United States Department of Agriculture 

National Agricultural Statistics Service

2008 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, 2008, 12:00 p.m. PDT 

WALNUT PRODUCTION FORECAST UP

The 2008 California walnut production is forecast at 

375,000 tons, up 15 percent from 2007's production of 

325,000 tons. This forecast is based on the 2008 

Walnut Objective Measurement (O.M.) Survey, which 

was officially conducted August 1 through August 25, 

2008. There were a few samples completed before 

August 1 for training and scheduling purposes. 

The 2008 Walnut O.M. Survey utilized a total of 689 

blocks with two sample trees per block. Survey data 

indicated an average nut set of 1,416 per tree, up 4 

percent from 2007’s average of 1,357. The Hartley nut 

set was down 14 percent; Chandler was up 33 percent; 

Serr was down 20 percent from 2007. Percent of sound 

kernels in-shell was 98.0 percent Statewide. In-shell 

weight per nut was 22.2 grams, while the average 

in-shell suture measurement was 32.6 millimeters. The 

in-shell cross-width measurement was 32.9 and the 

average length in-shell was 39.3 millimeters. 

Estimated nut sets, sizing measurements, average 

number of trees per acre, and estimated bearing 

acreage were used in the statistical models. 

CALIFORNIA WALNUTS

Sept. Objective Forecast vs. Final Production

180

200

220

240

260

280

300

320

340

360

380

400

95 96 97 98 99 00 01 02 03 04 05 06 07 08

Final Production September Forecast

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 338,000 tons 

to 412,000 tons. This means there is an 80 percent 

chance the 2008 production will fall within this range. 
2 

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

Per Bearing Acre Total Production Price Per Ton Total Value Year Bearing Acres Trees Per Acre 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 a/ 218,000 62.9 1.49 325,000 2,320 754,000 

2008 b/ c/ 218,000 65.0 1.72 375,000 --- --- 

a/ Price Per Ton and Total Value are July 2008 preliminary data. 

b/ Bearing years include plantings of the following: Chandler, Chico, Howard, Tulare (2004 & 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 (2003 and Earlier); Franquette, Franquette Scharsch, Mayette, Placentia, 

 Poe, Willsons/Willsons Wonder, Woodland (2001 & Earlier); all other varieties not specified (2002 & Earlier). 

c/ Price Per Ton and Total Value preliminary data will be released July 2009. 

CALIFORNIA WALNUTS

Bearing Acreage vs. Bearing Trees per Acre, 1995-2008

193 192 193

198 197

200

204

210

213 214 215 216

218 218

170

180

190

200

210

220

95 96 97 98 99 00 01 02 03 04 05 06 07 08

Thousand Acres

45

50

55

60

65

Trees per Acre

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 1997 20.9 23.7 22.2 22.9 

 (gm) 1998 21.2 22.4 20.3 21.4 

 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 

In-Shell Width 1997 32.3 33.0 31.1 32.3 

 (mm) 1998 31.4 32.2 31.5 31.9 

 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 

In-Shell Cross-Width 1997 32.3 33.2 31.9 32.6 

 (mm) 1998 31.2 32.1 31.5 31.8 

 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 

In-Shell Length 1997 38.2 39.4 37.6 38.6 

 (mm) 1998 39.1 40.0 39.0 39.5 

 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 

Kernel Grade - 1997 97.8 97.4 97.3 97.3 

 Percent Sound 1998 79.9 93.2 98.3 94.4 

 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 

Nuts Set Per Tree 1997 1,128 2,233 1,439 1,753 

 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 

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 1997 19.8 24.4 23.2 21.1 24.8 --- 20.4 21.3 20.5 --- 20.5 22.2 

 (gm) 1998 19.2 21.9 20.8 20.2 24.0 --- 19.6 19.5 19.5 --- 19.2 19.9 

 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 

In-Shell Width 1997 31.8 32.3 30.7 30.6 33.3 --- 31.5 33.3 32.0 --- 31.0 30.8 

 (mm) 1998 31.2 31.8 30.2 30.7 33.0 --- 31.4 32.1 31.2 --- 30.6 31.1 

 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 

In-Shell Cross-Width 1997 31.9 33.0 32.2 31.3 33.2 --- 32.0 33.0 32.1 --- 32.1 32.0 

