Jason Jimenez

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Bracken Fern CommunitiesBiomass Allocation and
Influence on Selected Soil Properties

• Jason Jimenez
• Soil and Land Resources
• PSES

Thesis Defense Seminar
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The Problem

• There is little to no conifer regeneration after
  timber harvest

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The Grand Fir Mosaic
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What is a Mosaic Ecosystem?

• Mosaic
• a pattern or patchwork of grand fir forest
  with differing shrub and forb communities.

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From Latin surface decoration made by
interlaying small pieces of variously colored
material to form pictures or patterns.
What is a Mosaic Ecosystem?
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Tesserae of Grand Fir Mosaic

• Grand Fir Forest
• (Abies grandis)
• Bracken Fern Glades (Pteridium aquilium)
• Sitka Alder Stringers
• (Alnus viridis spp. sinuata)

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Natural Bracken Fern Glade
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Artificial Bracken Fern Glade
Resulting from Timber Harvest
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Bracken Fern (Pteridium aquilium)
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Bracken Fern

• Sketch by Elizabeth Hughs Bass

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Andisols
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Nonallophanic Andisols
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So thenonallophanic classification of Andisols
tells us
Bracken Fern Glade Soils have the following
properties

• Soil acidity Very strongly acid

Aluminum Saturation High
KCl Exchangeable Al - Abundant
Aluminum Toxicity - Common
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Problems with Conifer Regeneration
The Short List

• Competitive Dominance

2. Allelopathy
3. Pocket Gophers
4. Changes in Soil Properties -Organic
Carbon -Aluminum Concentrations
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Objectives of the Research

• Compare Biomass Quantities

• Measure Soil Changes in Bracken Fern Glades over
  Time

• Learn As Much As Possible

• Live Outside

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Where?
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Fieldwork Completed
3800 plants clipped
600 kg of roots collected
167 Clif-bars
143 soil samples collected
83 trees measured
63 boxes of mac and cheese
58 vertical feet of augering
35 tons of soil excavated
27 soil pits described
8 pounds gained
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Aboveground Biomass

• Shrubs/Forbs/Grasses
• 1 x 1 m frame placed
• All plants clipped and bagged
• Dried and weighed

• Trees
• Cruiser prism plots
• Trees measured for DBH and height
• BIOPAK calculation used

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Belowground Biomass
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Soil Analysis

• pH
• Na-F pH
• Carbon
• Nitrogen
• Aluminum
• Iron
• Phosphorous
• Silicon

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Biomass Measurements
What were we trying to determine?
1) How much biomass do bracken fern produce? 2)
How do these GFM tesserae compare in live biomass?
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Biomass Results
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Aboveground Biomass
5000
4000
Biomass (g/m2)
3000
2000
1000
Natural Bracken Fern Glade
Grand Fir Forest
Artificial Bracken Fern Glade
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Belowground Biomass
4000
10 Year Old
Biomass (g/m2)
3000
2000
10 Year Old
1000
Natural Bracken Fern Glade
Grand Fir Forest
Artificial Bracken Fern Glade
Grand Fir Forest
Artificial Bracken Fern Glade
Artificial Bracken Fern Glade
Natural Bracken Fern Glade
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Aboveground to Belowground Biomass
3.0
10 Year Old
2.0
Ratio
10 Year Old
30 Year Old
40 Year Old
1.0
Natural Bracken Fern Glade
Grand Fir Forest
Artificial Bracken Fern Glade
Artificial Bracken Fern Glade
Artificial Bracken Fern Glade
Grand Fir Forest
Artificial Bracken Fern Glade
Artificial Bracken Fern Glade
Natural Bracken Fern Glade
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So I care because
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Selected Soil Properties
What were we trying to determine?

• Quantify differences in selected soil properties
  between GFM tesserae
• 2) Quantify changes in artificial bracken fern
  glades over time 10, 30, and 40 years

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Soil pH
Grand Fir Forest
Artificial Bracken Fern Glade
Natural Bracken Fern Glade
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Organic C ()
2.8
Grand Fir Forest
Artificial Bracken Fern Glade
Natural Bracken Fern Glade
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(No Transcript)
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And your telling me this because?
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Aluminum Results
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Iron Results
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So what is going on?
So what is going on?
Al
pH gt 4.9
allophane
NonallophanicAndisol
AllophanicAndisol
Al-humus complexes
Humus Si

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Acknowledgements

• Paul McDaniel
• Other Committee Members
• Dennis Ferguson
• Jodi Johnson-Maynard
• Anita Falen
• All the Graduate Students
• Jennifer and Megan
• Debbie and Joanne at RMRS
• Matt Hurteau and Harold Zald

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Any Questions?