gain of 573,969 cubic feet of added groundwater across Marian Meadow

19 Control Marian 7/20/2017 6/20/2017 5/20/2017 4/20/2017 3/20/2017 2/20/2017 1/20/ /20/ /20/ /20/2016 9/20/2016 8/20/2016 End of Conifer Removal Project 7/20/2016 6/20/2016 5/20/2016 4/20/2016 3/20/2016 2/20/2016 1/20/ /20/ /20/ /20/2015 9/20/2015 8/20/2015 7/20/2015 6/20/2015 5/20/2015 4/20/2015 3/20/2015 2/20/2015 1/20/ /20/ /20/ /20/2014 9/20/2014 8/20/2014 7/20/2014 6/20/2014 5/20/2014 4/20/2014 3/20/2014 2/20/2014 1/20/ /20/ /20/ /20/2013 9/20/2013 Average Volumetric Soil Moisture (%) Preliminary Soil Moisture Results Volumetric Soil Moisture on Marian and Control Meadow Upland Harvest Project

20 Statistical Analysis Overall volumetric soil moisture increased by 4% first year after conifer removal R 2 = 0.93 Estimated 289,227 cubic feet of soil moisture were added to the meadow the first year following restoration. Average Volumetric Soil Moisture (%) Meadow 2014 WY 2015 WY 2016 WY 2017 WY Marian Meadow Control Meadow

21 Conclusion Combined increase in water storage was 863,196 cubic feet. Annual increased water yield of 1,920 cubic feet/acre. Upslope harvest may improve inputs of increased water yield Further research is required

22 Thank you.