Development of Yield Estimates of Short Rotation Poplar and Mapping of U.S. Poplar Yield Potential

Bill Berguson, Dan Buchman, Mike Cunningham, Bernie McMahon, Ray Miller, Randy Rousseau, Rich Shuren, Brian Stanton and Jeff Wright

National Energy Crops Mapping Project- Requested by DOE (Bryce Stokes) to put current energy crop

production (including woody crops) into a national context

- Coordination of the project done by Laurence Eaton at ORNLCoordination of the project done by Laurence Eaton at ORNL

- Sun Grant/DOE Poplar Team provided data to construct a common Sun Grant/DOE Poplar Team provided data to construct a common national dataset (the best available at the current time)national dataset (the best available at the current time)

- Analysis done by Oregon State PRISM Climate group (Chris Daly Analysis done by Oregon State PRISM Climate group (Chris Daly and Mike Halbleib) using gridded climate and soils dataand Mike Halbleib) using gridded climate and soils data

- OSU developed crop production indices for regression against our OSU developed crop production indices for regression against our dataset to develop “backbone” for extension of poplar yield dataset to develop “backbone” for extension of poplar yield nationallynationally

Clarifying Notes - Stand Metrics

- Yield – all aboveground components without leaves in oven-dry condition

- Basal Area – the sum of the cross-sectional area of all trees expressed on an areal basis (square feet per acre in our case)

- The product of BA and height is linearly related to total stand volume

Yield Data Sources

- Data types and immediate utility varied across regions

- Minnesota – used research yield block data of new clones on commercial production acreage with extrapolation to age 10

- Pacific Northwest – Primarily irrigated dataset, decided to drop irrigated plots in final analysis – rain-fed only sites

- Mid-South and South Alluvial – measured commercial plantations established by MWV

- Southern Uplands (ArborGen data) – due to little data, we attepted to take advantage of new data from clone tests on uplands (pine and agricultural sites) in the region

Emphasis on potential yield using selected clones for each region

Minnesota Yield Data- Yield blocks embedded in operational plantings on Verso Paper land

- Typical 7 X 7 tree blocks with 3 replications

- Interior 9 trees measured X 3 reps = 27 observations per clone/site

- Mean annual increment extrapolated to age 10 using average free-to-grow incremental BA and height growth in recent history of each plot

Minnesota Yield Site Locations

Well-managed plantations with no significant fertilization history

All on agricultural sites of moderate productivity except Waseca (very highly productive agriculture site)

Minnesota Yield Dataset

• Relatively straightforward process with some concerns due to differences in spacing and rotation age

• Most stands at or near rotation age

• Used new hybrid clone set resulting from breeding program or select P. deltoides – some NM6, DN5

• Yields generally higher than those reported in “Growth, Yield, and Disease Resistance of 7- to 12-Year-Old Poplar Clones in the North Central United States” D.A. Netzer et.al. GTR-NC-229, 2002

Site YearEst Spacing(sqft) Clone 10yrMAI(OD tons/Acre)Joppru 1996 64 DN5 3.0Sebeka 1996 64 NM6 3.4Kniels 1999 70 D124 3.4Woelfel 2001 70 D109 3.5Hemming 2005 80 9732-19 4.0Hemming 2005 80 9732-31 5.1Hemming 2005 80 D113 4.9Hansen 2006 100 98121022 3.6Hansen 2006 100 D109 3.6Hansen 2006 100 9732-31 3.8Hansen 2006 100 D113 3.6LEA Grand Rapids 2007 64 9732-11 5.1LEA Grand Rapids 2007 64 9732-06 4.8Schultz 2007 100 9732-11 3.7Schultz 2007 100 9732-31 3.5Waseca 2007 25 9732-11 3.7Waseca 2007 25 9732-06 3.8Average 76 3.9

Example of extrapolation method for MN sites

- Used recent historical “free-to-grow” steady state production rate to age 10- Average gap of extrapolation is 3 years, average MN yield is 3.9 tons/ac/yr

solid line is measured, dashed line is extrapolated

• Long-term commercial plantation program with good plantation management, no fertilization throughout rotation

• Randy R. hired contractor to establish and measure growth plots at eight sites and 30 clone/site combinations

• At total of 1,495 DBH measurements on 55 plots with subset of height (n=164)

• Numbers input and crunched at UMD-NRRI and yields estimated

Mid-South Alluvial Dataset

- Average spacing is 270 TPA or 13 X 13 feet spacing (potential at higher density unknown currently)

- Data ultimately collapsed to eight sites with the average of the clones occurring at those sites

- Due to wide spacings, a 9 year rotation age assumed with data either used directly for those sites greater than age 9 or extrapolated based on MAI:age relationship across the dataset and ratio of current to predicted

