(IX-B8, 2012
e GILMAY
= GTI JUNE
—
PENES IONE
eM IH PRISSNW MAY
sie PBISS.NW JUNE
r May and June, in
ids: GT1, PB235-
data the spectral
| the late autumn is
larity is imposed
(Figure 15) the
ent and happens
senses GTIPBAIS SE MAY
i STIFBI3E-NW MAY
v TB13SEPBI3-NY MAY
vere GTUPBIM-SE JUNE
— STLIPRIMCNW JUNE
vov BBIM.SEPRIS-NW JUNE
Mis 2964
bber trees stands
0 to 1,300nm for
de
so GTUPRIE-SE MAY
e GTUPBISNW MAY
e PBIM-SEPBIN-NW MAY
voce GEVPBISI-SE JUNE.
n GTUPB2SENW JUNE
eren PRIS.SEBIMONW JUNE
4
26 91
bber trees stands
0 to 1,300nm for
»
/
2,500nm)
1,420nm. The data
y in the leaf scale,
absorption by the
clone presents the
g for May in leaf
35-SE stands are à
of the reflectance
1ed by the fact that,
ie lighting intensity
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
decrease is not able to stimulate the plasticity of thickness
reduction of their leaves. Thus, as mentioned before, there is no
evidence of the structural compounds by the reduction of the
intercellular gaseous space, between the studied months.
er GTI MAY
~a~GT1 JUNE
nen PHIIS.SE MAY
wana PR2IS.SE JUNE
cos PRI3S-NW MAY.
sv PB135-NW JUNE
Reflertance (%)
Hr Hay Hay
Wavelength (nm)
Figure 16. Spectral behaviour in leaf scale in the region
1,420nm of the Rubber trees stands: GT1, PB235-SE and
PB235-NW
A more isolated absorption peak of the foliar starch, that
happens around 2,220nm, indicated in May the lowest
reflectance values for the most shaded stands (GT1 and PB235-
SE). In June, even though GT1 presented the lowest values also
on both scales, the PB235-NW presents, in canopy scale, the
lowest values if compared to the PB235-SE. The PB235-SE
was the only one to present the reduction of this compound on
both scales. Although, in general terms, this compound is
reserved to be consumed in stressful conditions, presenting
seasonal variations and its reserve, other factors are also
determinant to this compound concentration in the leaves, such
as the leaf position on the branch (Dantas et al., 2007) and the
period of the day (Taiz & Zeiger, 2002). These interferences
happen in a less significant way in the canopy scale, because of
the leaves distribution and proximity to the imaging time (2pm
and 4pm respectively). For this data, the variation analysis for
the studied dates is simpler to read: for the leaves from the most
shaded stands, where the lighting deficit is worse, it is noticed a
decrease of starch concentration from May to June, indicating a
greater consumption of its sugar reserves.
ween GTI MAY
m GEL JUNE
“a ^de PBISE.SE MAY
7 PBISESE JUNE
rg “5. ces PBIENW MAY
yy wee. PBIIS.NW JUNE
“a
=
ng
Ie : : ; : : : :
as May Yo Mg, ng My, Wy gg Wy Ha, Ue, A,
Wavelength (am)
Figure 17. Spectral behaviour in canopy scale in the region
2,220nm of the Rubber trees stands: GT1, PB235-SE and
PB235-NW
e GILMAY
GT] JUNE
cue PHISCSE MAY
v PB231-SE JUNE
cse PHISCNW MAY
cbe PHIS-NW JUNE
Reflectance (95)
0g, Mpg May Wey Wp, Wy gy Ne, As,
Wavelength (om)
Figure 18. Spectral behaviour in leaf scale in the region
2,220nm of the Rubber trees stands: GT1, PB235-SE and
PB235-NW
The SWIR was the spectral region which presented the greatest
differences between the data collection dates (Figures 19 and
20). Analysing the ratios between the studied stands, in May the
GT1 and PB235-SE were spectrally more similar, indicating
differences from the PB235-NW one. In June, with the
approach of winter, both PB235 stands started presenting
similar patterns but different from the GTI. This point was
found incontestable for the behaviours in leaf scale, as
presented in the Figure 20.
182
1
0.58
996
$94
[271
c GTUPBIM-SE MAY
— GTL?BI3-NW MAY
tatu PB235-SE PB13E-XW MAY
Ratio value
1802 4 847.5 194 Tig 760 3 2a 7 Fug, Pig Ang Fig, ty Pag Toe ay 30g 2p,
Waveleogth (am)
v GELPB28-SE JUNE
i GTUPBISENW JUXE
sue PB23S-SE/PBII5-NW JUNE
Ai
pof
re patiné EE
i
T8), 5, Sy 9 7005 p Pap Dey, aa, Sig Ha i gy V4 7000 50027 SM 57004
Wavelength (nm)
Figura 19. Ratios among spectra of the Rubber trees stands
(GT1, PB235-SE and PB235-NW) from 1,300 to 2,500nm, for
May and June, in canopy scale
co GELPB235-SE MAY
mono GTUPBIIS-NW MAY
aeons PB23£-SE/PRIIS-NW MAY
Ratio value
3044 1847 > LO 16343 LM 24 Derg 2g, 36s, 31a 185 220 2244, Ly 2033 , 2005 9.
Wavelength (sm)
mo TLIPBISS-SE JUNE
a GILPBISS-NW JUNE
^ PRI3S-SEPB235-NW JUNE
Ratio value
A
TN
Wavelength (am)
Figura 20. Ratios among spectra of the Rubber trees stands
(GT1, PB235-SE and PB235-NW) from 1,300 to 2,500nm, for
May and June, in leaf scale
4. CONCLUSION
It was possible to demonstrate the possibility of discriminating
different clone of Hevea brasiliensis using the hyperspectral
remote sensing, by comparing the responses of two different
moments of autumn. The tool was also demonstrated to be
efficient at the detection of small environmental variations.
Both canopy and leaf scales had not always similar results,
mainly in the SWIR. For the VIS region, mainly in June, the
spectra indicate a genetic similarity regardless of the sun expose
conditions.
The greatest loss of a and b chlorophylls suffered by GT1 clone
is the main point on the clones distinction. The measures at NIR
made in June, as indicators of environmental variations were
noticeable and very similar in both scales. At the SWIR, it is
enhanced the influence of the morphological differentiation
because of the sun exposure intensity. For the stand most
exposed to the sun, the parenchyma cells are more present and
better developed. That explains the NIR and the SWIR
behaviour by the presence of bigger intercellular gaseous space
in the leaves, and at the same time, by the lower water contents
considering the greater evapotranspiration of those leaves.
