New and Notable

“Big Plot” coming to the HJ Andrews

Joe LaManna

This summer, Dr. Joseph LaManna and his team from Marquette University (http://www.lamannalab.org/) will begin installation of a 25-hectare “big plot” at the HJ Andrews.  The HJA Big Plot will be the first of its kind in Oregon, adding to a growing network that is part of the Smithsonian Institution’s Global Earth Observatory Network, or ForestGEO (https://forestgeo.si.edu/).  Presently there are 67 big plots in 27 countries around the globe, representing millions of trees and thousands of species.  The location of the HJA Big Plot and smaller “satellite plots” will be arrayed across an elevation-climate gradient within the HJA, leveraging and expanding on our existing network of permanent plots.  Dr. LaManna’s research will examine how interactions between forest tree species and their natural enemies or mutualists influence community assembly along the climate gradient.  He will also study density dependence and genetic diversity of tree seedlings in relation to nearby mature trees.  The PNW-PSP team and the HJ Andrews welcome Joe and this partnership with The Smithsonian ForestGEO network!

LiDAR Change Detection: Coupling remote sensing with permanent plot data

Forest landscape change depends on fine-scale patterns of tree growth, mortality, and recruitment.  While long-term forest inventory plots provide some of the most robust assessments of individual- to stand-level changes, their spatial extent (< 4 ha) limits their capacity to represent dynamics across the entire landscape. In this study, we are using high-resolution remote sensing of vegetation structure (i.e., light detection and ranging, or LiDAR) from multiple years coupled with our long-term measurements and stem maps to assess patterns of tree mortality and growth over complete landscapes. This research aims to both (1) understand the landscape drivers of forest growth and mortality, and (2) map areas of forest vulnerable to changing environmental stressors.LiDAR change detection

     Examples of canopy height losses from 2008 to2014 associated with individual tree mortality and canopy gap formation.

Long-term Response of Coastal Forests to Wind Disturbance

Mark Harmon and Rob Pabst have authored a new paper in a special issue of the journal Forests on wind disturbance (http://doi.org/10.3390/f10020119).  Harmon and Pabst took advantage of tree measurements spanning 78 years in ten plots at Cascade Head Experimental Forest to examine the cumulative effects of wind disturbance on forest structure, tree mortality, and net primary productivity.  This set of permanent plots was established in 1935 for the purpose of understanding growth and yield of coastal forests dominated by western hemlock and Sitka spruce.  However, since 1951 the plots have experienced hurricane-force winds at least ten times, providing an opportunity to examine long-term response of coastal forests to wind.  Not all plots were substantially impacted by all the storms; rather, the major wind events had differential effects on the plots, suggesting that wind impacts at a broader landscape level are cumulative over time.  Key findings include: (1) the proportion of wind-related tree mortality has increased 5- to 8-fold since 1940, and (2) despite the increase in wind-related tree mortality over time, impacts to net primary productivity were only noticeably when biomass loss exceeded 50%.  The long-term nature of this and other permanent plot research offer poignant lessons in how repeated observations over long time periods help us understand how and why forests change.

CH08 sunshineCH08 windthrow

Stephen Calkins, Master’s Student

Stephen Calkins joined the Department Forest Engineering, Resources and Management as a graduate student pursuing an M.S. degree with Dr. David Shaw.  Stephen graduated with his Bachelor’s degree in Sustainable Forest Management from the University of Washington and afterwards worked as a forester and arborist before coming to Corvallis.  Stephen and Dave are interested in tree canopy structure and a parasitic seed plant - hemlock dwarf mistletoe - in mature and old-growth forests in the Pacific Northwest.  Their research will examine the effects of mistletoe on the canopy structure of western hemlocks, how the vertical organization of infections affect sapwood area, and how this information can be used by forest managers.  Catch them in the canopy this summer at HJ Andrews! (Photo credits: Stephen Calkins and Kasey Swenson)


 Infested hemlock





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