Consequences of forest connectivity from beech bark disease in Pictured Rocks National Lakeshore in the Upper Peninsula of Michigan

Science Center Objects

In this study, we are working with Pictured Rocks National Lakeshore (PIRO, or Park) in the Upper Peninsula of Michigan (Figure 1) to produce multiple geospatial layers of Park forest connectivity to reveal the effects of beech bark disease (BBD). There has been a 92% mortality rate of American beech (Fagus grandifolia) since BBD was first discovered in the Park in 2001. Park biologists are interested to learn how recent forest canopy loss caused by BBD is affecting wildlife species. To better understand how the forest canopy has changed since BBD infestation, geospatial layers will be developed from imagery collected in September 2005, and a collection of imagery from 2016, 2018, and 2019 to represent present day. By creating shapefiles identifying forest canopy connectivity for these years, the Park can have a better understanding of the condition of the canopy shortly after infestation and in present day. We will also conduct a forest canopy change analysis to locate areas of canopy loss or growth to assist biologists with management decisions and future research and restoration.

Forest canopy gaps will be distinguished from satellite and aerial imagery using multi-resolution segmentation algorithms in eCognition (Trimble, Inc.). Canopy gaps can be identified using spectral values to distinguish between brighter cell values (i.e., tree canopies) and darker cell values (i.e., shadows or holes in the tree canopy). Segmentation algorithm settings established by Nymageroh et. al. will be used to determine settings in this project. Forest canopy gaps will be identified on both present day and 2005 imagery; a shapefile identifying these gaps will be created for the purposes of assessing change over time and to locate areas with forest canopy growth or decline since the BBD infestation.

Potential uses for these geospatial products are:

  • Looking at fragmentation or “holes” in the forest canopy due to BBD to evaluate the impacts on forest-interior nesting birds.
  • Visualizing areas with total forest canopy loss to direct field work measuring soil temperature and moisture to determine changes and impacts to amphibians and vernal pools.
  • Mapping forest gap density across the Park to guide targeted searches for remnant and resistant beech and to guide efforts to find and limit potential outbreaks of other invasive species.
Digital terrain model, or bare earth model, of Pictured Rocks National Lakeshore park along with the boundary of the p

Figure 1: Digital terrain model, or bare earth model, of Pictured Rocks National Lakeshore park along with the boundary of the park.

(Public domain.)

References:

Nyamgeroh, Beryl B., Thomas A. Groen, Michael J.C. Weir, Petar Dimov, and Tzvetan Zlatanov. “Detection of forest canopy gaps from very high resolution aerial images”. Ecological Indicators 95 (2018): 629-636. https://www.sciencedirect.com/science/article/pii/S1470160X18306101 (accessed March 6, 2020).

U.S. Geological Survey. “3DEP Elevation Program.” USGS. https://www.usgs.gov/core-science-systems/ngp/3dep (accessed September 5, 2019).