United States Department of Agriculture 

National Agricultural Statistics Service

2009 California Walnut 

Objective Measurement Report 

Cooperating with the California Department of Food and Agriculture 

California Field Office · P.O. Box 1258 · Sacramento, CA 95812 · (916) 498-5161 · (916) 498-5186 Fax · www.nass.usda.gov/ca 

Released: September 4, 2009, 12:00 p.m. PDT 

WALNUT PRODUCTION FORECAST DOWN

The 2009 California walnut production is forecast at 415,000 

tons, down 5 percent from 2008's production of 436,000 tons. 

This forecast is based on the 2009 Walnut Objective 

Measurement (O.M.) Survey, which was officially conducted 

August 1 through August 22, 2009. There were a few samples 

completed before August 1 for training and scheduling 

purposes. 

Following a record crop, the 2009 walnut crop is generally in 

good condition. There were adequate chilling hours during the 

winter and mostly ideal weather conditions during the spring, 

with the exception of some rain which caused minimal blight 

damage in some areas. A mild summer, with the exception of 

some heat spells, has resulted in sunburn at modest levels. 

Irrigation water is a concern in some areas, but the crop was 

mostly unaffected by the drought. 

The 2009 Walnut O.M. Survey utilized a total of 736 blocks 

with two sample trees per block. Survey data indicated an 

average nut set of 1,523 per tree, up 8 percent from 2008’s 

average of 1,416. The Hartley nut set was up 34 percent; 

Chandler was down 6 percent; and Serr was down 22 percent 

from 2008. Percent of sound kernels in-shell was 97.9 percent 

Statewide. In-shell weight per nut was 22.0 grams, while the 

average in-shell suture measurement was 32.5 millimeters. 

The in-shell cross-width measurement was 33.0 and the 

average length in-shell was 39.3 millimeters. 

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

96 97 98 99 00 01 02 03 04 05 06 07 08 09

CALIFORNIA WALNUTS

Sept. Objective Forecast vs. Final Production

Final Production September Forecast

Estimated nut sets, sizing measurements, average number of 

trees per acre, and estimated bearing acreage were used in 

the statistical models. 

SURVEY HISTORY

The Walnut O.M. Survey began in 1958 to fulfill industry needs 

for an accurate walnut production forecast prior to harvest. 

The original sample was chosen proportionally to county and 

variety of bearing acreage. With each succeeding year, 

additions and deletions have been made in the sample to 

adjust for acreage removed, new bearing acreage, and 

operations that choose not to participate in the survey. 

SAMPLING PROCEDURES

Once a block is randomly selected and permission is granted 

by the operation for enumerators to enter the block, two trees 

are randomly selected. An accessible branch is chosen, which 

is 5-15 percent of the total cross-sectional area of the primary 

limbs and reachable with a twelve-foot ladder. Measurements 

are made on the trunk, each primary, and each split leading to 

and including the accessible branch. The sample tree and 

accessible branch are marked by a single tag. 

On the accessible branch, every first of five nuts is picked for 

use in size and grade determinations. If available, at least ten 

nuts are harvested from the accessible branch for this purpose. 

The following measurements are made on nuts selected for 

sizing: 

1. Weight of nut including hull 

2. Width of shell at suture 

3. Width of shell 90 degrees to suture line (cross-suture) 

4. Length of shell 

5. Kernel grade 

6. Weight of nut in-shell 

DATA RELIABILITY

The 80 percent confidence interval is from 376,000 tons to 

454,000 tons. This means there is an 80 percent chance the 

2009 production will fall within this range. 
2 

California English Walnut Acreage, Production, Price And Value In-Shell 

Year Bearing Acres Trees Per Acre Per Bearing Acre Total Production Price Per Ton Total Value 

