density for the 72 outer points. The TLS is scheduled to be 
captured for the centre point of this grid for later comparison. 
  
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Figure 2: Gridded sampling design for the Rushworth plot. 
An initial comparison was conducted for LAI between the LAI- 
2200 and the DHP for 72 points sampled at the 4m density 
(Figure 2). The mean values for the LAI-2200 and the DHP are 
0.95 and 0.50 respectively (Table 1). 
  
LAI Values 
  
  
  
  
  
  
13 f! 16 13 ib 135 22 25 JR 31 13 32 30 43 26 49 $2 55 5% DI 63 67 A873 
Measurement Number 
Figure 3: LAI comparison of LAI-2200 and DHP 
  
  
  
  
  
  
  
LAI (2200) LAI (DHP) 
Mean 0.95 0.50 
Standard Error 0.02 0.01 
Std Deviation 0.18 0.08 
Range 0.87 0.41 
Minimum 0.65 0.34 
Maximum 1.52 0.75 
  
Table 1: LAI summary statistics for LAI-2200 and DHP 
A large discrepancy was found between the mean LAI values. 
The graph in Figure 3 demonstrates the bias between the two 
technologies. The DHP is consistently providing an LAI value 
lower than the LAI-2200. However, correlating the two 
technologies produced an R? of 0.46 (linear regression 
intercepting LAI-2200 vertical axis at 0.23) which indicates an 
inconsistent bias. 
   
The results for LAI produced by the DHP and LAI-2200 are 
different from the comparison reported by Coops et al., (2004). 
Coops ef al. (2004) found that the DHP and LAI-2000 
produced higher R? value of 0.65 for a linear regression with an 
intercept at the LAI-2000 axis at 0.72. 
Further differences between the two studies may be explained 
by vegetation type, number of measurements, measurement 
aggregation, and different DHP processing software to derive 
LAL The dominant tree species found in the Coops ef al, 
(2004) were the Eucalyptus delegatensis and the Eucalyptus 
dalrympleana. These species are significantly taller and 
produce a more uniform upper canopy to the species found in 
Rushworth. Furthermore, the mean LAI values reported in 
Coops et al., (2004) are greater than the study area in 
Rushworth, and are indicative of the lower biomass of the tree 
species found in Rushworth. Coops et al., (2004) also 
aggregated plot measurements, whereas this study compared 
individual measurements over one plot. Lastly, different 
software packages were used to derive LAI from DHP in the 
two studies. Coops et al., (2004) used HemiView 2.1 software 
which requires the user to manually define a threshold for 
classifying the image into sky and non-sky elements for gap 
fraction analysis. Conversely, the DHP software used in this 
study automatically thresholds each image. 
2.5 Further Analysis to be completed at Rushworth 
The gridded sampling strategy provided an increased coverage 
area for a similar time cost by modifying the measurement 
spacing. The strategy will allow for a comparison of results at a 
variety of sampling densities and designs (Nelder, 1962). The 
design allows for comparison at the point level of a variety of 
metrics, and also enables comparisons to be undertaken at a 
variety of scales through aggregation of measurements. 
The comparison of metrics at the individual point scale will be 
extended to MTA, FAPAR and FCOVER metrics for both the 
DHP and CI-110 data. Comparing the same metrics from 
different technologies is important for determining the degree 
of consistency within each study area. Different metrics will be 
correlated against each other to determine the degree of 
relatedness. 
Another factor of significance for LAI is the ratio of woody to 
non-woody vegetation. The FPC transect will enable the ratio 
of woody to non-woody vegetation to be calculated. This ratio 
could be utilised when determining the link between LAI and 
PAL 
The aggregation of point scale measurements for comparison 
enables different metrics to be correlated with each other over 
multiple scales. Aggregation is relevant as each instrument has 
a varying FOV and sample radius. For example, FCOVER 
produced by the passive imaging devices is derived over a FOV, 
which allows for the FPC value to be aggregated of the same 
FOV for comparison. Furthermore, FCOVER can be 
aggregated and averaged at the plot scale and then compared to 
the site’s aggregated FPC value. 
The gridded sample design, which allows for testing of various 
sampling designs at different densities, will enable the 
  
  
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