2021 Timber Inventory – UMR Regional Forestry PDT Standard Protocol – Pool 17: Port Louisa
On September 21st and 22nd a collective force of natural re-source specialist and willing participants gathered at the Port Louisa National Wildlife Refuge, Louisa Division to collect timber data. In total, there were eleven different offices represented by the twenty individuals included in this vegetative data collection effort from the Iowa Department of Natural Resources (IADNR), National Wild Turkey Federation (NWTF), U.S. Fish and Wildlife Service (USFWS), and the U.S. Army Corps of Engineers (USACE).
The two day effort included timber data collection on almost 600 acres of the USFWS refuge portion of backwater complex; 140 plot locations in total were visited by the data collection
team. The entire complex area is in USACE fee title and made available to the USFWS and IADNR for management of nearly 6,800 acres of navigation Pool 17.
The entire complex is behind a levee system and is unique in landscape position having
Lock and Dam 17 positioned midway of the backwater complex on the main channel of the Mississippi River. This allows the IADNR and USFWS to work together in water level management per an inlet structure at the upstream end and outlet structure at the downstream end with only gravity flow due to the head difference of Lock and Dam 17. This last summer marked the completion of a contracted timber inventory data collection on the IADNR managed portion of the complex; this is the Lake Odessa Wildlife Management Area which includes the lower two-thirds of the complex.
That timber inventory contract was funded by the Upper Mississippi River Restoration (UMRR) program and has already produced priorities for timber management actions that are currently being implemented this fall in Lake Odessa. The two-day effort completed by the collection of valued UMRCC members made it possible to rapidly finish out key remaining forested area left without timber data collection for the entire complex. The Mississippi River Project Office (ODMN) staff of Rock Island District were able to continue some final efforts to finalize data collection at plot locations that complete out delineated management areas of the refuge.
To date, approximately 400 acres remain to be completed to have the entire complex with entire current data coverage. The intent is to continue the effort locally next growing season to complete data collection of the entire complex. The UMRCC vegetation sampling effort has provided a significant advantage for data analysis of much of the complex to allow local management of the area to determine management actions to address concerns to forest health in the complex with implementing forest management actions.
Each morning started off with a quick gathering of all the necessary forestry tools of the trade and assignment of data collection crews. Each crew was assigned at least one Forester that knew the timber inventory data collection protocol and provided oversight to collecting the required information. Both days the group was able to divide up into six different crews and spend the day out in the trees making measurements and observations to the forest health. In total, 1,798 trees were measured at the 140 plot locations. In addition to measuring trees by prism plot methods, there were 20 trees selected to be aged by collecting a tree core; tree aging was not conducted during the field effort to increase time spent covering more ground, tree cores were later reviewed in the office by ODMN.
Trees that were measured by prism plot were coded by these health codes: healthy, stressed, significant decline, and dead. Unfortunately, due to the extensive high water duration events of 2018 and 2019 there was high mortality rates within the entire managed complex; primarily a loss of silver maple. This was well documented in the area surveyed by the UMRCC team; 1,032 trees measured (or 57% sampled) were coded with the health condition of dead.
This is extremely high and historically under this data collection protocol was not considered to be a normal occurrence rate of documented standing dead trees. However, this pattern of significant zones of the Mississippi River has this high or higher rate of tree mortality during recent years of data collection post the 2018 and 2019 high water event years. For decades trees were subjectively and later measured to be under stress and in some level of decline, the significant high-water events in back-to-back years were too much of a stressor event for these trees to remain living. Additionally, a fair portion of these recently killed off trees were nearing the end of their expected life span, which compounded the potential for high mortality. There are many factors being discussed to further understand significant forest changing events on the river and indicators of potential stand col-lapse having high tree mortality rates such as what was documented during this collection effort.
The regional forestry team is continuing to study forest dynamics that indicate areas that are prone to stand collapse and chronic conditions that lead to such changing events. This data collection effort will assist in documenting that understanding that will likely be ongoing for a decade or more in parlay with other forest data collection efforts.
Only 16% of the trees sample during this event were coded as being healthy, the remaining trees measured were in decline or dead. Unique to this complex, tree species that are considered more diverse tree species to bottomland forest, especially the hard mast species of oak and hickory have a significantly higher rate of survival and do not match the rate of mortality seen in maple, willow, and cottonwood. In total, 9 tree species were documented through the prism plot data collection. This correlation to mortality has no significance to elevation within the complex; this fact is something that has of high interest to be further evaluated by the foresters. Boating around the complex one can see expansive zones of forest with complete mortality except for sparse surviving individuals, which are primarily of hard mast species.
At the end of each day, the UMRCC team dedicated at least a half hour to discuss what had been ob-served by each crew during the day while conducting the data collection efforts. This discussion at the end of each day was very interactive and all had significant items to share to the group. In general, the group discussed extensive growth of herbaceous vegetation within the high mortality zones, tree health conditions observed throughout the day, locations that there was some natural regeneration observed, impacts to avian communities and possible concerns to long term roosting habitat for eagles and bats, importance to timber stand improvements in portions of residual health, and possible management ac-tions to restore areas of complete stand collapse.
This UMRCC event was by far a very successful effort on both intended fronts. First being the need for providing much data collection for local management direction and big picture understanding to forest health and development. Second being able to provide the cross-discipline interaction and discussion that better unifies understanding to the great collection of natural resources we care greatly about on the Upper Mississippi River.
The St. Louis District will be providing a proposal to conduct a similar vegetation data collection effort at the annual Spring UMRCC meeting. If that proposal moves forward for data collection to occur in 2022, the Foresters look forward to seeing you there to share in another great cross-discipline event.
Ben Vandermyde
Lead Forester
Mississippi River Project
Rock Island District – USACE
