Young Forest Conservation

Using Minnesota Outdoor Heritage Fund dollars allocated in this grant, ABC created it's Minnesota Public Lands Program to focus on completing targeted young forest and brushland (also termed early successional) habitat projects on County, State, Federal, and Tribal lands with the assistance of associated public agencies. These enhancement projects were implemented using science-based Golden-winged Warbler Best Management Practices to create breeding habitat for the golden-winged warbler, American woodcock, and associated species in deciduous forests of northern MN. Habitat treatments concentrated on non-commercial habitat types, the majority of which fell in lowland or upland brush stands dominated by alder, willow, and hazel within or adjacent to deciduous forest stands. Brush stands that were treated contained a mix of scattered and clumped hardwood tree species that were retained as residual structure along with scattered brush clumps.
Early successional habitat project sites that have reached the stage where they require cutting treatments contain very old and dense brush dominated by upland and lowland brush species measuring 1-5” diameter per stem in dense clumps that may contain 10+ stems at the base of the clump and often stand 10-20ft tall within a deciduous forest matrix. In the absence of natural disturbance such as low severity fire, these sites have become dominated by a closed canopy of brush species due to their extensive size and age (see attached pretreatment images), resulting in a greatly reduced component of understory forb species and also a reduced component of seedling and sapling tree regeneration. These closed brush canopies limit or remove the ability of ground nesting avian species such as the golden-winged warbler to occupy these sites for the purposes of nesting and brood rearing. On each project site, this brush component was thinned and, when present, all singly spaced or patches of mature tree species were retained onsite to provide residual structural diversity.
Most project sites were located in non-commercial brushland/forest interfaces, though a small number of projects were completed in forested covertypes to create habitat openings and multi-aged stands. The latter sites were completed using similar methodology as those described in brushland habitats in terms of the design of the project site and the retention of residual internal vegetation. Once complete, project sites have also been identified as producing high quality habitat for a suite of additional non-game and game species including ruffed grouse, sedge wren, veery, Nashville warbler, chestnut-sided warbler, rose-breasted grosbeak, bobcat, snowshoe hare, white-tailed deer, and elk (where they occur on the landscape).
A great deal of initial effort went into the process of finding new public lands partners who had the need within their management jurisdictions to complete the habitat enhancement projects described above. However, it quickly became apparent that public lands agencies indeed had a tremendous interest and willingness to complete habitat projects of this type and the number of project partners has grown every year since the inception this program. On multiple occasions and with a variety of different area natural resource managers (esp. within state and federal agencies) it was expressed that they had projects in deciduous forest brushland habitats that they had not had the funding to complete in many years. As such, it became apparent that ABC (with the assistance of the MN OHF) was filling a needed role within the state. The ABC public lands manager worked with these public agency in every phase of the project planning and implementation process.
It is important to note that ABC has partnered with Cornell University Lab of Ornothology and Indiana University of Pennsylvania-Research Institute to complete songbird and American woodcock monitoring on sites completed using this grant. These results will help identify post treatment site conditions that maximized the benefit to our target species and associated avian species. Through this monitoring, it is our hope to continue to refine our management techniques to continue to provide the best management possible on completed project sites.
The greatest challenge of this program was the level of knowledge needed by all partner natural resources managers concerning target post treatment habitat conditions and an equal need to convey those management objectives to the associated contractors. As such, a very understated aspect of this project was the need to educate a wide array project partners. Often similar work that was completed in these habitat types before the creation of this program focused on cutting most of the brush on any given project site. This usually meant that most saplings of any tree species were also cut with very little internal structure remaining. What makes this program unique is the project design focus to retain diverse internal structure in the form of scattered trees, clumps, and legacy patches that results in post treatment conditions that benefits a wider range of young forest species and allows the interior of larger sites (>10 acres) to be occupied by a higher density of avian species requiring this dynamic structure as well as openings on the forest floor for nesting and brood rearing. With projects with various partner agencies often separated by hundreds of miles, high quality natural resource managers and contractors that I could work with directly on the ground and would assist overseeing projects when I needed to visit other sites across the state was crucial to the success of this project. Thankfully, the foresters and biologists from partner agencies and the contractors ABC has now worked with over the past 4 years accepted the challenge and the associated learning curve and have become very proficient at interpreting the often unique ecological and biological features of our project sites as they relate to the implementation of the BMPs. With their help, ABC continues to identify and complete 500-1000 acres of early successional habitat each year given sufficient winter cutting conditions.
An additional challenge associated with the implementation of habitat projects located in lowland covertypes that require frozen ground conditions for cutting equipment to be used safely, was the extremely warm winters experienced by northern Minnesota over the past two years. Winters with high average temperatures and warm periods rising above freezing can limit the depth of ground frost on certain sites. This can be exacerbated when warm temperatures are followed by deep snows that provide insulation to the ground and reduce the ability of the ground to freeze once the temperature again falls below 32 degrees. During the winter project season, ABC and our agency partners were very diligent to assess frost depth to make sure that cutting equipment used on those sites did not risk damaging the soil resource. When it was not sufficiently frozen, projects were delayed until the frost depth became safe for project operations.