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--- File: spike.hydrometric.II ---

spike.hydrometric.II contains data collected during the SPIKE II experiment.

TIMESTAMP started on 2018-05-10 0:00 (UTC+1). The timestamp is uniformily 15 minutes. Missing data are indicated as NA.

Variables:

pF - soil tension data recorded in pF.
There are four soil depths: 25 , 75 , 125 and 175.
pF## - where ## indicates the soil depth data was recorded

vwc - volumetric water content (vwc) collected recorded in cm3 cm-3.
The data was collected in three sections of the lysimeter (A, B, and C).
There are four soil depths per section: 25, 75, 125, 175
vwcX### - X indicates the section (A, B, C) and ### the depth.
Data from C25, B75, C125, and A175 are missing due to sensor failure prior SPIKE II.

Air.Temp - Air temperature recorded in °C. 

VPD - Vapour pressure deficit in kPa

Solar.Rad - Solar radiation recorded in Wm-2

Wind.Speed - Wind speed recorded in gusts m s-1

Rel.Hum - Relative Humidity in %

Precip. - Precipitation recorded in mm h-1

Irrig. - Artificial irrigation recorded in mm h-1

Storage - Lysimeter soil water storage recorded in mm

Leakage - Bottom leakage of lysimeter collected in the mm h-1

SR.av - Stem radius of averaged stems recorded in µm

SR.N - Stem radius of stem labelled 'N' in µm

SR.SE- Stem radius of stem labelled 'SE' in µm

SR.SW- Stem radius of stem labelled 'SW' in µm

GRO - Stem growth (of SR.av) in µm

TWD - Tree water deficit in µm

T.rates - Transpiration rates in mm h-1
The transpiration rate was obtained from upscaled sapflux measurements of main stems to match based on lysimeter ET measurements, due to limitations of sap flow sensors. 

Tree hydraulic measurements (SR.av, SR.N, SR.SE, SR.SW, GRO, TWD, and, T.rates) starts on 2018-05-12 0:00 (UTC+1). 

ET - Willow lysimeter (#2) evapotranspiration rates in mm h-1

ET_1 - Grass lysimeter (#1) evapotranspiration rates in mm h-1

ET_3 - Bare soil lysimeter (#3) evapotranspiration rates in mm h-1

ET_4 - Grass lysimeter (#4) evapotranspiration rates in mm h-1

For vizual understanding of the lysimeters location see Figure 1 (file: Figure1_SpikeII_Aerial_Image.png).

 --- File: spike_isotope.II ---

spike_isotope.II contains isotopic data collected during the SPIKE II experiment.

ID - Sample identification

Type - Type o sample material collected

Depth - Soil depth in cm of collected soil sample

Sector - Soil spatial location in the lysimeter (A, B, C)
Observation: Soil samples from 50 to 150 cm were collected laterally through access ports in the lysimeter.
	     Soil samples from 10 and 25 cm were collected vertically at the surface and do not have an assigned sector.

Stem - Main stems (N, SW, SE)

TIMESTAMP - Date and Time of collected sample (UTC+1)

Date - Date of collected sample

Input.volume - Precipitation and irrigation (with tap water) volume in mm 

d18O.UoS - oxygen isotope ratios reported in per mil of water samples analyzed at the Hillslope Hydrology Laboratory at University of Saskatchewan, Canada

d2H.UoS - hydrogen isotope ratios reported in per mil of water samples analyzed at the Hillslope Hydrology Laboratory at University of Saskatchewan, Canada

d18O.EPFL - oxygen isotope ratios reported in per mil of water samples analyzed at the CEL Laboratory at École Polytechinque Fédérale de Lausanne (EPFL), Switzerland

d2H.EPFL - hydrogen isotope ratios reported in per mil of water samples analyzed at the CEL Laboratory at École Polytechinque Fédérale de Lausanne (EPFL), Switzerland

Missing isotopic data is indicated with NA.

Observation1: Isotope analyses of xylem water were performed using isotope ratio mass spectrometry (IRMS), at University of Saskatchewan, Canada.
All other water samples were analyzed using a IWA-45EP off‐axis integrated cavity output spectroscopy (OA-ICOS) (Los Gatos Research Inc., United States) at University of Saskatchewan, Canada, 
and a Cavity Ring Down Spectrometer L2130 (Picarro, United States) at École Polytechinque Fédérale de Lausanne (EPFL), Switzerland.

Observation2: Xylem samples on June 29th were collected in higher spatial frequency. 
Therefore, sample type also indicates location of xylem sample. Specifically: 
'Xylem Main Stem - Top' - Idicates that xylem sample was collected from main stem in location close to tree crown
'Xylem Main Stem - Base' - Idicates that xylem sample was collected from main stem in location close to the soil.
'Xylem - 2nd order' - Idicates that xylem sample was collected from a second order branch
'Xylem - 4th order' - Idicates that xylem sample was collected from a forth order branch

Observation3: "Saturated filter" refers to the water volume in the bottom of the lysimeter.
	      In the end of the experiment there was 30 L of water in the Saturated filter.


 --- File: fineroots_spike.II --- 

spike.hydrometric.II contains fine roots information collected during the SPIKE II experiment.

ID - Sample identification

Core - Soil core identification

Depth - Soil depth in cm of limit of soil core range collected. 
Example: 25 cm Depth - sample range 0-25 cm.

SRL - specific fine root length (SRL) m g-1

RTD - Root tissue density (RTD) g cm-3.

RLD - root length density (RLD) cm cm-3