Tons Dollars 1,000 Dollars 

1988 177,000 43.8 1.18 209,000 922 192,698 

1989 179,000 45.3 1.28 229,000 1,070 245,030 

1990 181,000 45.7 1.25 227,000 1,040 236,080 

1991 181,000 46.8 1.43 259,000 1,060 274,540 

1992 178,000 47.5 1.14 203,000 1,410 286,230 

1993 185,000 47.9 1.41 260,000 1,390 361,400 

1994 189,000 48.7 1.23 232,000 1,030 238,960 

1995 193,000 49.0 1.21 234,000 1,400 327,600 

1996 192,000 49.4 1.08 208,000 1,580 328,640 

1997 193,000 50.4 1.39 269,000 1,430 384,670 

1998 198,000 50.4 1.15 227,000 1,050 238,350 

1999 197,000 51.5 1.44 283,000 886 250,738 

2000 200,000 54.8 1.20 239,000 1,240 296,360 

2001 204,000 55.6 1.50 305,000 1,120 341,600 

2002 210,000 56.5 1.34 282,000 1,170 329,940 

2003 213,000 57.7 1.53 326,000 1,160 378,160 

2004 214,000 60.3 1.52 325,000 1,390 451,750 

2005 215,000 61.1 1.65 355,000 1,570 539,600 

2006 216,000 62.4 1.60 346,000 1,630 563,980 

2007 218,000 62.9 1.50 328,000 2,290 751,120 

2008 a/ 223,000 65.0 1.96 436,000 1,210 527,560 

2009 b/c/ 223,000 65.1 1.86 415,000 --- --- 

a/ Price Per Ton and Total Value are July 2009 preliminary data. 

b/ Bearing years include plantings of the following: Chandler, Chico, Howard, Tulare (2005 & Earlier); 50-55, 59-124, 4946, Amigo, 

 Ashley, Bardoni, Cisco, Earhorn, Grove, Gustine, Honeycutt, Houston, Jensen, Lompoc, Marchetti, Nuggett, Payne, Pedro, Serr, 

 Sunland, Tehama, Trinta, UCD 67-13, Vina, Westside (2004 and Earlier); Franquette, Franquette Scharsch, Mayette, Placentia, 

 Poe, Willsons/Willsons Wonder, Woodland (2002 & Earlier); all other varieties not specified (2003 & Earlier). 

c/ Price Per Ton and Total Value preliminary data will be released July 2010. 

