FOREST TREE SEED AND SEED COLLECTING 169 



33. STORAGE UNDER FLUCTUATING TEMPERATURE AND HUMIDITY 



Most forest tree seed is stored over winter only, namely, from 

 the time of ripening in the autumn until required for sowing the 

 following spring. Many seed dealers handle only fresh seed, i.e., 

 seed that has been stored from one to six months. Some dealers 

 in the United States have in recent years undertaken the storage 

 of certain species for two or even three years. The uncertainty of 

 the seed crop has led to marked improvements in seed storage. 

 At times of heavy seed crops many species can be collected in 

 excess to be used at times of shortage. 



When the seed is stored over winter only, all species that are 

 stored dry can be kept in bins, bags, or boxes in a special storage 

 house, warehouse, or ordinary loft where they are subjected to the 

 normal fluctuations in atmospheric temperature and humidity. 

 The low winter temperature prevents deterioration, even when 

 there is considerable fluctuation in humidity. When the store- 

 house or loft is heated, although the humidity is lowered, the in- 

 creased temperature often causes unfavorable conditions. When 

 stored in a basement or cellar under more uniform but higher 

 temperature conditions and increased humidity, there appears to 

 be a falling off in germination values. 



34. COLD STORAGE 



The length of storage of all species can be increased by keeping 

 the seed in cold storage. This applies to seeds like pine and spruce 

 which are stored dry, and chestnut and oak which are stored wet. 

 Cieslar has demonstrated that the seeds of beech and oak keep 

 much better in wet condition at a low temperature than when 

 stored under a fluctuating temperature in drier condition. Pine, 

 spruce and other coniferous seeds are often stored over the first 

 winter in a seedhouse or loft where the temperature averages low 

 because of the season. The seed which is not used the following 

 spring is put in sacks or boxes and placed in cold storage. The 

 low temperature checks destructive assimilation and prevents the 

 loss incident to storage under the high fluctuating temperature of 

 the summer season. 



When forest tree seed is stored over summer in a dry condition 

 it is good practice to place it in cold storage if facilities are not 

 afforded for enclosing it in air-tight receptacles. The effect of 