Mid-South Alluvial Sites(MO, KY, IL)

Age 4 superior clone in DOE/Sun Grant Consolidated Clone Test (photo courtesy of Randy Rousseau)

Mid-South Alluvial Dataset

Site EstYear Age Clone Tree/Acre AvgHt(ft) MDbh(in)Ba/Acre

(sqft)MAI

(BA/acre/yr) tons/acreMAI

(tons/acre/yr)Angelo 1999 11WV316 255 104 10.5 152.6 13.9 85.7 7.8Angelo 1999 11WV335 240 98 10.2 135.0 12.3 71.6 6.5Angelo 1999 11WV369 250 121 10.1 138.9 12.6 90.6 8.2Angelo 1999 11WV94 225 95 10.2 125.9 11.4 64.8 5.9Island 3 1999 11unknown 270 86 9.0 119.1 10.8 55.0 5.0Island 3 2000 10unknown 250 72 8.5 99.3 9.9 38.8 3.9Island 3 2001 9unknown 250 86 8.9 108.9 12.1 50.5 5.6Island 3 2002 8WV316 290 67 7.8 95.8 12.0 34.7 4.3Island 3 2002 8WV90 290 65 7.3 84.2 10.5 29.4 3.7Island 3 2002 8WV94 290 70 8.0 100.5 12.6 37.9 4.7Island 3 2002 8WV99 250 67 7.6 78.6 9.8 28.3 3.5

Wolf Island 2002 8unknown 300 67 7.3 88.3 11.0 31.9 4.0Island 3 2003 7WV98 270 58 6.6 64.8 9.3 20.2 2.9

Shelby Wilson 2003 7WV90 290 59 6.5 65.8 9.4 21.0 3.0Shelby Wilson 2003 7WV98 295 61 6.9 75.4 10.8 24.9 3.6

Shelby Wilson 2003 7WV99 280 60 7.1 77.8 11.1 25.4 3.6Wise 2003 7WV316 270 80 8.5 105.7 15.1 45.6 6.5

Wolf Island 2003 7WV370 280 73 8.4 106.9 15.3 42.0 6.0

Wolf Island 2003 7WV98 270 78 7.7 87.9 12.6 36.8 5.3Ice Grain 2004 6WV335 270 47 6.0 53.6 8.9 13.6 2.3Ice Grain 2004 6WV90 270 46 5.6 46.8 7.8 11.7 1.9WMA 2004 6WV413 275 65 8.0 96.5 16.1 33.9 5.6WMA 2004 6WV90 290 57 6.1 59.7 9.9 18.2 3.0WMA 2004 6WV99 275 68 7.8 90.5 15.1 33.2 5.5

Wolf Island 2004 6unknown 265 66 6.7 64.6 10.8 23.0 3.8

Wolf Island 2004 6WV413 275 65 7.5 84.0 14.0 29.5 4.9

Wolf Island 2004 6WV98 270 76 8.5 105.7 17.6 43.3 7.2Island 3 2005 5WV90 270 65 7.5 82.7 16.5 28.9 5.8Peck 2005 5WV98 265 62 7.8 87.3 17.5 29.0 5.8Wolf Island 2005 5WV98 279 64 6.7 68.3 13.7 23.7 4.7

Southeast Uplands Dataset

Very difficult to find single-clone blocks over a sufficient time period using material selected from tests in the region

Used ArborGen’s unique series of clone tests across the Southeast ranging from sites in GA, SC, NC and AL

Development of Reference Yield Curves for Clone Tests on Southern Uplands

- Lack of data on selected clones planted on upland sites in the Southeastern US in yield blocks on representative sites

- Growth from some published studies showed very low growth rates which were not consistent with observations across the ArborGen’s network of trials in the area

- Any existing yield data is in private hands and unavailable (lost/discarded after program termination)

- Challenge – how to make use of ArborGen’s clone trial network data to estimate yield potential

- Can we use measured clone trial height of top clones as indicator of yield potential?

Development of Reference Yield Curves for Clone Tests on Southern Uplands

- Decided to evaluate long-term datasets of poplar growth in regions particularly if spacing varied in the study and data were collected over a rotation

- Through help of Rich Shuren and Brian Stanton, we were provided with two long-term datasets with variable spacing

- 1984 study- 1990 study

- USFS-Stoneville – Roger Krinard- Nelder plot spacing trial- Large block test

Selected the GreenWood Resources 1984 and Krinard Nelder Plot datasets as these included a range of spacings over a sufficient period with tree height and diameter

Evaluated expected stand basal area and height growth through time to develop a set of expected stand BA and height with known final rotation MAI

Used expected height to compare against measured clone trial height growth to estimate stand production

GreenWood 1984 Study(Thanks to Rich and Brian)