192 193

198 197

200

204

210

213 214 215 216

218

223 223

45

50

55

60

65

170

180

190

200

210

220

230

96 97 98 99 00 01 02 03 04 05 06 07 08 09

Trees per Acre

Thousand Acres

CALIFORNIA WALNUTS

Bearing Acreage vs. Bearing Trees per Acre, 1996-2009

Bearing Acreage Bearing Trees Per Acre
3 

Walnut Objective Measurement Survey Date, By District

Measurement Year Coast 1/ Sacramento Valley 2/ San Joaquin Valley 3/ State 4/ 

In-Shell Weight 1998 21.2 22.4 20.3 21.4 

(gm) 1999 21.0 24.9 19.5 23.0 

 2000 19.7 22.4 19.7 21.2 

 2001 21.9 23.7 18.1 21.5 

 2002 19.1 22.9 20.5 22.0 

 2003 23.0 24.6 19.2 22.4 

 2004 22.0 24.1 19.7 22.5 

 2005 23.1 21.3 18.1 20.0 

 2006 19.8 24.1 21.0 22.7 

 2007 19.1 21.4 18.7 20.3 

 2008 20.0 23.5 20.7 22.2 

 2009 17.0 23.1 20.6 22.0 

In-Shell Width 1998 31.4 32.2 31.5 31.9 

(mm) 1999 31.2 32.6 31.6 32.2 

 2000 31.5 32.4 32.1 32.2 

 2001 31.7 31.8 31.6 31.7 

 2002 31.4 32.2 32.7 32.4 

 2003 32.1 32.8 32.0 32.5 

 2004 31.4 32.5 32.7 32.6 

 2005 32.9 31.4 32.1 31.7 

 2006 29.5 30.3 32.9 31.4 

 2007 31.6 31.5 32.4 31.9 

 2008 31.4 32.7 32.6 32.6 

 2009 29.8 32.5 32.9 32.5 

In-Shell Cross-Width 1998 31.2 32.1 31.5 31.8 

(mm) 1999 31.6 33.3 31.8 32.7 

 2000 31.3 33.0 32.6 32.8 

 2001 31.1 31.7 31.5 31.6 

 2002 31.0 32.6 33.1 32.7 

 2003 31.7 32.7 32.0 32.4 

 2004 31.5 32.2 33.1 32.5 

 2005 32.2 31.3 32.0 31.6 

 2006 32.3 34.0 33.2 33.6 

 2007 31.6 32.5 32.9 32.6 

 2008 31.4 33.2 32.6 32.9 

 2009 29.9 33.1 33.1 33.0 

In-Shell Length 1998 39.1 40.0 39.0 39.5 

(mm) 1999 38.3 39.7 38.9 39.4 

 2000 37.4 38.2 38.4 38.2 

 2001 38.6 38.5 37.9 38.3 

 2002 37.5 38.4 38.8 38.5 

 2003 38.8 39.7 38.3 39.1 

 2004 37.7 39.1 38.7 39.0 

 2005 42.0 38.4 38.7 38.6 

 2006 38.6 39.6 39.5 39.5 

 2007 37.4 37.3 38.1 37.6 

 2008 39.2 39.5 39.1 39.3 

 2009 36.9 39.6 39.1 39.3 

Kernel Grade - 1998 79.9 93.2 98.3 94.4 

Percent Sound 1999 96.8 98.2 97.4 97.9 

 2000 98.0 96.7 97.0 96.9 

 2001 98.3 97.5 98.1 97.8 

 2002 96.0 95.3 98.7 96.3 

 2003 95.5 95.4 99.3 97.0 

 2004 97.6 97.7 99.2 98.2 

 2005 97.4 96.5 98.8 97.5 

 2006 98.1 98.5 97.2 98.0 

 2007 97.8 97.9 99.2 98.4 

 2008 96.4 98.6 97.3 98.0 

 2009 94.9 97.0 99.6 97.9 

Nuts Set Per Tree 1998 1,070 1,654 1,253 1,407 

 1999 1,355 2,180 1,250 1,709 

 2000 1,195 1,812 1,204 1,483 

 2001 937 2,020 1,478 1,719 

 2002 1,254 1,982 1,142 1,572 

 2003 640 1,846 1,429 1,599 

 2004 924 1,943 1,168 1,526 

 2005 818 1,854 1,372 1,575 

 2006 1,316 1,660 1,267 1,458 

 2007 1,221 1,548 1,162 1,357 

 2008 973 1,592 1,270 1,416 

 2009 1,531 1,758 1,250 1,523 

1/ Coast includes: Contra Costa, Lake, Monterey, Napa, San Benito, San Luis Obispo, Santa Clara, and Sonoma counties. 

2/ Sacramento Valley includes: Butte, Colusa, El Dorado, Glenn, Sacramento, Solano, Sutter, Tehama, Yolo, and Yuba counties.

3/ San Joaquin Valley includes: Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, and Tulare counties. 

4/ District and State averages are derived by weighting county averages by county bearing acreage figures. 
4 

Walnut Objective Measurement Survey Date, By Variety 

Measurement Year Ashley Chandler Eureka Franquette Hartley Howard Payne Serr Tehama Tulare Vina Other 1/ 

