TREATING CHRISTMAS TREES TO MAKE THEM SAFE FROM FIRE Nov€itiber 1940 IF FL LIB. DOCUMENTS DEPT ■EPOSITORY nn LIBRARY 'URE UNITED STATES DEPARTMENT OF AGRICULT FOREST SERVICE FOREST PRODUCTS LABORATORY Madison, Wisconsin In Cooperation with the University of Wisconsin ¥t fc*., Digitized by the Internet Archive in 2013 http://archive.org/details/treatinOOunit TREATING CHRISTMAS TUBUS TO MAKE THEM SAEE FROM EIRE By ARTHUR VAN KLEECK, Associate Chemist After investigating various treatments suggested for the purpose of making spruce and balsam Christmas trees less inflammable, the Forest Products Laboratory at Madison, Wisconsin, has reached the conclusion that keeping the tree standing in water is about the most satisfactory and convenient method of those tried that will keep the fire hazard low and, at the same time, will keep the needles from discoloring or falling. The procedure recommended is as follows: 1. Purchase a tree that has not been allowed to dry out after being cut and that has been cut as recently as possible. 2. Cut off the end of the trunk diagonally, at least 1 inch above the original cut end. Stand the tree at once in a container of water and keep the water level above the cut surface during the entire time that the tree is in the home. If the tree is bought several days before it is to be set up in the home, it should be kept standing in water in a cool place. If started in time, this treatment not only prevents the needles from drying out and becoming inflammable, but will also keep the needles fresh and green and retard the needle fall of such sjecies as spruce, which lose needles very easily. Ereshly cut spruce or balsam fir trees standing in water cannot be set on fire by candle or match fires, but, of course, cannot withstand a large source of heat. In addition to the water treatment of the tree, all the usual precautions against fire should be taken, particular pains being taken to avoid the use of defective electrical connections, to prevent the accumulation of large amounts of combustible decorations on or beneath the tree, unless they are fireproofed, and to place the tree so that its accidental burning would not easily ignite curtains or furnishings, or trap the occupants of the room or building. Spruce represents the type of tree which loses needles very readily upon drying. Balsam fir, on the other hand, represents the type which retains its needles well. Even when the branches are extremely dry, balsam fir needles will not fall, although they will become brittle enough to break readily when handled. t ■ Luring the investigation, solutions- of a number of f ire-retardant chemicals were introduced into spruce and balsam fir trees or branches by the same method as that used for water. The quantity of solution taken up by the specimens and their changes in weight were determined by R12UU weighing the containers and specimens at frequent intervals. The method most commonly used -for determining the fire resistance of the specimens was to measure the rate of loss in weight of a small pile of tranches ex- posed to a low Bunsen burner flame for a standardized period of time. Some tests were also made with match flames and excelsior fires. Observa- tions were also made on the effect of the treatments on the color and fall of needles. A summary of the results with water and with k fire-re tardant chemicals — ammonium sulfate—, ammonium phosphate, ammonium sulfamate, and calcium chloride— — fellows. This summary is of tests on spruce and balsam fir trees only. It is probable that the effect of the treat- ment with water on other species would be more or less similar to that on spruce- and balsam fir, but other species may or may not react similarly to treatment with the chemical solution. Specimens, cut several days previously to being placed in water, gain a little in weight afthe start of treatment, then gradually lose weight, reaching the original weight after about 1 week and about SO per- cent of the'' original weight after 2 weeks of treatment. luring treatment the specimen takes up water very readily to replace that lost by evapora- tion, an amount equal in weight to the original tree being absorbed in U to 5 days, in a relatively dry atmosphere. However, since the loss by evaporation equals the gain by absorption, the weight of the tree during treatment does not fluctuate widely. On the -other hand, the chemical solutions tried were neither taken up so rapidly nor in such large amounts as was water, and the trees lost weight while being treated. In other words, while they are taking u; fire retardant chemical, they are losing another good fire retardant, water. In general, the more dilute the chemical solution, the greater was the rate of absorption. Specifically, treatments with solutions of the k fire retardant chemicals tested gave the following results: Ammonium sulfate . — Tests were made with 5> 20, and U0 percent solu- tions (by weight). All solutions caused bad discoloration of both spruce and balsam fir needles. The needles from the spruce specimens started to fall 2 days after treatment and by k to 5 days were falling freely. Fire tests showed the spruce specimens to be decidedly more inflammable than -Solutions of these chemicals are recommended in Department of Agriculture Leaflet 193, "Fireproofing of Christmas Trees." The Bureau of Agricul- tural Chemistry and Engineering states that their findings, based on tests on small trees of eastern redcedar ( Juniperus virginiana ) and Virginia pine ( Pinus virginiana ) indicate that these species are more ceptible to • treatment with solutions of ammonium sulfate and calcium chloride than trees of spruce and balsam fir, R124U -2- specimens treated, with water. The balsam fir specimens were not so inflam- mable as the spruce, but no significant improvement over the water-treated specimens was noted. Ammonium phosphate . — Tests were made with solutions of both mono- and diammonium phosphate and of a mixture of the two. The effect was similar to that of ammonium sulfate. Calcium chloride . — Tests were made with 5> 20, and 40 percent solu- tions. This chemical did not affect the color or the fall of the needles seriously. The fire resistance of specimens treated with kQ percent solu- tions was less than that of water- treated specimens, probably due to the fact that the specimens failed to take up an appreciable amount of calcium chloride and at the same time lost considerable moisture*. 3ome specimens treated with 20 percent solution compared favorably with water- treated specimens, but were not significantly superior in fire resistance. Ammonium sulfamate . — This chemical was the most promising of all tested. Its solutions causeddiscoloration of needles, but did not cause needle fall in spite of the fact that the specimen lost weight while being treated. The needles became very brittle and were easily loosened by handling, but did not fall by being jarred. The fire retardance of the few specimens treated with a kC percent solution of this chemical was very good, being approximately equal to that of water treated specimens. Specimens treated with this chemical were removed from the tre: tin : solu- tion and air dried until no further loss in weight occurred. Fire tests made on the dry specimens showed that the fire resistance was still good. While these experiments failed to disclose a chemical treatment more practical than water, they do not prove that such treatment is impossible. Until some other treatment for balsam fir and spruce is proven to be substantially superior, however, water, if used under the conditions specified, will do a good job at little cost. E12UU _3_ UNIVERSITY OF FLORIDA 3 1262 08927 4269 Oh. HB ™ Oi ZZ«N 9 H0I33J