Notes Retention and Dimensional Changes of Evergreen Brush Piles Within a Flood Control Reservoir Caleb A. Aldridge,* David M. Norris, Hunter R. Hatcher, Giancarlo Coppola, Michael E. Colvin, Leandro E. Miranda C.A. Aldridge, M.E. Colvin Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Thompson Hall Mail Stop 9690, Mississippi State, Mississippi 39762 D.M. Norris Louisiana Department of Wildlife and Fisheries, Bourg, Louisiana 70343 H.R. Hatcher Virginia Department of Game and Inland Fisheries, 107 Foxwood Drive, Farmville, Virginia 23901 G. Coppola Wisconsin Cooperative Fishery Research Unit, University of Wisconsin–Stevens Point, Trainer Natural Resources Building, 800 Reserve Street, Stevens Point, Wisconsin 54481 L.E. Miranda U.S. Geological Survey, Mississippi Cooperative Fish and Wildlife Research Unit, Mississippi State University, Thompson Hall Mail Stop 9691, Mississippi State, Mississippi 39762 Abstract Brush piles (i.e., trees and large woody debris) are often installed in reservoirs to supplement fish habitat. The retention and dimensional change of brush piles after installation is important information that can be used to maximize the effectiveness of this management action. We evaluated the retention and dimensional change of 70 eastern red cedar Juniperus virginiana and bald cypress Taxodium distichum brush piles in an embayment of a drawdown reservoir up to four annual cycles of submergence and exposure. We used satellite imagery to supplement our onsite measurements of retention. We also examined spatial patterns of brush pile retention and dimensional change. Brush piles were lost at 10% per year, and their volume was lost at 14% per year. We compared our rates of brush pile retention and dimensional change with those from a holdout data set of 50 brush piles. Estimates between data sets did not differ statistically. Spatial patterns of retention and dimensional change coincided with morphological features in our study area, suggesting that retention and dimensional change is influenced by variable physical forces (e.g., wave action and flow) at installation locations. Our estimates of brush pile retention and dimensional change can be used to generally sustain desirable brush densities. For example, to maintain a fixed total volume of brush in our study embayment, roughly 23% of the total brush volume installed would need to be replaced annually. Similar research in reservoirs managed for other purposes is needed, as length and cycle of inundation could lead to variable rates of retention and dimensional change. Additionally, advancements into computer-assisted detection and volume estimation could reduce the time and effort needed to monitor brush piles. Keywords: large woody debris; reservoir fish habitat monitoring; photogrammetry; fisheries management planning Received: March 2021; Accepted: October 2021; Published Online Early: October 2021; Published: June 2022 Citation: Aldridge CA, Norris DM, Hatcher HR, Coppola G, Colvin ME, Miranda LE. 2022. Retention and dimensional changes of evergreen brush piles within a flood control reservoir. Journal of Fish and Wildlife Management 13(1):223– 235; e1944-687X. https://doi.org/10.3996/JFWM-21-033 Copyright: All material appearing in the Journal of Fish and Wildlife Management is in the public domain and may be reproduced or copied without permission unless specifically noted with the copyright symbol &. Citation of the source, as given above, is requested. The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service. Journal of Fish and Wildlife Management | www.fwspubs.org June 2022 | Volume 13 | Issue 1 | 223 Downloaded from http://meridian.allenpress.com/jfwm/article-pdf/13/1/223/3085272/i1944-687x-13-1-223.pdf by guest on 19 July 2022