814 JOURNAI, OF FORESTRY 



On the L1AB11.1TY OF Tree Seeds After Storage for Ten Years 



In the autumn of 1910 seeds from each of fhirty species of forest 

 trees were prepared for storage and placed in fruit jars and the covers 

 loosely screwed in place. The jars with their contained seeds w-ere'kept 

 until the spring of 1921 on the window sills in a basement laboratory in 

 Marsh Hall, Yale School of Forestry, where they were exposed to the 

 air and light. The windows faced the west and in the late afternoon 

 the jars were in part exposed to the direct rays of the sun. The sum- 

 mer temperature and humidity were approximately that of the outside 

 air. In winter the temperature varied from 40° to 78° F., the temper- 

 ature of a furnace heated building. The humidity was considerably 

 lower than that of the outside air. 



In May, 1931, samples of 200 seeds. each were removed from, the 

 jars and sown in carefully prepared and protected seed-beds in the 

 School of Forestry nursery and the progress of germination and early 

 growth noted. 



The following table gives the list of species and the tree per cent 

 obtained in 1921 over a period of five months. The term- "tree per 

 cent" as here used, is the actual percentage of seedlings to seeds sown 

 that appeared above the surface of the soil. 



Species 



Tree per cent 

 in 1921 



Abies f raseri 



Betula alba 



Betula papyrifera , .. 



Catalpa kempheri 



Chamsecyparis lawsoniana. 



Cladrastis lutea 



Cupressus arizonica 



Cupressus goveniana. . . . . . 



Cupressus macrocarpa. . . . 



Fraxinus oregona 



Koelreuteria paniculata. . . 



Morus alba 



f icea sitchensis.", .■ 



Picea canadensis 



Pinus echinata 



Pinus austraca 



Species 



Pinus coulteri 



Pinus divaricata 



Pinus ponderosa 



Pinus ponderosa. 



Pinus sylvestris 



Pinus attenuate 



Pinus massoniana^ , 



Pinus rigida 



Pseudotsuga mucronata. 

 Robinea pseudacacia. . . . 



Staphylea trifolea 



Sequoia sempervirens. . . 



Thuja plicata > . , 



Tsuga heterophylla-. . . . . 

 Tsuga mertensiana 



Tree per cent 

 in 1921 





 13 

 



An interesting result of these tests is out of thirty species of conif- 

 erous and hardwood species selected almost at random ten species,, or 

 one-third of the whole, contained viable seeds after storage for ten 

 years in unsealed cans subjected to normal laboratory conditions as to 

 teihperattire and humidity. J. W. T. 



