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)

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.  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.  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.  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.  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. 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. 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. 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.  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.  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)