Recipient Organization
MICHIGAN TECHNOLOGICAL UNIV
1400 Townsend Drive
HOUGHTON,MI 49931
Performing Department
School of Forest Resources and Environmental Science
Non Technical Summary
Tree diversity in Michigan's northern hardwood forests has significantly changed since European settlement in the late 1800s. Two species, yellow birch and eastern hemlock, have significantly declined, while sugar maple (Acer saccharum) and red maple (Acre rubrum) have remained constant or dramatically increased. This change in composition not only impacts local timber markets, but also a wide-variety of mammals, amphibians, neotropical birds, raptors, and invertebrates. Michigan Natural Features Inventory (MNFI) classifies northern hardwoods as the most complex forest system in Michigan (MNFI website 2008), while the MI DNR has determined that 84 species are dependent upon northern hardwoods for breeding, nesting, foraging, or as cover (MI WILD software). Recent findings from the Great Lakes northern hardwood forest research predict declining populations of YB and EH. Though the studies indicate that YB and EH seedling regeneration is sufficient for successful
recruitment into the canopy, it is the deficit in current sapling stocking levels that has led to concerns about declining population trends. We will investigate relationships between microsite variables and northern hardwood diversity and recruitment success across a variety of sites. This will allow us to identify specific abiotic and biotic mechanisms that have been previously identified as influential in YB and EH regeneration. This unique combination of field sampling will provide in-depth associations in determining recruitment success. Key results will help clarify the factors that have a significant influence on recruitment.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Recent findings predict declining populations of yellow birch (Betula alleghaniensis) and eastern hemlock (Tsuga canadadensis) across the Great Lakes northern hardwood forests. These results may reflect short-term, high intensity, localized sampling design or the use of isolated and fragmented old-growth forests as population benchmarks. The primary objective of this project is to investigate northern hardwood forest population dynamics using data from long-term studies and inventories from a variety of Michigan Upper Peninsula public and private forests. Specifically, our objectives are to: 1) Determine if pedodiversity (pit and mound) frequency is positively correlated with recruitment success of yellow birch (Betula alleghaniensis) and eastern hemlock (Tsuga canadensis) 2) Determine if down and dead wood (DDW) volume by species and decay classes are better indicators of recruitment success than total DDW biomass volume 3) Determine if light availability at
recruitment height (2 meters) is significantly greater in unmanaged stands than managed stands 4) Determine if yellow birch-eastern hemlock spatial frequency is positively correlated to higher recruitment rates of both yellow birch and eastern hemlock
Project Methods
A) Study Sites: Two northern hardwood sites have been selected in the Upper Peninsula of Michigan for the first year of the study (MTU's Ford Forestry Center in Alberta, MI and the USFS Dukes Experimental Forest near Marquette, MI). B) Data Collection and Analysis: For each stand, we will determine the number of variable-radius plots needed to sample 5-10% of the area. The variable-radius plots will be installed using a systematic grid with a random start point. These macro-plots will use a 10BAF prism to determine tally trees and limited distances will be. At each cardinal direction and 12 feet away from plot center, a regeneration and understory micro-plot will be installed with a radius of 6.8ft (1/300 acre). On the macro-plot, all trees with a dbh greater than 4.5 inches will be measured. Additional variables measured on tally trees will consist of species; alive or dead status; height; dbh; crown position; compacted crown ratio; height to first live branch;
diseases or damages; if germination occurred on pit, mound, or flat area; and evidence of root stilting (i.e., a perched root system that reflects germination history in CWD or mound which has now decayed or eroded). On the micro-plot, all saplings with a dbh between 1.0 and 4.5 inches will be measured. The variables measured will be the same as those on the macro-plot. Those trees less than 1.0 in dbh and taller than 0.5 ft in height will be counted as seedlings. Ungulate browse will be documented as a presence/absence per seedling and sapling stem, giving a total count per species per micro-plot. Non-woody understory species abundance will be documented as percent cover. Additional measurements will include: 1) Pedodiveristy: From each macroplot center four 49.9-foot transects will radiate in each cardinal direction, along which we will determine coverage of pits, mounds, and flat areas using the line intercept method. 2) Down and Dead Wood (DDW): A 393-foot transect, in the shape
of an equilateral triangle comprised of 131-ft segments, will be installed at each macro-plot. All DDW greater than 1-inch diameter at the transect intersection will have decay class and species recorded. 3) Hemispherical Photography for Light Availability: Hemispherical photography is a field technique, by way of a camera and a fisheye lens, which captures the available sunlight in a variety of open and forested conditions. At plot center of each variable-radius plot, a photograph will taken 2 m above the ground to minimize vegetation interference. A Nikon D300 digital camera with 10.1MB pixel capabilities and an attached hemispherical lens will be mounted on a tripod with a leveling device. A minimum of three pictures will be taken at each plot to capture variability. Photographs will be analyzed using MTU's Gap Light Analyzer software to determine the light regime. C) Deliverables: We expect at least three scientific, peer-reviewed publications to result from this research. D)
Timeline: Two sites will be measured during each field season, with data analysis and report writing occurring during the winter months.