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Evaluating the effects of forest management on development of canopy structural complexity and light use efficiency

Project Abstract: 
Canopy structural complexity is an important functional aspect of forest ecosystems that helps drive light use efficiency and productivity. Canopy structure is also an important determinant of resilience to various types of disturbance, including wind and ice storms. Although recent work has begun to illustrate linkages between canopy structural complexity and functioning in forests, the effects that forest management practices can have on canopy structure and linkages with light use efficiency and productivity are largely unknown. Traditional silvicultural practices may reduce complexity in forests, while recently developed management treatments focused on ecological or resilience objectives may have more positive impacts. The proposed project will quantify the effects of traditional forest management regimes and ecologically-focused treatments on canopy structural complexity and light use efficiency in eastern hardwood forests. This information will be useful in understanding potential consequences of management decisions on forest structure, function, and resiliency. Results will also be useful in designing management treatments explicitly focused on promoting canopy structural complexity and light use efficiency in eastern hardwood forests.
Status of Research Project: 
Years Active: 
Research sites: 
The effect of traditional forest management on Canopy Structural Complexity (CSC) will be assessed in a variety of long-term forest management research sites at UMBS and USFS Experimental Forests. At UMBS we will sample in long-tern Forestry plots and other areas that have undergone different types of forest management. Additional study systems with existing ecological silviculture experiments will be used to evaluate the effect of ecological/resilience-focused forest management treatments on CSC. In each research site we will quantify CSC using both 3D terrestrial scanning lidar (TSL) and a ground-based portable canopy lidar (PCL) system. Metrics of canopy structural complexity will be calculated using PCL transect data according to the methods of Atkins et al. 2018 using the forestr package in R. In order to better understand linkages between CSC, NPP, and light use efficiency (LUE) we will measure canopy light transmittance (percent of photosynthetically active radiation transmitted by the canopy – fAPAR) and wood productivity (ANPPw - from repeated diameter measurements) and use these to calculate canopy LUE as ANPPw/fAPAR. Also, LAI will be estimated in each study site using a Decagon LP-80 Ceptometer to separate the effects of CSC from that of differences in leaf quantity. This combination of data will be used to evaluate potential management impacts on relationships between complexity and LUE/productivity. Finally, we will employ TLS in mapped stands at UMBS to create full 3D canopy models with segmented tree crowns to use in a recently developed disturbance/management simulator that is being used to evaluate relationships between disturbance severity and pattern and canopy structural outcomes.
Funding agency: 
USDA McIntire-Stennis Formula Fund