Journal ArticleDOI
Ecological Importance of Snowbrush Ceanothus Velutinus in the Oregon Cascades
J. Zavitkovski,M. Newton +1 more
Reads0
Chats0
TLDR
Snowbrush did not add to the soil any significant amount of nitrogen by nitrogen fixation, but the species contributes to the formation of a new organic layer, however, through large amounts of nitrogen—rich litter.Abstract:
Twelve stands of snowbrush were selected for a biomass study to estimate nitrogen fixation under field conditions west of the summit of the Oregon Cascades Total nitrogen in the upper 2 ft of soil was higher under snowbrush than in the open, but the difference may have been caused by loss of nitrogen from open areas rather than by nitrogen fixation Total nitrogen in the upper 15 cm of soil under snowbrush did not differ from that found under nonfixing shrub species Various shrub species may increase the total soil nitrogen under their canopies, however, if only by accumulation from sites that lack vegetation More nitrogen may be tied up in the biomass of mature snowbrush stands than in stands of other shrubs The difference could be explained by nitrogen fixation, which may range from zero to about 20 kg/ha per year under conditions of this study Nodulated snowbrush seedlings produced 25 times the dry weight that non—nodulated seedlings produced in a nitrogen deficient soil Sixty—one per cent of the nitrogen in nodulated greenhouse seedlings was fixed Such fixation rates may be reached on infertile soils in the field, but they seem unlikely on soils of medium or better fertility This point seems to be substantiated by delay in nodulation of snowbrush in soils with increased levels of organic matter Bioassay tests using Douglas fir seeds and hemlock seedlings showed that snowbrush did not add to the soil any significant amount of nitrogen by nitrogen fixation The species contributes to the formation of a new organic layer, however, through large amounts of nitrogen—rich litterread more
Citations
More filters
Journal ArticleDOI
Nutrient cycling and nutrient use efficiency
TL;DR: The pattern for nitrogen circulation and nitrogen use efficiency in forests has important implications for ecosystem-level properties, including the development of low nitrogen availability in soil.
Journal ArticleDOI
Pattern, process, and natural disturbance in vegetation
TL;DR: The importance of disturbance regime as part of the environmental context of vegetation means that allogenic and autogenic models of vegetation are difficult to apply.
Journal ArticleDOI
Early Successional Patterns of Forest Species: Interactions of Life History Traits and Disturbance
TL;DR: Observations suggest that early secondary succession in Pseudotsuga forests has a deterministic component, founded in the life history traits of the available species, and temporal and spatial variation in disturbance intensity.
The regulation of chemical budgets over the course of terrestrial ecosystem succession [Forested watersheds].
TL;DR: In this paper, the authors have suggested that change in net ecosystem production is a major determinant of the balance between inputs and outputs of elements in terrestrial ecosystems, and that in most cases of secondary succession, net ecosystem output is negative immediately following disturbance, and in such cases output rates can exceed input rates.
Journal ArticleDOI
The regulation of chemical budgets over the course of terrestrial ecosystem succession
TL;DR: In this article, the authors have suggested that change in net ecosystem production is a major determinant of the balance between inputs and outputs of elements in terrestrial ecosystems, and that in most cases of secondary succession, net ecosystem output is negative immediately following disturbance, and in such cases output rates can exceed input rates.
Related Papers (5)
Soil development in relation to vegetation and surface age at glacier bay, alaska*
Robert L. Crocker,Jack Major +1 more