Characteristics of free air carbon dioxide enrichment of a northern temperate mature forest

Abstract

In 2017, the Birmingham Institute of Forest Research (BIFoR) began to conduct Free Air Carbon Dioxide Enrichment (FACE) within a mature broadleaf deciduous forest situated in the United Kingdom. BIFoR FACE employs large‐scale infrastructure, in the form of lattice towers, forming ‘arrays’ which encircle a forest plot of ~30 m diameter. BIFoR FACE consists of three treatment arrays to elevate local CO2 concentrations (e[CO2]) by +150 µmol/mol. In practice, acceptable operational enrichment (ambient [CO2] + e[CO2]) is ±20% of the set point 1‐min average target. There are a further three arrays that replicate the infrastructure and deliver ambient air as paired controls for the treatment arrays. For the first growing season with e[CO2] (April to November 2017), [CO2] measurements in treatment and control arrays show that the target concentration was successfully delivered, that is: +147 ± 21 µmol/mol (mean ± SD) or 98 ± 14% of set point enrichment target. e[CO2] treatment was accomplished for 97.7% of the scheduled operation time, with the remaining time lost due to engineering faults (0.6% of the time), CO2 supply issues (0.6%) or adverse weather conditions (1.1%). CO2 demand in the facility was driven predominantly by wind speed and the formation of the deciduous canopy. Deviations greater than 10% from the ambient baseline CO2 occurred <1% of the time in control arrays. Incidences of cross‐contamination >80 µmol/mol (i.e. >53% of the treatment increment) into control arrays accounted for <0.1% of the enrichment period. The median [CO2] values in reconstructed three‐dimensional [CO2] fields show enrichment somewhat lower than the target but still well above ambient. The data presented here provide confidence in the facility setup and can be used to guide future next‐generation forest FACE facilities built into tall and complex forest stands.

High-Frequency Monitoring Reveals Multiple Frequencies of Nitrogen and Carbon Mass Balance Dynamics in a Headwater Stream

“…), and sycamore (Acer pseudoplatanus). Common alder (Alnus glutinosa), goat willow (Salix caprea), and wych elm (Ulmus glabra) are also present adjacent to the stream (Hart et al, 2020). Dense canopy cover resulted in intensive shading throughout the reach during periods of full leaf-out (April to October; Day of year [DOY] ∼90-300).…”

BIFoR FACE: Water–soil–vegetation–atmosphere data from a temperate deciduous forest catchment, including under elevated CO2

“…The BIFoR FACE forest (Mill Haft, Figure 1), at the bottom of the Wood Brook catchment, is a deciduous woodland, with dominant (25‐m tall) English oak ( Quercus robur ) planted around 1850 (Hart et al, 2019). Each stem with diameter‐at‐breast‐height greater than 10 cm has been geolocated and tagged.…”

“…The central, eCO 2 component of BIFoR FACE consists of nine experimental patches of 15 m radius (Figure 2; Hart et al, 2019; Norby et al, 2015). Three undisturbed patches have no CO 2 ‐dosing infrastructure.…”

Unmanned Aerial Systems (UAS)-Based Methods for Solar Induced Chlorophyll Fluorescence (SIF) Retrieval with Non-Imaging Spectrometers: State of the Art

“…Additionally, a Piccolo-Doppio was also installed on a DJI Matrice 600 Pro [44] to monitor SIF in a mature oak woodland (UK) over a 30 m diameter free air CO 2 enrichment experiment [45]. A significant correlation of R 2 = 0.8821 (p < 0.01; Figure 3b) was found between UAS-based SIF and the incoming radiation, suggesting reliable variations of the SIF data retrieved with this system especially in a context where other approaches (e.g., eddy covariance) are not appropriate due to the scale of the treatments.…”