Irrigation agriculture in its relation to lumber requirements

as illustrated by the California Fruit and Vegetable industry

By GEORGE F. BURKE and RUSSEL W. BEESON¹

¹ This article is based on a survey made by the authors in 1945, with some emendations by them and by FAO officials.

IN areas where agriculture produces fruits and vegetables for distribution and sale in urban markets, the producer requires wood packaging for his wares, so that they will reach distant markets in usable condition. This is most notably true where irrigation agriculture is the common practice, since the regular and assured flow of goods from it falters or breaks down unless wooden crates and boxes are available as needed.

The importance of fruits and vegetables as "protective foods" in the diet is generally recognized by world experience and research. In many lands where agriculture now concentrates on grain crops, some shift to- fruit and vegetable crops is most desirable from the international standpoint. It is well to recognize that to make these widely available to consumers, a supply of forest products suitable for boxes must be at hand.

Agricultural boxes can be made from fairly low-quality trees, logs, and boards. This is common practice, and keeps the cost down. It is important that, as a matter of cost, the source of raw material - the forests - be as close as possible to the centers of agricultural production.

A country that aims to diversify its agriculture, to produce protective food supplies for its people, would be well advised to look to the proper development and management of its forests.; A healthy, diversified agriculture, adequate nutrition, and effective forestry are all related elements in the one great problem of bettering human welfare.

The dependence of irrigation agriculture on forests and wood is well illustrated by the situation in the state of California, U.S.A. In this state agriculture is a highly organized business; its products are standardized, packaged for consumer use, and widely distributed.

Reports of this kind are not too commonly made, and the comparatively recent California experience may be useful to other areas in other countries which have a similar development of irrigation agriculture and make similar use of wood for handling and shipping fruits and vegetables.

California has 17 million acres (6.9 million ha.) of commercial forest lands from which is cut annually more than 2,500 million board feet (5.9 million m³ (s)) of lumber. Approximately 840 million board feet (2 million m³ (s)) of lumber, or the equivalent of 34 percent of tile total production, is used locally for agricultural containers. To the agriculturists of California, as well as to many other users of California timber, maintenance of productive forests is thus a matter of prime importance.

Agricultural shook for field and shipping containers is the largest use of lumber² produced in California. Wood has proved to be the most suitable material for such containers because of its ability to withstand comparatively hard usage and its relative resistance to moisture and temperature changes. Boxes constructed of wood combine the qualities of rigid support and flexibility, which have not yet been satisfactorily duplicated in other materials.

² Excludes plant maintenance and new construction.

This foremost lumber use derives from the importance of fruit and vegetable production in California. In 1944 California led all other states of the U.S.A. in cash receipts from farm marketing of fruit and vegetables. Its cash farm income of about 662 million dollars for fruits and of 284 million dollars for vegetables represented 47 percent and 19 percent respectively of the national cash farm income for these products.

Several of the more important fruits and vegetables are harvested and transported to packing or processing plants in the customary picking box or field lug. For commercial marketing, fruits and vegetables are shipped largely in specially designed wooden shipping containers, which prior to the war varied widely in size and form but during the war tended more to standardization for each commodity. Rail shipments are held in place by bracing lumber and stripping material. Wooden trays are used in sun-drying and dehydration of certain fruits and raisin grapes, and sweatboxes serve mainly as farm storage receptacles for dried fruits and raisins during the period of moisture equalization termed " sweating. "

A preliminary study of agricultural box shook requirements in California was made in January 1943 by the California Forest and Range Experiment Station, at the request of the Office of Agricultural War Relations of the U. S. Department of Agriculture. This study revealed that construction of agricultural containers constituted the most important use of lumber in California. When a national reappraisal of timber supplies was being made in 1945, it seemed advisable to investigate further this part of the lumber consumption picture, which is so important to California agriculture.

Scope of study

The report comprises (1) estimated lumber requirements for agricultural shook for the California fruit and vegetable industries as a whole, and for fresh and processed products separately; (2) estimated production of agricultural shook in California; and (3) the outlook after 1945, including a discussion of probable requirements, possible developments, and requirements compared with production. Lumber for plant construction and maintenance is not included in these estimates.