GreenWood Resources 1984 study

- Westport - unirrigated- Spacing treatments in a 5 X 5 matrix of 3, 4, 6, 8 and 12 feet width

reciprocal combinations for a total of 25 treatments- Spacing ranged from 3X3 feet to 12 X 12- Three replications, 25 tree/plot, 1,876 observations- Diameter measured age 2 through 8 annually- Height measure age 3 through 7- Clone Hybrid 11- Unique opportunity to explore growth curves through time and spacing

effects

Regression Analysis Results for Tree HeightGreenWood Resources 1984 Study

AvgHT = 17.1 + 4.48 StandAge - 0.234 SqftperTree + 0.0632 AgeXSqft-tree (R-squared = 85%)

Regression Analysis Results of Stand Basal AreaGreenWood Resources 1984 Study

StandBA = - 7.94 + 27.4 StandAge - 0.333 SqftperTree - 0.0692 AgeXSqft-tree (R-squared = 84%)

GreenWood 1984 MAI Biomass Production

Although not shown, age 8 BA and volume decreases in dense treatments and increases at wider spacings

Stands appear to hit a maximum of 190 square feet per acre and then begin slow decline (max MAI has been reached) regardless of spacing

Similar behavior in the North

Spacing Age3 Age4 Age5 Age6 Age79 4.7 6.2 6.3 6.6 6.212 4.2 5.9 5.9 6.8 6.516 2.9 4.7 4.6 5.4 5.318 3.9 6.3 6.9 7.3 7.224 3.0 5.2 6.0 6.8 6.832 2.4 4.3 5.5 6.4 6.836 1.9 3.8 4.9 6.1 6.448 1.5 3.2 4.6 5.7 5.964 1.7 3.6 5.0 6.5 6.772 1.1 2.6 4.0 5.4 5.896 0.9 2.2 3.4 4.9 5.6144 0.6 1.7 2.9 4.3 5.2

Krinard Nelder Plot Study (USFS - SO 322)

- Study reported on data through age 19 but used through age 9- Reported average diameter and height in plots, we translated to MAI- Nelder Spoke Design – from 6 X 6 equivalent (1135 tpa) to 26 X 26 feet (63 tpa)

Trees/AcreTree Spacing(sq.ft./tree) StandAge

Height(ft)

AvgDBH(in)

StandBA (sq.ft./acre)

Estimated MAI(dry tons/acre/year)

63 691 2 26 4.1 5.8 0.4113 385 2 27 4 9.9 0.7201 217 2 27 3.8 15.8 1.2356 122 2 28 3.6 25.2 1.9637 68 2 28 3.1 33.4 2.5

1135 38 2 28 2.6 41.8 3.163 691 4 49 8.6 25.4 1.7

113 385 4 51 7.9 38.5 2.6201 217 4 52 7 53.7 3.8356 122 4 51 6 69.9 4.8637 68 4 49 4.8 80.0 5.3

1135 38 4 45 4 99.0 6.063 691 6 67 10.8 40.1 1.8

113 385 6 67 9.76 58.7 2.7201 217 6 67 8.4 77.4 3.5356 122 6 64 7 95.1 4.1637 68 6 60 5.88 120.1 4.8

1135 38 6 55 4.8 142.6 5.263 691 9 77 13 58.1 2.7

113 385 9 76 11.4 80.1 3.7201 217 9 75 9.8 105.3 4.7356 122 9 70 8.1 127.4 5.4637 68 9 63 6.6 151.3 5.7

1135 38 9 58 5.8 208.2 7.3

Regression of Tree Height on Age and SpacingKrinard Nelder Plot

Height = 21.1 + 5.32 StandAge + 0.00237 SqftXAge (R-squared = 0.86)

Regression of Stand Basal Area on Age and SpacingKrinard Nelder Plot Data

StandBA = 10.2 + 17.8 StandAge - 0.0385 Sqft-Tree - 0.0140 SqftXAge (R-squared = 0.85)

Yield Estimates for Southeast Uplands- Were used the ratio of mean height of the top 10 clones in clone tests to that estimated from the mean of the two models (Krinard-Nelder and GWR84)

- Calculate the % reduction in MAI based on same models estimating MAI using age and stand spacing

- Used expected versus actual height to adjust MAI accounting for spacing

- Need more data and will continue to collect over time

- Assumed a rotation age of 7 except for slow-growing sites such as Moultry (8)

Stand Data Pred Ht (ft) Pred BA (sq.ft/ac)

