In planning for the best piling practice there is one further consideration that must not be overlooked. Where checking and other defects due to air-seasoning become serious, care must be taken to pile the lumber so that too-rapid drying shall not take place. A balance is required between rapid drying to prevent sap stain and too-rapid drying which may result in excessive checking. Both checking and sap-stain losses should be reduced to a minimum, and these somewhat opposing requirements add to the difficulty of the problem.

BETTER PILING PREVENTS WASTE

That the loss due to blue stain is a drain on our forest resources is not always recognized, but when one considers the fact that

FIGURE 32.-View taken in the air-seasoning yard of a southern hardwood mill. The methods of piling used here are of the type that produce rapid drying and a minimum of sap stain. Note the high open foundations and the narrow piles

potentially high-grade lumber is reduced to lower grades through stain it is easy to see that an increased supply of the best logs is needed to fill the gap thus formed. Necessarily, a more rapid depletion of our forests follows, along with an overproduction of lower, less easily marketed grades of lumber. In an analysis of air-seasoning data to be presented later, it will be shown that better piling methods greatly reduce the amount of sap stain appearing in lumber. (Fig. 32.) Such a result points the way to scientific piling as a means of cutting down the annual blue-stain loss, increasing the proportion of high-grade lumber from the log, and assisting directly in the conservation of our timber supply.

Proper piling practice is a matter of locally applying the principles involved to the particular problems encountered. In some regions

blue stain overshadows the other seasoning defects and must be dealt with accordingly. Again, end checks may be the major defect that needs to be eliminated, or two or more defects may appear in sufficient amounts to warrant special piling. Conditions influencing air-drying vary greatly within the same region, and with the wide variations of climate, topography, mill practices, and wood species to be found in the United States it is impossible to present any specific rules for preventing sap stain. Since blue-stain fungi are tiny plants greatly dependent upon water for their development, the rapid removal of moisture from the surfaces of sapwood lumber during the first few days of air-seasoning is the process underlying the successful prevention of sap stain. To accomplish this the circulation of air over the green boards must be rapid to carry away the necessary moisture but not so rapid as to cause end checks and center checks to appear in the lumber. The problem then becomes one in which the circulation of air through the pile and the removal of moisture-laden air from the lower part of the pile must be carefully regulated to meet local conditions. Since the general movement of air in a pile during the early period of seasoning is downward,48 49 50 the height of foundations, topography of ground, and amount of weed growth must be taken into account in order to get this soggy air drained away from the piles. Increasing the foundation heights will be of no avail unless care is taken to control the weeds.

EFFECT OF WEEDS IN THE LUMBER YARD

Weeds or any kind of rank growth in the yard where lumber is seasoning usually mean a reduction of the air circulation under the lumber piles and an increase in moisture about the base of the pile. These conditions encourage blue stain in the lumber and may also slow down the drying rate within the piles. Weeds give an untidy appearance to the best of yards and should be removed to prevent their spread. In the late summer and in the fall, or whenever the vegetation begins to turn brown and becomes dry, a large weed represents a serious fire risk in any yard and should not be tolerated. The slogan, "Everybody loses when timber burns," applies to the wood in a lumberyard as well as to the green timber in the forest. There are several ways in which weeds may be kept down or eradicated in the lumberyard. Cultivation of the area or mowing with a scythe are out of the question, since the weeds and grasses growing closely about the pile foundations can not easily be reached by either of these methods. Grazing the area regularly with sheep or other stock has been successful at several plants. Treating with chemicals presents a practical method that has much in its favor. Common salt is among the more common and less expensive chemicals and is usually applied at the rate of 50 to 75 gallons per acre, using 150 pounds of common salt to 50 gallons of water. For the broad-leaved plants a solution made up of 100 pounds of iron sulphate to 52 gallons of water is often used and sprayed on the plants

48 Fullaway, S. V., jr., and Hubert, E. E., The Air-Seasoning of Lumber in the Inland Empire: Timberman 26; April, 1925.

49 Green. C. B., The Air-Seasoning of Lumber in the California Pine and Redwood Regions: Timberman 26; October, 1925.

Johnson, H. M., and Gibbons, W. H., The Air-Seasoning of Lumber in the Douglas Fir Region: Timberman 27; October, 1926.

while the leaves are still young and tender. This chemical, however, does not kill all the noxious plants and often kills only the tops, the roots remaining alive and producing new shoots.