Lumber requirements for agricultural shook

Table 1 summarizes the lumber requirements for the fruit and vegetable industries in California for 1944 in terms of shook and for 1940-44 in terms of both shook and gross lumber footage.

For fresh fruit and vegetable shipments

Box Shook

Container requirements for shipment of fresh fruits and vegetables in terms of gross lumber volume represent about 84 percent of the total requirements for the California fruit and vegetable industries. For 1940-44, roughly 600 million board feet (1.42 million m³ (s)) of lumber was used for fresh fruit and vegetable containers. By commodity groups the requirements were 247 million board feet (0.583 million m³ is)) for vegetables, 215 million (0.507 million m³ (s)) for citrus fruits, and 138 million (0.326 million m³ (s)) for deciduous fruits and grapes.

Shook requirements are given in Table 2 by commodities. The estimates are based on the amount of shook required for containers per ear and the number of carlot shipments of major commodities.

Pears are sorted, wrapped and boxed in a California packing house.

TABLE 1. - LUMBER REQUIREMENTS FOR AGRICULTURAL SHOOK, FRUIT AND VEGETABLE INDUSTRIES, CALIFORNIA;

1944 AND AVERAGE 1940-44¹

Container or other use	Shook requirements (average " fall-down" in manufacture: boxes, 15%; trays, 25%)		Gross lumber requirements, average
	1944	Average 1940-44	1940-44
	(...1,000 bd. ft.2 ...)
Vegetable	264,540	247,010	290,600
Citrus fruit	1.99,220	214,690	252,580
Deciduous fruit and grapes	128,240	138,430	162,860
Total for fresh fruits and vegetables	592,000	600,130	706,040
Stripping lumber	29,610	28,680	28,680
Bracing lumber	7,14	26290	26,290
Dried fruit	24,980	24,980	29,390
Picking boxes	25,000	25, 000	29,410
Drying trays	10,040	10,040	13,390
Dehydrator trays	2,360	2,360	3,150
Sweatboxes	4,000	4,000	4,710
Total for miscellaneous uses	123.130	121,350	135,020
TOTAL	715,130	721,480	841,060

¹ Bases for estimates are described in the text under the separate headings.
² 1,000 bd. ft. of lumber equal 2.36 m³ (s).

The amount of shook required for containers per ear was calculated from the following information: (1) size of container most commonly used for each commodity; (2) number of board feet per container; (3) number of packages per carload. An average of 1,525 board feet (3.6 m³ (s)) of shook is required per carload of vegetables, 1,914 board feet (4.5 m³ (s)) per carload of citrus fruits, and 2,500 board feet (5.9 m³ (s)) per carload of deciduous fruits.

The carlot shipments include the carlot equivalents of total truck shipments within the state. Total intrastate truck shipments are usually assumed to be double the unloads at San Francisco and Los Angeles because only about half the state's population is in these two metropolitan areas. However, many of the products consumed in the interior valleys or received in metropolitan areas, particularly Los Angeles, are not packed in the usual shipping containers but are handled in bulk or in second-hand containers. To reflect truck shipments requiring new shook, therefore, a more reliable figure was obtained by adding to the San Francisco-Los Angeles truck unloads only 50 percent of the volume of such receipts instead of doubling it. Carlot shipments of peaches, pears, apricots, and grapes have been adjusted to exclude rail shipments of these products to processing plants, since the container used is the usual field lug box' which remains in service for years.

Car Bracing and Stripping

In addition to the boxes, each carload of fruit or vegetables requires, on an average, 110 board feet (0.26 m³ (s)) of bracing lumber and 120 board feet (0.28 m³ (s)) of lath stripping to secure the load. As about 239,027 carloads were shipped annually by rail during 1940-44, the estimated volume of lumber used was about 26 million board feet (61,000 m³ (s)) for bracing and about 29 million board feet (68,000 m³ (s)) for stripping.

