Seasonal changes in shoot and root production and in carbohydrate content of salmonberry (Rubusspectabilis) rhizome segments from the central Oregon Coast Ranges

Abstract

An extensive rhizome system is an important aspect of the morphology and architecture of salmonberry (Rubusspectabilis Pursh) and of its potential for regrowth following disturbance. Seasonal activity of the rhizome system was studied by collecting rhizome segments monthly from February through October 1988 and February 1989 from four sites. Total nonstructural carbohydrate content was determined and segments were incubated in a growth chamber to determine periodicity of shoot and root production. The number and dry weight of shoots peaked in February and March, declined from April through June when aboveground shoot growth was greatest and were generally low through the dry summer months. Root production was highest from August through October and generally lower the rest of the year. Total nonstructural carbohydrate content was highest during the dormant season and dropped to the lowest level in midsummer. Shoot production was more closely associated with total nonstructural carbohydrate content than was root production. The significant reduction in shoot production potential suggests a time in the annual growth cycle when the species capacity for regrowth following disturbance is at a relatively low level.