Journal Article

Sustained carbon uptake and storage following moderate disturbance in a Great Lakes forest

Hardiman, Brady S., Nave, Lucas E., Nadelhoffer, Knute J., Vogel, Christoph S., Curtis, Peter S., Bohrer, Gil, Maurer, Kyle D., Gough, Christopher M.

2013

Overview

Carbon (C) uptake rates in many forests are sustained, or decline only briefly, following disturbances that partially defoliate the canopy. The mechanisms supporting such functional resistance to moderate forest disturbance are largely unknown. We used a large-scale experiment, in which >6700 Populus (aspen) and Betula (birch) trees were stem-girdled within a 39-ha area, to identify mechanisms sustaining C uptake through partial canopy defoliation. The Forest Accelerated Succession Experiment in northern Michigan, USA, employs a suite of C-cycling measurements within paired treatment and control meteorological flux tower footprints. We found that enhancement of canopy light-use efficiency and maintenance of light absorption maintained net ecosystem production (NEP) and aboveground wood net primary production (NPP) when leaf-area index (LAI) of the treatment forest temporarily declined by nearly half its maximum value. In the year following peak defoliation, redistribution of nitrogen (N) in the treatment forest from senescent early successional aspen and birch to non-girdled later successional species facilitated the recovery of total LAI to pre-disturbance levels. Sustained canopy physiological competency following disturbance coincided with a downward shift in maximum canopy height, indicating that compensatory photosynthetic C uptake by undisturbed, later successional subdominant and subcanopy vegetation supported C-uptake resistance to disturbance. These findings have implications for ecosystem management and modeling, demonstrating that forests may tolerate considerable leaf-area losses without diminishing rates of C uptake. We conclude that the resistance of C uptake to moderate disturbance depends not only on replacement of lost leaf area, but also on rapid compensatory photosynthetic C uptake during defoliation by emerging later successional species.

• Publisher: Ecological Society of America
• Subject: absorption / Animal and plant ecology / Animal, plant and microbial ecology / Applied ecology / Betula / Biological and medical sciences / Boreal forests / canopy / canopy defoliation / carbon / Carbon - chemistry / Carbon - metabolism / carbon cycling and sequestration / Carbon Dioxide - metabolism / Coniferous forests / Conservation, protection and management of environment and wildlife / Deciduous forests / Defoliation / disturbance resistance / Ecosystem / ecosystem management / ecosystem management and resilience / Environmental Monitoring / Forest canopy / forest damage / Forest ecology / Forest ecosystems / Forest management / Forest succession / Forestry / forests / Fresh water ecosystems / Fundamental and applied biological sciences. Psychology / General aspects / General forest ecology / Generalities. Production, biomass. Quality of wood and forest products. General forest ecology / Great Lakes / Great Lakes Region / Human Activities / Humans / leaf area index / leaf-area index, LAI / light-use efficiency / Meteorology / Michigan / net ecosystem production / net primary production / Nitrogen / northern Michigan, USA, forest / photosynthesis / Plant Leaves / Plant Transpiration / Populus / primary productivity / structure-function relationships / Synecology / Time Factors / Trees / wood