Predicting the water-use of Eucalyptus nitens plantations in ...

3.2. Weather Station
An automatic weather station was placed in a clearing adjacent to the research plantation. It
recorded rainfall, air temperature, ground temperature, humidity, solar radiation, wind speed
and direction. Data prior to May 2011 were lost due to technical difficulties. The tippingbucket
rain gauge recorded less rain than the bulk rain gauge (tipping bucket = 456 mm of
rain between 7/5/2011 and 31/1/2012) and was deemed to be defective. The maximum
temperature recorded was 29 o C, the minimum recorded was 0 o C.
3.3. Plantation basal area and sapwood area
A 20 m x 20 m (400 m 2 ) measurement plot containing 39 trees (some with multiple stems)
was established on 26/2/2011. The diameter of every stem within the plot was measured at
1.3 m. Stems were remeasured on 20/6/2011, 19/10/2011 and 7/2/2012. Plot basal area grew
from 29.27 m 2 /ha on the 26/2/2011 to 32.52 m 2 /ha on 7/2/2012.
Sapwood area was determined for a number of trees using an increment corer and assuming
radial symmetry. Sapwood area was strongly correlated with basal area (R 2 =0.78) for
individual trees (Figure 7). Plot sapwood area was estimated at 10.75 m 2 /ha at
commencement and 11.77 m 2 /ha at completion of the experiment.
Sapwood Area (cm 2 )
180
160
140
120
100
80
60
40
20
0
Figure 7. Relationship between stem basal area and stem sapwood area of E. nitens at
Forestier
13
y = 0.3051x + 17.8
R² = 0.78
0 50 100 150 200 250 300 350 400 450 500
Basal Area (cm 2 )