TABLE 2. - CARLOT SHIPMENTS AND SHOOK REQUIREMENTS, CALIFORNIA FRESH FRUIT AND VEGETABLES, 1944 AND AVERAGE PER YEAR 1940-44

Commodity	Wood content of shook in commonly used container	Packages per car	Shook per car	Carlot shipments		Shook requirements
				1944	Average 1940-44	1944	Average 1940-44
	Bd. ft.					(...1,000 bd. ft.1...)
Vegetables
Asparagus	3.33	640	2,131	3,212	3,855	6,844	8,215
Beans (snap & lima)	4.60	320	1,472	2,352	3,100	3,462	4,563
Beets	4.60	320	1,472	1,003	1,223	1,476	1,800
Broccoli	3.31	440	1,456	2,362	1,881	3,439	2,739
Cabbage	3.07	400	1,228	6,749	6,510	8,288	7,994
Cantaloupes	4.10	288	1,181	14,291	10,925	16,878	12,902
Carrots	4.60	320	1,472	17,913	16,275	26,368	23,957
Casabas	4.10	288	1,181	596	472	704	557
Cauliflower	3.31	440	1,456	10,844	9,123	15,789	13,283
Celery	3.19	350	1,116	15,903	16,963	17,748	18,931
Corn	3.07	600	1,812	2,258	2,310	4,159	4,255
Cucumbers	2.57	1,000	2,570	717	887	1,843	2,280
Greens (except spinach)	4.60	300	1,380	1,185	1,155	1,635	1,594
Honey Ball melons	4.10	288	1,181	326	564	385	666
Honey Dew melons	3.40	500	1,700	4,142	3,317	7,041	5,639
Lettuce and romaine	4.60	320	1,472	57,364	49,416	84,440	72,740
Mixed melons	3.40	500	1,700	970	1,172	1,649	1,992
Mixed vegetables	4.60	320	1,472	11,198	9,739	16,483	14,336
Peas (green)	2.68	650	1,742	4,307	4,644	7,503	8,090
Peppers	3.90	400	1,560	1,208	1097	1,884	1,711
Persian melons	3.66	288	1,054	802	670	845	708
Spinach	4.60	320	1,472	2,272	2,479	3,344	3,649
Strawberries	1.26	1,200	1,512	345	1,420	522	2,147
Sweet potatoes	3.25	500	1,625	2,116	1,939	2,438	3,151
Tomatoes	2.68	650	1 742	14 962	15321	26064	26,689
Turnips, rutabagas	4.60	320	1,472	1567	1644	2 307	2420
TOTAL VEGETABLES				180,964	168,101	264,538	247,006
Citrus fruits
Grapefruit	4.26	460	1,960	4,231	5,081	8,293	9,959
Lemons	4.44	400	1,776	20.384	22,451	36,202	39,873
Mixed citrus	4.26	460	1,960	2,913	2,793	5,709	5,474
Oranges and Satsumas	4.26	460	1.960	76,030	81319	149,019	159,385
TOTAL CITRUS				103,558	111644	199,223	214, 691
Deciduous fruits and grapes
Apples	4.79	760	3,640	3,291	4,294	11,979	15,630
Apricots	2.45	1,100	2,695	2,389	1,309	6,438	3,528
Cherries	2.68	1,100	2,948	7,390	1,111	4,098	3,275
Grapes	2.57	1,000	2,570	24,533	30,296	63,050	77,861
Mixed fruits	1.41	1,300	1,833	620	464	1,136	851
Peaches	1.41	1,300	1,833	10,482	8,397	19,213	15,392
Pears	2.62	675	1,768	4,365	5,501	7,717	9,726
Plums, fresh prunes	2.57	900	2,313	5,980	4,891	13,832	11,313
Tangerines	3.63	800	2,904	267	294	775	854
TOTAL DECIDUOUS FRUITS AND GRAPES				53,317	56,557	128,238	138,430
TOTAL				337,839	336,302	591,999	600,127

¹ 1,000 bd. ft. of lumber equal 2.36 m³ (s).

