LAI in the quantification of vegetation
disturbance in Irish peatlands
Jerome O Connell, Nick Holden, John Connolly
Biosys...
 LAI ( Leaf Area Index)
 Ratio of the total area of all leaves on a plant to the area of ground covered by
the plant.
 ...
 Issues in this project
 Change detection of peatland vegetation
 Need to establish natural growth trends of specific p...
 Materials
 Garmin 60CSx GPS
 Typically ±2m accuracy
 SPOT 4/5 data
 Auxiliary data
 SunScan Canopy Analysis
System,...
 Sites
 2 raised, 2 blanket, 1 upland
heath.
 Sampling
 Strategy
 Unsupervised classification.
 Pixels to sample poi...
Results
Slieve Bloom
Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
0.00
1.00
2.00
3.00
4.00
...
Results
Moanveanagh
Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
0.00
0.50
1.00
1.50
2.00
2...
Results
Kerryhead
Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
0
2
4
6
8
10
12
LAI_23_03 LA...
 Continue sampling until Oct-Nov
(zenith angle <60°).
 Resolve issue with decreasing
LAI in spring/summer.
 Examine dyn...
 ISIS programme under the French Space agency (CNES)
 National Parks andWildlife Service
 Ordinance Survey Ireland
 En...
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Leaf Area Index (LAI) in the quantification of vegetation disturbance in Irish Peatlands

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Dr Jerome O Connell - presentation made at various conferences throughout Europe as part of PhD which was funded by the EPA under the STRIVE Research Programme 2007-2013 (2007-PhD-ET-2)

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Leaf Area Index (LAI) in the quantification of vegetation disturbance in Irish Peatlands

