Northwest Advanced Renewables Alliance

Douglas-fir biomass and nutrient removal under varying harvest intensities designed for co-production of timber and biofuel

Kristin Coons, Doug Maguire, Doug Mainwaring, Andy Bloom, Rob Harrison, and Eric Turnblom

http://liferefocused.wordpress.com/

Background• Biofuel is a viable, renewable

alternative to fossil fuels.

• The leading national level assessment proposes displacing 30% of the petroleum consumed in the U.S.

• Biofuel produced from forests comprises 50% of energy derived from all biomass in the U.S.

• The majority of aboveground biomass in the PNW is Douglas-fir.

OutlineI. Background

II. Objectives

III. Hypotheses

IV. Study Sites

V. Methods

VI. Preliminary Results

Northwest Advanced Renewables Alliance

Knowledge Gap• Current biomass equation insufficiencies:

­ Based on only diameter at breast height (DBH)

­ Developed on stands with limited range in stand density, height-diameter combination, and stem profile

­ Lack of inclusion of above- and below-ground components

­ Not applicable on a scale pertinent to biofuel production.

• Implications of differing types and intensities of biomass harvest to long term site productivity are not known.

ObjectivesI. Quantify nutrient and

biomass contents of the major tree components and understory vegetation

II. Model of biomass and nutrient distribution in stands managed under varying silvicultural regimes.

III. Infer or estimate the long term implications to site productivity

HypothesesH1: Large portions of the above-ground biomass can be removed for biofuel production without declines in long-term site productivity.

­ H1a: Whole tree harvest

(aboveground)

­ H1b: Stem only harvest

­ H1c: Stem with other clean chip

components harvest 

Leaching

Atmospheric Deposition

Uptake Rate

Mortality Rate

Decomposition Rate

Cation Exchange Capacity

Nutrient Model

Weathering

Understory vegetation

Tree Sampling Installations• 4 Stand Management

Cooperative (SMC) TYPE 1 installations

• 4 Vegetation Management Research Cooperative (VMRC)

• Large trees from operational units

SMC IntallationsNo. - Location Site index Initial stems/ac704 - Ostrander Road 120 575705 - East Twin 90 700718 - Roaring River 128 400726 - Toledo 135 362

Installation & plot selection for Destructive Tree Sampling

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Data Sources for Biomass Equations

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Individual Tree Stem Mass

• Double Bark Thickness Equation- Maguire and Hann 1990

• Inside Bark Volume Taper Equation - Walter and Hann 1986

• Sapwood Taper Equation- Maguire and Batista 1996

• Mass estimated using volume and weighted average density

Individual Tree Branch and Foliage Mass

Live branches (X) = a0 (BrD)a1 (RHACB) a2 (DINC) a3

Dead Branches(X) = b0 (BrD) b1 (RHAB) b2

X = Foliage or Wood mass (g)

BrD = Branch diameter (mm)

DINC = Depth into crown (m)

RHACB = Relative height above

crown base (m)

RHAB = Relative height above tree base (m)

Branch Diameter (mm)

Whole tree biomass models tested……Linear Models

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht) + β3Ln(cl) + β3(cl) + β4(cbl) + β4Ln(cbl) 

Non-Linear Models•B = βo dbh 1β

•B = βodbh 1 β * ht 2β

•B = βodbh 1 β * ht 2β * cl 3β

•B = βodbh 1 β * ht 2β * e 3*clβ

•B = βodbh 1 β * ht 2β * cbl 3β

•B = βodbh 1 β * ht 2β * e 3*cblβ

Weights –1 / dbh–1 / dbh2

–1 / (ht * dbh2)–1 / (ht2 * dbh2)–1/ (ht * dbh2)2

–1 / (cl * dbh2)–1 / (cl2 * dbh2)–1/ (cl * dbh2)2

http://gemtreeart.com/

*D = DBH (cm), H= Height (m), CL = Crown length, CBL=Clear bole length (m)

Site Independent

Equations

Relationship between dbh, height, and total biomass for the SMC Type 1 sites, constructed

with a site-independent model.

*Crown length fixed at 14 (m) and clear bole length at 12.5(m)

Proportion of biomass (kg/ha) by component

Average N, P, K, Mg, Ca and

S by site

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Average nitrogen by component on SMC TYPE 1 sites

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Preliminary maximum nutrient removal by harvest type

Any Questions or Comments?

Distribution of Forest residuals with logging systems in Western Oregon

Photo: Francisca Belart

Photo: http://www.jmbrowninglogging.com/logging/shovel-logging.htm

WT- Cable loggingWT- Shovel logging

Nutrient Concentration Variability

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Component biomass(%) averaged over treatment type

Component biomass averaged by site over

treatment types

presentation title

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control fert thin control fert thin control fert thin control fert thinTREATMENT

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Change in Average Nutrient Concentration with Height

presentation title

More Specific Plot Treatments

presentation title

Installation Site Index (ft @50 yrs) Initial stems/ac

Treatment

ISPA: RD55-->RD35, RD55-->RD40, RD60-->RD40, . . .704 – Ostrander Road 120 575 ISPA/2: RD55-->RD35, no further thinning ISPA/4, no thinning ISPA: RD55-->RD35, RD55-->RD40, RD60-->RD40, .705 - East Twin 90 700 ISPA/2: RD55-->RD35, no further thinning ISPA/4, no thinning ISPA: RD55-->RD35, RD55-->RD40, RD60-->RD40, .718 - Roaring River 128 400 ISPA/2: RD55-->RD35, no further thinning ISPA/4, no thinning ISPA: RD55-->RD35, RD55-->RD40, RD60-->RD40, .726 - Toledo 135 362 ISPA/2: RD55-->RD35, no further thinning ISPA/4, no thinning

Models Tested………Linear Models•Ln(B) = β0 + β1Ln(dbh)

•Ln(B) = β0 + β1Ln(ht)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(cl)

•Ln(B) = β0 + β1Ln(dbh) + β2(cl)

•Ln(B) = β0 + β1Ln(ht) + β2Ln(cl)

•Ln(B) = β0 + β1Ln(ht) + β2(cl)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht) + β3Ln(cl)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht) + β3(cl)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(cbl)

•Ln(B) = β0 + β1Ln(dbh) + β2(cbl)

•Ln(B) = β0 + β1Ln(ht) + β2Ln(cbl)

•Ln(B) = β0 + β1Ln(ht) + β2(cbl)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht) + β3Ln(cbl)

•Ln(B) = β0 + β1Ln(dbh) + β2Ln(ht) + β3(cbl)

 

Non-Linear Models• B = βo dbh 1β

• B = βodbh 1 β * ht 2β

• B = βodbh 1 β * ht 2β * cl 3β

• B = βodbh 1 β * ht 2β * cbl 3β

• B = βodbh 1 β * ht 2β * e 3*clβ

• B = βodbh 1 β * ht 2β * e 3*cblβ

Weights • 1 / dbh• 1 / dbh2

• 1 / (ht * dbh2)• 1 / (ht2 * dbh2)• 1/ (ht * dbh2)2