FOREST TREE SEED AND SEED COLLECTING 167 



ture, by lowering respiration and transpiration, causes a decrease 

 in destructive assimilation, a fact of the utmost importance in the 

 storage of seed. The successful storage of seed requires that respi- 

 ration and transpiration be reduced to the lowest possible degree. 

 This condition can be brought about in two ways: 



o. By maintaining the seed in a moist condition at a low tem- 

 perature. 



b. By maintaining the seed in a dry condition, that is, at a low 

 but uniform degree of moisture. 



The seeds of different species vary greatly in the degree of des- 

 iccation which they will endure without injuring or destroying 

 their vitality. The seeds of oak and chestnut become overdry 

 when stored at the normal humidity and temperature of the open 

 air in winter. Under similar storage locust and catalpa are unin- 

 jured. Seeds that will not withstand a high degree of desicca- 

 tion cannot be stored at normal summer temperature. When the 

 humidity is maintained sufficiently high to prevent desiccation, 

 respiration and transpiration are increased to such an extent that 

 they soon die through destructive assimilation. On the other 

 hand, the seeds of locust, catalpa, pine, and spruce remain alive 

 for many months when kept in an atmosphere sufficiently dry to re- 

 duce respiration and transpiration below the point of rapid injury. 



The method of storage best adapted to a given species does not 

 deviate in a marked degree from the method of natural preserva- 

 tion of the seed up to the time of germination. Seed which 

 matures in the autumn and is disseminated at once and covered 

 with leaves after it falls to the ground is exposed to a low winter 

 temperature and excessive moisture. From Zederbauer's experi- 

 ments it appears that such seed when stored is favored by con- 

 ditions which afford low temperature and high humidity. Seed 

 which matures in the autumn but is retained on the trees over 

 winter is exposed to low temperature and normal atmospheric 

 humidity. When stored it appears to be favorably affected by 

 low temperature but not by excessive moisture. Cieslar found 

 that the germinative capacity of acorns is best preserved by 

 storage at low temperature and a high degree of humidity, while 

 the temperature and moisture conditions in the ordinary cellar, 

 warehouse, or heated room are very unfavorable. Haack, 1 from 



1 Haack, Oberforster: Der Kiefernsamen. (Zeitschrift f. Forst- u. Jagd- 

 wesen, S. 353-381. 1909:) 