Sodium arsenite, 2 pounds to 52 gallons of water, is very effective, although it is a very poisonous chemical to handle, and care must be used in applying it where stock may feed on the treated plants. Another chemical recommended as a positive killer of many weeds. is carbon bisulphide, but this is rather expensive, costing about $1.25 per gallon. This chemical is applied to the roots of the plants by means of small holes 18 inches deep and 2 feet apart each way, filled with 2 ounces of the chemical. A gallon of the chemical will treat about 200 square feet. The chemical should be applied wher the soil is quite moist. Care must be exercised in handling this liquid, as it is very inflammable. Many other "weed killers" may be found on the market and tried out for their effectiveness in disposing of plant growth in the lumber seasoning or storage yards.

51 52 53 54

OUTLINE OF PILING PRACTICES

In order to present to the reader the many variables that may be used in improving the piling practice, with particular reference to the prevention of blue stain, a condensed outline has been prepared from a review of the various articles recently published on air seasoning. The yard superintendent can study the outline and select such variables in piling practice as will best fit the local conditions. Special attention is called to four publications issued by the National Committee on Wood Utilization, of the Department of Commerce, Washington, D. C., in which seasoning, handling, and piling problems are discussed in minute detail. Four reports have been printed treating these matters as they affect consumers, distributors, fabricators, and sawmill operators. The title of each of these reports is shown on page 1 of this report under the heading of Publications of the National Committee on Wood Utilization.

YARD AND PILING PRACTICE TO REDUCE STAIN

YARD LAYOUT

Drainage, slope. Proper drainage for both air and water.
Exposure to sun and to prevailing winds.

Nearness to rivers, lakes, swamps. Affects drying rate.

"Hog fuel" fills not desirable.

Direction of alleys. (North and south.)

Width of alleys-varies from 16 to 20 feet.

Cross alleys every 200 to 500 feet.

Spacing between piles should be continuous and about 4 feet
wide.

Blocking of alleys and spaces between piles should be avoided.
Spacing between rear of piles should be about 10 feet.

51 Fullaway, S. V., jr., and Hubert. E. E., The Air-Seasoning of Lumber in the Inland Empire: Timberman 26; April, 1925.

2 Green. C. B.. The Air-Seasoning of Lumber in the California Pine and Redwood Regions: Timberman 26; October, 1925,

Johnson, H. M., and Gibbons, W. H.. The Air-Seasoning of Lumber in the Douglas Fir Region: Timberman 27; October, 1926.

54 Newins, H. S., The Proper Piling of Lumber: Southern Lumberman 121:185–188; December, 1925.

HANDLING BEFORE SEASONING

Avoid long bulking of green stock before transportation to yard.

Keep free from dirt.

Use cover boards on uncompleted piles.

Chemical dip.

Steaming.

YARD TRANSPORTATION

Avoid bulk piling of green lumber before placing in piles.
Plank driveways, trams v. metal tracks.

Sanitation of yard. Removal of all infected wood.

Removal of weeds. Increases circulation, reduces fire hazard.

PILING METHODS

General.-Type of pile (square in softwoods, narrow in hardwoods).

Size of pile (60 to 100 courses).
Pitch, slope.

Parallel to or right angles to alley.

Roof construction. Water-tight.

Roof overhang, front, rear, and sides.

Drip boards. (Not always effective.)

Overlap of crossers. Useful in reducing end checks.

Random length stock (box piles).

Random width stock.

Insufficient foundations and crossers cause sag. Pile foundations (18 to 24 inches clear at rear). Crossers.

Size, number (three crossers to 16-foot stock).

Kind (heartwood, new, clean, dry, and narrow).

Condition (kiln-dry, rough, not too old). Old crossers carry

spores.

Overlap (2 to 4 inches for 4 to 8-inch stock). Prevents end checks.

Storage (off the ground; keep dry and clean).

Stock crossers (cause crosser stain, checks, etc.).

Opening up the pile (center, lower third of pile usually shows greatest stain).

Foundation heights.

Crosser heights (thickness).

Thick crossers or double crossers in lower pile.

Spacing between boards in a course. (Fig. 33.)

Chimneys (the use of three 8-inch, one 12-inch, or of single,

flared chimneys).

Horizontal openings in lower part of pile.

Boards edge to edge, several chimneys.

Roofs. Raised above top of pile.

Seasonal methods.

Special methods.

End coatings (to prevent stain, decay, and checks in logs and

thick plank stock).