are wind or water disseminated. Water dissemination is probably more
important because water deposits the seeds on moist shores favorable to
germination and establishment . The seeds germinate rapidly in
moist alluvial soil, often in large numbers, forming thickets on
sandbars . The seeds are apparently viable only a few days .
However, Koevenig  reported that seeds with the fruit wall and seed
coat removed will germinate even after 5 months in storage. He
concluded that a germination inhibitor builds up in either the fruit
wall or seed coat.
River birch does not spread vegetatively, but multiple stems arising
from stump sprouts are common . Because of this, river birch is
resilient to flood damage. On a frequently flooded site in Wisconsin,
77 percent of river birch stems were of sprout origin, and the remainder
were from seedlings .
- 2. Barnes, W. J. 1985. Population dynamics of woody plants on a river island. Canadian Journal of Botany. 63: 647-655. 
- 13. Grelen, H. E. 1990. Betula nigra L. river birch. In: Burns, Russell M.; Honkala, Barbara H., technical coordinators. Silvics of North America. Volume 2. Hardwoods. Agric. Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 153-157. 
- 24. Myers, Charles C.; Buchman, Roland G. 1984. Manager's handbook for elm-ash-cottonwood in the North Central States. Gen. Tech. Rep. NC-98. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 11 p. 
- 39. Whitford, Philip Clason. 1990. River birch in central Wisconsin: a case study of colonization. Michigan Botanist. 29(4): 115-120. 
- 42. Koevenig, James L. 1976. Effect of climate, soil physiography and seed germination on the distribution of river birch (Betula nigra). Rhodora. 78(815): 420-437. 
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