For processed fruits and vegetables³

³ Excludes cannery shook. Fiberboard has largely replaced wood in the manufacture of shipping containers for this purpose and lumber now used is relatively unimportant.

Dried Fruit

About 560,000 short tons (508,000 metric tons) of dried fruit was produced in California in 1944 of which 25 percent, or 140,000 shot tons, was packed in wooden boxes. The standard 25-pound dried-fruit box contains 2.23 board feet (0.0053 m³ (s)). The shook requirement for dried-fruit boxes, therefore, is 25 million board feet (59,000 m³ (s)).

Picking Boxes

It is extremely difficult to estimate the annual requirement for picking boxes because of the almost complete lack of reliable data. These boxes are used extensively in harvesting eight fruits and two vegetables. They are often reused several times during a season, and the number of years they remain in service depends upon the care used in handling. Information on this subject was solicited from canners, shippers, and growers. The consensus seemed to be that about five picking boxes were required per ton of produce Therefore, on the basis of tonnage produced and an average life of 10 years for the container, approximately 2,582,000 boxes are required annually for replacement. As these boxes contain 4.7 board feet (0.011 m³ (s)), the annual shook requirement for new picking boxes is about 12 million board feet (28,000 m³ (s)). The information received also indicated that an approximately equal footage was needed for the repair of old picking boxes. The total requirement, therefore, for box shook used in new picking boxes and for repair is roughly 25 million 'board feet (59,000 m³ (s)).

Peaches unloaded at a California cannery.

Sun-Drying and Dehydrator Trays

It is estimated that about 10 million board feet (24,000 m³ (s)) of shook is required annually for trays used in sun-drying deciduous fruits and raisin grapes and slightly more than 2 million board feet (4,700 m³ (s)) for dehydrator trays. For each fruit separately and for each method of drying, these estimates take into account (1) the average annual volume dried; (2) the length of the drying season; (3) the time required to dry each spread or charge; (4) the number of times each tray is used per season; (5) the number of pounds of fresh fruit per tray; (6) the ratio of fresh weight to dry weight or drying rates; and (7) the average tray life, which was assumed to be 10 years for sun-drying and 6 years for dehydration. From these data it was possible to estimate the total number of trays required and the number of each kind required annually for replacement. The conversion to board feet of shook was accomplished by multiplying the number of trays needed for replacement by the footage contained in the average-sized tray, 10.31 board feet (0.024 m³ (s)).

Sweatboxes

Approximately 4 million board feet (9,400 m³ (s)) of shook is required annually for sweatboxes used in storing dried peaches, apricots, figs, and raisins during the period of moisture equalization and preceding final packaging for market. The sweatbox preferred in practice is constructed of pine lumber and has a capacity of about 200 pounds (91 kg). This size box contains about 16.11 board feet (0.038 m³ (s)) of shook. It is generally used once during the season and has an average life of about 12 years. The annual shook requirements were estimated from these data and the average volume of the designated fruits dried per season.

Estimated production of agricultural shook

Approximately 45 box factories in California produce agricultural shook. Most of them are operated in conjunction with sawmills. Although a few factories maintain selling organizations, the majority sell through distributors handling only this phase of the business. The four distributors that handle the bulk of the sales maintain storage warehouses and assembly plants strategically located throughout the state. Because of lack of labor many of the assembly plants were closed during the war. With the advent of normal times it is presumed that these services will again be offered to purchasers of box shook.

During the war, inventories of box shook in the hands of producers, distributors, and consumers were extremely low. Therefore the records of shipments from mills were a fairly accurate representation of production for the period. Box lumber in normal times grades about 75 percent No. 3 Common and 25 percent No. 4 Common. Obviously, with this grade of lumber, there is considerable " fall-down " in the manufacture of shook. The accepted figure is 15 percent.

In 1944 California factories produced approximately 500 million board feet (1.18 million m³ (s)) of agricultural shook⁴ from 588 million board feet (1.39 million m³ (s)) of lumber. Not all of California's shook production, however, was available for local use. About 5 percent, or 25 million board feet (0.06 million m³ (s)) was shipped to consumers in such states as Utah, Nevada, New Mexico, Colorado, Arizona and Texas.