 (mm) 1998 31.2 30.9 30.5 31.2 32.5 --- 31.4 31.6 30.8 --- 30.8 31.7 

 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 

In-Shell Length 1997 36.2 39.2 41.0 37.8 39.5 --- 36.6 37.4 37.2 --- 38.1 38.5 

 (mm) 1998 37.2 40.0 40.8 39.6 40.9 --- 38.0 37.7 37.7 --- 38.4 39.6 

 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 

Kernel Grade - 1997 96.2 97.8 94.9 96.6 98.1 --- 96.5 97.0 96.7 --- 97.5 96.6 

 Percent Sound 1998 94.4 91.4 99.8 89.5 94.4 --- 96.3 97.9 94.3 --- 95.2 95.2 

 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 

Nuts Set Per Tree 1997 1,406 1,570 1,414 2,162 2,228 --- 1,304 796 1,703 --- 1,894 1,839 

 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 

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 

U.S. Standards Size Intervals 1/ 

District and Variety 2004 2005 2006 2007 2/ 2008 

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 0 50 12 20 16 1 1 71 15 9 4 0 0 30 15 18 26 11 9 30 17 24 20 0 0 49 18 17 15 0 

Sacramento Vly. 2 62 15 11 10 1 1 47 19 15 12 3 0 38 11 16 28 5 1 50 16 17 15 1 0 68 15 11 5 0 

San Joaquin Vly. 2 65 15 11 7 0 1 56 20 17 6 0 2 68 16 9 5 0 1 63 16 11 8 0 1 66 16 10 6 1 

VARIETIES: 

Ashley 1 56 16 12 16 1 1 47 17 17 16 1 0 46 19 15 18 2 5 31 16 23 21 3 0 60 18 15 7 1 

Chandler 1 63 16 11 8 0 0 42 23 21 10 3 1 48 15 14 19 3 1 54 17 15 13 1 0 63 19 11 6 0 

Eureka 1 47 30 10 12 0 0 29 37 21 11 1 1 56 34 4 5 0 0 48 28 9 16 0 0 34 40 19 7 0 

Franquette 0 51 21 18 9 1 0 53 19 17 11 0 0 21 15 19 34 12 0 23 17 30 28 1 0 43 18 23 15 0 

Hartley 1 69 14 9 6 1 1 64 14 9 7 2 0 52 10 14 20 4 1 63 14 13 9 0 0 83 9 4 3 1 

Howard --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 1 55 19 15 10 0 0 58 21 15 6 0 

Payne 1 67 13 10 8 0 1 51 19 19 8 1 0 72 16 5 7 1 0 60 19 12 8 1 1 73 14 8 4 0 

Serr 2 77 10 6 5 0 2 60 16 11 11 0 2 69 11 8 10 1 1 69 11 10 8 1 0 73 11 9 5 1 

Tehama 0 53 13 18 15 1 0 45 19 18 15 1 1 52 14 12 17 5 0 38 26 21 14 1 0 74 10 10 6 0 

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

Vina 0 39 18 18 22 2 4 32 27 21 12 1 0 39 18 18 20 4 0 32 21 21 23 2 1 44 24 19 12 0 

Other 8 60 11 12 9 0 2 57 15 12 11 1 4 54 10 12 16 3 0 29 18 22 30 0 2 37 15 29 16 1 

STATE 2 63 15 11 9 1 1 51 19 16 10 2 1 51 13 13 18 3 1 55 16 15 12 1 1 67 16 11 6 0 

Number of 

 Shells Measured 13,822 12,736 13,491 13,219 13,485 

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 

JACK RUTZ – SARAH HOFFMAN, Deputy Directors 

DOUG FLOHR – JENNIFER VAN COURT 

Statisticians – Estimates Group