Germination was reduced if the seeds overwintered beneath the canopy of mature 

 pine trees, or if the seeds were germinated in soil collected from beneath the canopy 

 of mature trees. The exact cause of this reduction was not determined although it 

 could be explained by weak phytotoxins, the moisture conditions of the seeds, or a com- 

 bination of the two. If phytotoxins were responsible, they did not affect the growth 

 of the seedlings that did germinate. 



PUBLICATIOIMS CITED 



Al-Naib, F. A., and E. L. Rice 



1971. Allelopathic effects of Platanus oao-identat-is. Bull. Torrey Bot. Club 

 98:75-82. 

 Biswell, H. 



1973. Fire ecology in ponderosa pine-grassland. Proc. Annu. Tall Timbers Fire Ecol . 

 Conf. 12:69-96. 



Brown, R. T. , and P. Mikola 



1974. The influence of fruticose soil lichens upon the mycorrhizae and seedling 

 growth of forest trees. Acta For. Fenn. 141:1-22. 



Cooper, F. 



1960. Changes in vegetation, structure, and growth of southwest pine forests since 

 white settlement. Ecol. Monogr. 30:129-164. 

 Curtis, J. D., and D. W. Lynch. 



1965. Ponderosa pine. In Silvics of forest trees of the United States. USDA For. 

 Serv. Agric. Handb. 271, p. 217-431. 

 DeBell, D. S. 



1971. Phytotoxic effects of cherrybark oak. For. Sci. 17:180-185. 

 del Moral, R. , and R. Cates. 



1971. Allelopathic potential of the dominant vegetation of western Washington. 

 Ecology. 52:1030-1037. 

 del Moral, R. , and C. H. Muller. 



1969. Fog drip: a mechanism of toxin transport from Euaalyptus globulus. Bull. 

 Torrey Bot. Club 96:467-475. 



del Moral, R. , and C. H. Muller. 



1970. The allelopathic effects of Euaalyptus camaldulensis . Am. Midi. Nat. 

 83:254-282. 



Djavanshir, K. , and C. P. P. Reid. 



1975. Effect of moisture stress on germination and radicle development of Pinus 

 eldariaa Medw. and Pinus ponderosa Laws. Can. J. For. Res. 5:80-83. 



Eckert, J. R. 



1975. Roles of fire and allelopathy in ponderosa pine forest of the Colorado Front 

 Range. J. Colorado -Wyoming Acad. Sci. 7:31. 



Foiles, M. W. , and J. D. Curtis. 



1973. Regeneration of ponderosa pine in the northern Rocky Mountains- Intermounain 



Region. USDA For. Serv. Res. Pap. INT- 145, 44 p. Intermt. For. and Range Exp. Stn., 



Ogden, Utah. 

 Hall, F. C. 



1976. Fire and resource dynamics. Symp. , Fire Manage. Executive, Pajaro, Calif., 

 Jan. 19-23, 1976. 



Hamilton, M. A. 



1965. Multiple comparison procedures. USDA For. Serv. Res. Note RM-44, 12 p. 

 Rocky Mt . For. and Range Exp. Stn., Fort Collins, Colo. 



21 