In-Shell Weight 1998 19.2 21.9 20.8 20.2 24.0 --- 19.6 19.5 19.5 --- 19.2 19.9 

(gm) 1999 20.3 24.9 22.1 20.0 24.6 --- 19.0 20.3 19.1 --- 20.7 20.9 

 2000 17.5 22.9 21.7 18.3 22.8 --- 18.8 19.3 19.8 --- 19.3 19.9 

 2001 17.8 22.7 20.0 21.2 23.2 --- 16.9 17.8 21.7 --- 19.9 19.3 

 2002 18.0 24.1 20.8 18.3 23.6 --- 19.3 19.4 19.6 --- 20.0 21.0 

 2003 17.1 23.6 21.0 23.7 25.2 --- 16.6 17.2 20.8 --- 19.8 22.1 

 2004 18.4 23.4 20.4 22.1 24.5 --- 17.7 18.5 20.3 --- 19.1 22.2 

 2005 16.3 19.8 18.9 20.3 22.9 --- 16.4 16.7 16.6 --- 18.1 20.0 

 2006 18.1 23.0 22.3 19.2 24.8 --- 19.0 20.4 21.8 --- 21.3 22.6 

 2007 15.8 21.5 21.0 18.6 22.2 22.5 17.2 15.7 16.8 22.2 18.2 17.5 

 2008 19.7 22.2 21.1 20.3 25.0 23.8 18.4 18.6 22.5 22.8 20.0 19.3 

 2009 19.9 22.9 21.0 19.3 23.7 22.3 18.2 18.5 20.6 21.8 18.7 17.3 

In-Shell Width 1998 31.2 31.8 30.2 30.7 33.0 --- 31.4 32.1 31.2 --- 30.6 31.1 

(mm) 1999 30.7 32.8 30.4 31.0 32.8 --- 31.5 32.6 30.9 --- 30.4 31.2 

 2000 31.0 32.8 31.3 30.6 32.8 --- 32.3 33.1 31.1 --- 30.9 31.0 

 2001 30.3 32.0 32.0 30.5 32.3 --- 31.2 31.8 31.3 --- 30.3 30.7 

 2002 31.7 32.9 31.8 29.8 32.8 --- 33.0 32.9 31.7 --- 31.0 31.7 

 2003 31.0 32.9 32.1 32.4 33.2 --- 31.7 31.5 31.6 --- 30.8 32.3 

 2004 32.1 32.5 31.5 31.8 32.8 --- 32.9 33.4 31.5 --- 30.8 33.4 

 2005 31.4 31.1 30.7 31.6 32.5 --- 31.7 32.2 31.0 --- 31.4 32.4 

 2006 31.0 31.1 31.9 28.8 31.4 --- 32.7 32.9 31.4 --- 30.5 32.1 

 2007 31.0 31.7 31.1 29.9 32.3 32.0 32.1 32.5 31.0 34.5 30.3 30.3 

 2008 32.0 32.3 31.2 31.0 33.6 32.1 32.6 32.7 32.8 34.8 31.4 31.1 

 2009 32.4 32.4 31.6 30.1 33.2 32.1 32.7 33.1 32.0 34.3 30.7 31.5 

In-Shell Cross-Width 1998 31.2 30.9 30.5 31.2 32.5 --- 31.4 31.6 30.8 --- 30.8 31.7 