AgeSpacing

(sqft/tree)Height

(ft) GWR 84 Krinard Average Actual/Pred GWR 84 Krinard Average EstMAI

Floyd, GA 9 96 77 89.6 66.6 78.1 0.99 105 109 107.5 5.7

Eastover, SC 5 40 42.1 42.8 43.4 43.1 0.98 151 137 144.2 5.6

Moultry, SC 4 84 27.9 36.6 42.4 39.5 0.71 115 115 115.4 3

Randolf, AL 4 84 22.1 36.6 42.4 39.5 0.56 115 115 115.4 1.9

Randolf, AL 4 48 21.9 35.9 39.4 37.7 0.58 144 133 139.0 1.9

Greenville, NC 3 40 28.3 28.8 34.1 31.4 0.90 151 137 144.2 4.7

Bellville, GA 3 40 31.4 28.8 34.1 31.4 1.00 151 137 144.2 6

Comparison of Krinard (SO 347) and 0.4085XBAXHt Bole Volume Estimation

(outside-bark volume total bole)

Arborgen Poplar Specific Gravity Study

Source – ArborGen, Bijay Tamang, SFTIC Conference

Blue bars: Hybrid

Red bars: P. deltoides

• Average SG of 0.35 for poplar in South, Mid-South and Midwest = 22 lbs/cubic foot densityAverage SG of 0.35 for poplar in South, Mid-South and Midwest = 22 lbs/cubic foot density• Generalized biomass equation: OD tons (all aboveground components – top, limb, bole, bark) = Generalized biomass equation: OD tons (all aboveground components – top, limb, bole, bark) =

BA X Ht X 0.4085 X 22 X 1.2 BA X Ht X 0.4085 X 22 X 1.2 • Consistent with Krinard and northern volume estimates (actually universal) with density Consistent with Krinard and northern volume estimates (actually universal) with density

remarkably similar across regionsremarkably similar across regions

Final Dataset for Calibration

- After meeting with OSU staff in Corvallis, collapsed dataset to 19 sites

Site Name Site Score MAI (dry tons/ac/year)

Moultry 2009 normals 56 3

Kniesel 1999 normals 62 3.4

Sebeka 1996 normals 62 3.4

Woelfel 2001 normals 62 3.5

Schultz 2007 normals 61 3.6

Hansen 2006 normals 61 3.6

DOE 2005 Puyallup 2005 normals 47 4.2

Joppru 1996 normals 57 4.5

Island 3 2005 normals 80 4.6

Hemming 2005 normals 62 4.7

Wolf Island 2005 normals 80 4.7

Wooten Farm 2010 normals 62 4.7

LEA Grand Rapids 2007 normals 66 4.9

Peck 2005 normals 79 5.5

Eastover 2008 normals 62 5.6

Floyd 2003 normals 70 5.7

Bellville 2010 normals 65 6

Wise 2003 normals 80 6.2

Angelo 1999 normals 80 6.8

Final model calibration from OSU site scores (Mike Halbleib/Chris Daly)

South Uplands - Bellville, GA, Floyd, GA, Eastover, SC

Alluvial Mid-South

Minnesota – Improved Clones

Moultry, SC – Extremely Droughty

U.S. Map of Poplar Production Potential

- Note: red stars indicate site locations in the calibration dataset – not the case for PNW

Observations- Analysis of available yield data from Alluvial South (USFS-Krinard) and Pacific Northwest (GWR-Stanton/Shuren) shows that height growth is significantly higher in the PNW and South compared to Midwest

- However, stand basal area production across all regions is much more consistent through time with final age stand BA of 160 to 180 ft2 acre-1 across regions expected (mean annual production higher in South and PNW due to tree height and slightly higher BA growth)

- Growth curves in height and stand basal area developed from GWR dataset may have utility in guiding research in high-density plantings in other locations

- Due to heavily leached soils in the Southern upland region, site selection (pH) and fertilization will likely play a greater role in that region

- Unique opportunity to compare loblolly pine growth rates to cottonwood in paired sites in ArborGen’s set of trials (pellet market may be very attractive for cottonwood and hybrids)

- Continued measurement and expansion of tests in all regions and, particularly Southeast Uplands, will help better define yield potential and site effects

Final Thoughts- Dataset fraught with various issues that leads to imperfect, but reasonable estimates of yield potential based on actual field data

- Spacing and coppice effects on yield in all regions unknown and need work

- SE US yield – continued measurement of existing clone trials and next generation of large-block yield tests needed using best clones

- SE US – effects of drought periods on uplands unknown but poplar surviving well on some very drought-prone sites (Moultry)

- Clone selection critical and extreme variation is evident in clone tests in all regions

- Opportunities for significant yield improvement through genetics at all locationsAcknowledgments:

Sun Grant Program – Tim RialsChris Daly, Mike Hableib – OSU

Laurence Eaton – ORNLBryce Stokes – CNJV

Don Kaczmarek - perspective on poplar yield in the SE