You are here

Harvard Forest >

Harvard Forest REU Symposium Abstract 2019

  • Title: Carbon Sinks & Dendro Links: Cross-comparison of dendrometer & tree ring estimates of Net Ecosystem Productivity
  • Author: Elida Kocharian (Harvard University)
  • Abstract:

    The Harvard Forest Environmental Measurement Site, the longest running eddy flux tower of its kind, has been measuring Net Ecosystem Productivity (NEP) in the temperate red oak- and red maple-dominant transitional forest since 1992 and has documented a strong carbon sink. However, eddy flux measurements of NEP and biomass inventories derived from dendrometer band measurements of above-ground woody increment don’t match up perfectly, indicating unaccounted uncertainties in estimating biomass increment as well as variable contributions from carbon storage pools other than tree trunks. Cross-comparison of dendrometer measurements to annual growth rings offers a robust chronology of inter-annual growth that can be compared against tower data to understand how age and size distributions in the forest impact carbon cycling patterns over time. Monthly dendrometer band increment measurements from 600 trees of varying species, age (42-124 years), and size (10-70 cm DBH) in 34 plots in the Prospect Hill tract of Harvard Forest were compared with ring-width measurements derived from tree cores of a random subsample of 60 trees representative of the distribution of size and species in the plots. Basal area increment from the two methods were linearly correlated with a slope very close to 1 (p <0.001, R2 = 0.49). We intend to compare NEP estimates with environmental variables to better understand what drives patterns in tower estimates of NEP. Understanding how carbon is stored inter-annually in forests affected by climate change will inform models of climate response and carbon sequestration across the terrestrial biosphere.

  • Research Category: Large Experiments and Permanent Plot Studies; Forest-Atmosphere Exchange