STORAGE OF CONIFEROUS TREE SEED 



By C. R. TiLLOTSor^ 



Forest Exartmier, Forest Service, United States Department of Agriculture 



During the period from 1909 to 19 13 the United States Forest Ser\'-ice 

 was especially active in its reforestation program. There were large 

 areas of deforested land on the national forests, and there was a sincere 

 desire on the part of the organization to serve the public interest by 

 bringing these lands into a productive state as soon as possible. The 

 program involved the growing in nurseries and planting of many millions 

 of young trees each year and also the sowing of seed directly on extensive 

 areas of deforested land. To carry out the program large quantities of 

 seed were needed. In the year 19 10 alone, 63,000 pounds of seed were 

 collected. Foresters know that seed is not borne in the same abundance 

 upon trees each year. A good seed crop in any region is often followed 

 by one to several very poor or lean crops. It accordingly is desirable 

 to collect during years of plenty seed in large enough quantities to last 

 several years. The Forest Service did pursue this course and thereupon 

 became confronted with the problem of how to store the seed so that 

 it would not deteriorate greatly in germinative ability and energy before 

 it could be used. This problem was not a new one. European foresters 

 had been faced with it a good many years ago and had made substantial 

 progress in its solution for some species. One of the most intensive 

 sets of European experiments with coniferous seed was perhaps that of 

 Dr. Adolf Cieslar ^ which was begun in the spring of 1886 and continued 

 over a period of 1 1 years. Dr. Cieslar attempted to determine not only 

 the efifect of air-tight storage on seeds of Norway spruce, black (Austrian) 

 and white pine, but also the effect of heating these seeds before placing 

 them in storage. He came to the conclusions that (i) storing under 

 air-tight covering lengthens the life of these species of seed so that when 

 stored in this way they often show a considerably higher germination 

 percentage, especially in the later years of storing, than seeds of the same 

 origin stored in the air, this difference in favor of air-tight storing of 

 seed amounting to 33 per cent in the case of 6-year-old Norway spruce 

 seed ; (2) storing seed away from the air also results in higher germinat- 

 ing power; (3) tbe application of heat at 45° to 55° C. to seeds of white 

 and black pine at the beginning of storing injures the viability of these 

 seeds and also their germinating power to a considerable extent, but Nor- 

 way spruce is injured less by this means, and its germinating power is 

 even kept at a high point by strong heating; (4) heating at 30° to 40° C. 

 for one hour has a not unfavorable effect on the seed of these three species. 

 When stored away from the air, such seed maintains both viability and 

 germinating energy at as high a point as that of unheated seed; in fact, 

 the slightly heated seed shows in later years of storing, a tendency to 

 germinate in a very rapidly rising curve. 



1 Cieslar, Adolf, versuche uber aufbbw.\hruno vo^f NADELHOLWAME>f unter luftdichtem 

 VBRSCHLussE. /» Centlbl. Gesam. Forstw., Bd. 23, Heft 4, p. 167-174- i^97- 



Journal of Agricultural Research, Vol. XXII, No. 9 



Washington, D. C. Nov. 26, 1921 



aar Key No. F-7 



(479) 



