This week we started some timber stand improvement (TSI) work on the area. Although this isn't “renovation work” in the sense of construction, it is work being done to improve the habitat on Duck Creek in the long-term...so in a way you could still classify it as “renovation work.” Below is a little background on why we are cutting down some trees in order to “turn a new leaf” and make room for the future timber stand at Duck Creek.
Forest management practices on Duck Creek were limited during the first 40 years (1955–1995). The only disturbances to the timber since the initial establishment of the area has been the salvage of logs from construction sites and tornado-damage areas, small research projects and clearing with heavy equipment in attempts to improve waterfowl hunting.
Since 1996 managers have responded to forest health issues with applied forest management techniques such as timber stand improvement (TSI) and improved water management in portions of Pools 2 and 3 green tree reservoirs (GTRs). These management practices have been applied in a fairly conservative manner for the most part. Ultimately, the goal of forest management on Duck Creek CA is to sustain the forest ecosystem and desirable community types, not the production of wood fiber.
Unfortunately, the years of little to no forest management and the flooding regime that were implemented early on in the GTRs have left us with an aging overstory of desirable species, particularly red oak species such as pin oak and willow oak, and a less desirable understory with a high maple and ash component. This puts us in a serious dilemma. The forest of tomorrow (the understory) isn't the forest community that we have and are enjoying today. This situation is common across many GTRs in the lower Mississippi Alluvial Valley.
For the last 20 years managers of GTRs across the lower Mississippi Alluvial Valley have been contemplating this problem and trying to find the “magic” technique that guarantees successful establishment of red oaks in the understory to replace the aging overstory. We aren’t there yet, but we have made some definite steps in the right direction. At Duck Creek there have been several research projects and numerous attempts at recruiting good stands of young red oaks. Some of these attempts have been successful, although we have not been able to consistently repeat the results. Each time we learn a little more and try to implement that knowledge the next time.
In 2002, in cooperation with Mingo National Wildlife Refuge, the U.S. Forest Service and the University of Missouri, we started a research project with a goal of regenerating desirable oak species. In this project we looked at removing the midstory and understory using TSI, along with several methods of planting red oak seedlings, including sowing acorns, planting seedlings and use of RPM seedlings. We also got very lucky in the spring of 2003 and had a very successful crop of natural pin oak regeneration. Over the years we have watched these sites develop and now, eight years later, we have inventoried the plots again and found that it is time to revisit the sites and add a new chapter to this research.
As oak species develop into small trees and poles, they require more sunlight to thrive and compete. Now that the natural and artificial pin oak regeneration is well established and plentiful in the research blocks, we are going to attempt to establish or release them into the overstory. We need to know just how much light is necessary for the oak seedling understory to make the big leap into the forest overstory. To do this we will be testing three different tree harvest levels: light, medium and heavy harvest of the remaining overstory trees in the research blocks.
In the light harvest we are going to remove about 10 to 15 percent of the trees in the overstory. In areas that have clumps of regeneration, the gaps will be a little larger to increase the amount of light reaching the regeneration. This type of harvest is often referred to as a single–tree selection harvest.
In the medium harvest we are removing approximately 50 percent of the overstory trees. Target trees for this harvest include: 1) Large or poor quality trees that will more than likely not live another 15 years or that add little value to the forest community type. 2) A single tree or groups of trees that release clumps of oak regeneration. 3) Enough trees to reach our target of 50 percent. For this we are looking at species, condition and spacing to make our selections. This is an improvement thinning that combines single-tree selection and small group opening to create canopy gaps.
For the heavy harvest, our goal is to retain 30 to 40 percent of the existing overstory, or remove 60 to 70 percent of the existing stand. The target leave trees should all be healthy, well formed, and of desirable species, such as pin oak, willow oak, cherrybark oak, overcup oak, cypress and so on. This type of harvest will result in a two-aged stand; the older overstory and the younger understory, which should have a good percentage of red oak in it. This type of harvest is often referred to as a Shelterwood with reserves.
In all of the sites, we are leaving standing dead trees, as they are an essential component to the bottomland forest habitat, particularly for forest interior songbirds, wood ducks and hooded mergansers. After the timber harvest the woody debris left on the ground should also provide good habitat for the many other species, such as swamp rabbits, reptiles and amphibians, and the brushy cover will no doubt provide some habitat diversity for the deer population. Increasing the percentage of red oaks will also increases the amount of pin and willow oak acorns, an important component for a GTR.
We have already learned a lot from the first chapter of this project, and hopefully the next chapter in this research will continue to assist us with managing the bottomland forests in and around Duck Creek and southeast Missouri. Hopefully, this gives you a little better idea of how and why we are managing our timber for the future. Thanks again for your interest.