Record Details
Context matters : a multi-scale assessment of riparian tree response to upslope density reduction
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Context matters : a multi-scale assessment of riparian tree response to upslope density reduction |
| Names |
Ruzicka, Kenneth J., 1982-
(creator) Puettmann, Klaus (advisor) Olson, Deanna (advisor) |
| Date Issued | 2014-12-10 (iso8601) |
| Note | Graduation date: 2015 |
| Abstract | Forest management is rapidly undergoing a transformation from a discipline based on efficient commodity production to one for multiple uses, especially on federally managed land in the United States. This new management paradigm has challenged silviculturists to develop and adapt forest management techniques that can deal with increased demands. Using the Density Management and Riparian Buffer Study of western Oregon, USA I highlight the importance of context in forest management in three interconnected studies. When viewed together, these studies show the implications of understanding both regional-scale climate and plant-plant interactions for forest stand management. In the first study I examined the Density Management and Riparian Buffer Study of western Oregon in a social context, specifically of the Northwest Forest Plan. I briefly discuss the development of the Northwest Forest Plan and how it changed the way forest policy was developed in the region. The Density Management and Riparian Buffer Study came to fruition within this new management framework and resulted in a proof-of-concept for adaptive management approaches. The Density Management Study serves as a model for integrated knowledge discovery and adaptive management within the context of the federal forest plan. The future of the study appears to be similarly interconnected with interagency plans for federal lands management. In the second study, I examined the potential of using upslope density management to influence growth and drought tolerance of trees in untreated downslope riparian forests. Trees responded to an apparent edge effect up to 15 m downslope of thinned areas but not downslope of clearcut gaps. Additionally, in a retrospective analysis of tree growth and seasonal growth allocation patterns (represented by ratio of early to latewood) and climate after treatment over a 12-year period, trees in our study area did not appear to be water limited and did not show a strong correlation with regional drought metrics. My study demonstrates that managers can affect riparian forests with upland treatments to a limited spatial extent. In the third study, I investigated potential cross-scale interactions that explain the variability found in the growth responses of the second study. Using the same trees but with the addition of water-use efficiency data, I investigate the impacts of thinning thorough progressively finer spatial scales. Trees at the wettest site were growing faster and responded more strongly to density reduction than trees at the driest site. Additionally, trees at the driest site responded with increased water-use efficiency while trees in treated stands at the wettest site showed no change in water-use efficiency. I hypothesized that water is not the primary limiting factor for growth at the wettest site, while water was a more-limiting factor at the driest site. When examining finer spatial scales I found that trees downslope of treated stands responded to an apparent edge effect that was primarily driven by changes in local density that were only found near the buffer edge. The results of this study demonstrate that forest management treatments, such as density reduction, although applied widely, may have different results. Forest ecosystems are a complex collection of interacting factors and changing a single factor will result in a cascade of different reactions based on local conditions and existing plant ecophysiology. The potential for these cross-scale interactions should be taken into account when planning forest management actions. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by/3.0/us/ |
| Topic | cross-scale interactions |
| Identifier | http://hdl.handle.net/1957/54927 |