  1. 1. LAI in the quantification of vegetation disturbance in Irish peatlands Jerome O Connell, Nick Holden, John Connolly Biosystems Engineering University College Dublin Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
  2. 2.  LAI ( Leaf Area Index)  Ratio of the total area of all leaves on a plant to the area of ground covered by the plant.  LAI characterises the canopy/atmosphere interface, therefore is an important structural measure, often used to derive various biophysical measures.  Direct and indirect approaches.  Gap fraction analysis is a popular indirect approach to LAI  LAI and Peatlands  Peatlands are critical to terrestrial soil carbon stocks.  Over 85% or Irish peatlands are “disturbed”.  Little published work on peatland vegetation disturbance and LAI. Background Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
  3. 3.  Issues in this project  Change detection of peatland vegetation  Need to establish natural growth trends of specific peatland habitats.  Need for ground based vegetation data for verification of satellite based change detection study.  Objectives 1. Characterise phenology of disturbed and undisturbed peatland habitats using field based LAI data. 2. Verification of satellite based change detection analysis using undisturbed (control) LAI vegetation data with know disturbance events.  Change on the ground correlating to change from satellites. High correlation between ground based LAI and EVI2 (Boegh et al, 2002; Huete et al, 2002; Potithep et al, 2009)  Undisturbed sites provide baseline conditions; 10% ± this condition = change. Introduction Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
  4. 4.  Materials  Garmin 60CSx GPS  Typically ±2m accuracy  SPOT 4/5 data  Auxiliary data  SunScan Canopy Analysis System, Delta-T Devices  Measures PAR above (BFS) and below (probe) the canopy.  SunScan use’s computable functions from modelled illumination data to calculate instant LAI values ( accurate to ±0.1 LAI). Materials BFS PDA Probe Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
  5. 5.  Sites  2 raised, 2 blanket, 1 upland heath.  Sampling  Strategy  Unsupervised classification.  Pixels to sample points.  Spatial thresholds applied.  Cross referenced with auxiliary data.  Procedure  Track to each point with 1m proximity alarm.  Sample 3 times in a east, south,west orientation.  Average of 3 readings is LAI for each point.  Take picture of west reading.  Data formatting  ArcGIS  ExpertGPS  Excel Methods Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013) Site Co-ordinates Designation Bog type Area (ha) Disturbance Clara N 53.3211°, W 7.6272° SAC, NHA Lowland raised 4.89 Burning, drainage Loughdan N 53.1048°, W 6.3292° SAC, NHA Upland blanket 5.00 Drainage, turf cutting Kerryhead N 52.4082°, W 9.8994° Commonage Upland heath 4.80 Burning Moanveanagh N 52.4545°, W 9.4075° SAC Lowland raised 5.48 Turf cutting, drainage Slieve Bloom N 53.0928°, W 7.5793° SAC, NHA Upland blanket 4.19 Drainage, afforestation
  6. 6. Results Slieve Bloom Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013) 0.00 1.00 2.00 3.00 4.00 5.00 LAI_28_05 LAI_23_07 LAI_20_08 LAI Mean LAI Plot 1 (Drier) Plot 2 Plot 3 (Clearfell) 0 20 40 60 80 100 LAI_28_05 LAI_23_07 LAI_20_08 %CV Coefficient ofVariation Plot 1 (Drier) Plot 2 Plot 3 (Clearfell)  Trends  All 3 sites show increasing LAI, with plot1 being the highest.  Standard deviation of plot 3 increases by over 40% in 10 weeks.  All plots show decrease in Coefficient of Variation (CV), with plot 1and 2 approaching similar levels. May reflect canopy closure.  Plot 3, the disturbed plot, shows the highest CV throughout the sampling periods.
  7. 7. Results Moanveanagh Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 LAI_19_03 LAI_24_05 LAI_20_07 LAI Mean LAI Plot 1 Plot 2 Plot 3 Plot 4 0 20 40 60 80 100 LAI_19_03 LAI_24_05 LAI_20_07 %CV Coefficient ofVariation Plot 1 Plot 2 Plot 3 Plot 4  Trends  Both cutaway plots show steady increase in mean LAI throughout.  Raised plots show decrease in mean LAI from March to May.  Both cutaway plots show highest CV with plot 3 showing the largest changes.  Both raised plots have slight increases in CV in May.
  8. 8. Results Kerryhead Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013) 0 2 4 6 8 10 12 LAI_23_03 LAI_19_05 LAI_07_07 LAI Mean LAI Plot 1 Plot 2 Plot 3 Plot 4 (Wet) 0 20 40 60 80 100 120 140 LAI_23_03 LAI_19_05 LAI_07_07 %CV Coefficient ofVariation Plot 1 Plot 2 Plot 3 Plot 4 (Wet)  Trends  Plot 1 vs plot 2 significant differences.  Plot 4 (Wet) shows slightly higher LAI than plot 3.  Standard deviation of plot 2 shows considerable increase from May to July.  Plot 4 shows peak CV in May, with plot 3 consistent.  Plot 2 (burnt) shows significant increase in CV from March to May, with gradual stabilisation from May to July.
  9. 9.  Continue sampling until Oct-Nov (zenith angle <60°).  Resolve issue with decreasing LAI in spring/summer.  Examine dynamics of the LAI data from disturbed sites with corresponding EVI2 data.  Threshold functions of change.  CV of standard deviation instead of absolute change in LAI and EVI2.  Correlation between LAI and EVI2. FurtherWork 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 01/2010 02/2010 03/2010 04/2010 05/2010 05/2010 06/2010 07/2010 08/2010 09/2010 09/2010 10/2010 11/2010 12/2010 MeanLAI Date Annual LAI Mean Cutover Mean Raised Hyp Mean Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)
  10. 10.  ISIS programme under the French Space agency (CNES)  National Parks andWildlife Service  Ordinance Survey Ireland  Environmental Protection Agency  ExpertGPS support  Delta-T Devices  Supervisors:  Dr. John Connolly  Prof. Nick Holden Acknowledgements Funded by the EPA, STRIVE under the National Development Plan (2007 – 2013)

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