(mm) 1999 30.8 34.0 31.0 31.2 33.2 --- 31.4 31.9 30.8 --- 31.5 32.0 

 2000 31.2 33.9 32.0 30.5 33.2 --- 32.7 32.6 31.6 --- 32.0 32.3 

 2001 30.1 32.0 31.1 30.6 32.2 --- 31.0 31.2 30.9 --- 30.6 30.8 

 2002 31.8 33.7 32.7 30.1 32.9 --- 33.1 32.6 31.8 --- 31.8 32.4 

 2003 30.6 33.1 32.2 32.3 33.1 --- 31.2 30.6 31.6 --- 31.3 32.2 

 2004 32.0 32.6 32.3 31.3 32.8 --- 33.1 33.4 31.0 --- 30.9 33.1 

 2005 30.9 31.1 31.7 31.4 32.1 --- 31.4 31.5 30.1 --- 31.6 32.6 

 2006 32.1 33.9 32.9 32.2 34.0 --- 32.6 33.0 32.9 --- 33.1 34.0 

 2007 31.6 32.7 32.0 30.9 32.8 34.1 32.4 32.3 31.4 34.8 31.7 31.9 

 2008 32.0 32.9 31.6 31.5 33.4 34.1 32.2 31.9 32.5 34.5 32.2 32.1 

 2009 32.6 33.0 32.3 30.7 33.2 33.8 32.7 32.7 32.4 34.3 32.0 32.5 

In-Shell Length 1998 37.2 40.0 40.8 39.6 40.9 --- 38.0 37.7 37.7 --- 38.4 39.6 

(mm) 1999 36.9 40.4 42.6 38.2 39.6 --- 38.1 38.5 37.3 --- 38.7 39.5 

 2000 35.8 39.4 43.0 37.4 38.2 --- 38.2 37.6 36.9 --- 37.3 38.3 

 2001 35.2 38.7 41.6 38.4 38.9 --- 37.0 36.4 37.2 --- 37.4 38.3 

 2002 36.1 39.7 41.4 37.0 38.7 --- 38.2 37.5 36.8 --- 37.6 38.5 

 2003 35.7 39.7 41.7 40.9 40.4 --- 36.5 36.0 37.6 --- 38.0 39.1 

 2004 36.4 39.6 41.3 39.3 39.7 --- 37.0 37.1 36.4 --- 37.4 38.8 

 2005 36.3 38.4 41.6 40.3 39.8 --- 37.2 37.0 36.0 --- 38.0 38.4 

 2006 37.4 39.5 44.2 38.5 40.4 --- 38.1 39.2 37.8 --- 39.3 38.7 

 2007 35.7 38.1 43.3 36.8 37.9 37.4 37.3 36.4 36.7 38.9 36.8 37.7 

 2008 37.4 39.2 43.4 39.3 40.9 38.0 37.4 37.6 37.7 39.3 38.4 39.7 

 2009 38.0 39.9 43.5 38.1 40.2 38.0 38.6 38.2 37.7 38.9 37.9 40.1 

Kernel Grade - 1998 94.4 91.4 99.8 89.5 94.4 --- 96.3 97.9 94.3 --- 95.2 95.2 

Percent Sound 1999 96.1 98.1 97.1 98.3 98.1 --- 95.0 98.3 96.4 --- 98.2 97.3 

 2000 95.6 96.7 93.1 97.8 96.4 --- 97.3 97.7 96.4 --- 98.2 97.3 

 2001 94.3 98.8 98.9 98.8 97.4 --- 97.3 96.3 98.0 --- 98.7 97.5 

 2002 96.4 96.8 98.6 97.2 96.1 --- 96.8 93.3 98.3 --- 97.0 96.8 

 2003 97.5 97.4 98.8 97.0 97.2 --- 99.2 96.1 91.8 --- 96.9 95.1 

 2004 97.9 99.0 98.4 95.6 98.2 --- 99.4 98.3 99.1 --- 98.0 96.7 

 2005 96.7 96.9 99.8 95.7 97.0 --- 98.4 99.5 97.0 --- 99.1 97.9 

 2006 98.4 99.2 95.1 99.6 97.7 --- 91.8 96.0 99.1 --- 98.2 97.7 

 2007 96.5 99.4 99.5 96.0 98.5 98.5 99.3 98.5 93.5 99.0 97.7 95.9 

 2008 93.5 98.7 91.7 97.6 99.2 99.0 99.0 94.5 96.5 98.1 99.1 93.5 

 2009 96.9 98.6 99.2 98.3 97.3 98.1 99.2 98.8 99.7 96.3 97.7 91.0 

Nuts Set Per Tree 1998 1,221 1,306 1,380 1,512 1,457 --- 1,170 1,622 1,347 --- 1,504 1,290 

 1999 1,073 1,540 1,369 2,818 2,241 --- 1,076 989 1,210 --- 1,374 1,536 

 2000 1,633 1,212 1,325 1,899 1,878 --- 1,696 886 1,167 --- 1,566 1,379 

 2001 1,510 1,741 1,718 1,819 2,049 --- 1,443 1,342 1,560 --- 1,488 1,533 

 2002 1,534 1,315 1,246 2,072 1,961 --- 1,246 1,259 1,446 --- 1,611 1,642 

 2003 1,421 1,594 1,858 1,195 1,735 --- 1,995 1,679 1,021 --- 1,544 1,377 

 2004 1,504 1,381 1,223 2,108 2,046 --- 1,152 1,172 1,488 --- 1,471 1,167 

 2005 1,323 1,783 1,639 1,267 1,729 --- 1,443 1,429 1,067 --- 1,251 1,256 

 2006 1,129 1,386 1,687 2,004 1,883 --- 1,345 1,172 462 --- 1,266 1,319 

 2007 1,875 1,069 1,731 1,569 1,738 1,197 1,202 1,710 2,058 963 1,183 1,640 

 2008 1,688 1,425 2,271 1,343 1,498 1,156 1,395 1,371 1,127 1,438 1,235 1,712 

 2009 1,691 1,346 1,512 2,220 2,001 1,419 1,306 1,066 1,893 1,281 1,755 1,074 

1/ Beginning in 2007, the Howard and Tulare varieties were taken out of "other" and published separately. 
5 