⁴ In addition, California factories produced about 86 million board feet (0.20 million m³ (s)) of war and industrial shook. Thus agricultural shook represented about 85 percent of total 1944 shook production. A much smaller anneal annual volume of non-agricultural shook is fore cast in peacetime. Agricultural shook will therefore make up a larger proportion of total production (possibly as much as 95 percent) in the years ahead

The difference between the volume of shook required in the state (721 million board feet = 1.70 million m³ (s)) and the volume produced and used locally (475 million board feet = 1.12 million m³ (s)) is 246 million board feet (0.58 million m³ (s)), or 34 percent. All but a small amount of this deficit was produced by factories located principally in the area from Bend to Klamath Falls in Oregon state. The production of factories in the Pacific Division area (western, central, and southern Oregon, California, Arizona, New Mexico, and Colorado) exceeded California's total requirements by only about 100 million board feet (0.24 million m³ (s)).

The outlook

Probable Requirements, 1945-64

In terms of carloadings per year, commercial marketing of California fruits and vegetables customarily marketed fresh in new wooden containers averaged about 10 percent more during five of the war years (1940-44) than during the 10-year period immediately preceding and about 7 percent more than during the 15-year period after 1930.

Requirements for agricultural containers at the time of this report (1945) were difficult to forecast. Material changes might occur during the next two decades in the proportions of fruits and vegetables marketed in fresh and in processed form. Competing areas of production might cut the volume of fresh products shipped from California, and changing methods of transportation and distribution are likely to affect the volume packaged in the customary types of containers - whether those containers be made of wood or other materials. Such changes cannot be predicted.

Nevertheless, most competent observers believe that California fruits and vegetables will retain approximately their present proportion of the national market and that commercial marketings of the major commodities will continue at about the present level. This assumption is based on past history and indicated trends of production and utilization.

Possible Developments

Since commercial marketings of California fruits and vegetables are expected to continue at about the present level, it follows that annual lumber requirements will also remain about as great - 841 million board feet (1.98 million m³ (s)). The greatest single factor than can logically be expected to reduce present-day shook consumption and force a shift to substitute materials for containers is the predicted decline in mill output in the relatively near future because of dwindling supplies of raw material.

Production of agricultural shook during the war years was a constant source of worry to consumer and producer. The shortness of supply was accentuated by the heavy demand for industrial shook for overseas shipment of military equipment - an obligation that had to be shouldered for the most part by existing agricultural shook factories. Supply after Pearl Harbor was barely adequate, and the situation will very likely remain unfavorable in view of a continuing heavy demand as contrasted to the ever-decreasing supply of suitable and readily available timber. It is estimated that many of the California pine region mills will be out of stumpage within a relatively few years. An indication of the anxiety about this is the recent purchase by the Fruit Growers Supply Company of 80,000 acres (32,000 ha.) of timber. The express purpose of this transaction was to secure an additional supply of timber badly needed to sustain its output of box lumber. Lumber used in the manufacture of citrus crates alone for the period 1940-44 grossed 252,580 thousand board feet (0.60 million m³ (s)). Only the requirements for vegetable shook exceeded this figure.

Continuing heavy demands for agricultural shook during the years ahead will very likely result in greater use of species now considered inferior to the commonly used ponderosa pine. A trend in this direction is already evident in the use of white fir for containers, which has increased considerably in recent years. White fir lumber production in California has nearly tripled since 1941. A continuing trend in this direction, together with a greater utilization of second-growth ponderosa pine, which theoretically should show a gradual increase as the old-growth timber is removed, will tend to relieve some of the pressure on old-growth ponderosa pine. However, it is doubtful whether these sources of supply will take up the full slack. A companion development, assuming a lumber deficit in the near future, will logically be substitutes for wood in the construction of containers for fresh shipment or greater reliance on lumber sources outside the state.