Percentage Distribution of Walnut Shell Suture Size, By District and Variety

District and Variety 

U.S. Standards Size Intervals 1/ 

2005 2006 2007 2/ 2008 2009 

Mth Jmb Lge Med Bby Oth Mth Jmb Lge Med Bby Oth Mth Jmb Lge Med Bby Oth Mth Jmb Lge Med Bby Oth Mth Jmb Lge Med Bby Oth

 - - - - - - - - - - - - - - - Percent of Total 3/ - - - - - - - - - - - - - - - 

DISTRICTS: 

Coast 1 71 15 9 4 0 0 30 15 18 26 11 9 30 17 24 20 0 0 49 18 17 15 0 0 25 13 25 37 0

Sacramento Vly. 1 47 19 15 12 3 0 38 11 16 28 5 1 50 16 17 15 1 0 68 15 11 5 0 0 66 14 11 8 0

San Joaquin Vly. 1 56 20 17 6 0 2 68 16 9 5 0 1 63 16 11 8 0 1 66 16 10 6 1 1 70 14 9 5 0

VARIETIES: 

Ashley 1 47 17 17 16 1 0 46 19 15 18 2 5 31 16 23 21 3 0 60 18 15 7 1 0 66 13 11 10 0

Chandler 0 42 23 21 10 3 1 48 15 14 19 3 1 54 17 15 13 1 0 63 19 11 6 0 0 67 16 10 6 0

Eureka 0 29 37 21 11 1 1 56 34 4 5 0 0 48 28 9 16 0 0 34 40 19 7 0 0 46 40 9 5 0

Franquette 0 53 19 17 11 0 0 21 15 19 34 12 0 23 17 30 28 1 0 43 18 23 15 0 0 27 18 25 31 0

Hartley 1 64 14 9 7 2 0 52 10 14 20 4 1 63 14 13 9 0 0 83 9 4 3 1 0 79 11 6 4 0

Howard --- --- --- --- --- --- --- --- --- --- --- --- 1 55 19 15 10 0 0 58 21 15 6 0 0 61 18 12 9 0

Payne 1 51 19 19 8 1 0 72 16 5 7 1 0 60 19 12 8 1 1 73 14 8 4 0 2 70 13 9 6 0

Serr 2 60 16 11 11 0 2 69 11 8 10 1 1 69 11 10 8 1 0 73 11 9 5 1 0 74 13 7 6 0

Tehama 0 45 19 18 15 1 1 52 14 12 17 5 0 38 26 21 14 1 0 74 10 10 6 0 0 62 19 10 9 0

Tulare --- --- --- --- --- --- --- --- --- --- --- --- 8 76 7 6 3 0 7 82 5 4 2 0 5 80 6 4 3 0

Vina 4 32 27 21 12 1 0 39 18 18 20 4 0 32 21 21 23 2 1 44 24 19 12 0 0 31 21 27 20 1

Other 2 57 15 12 11 1 4 54 10 12 16 3 0 29 18 22 30 0 2 37 15 29 16 1 3 42 13 18 23 1

STATE 1 51 19 16 10 2 1 51 13 13 18 3 1 55 16 15 12 1 1 67 16 11 6 0 1 66 14 11 8 0 

Number of 

 Shells Measured 12,736 13,491 13,219 13,485 14,625

1/ Sizes used are as follows: Mammoth -- Larger than 96/64" in diameter; Jumbo -- 80/64" to 96/64"; Large -- 76/64" to 80/64" for Eureka variety, 77/64" to 

 80/64" for all other varieties; Medium -- 73/64" to 76/64" for Eureka, 73/64" to 77/64" for all others; Baby -- 60/64" to 73/64"; and Others -- below 60/64". 

2/ Beginning in 2007, the Howard and Tulare varieties were taken out of "Other" and published separately. 

3/ Percentage distributions, based upon nut samples taken in the field, may not equal 100 percent due to rounding.

The California Walnut Industry has been very supportive. 

We appreciate your continued cooperation! 

VIC TOLOMEO, Director 

SARAH HOFFMAN – KELLY KRUG, Deputy Directors 

DOUG FLOHR – JENNIFER VAN COURT 

Statisticians – Estimates Group 

USDA, NASS, California Field Office publications are available free-of-charge on the Internet at:

www.nass.usda.gov/ca