Requirements Compared with Production

Although the fruit and vegetable industries in California require approximately 841 million board feet (1.98 million m³ (s)) of lumber annually for agricultural shook, only about 588 million board feet (1.39 million m³ (s)) of lumber from California, or approximately 24 percent of the volume produced (2,469 million board feet = 5.83 million m³ (s)) was converted into shook for agricultural use in 1944. Ponderosa pine is the species considered most suitable for containers and has been the species most widely used for this purpose over the years. According to census compilations, about 1,059 million board feet (2.5 million m³ (s)) of ponderosa pine lumber was produced by the California pine region mills in 1944. If ponderosa pine had been used exclusively, approximately 55 percent of this output would have been converted into agricultural shook. Other species, however (mostly sugar pine and white fir), were used to some extent and since practically all the agricultural shook manufactured in California is from lumber produced in the pine region the proportion of the regional output (1,821 million board feet = 4.3 million m³ (s)) that was converted into agricultural shook was 32 percent. About 46 percent of pine region production would be needed if the full requirements of the industries of 841 million board feet (1.98 million m³ (s) were supplied within the state.

Lumber production in California reached a new high in 1944, being about 5 percent more than in the peak year of 1943. Although production in the pine region was up 5.4 percent, it is significant to note that the output of ponderosa pine dropped 6.7 percent, while other species generally showed increases, mainly white fir (+ 60.9 percent), sugar pine (+ 16.7 per cent), and Douglas fir (+ 9.7 percent). The decrease in the cut of ponderosa pine and the increases noted for other species may be an indication of future trends.

Cherries being sorted and boxed in a California pocking house.

Summary

It is estimated in this study that the fruit and vegetable industries in California used approximately 721 million board feet (1.70 million m³ (s)) of shook annually during the five years 1940-44. The volume in terms of gross lumber requirements was 841 million board feet (1.98 million m³ (s)). The total lumber requirements in 1944 were only slightly less than the average for the 5 years. The major lumber requirements for different classes of use were: vegetables 291 million board feet (0.69 million m³ (s)), citrus 252 million board feet (0.59 million m³ (s)), deciduous fruits 163 million board feet (0.38 million m³ (s)), ear stripping and bracing 55 million board feet (0.13 million m³ (s)), dried fruits 29 million board feet (0.07 million m³ (s)), picking boxes 29 million board feet (0.03 million m³ (s)), drying trays 13 million board feet (0.03 million m³ (s)), dehydrator trays 3 million board feet (0.01 million m³ (s)), and sweatboxes 5 million board feet (0.01 million m³ (s)). The lumber used for containers for marketing fresh products alone was 706 million board feet (1.67 million m³ (s)) or 84 percent of total gross lumber requirements.

Although it is extremely difficult to forecast requirements, most competent observers assume, on the basis of past history and indicated trends of production and utilization, that California fruits and vegetables will retain approximately their present proportion of the national market and that commercial marketing will continue at about the present level. It presumably follows, therefore, that for many years to come annual lumber requirements will remain about as great as the 1940-44 average.

California factories are not able to supply all the shook required. In 1944 plants located in California produced approximately 500 million board feet (1.18 million m³ (s)) of agricultural shook, largely ponderosa pine. About 5 percent of this volume (25 million board feet = 0.06 million m³ (s)) was shipped mainly to consumers in nearby states. The 475 million board feet (1.12 million m³ (s)) remaining supplied about two-thirds of California requirements. Factories located principally in the area from Bend to Klamath Falls in Oregon produced all but a small amount of the deficit of 246 million board feet (0.58 million m³ (s)). About 46 percent of total lumber production from the pine region would be needed if the full requirements of the industries of 841 million board feet (1.98 million m³:(s)) were supplied within the state.

It is predicted that California's timber supply, particularly ponderosa pine, will continue inadequate in the years ahead Accordingly, it is expected that fruit and vegetable producers, in addition to using greater quantities of lumber from less desirable species, will be forced to rely more on lumber sources outside the state or to develop suitable substitute materials.

Many other areas of the world, with similar agricultural production and a waning timber supply, may be faced with the same set of problems.

Photos accompanying this article were furnished by the U. S. Forest Service.