565 
. «.^3 
In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
fruit plantations and study the relationships between remotely- 
sensed indices and ground control measures of fruit trees. Based 
on field work unique data of all pear trees, registered in the 
genetic collection, were collected to one ESRI ARCGIS data 
base. Height measurements and digital photos of the trees were 
also carried out during the survey. Digital photos were taken of 
the fruits as well, although earlier taken photos of genetically 
typical, ripe fruits were set to the database. The pictures were 
geotagged to air photo based on coordinates. 
The n-dimensional hyperspectral image contained 359 channels. 
The bad bands, having bad signal/noise rate were excluded from 
further assessments (Tamas et. al 2005). 
The characteristics of the reflectance curves of each pear tree 
species result from the large amount of absorption of 
chlorophyll content at 450 - 670nm wavelength intervals. On 
the other hand, reaching the near infra-red (NIR) interval, the 
reflectance of the healthy fruit tree leaves are raising markedly 
at 700nm (Tamas, 2010). Besides, the reflectance value of the 
vegetation without any stress is high at NIR intervals, but low at 
red wavelength interval. The chlorophyll content is one of the 
indicators of the state of health before ripening phenological 
phase (Burai et al. 2009). The leaf samples taken with R- 
Row/T-Tree positions in the study area were collected and 
analyzed on the basis of the field measured spectral curves 
(Table 2). 
Pearl Species 
R/T 
NDVI 
SRI 
REP 
chlorophyll 
ftg/g 
Napoca 
19/ 
103 
0.62 
4.96 
718.4 
883.52 
Márianosztrai 
19/ 
113 
0.41 
4.95 
720.7 
509.12 
República 
19/ 
83 
0.58 
3.39 
712.1 
982.72 
Ananász 
(Ananas) 
19/ 
79 
0.69 
5.26 
710.9 
4522.88 
Nyári esperes 
(summer deán) 
19/ 
70 
0.67 
4.84 
712.9 
3960 
Kiev 
19/ 
109 
0.489 
2.79 
721.7 
407.36 
Table 2. Example for chlorophyll content and spectral indices 
The Pearson correlation between chlorophyll and Normalized 
Vegetation Index (NDVI) was 0.8, between chlorophyll and 
Simple Ratio Index (SRI) was 0.54, between chlorophyll and 
Red Edge Position (REP) was -0.76. 
During the survey NDVI index was calculated from the 
hyperspectral image. The segmentation of the NDVI image was 
based on the GIS database of field measurements. After 
vectorising the obtained segments, those pear species having 
different biomass weight were selected. Pixels covered by 
canopies of these trees, could be spectrally clear and unmixed. 
Although the results show, that real endmember pixels can only 
be found at trees having several canopy level and at least 1 m 
canopy diameter. Because of the replacement of necrotized trees 
the spectral properties of grass zone between rows can provide 
spectrally mixed values (as a 2 nd type errors of commission) due 
to the possible underdevelopement of trees. On the other hand, 
the spectral properties of neighboring trees can be mixed due to 
the overdeveloped tree canopy having more than 4 m diameter, 
which larger than the spacing in the row. Generally these errors 
of ommission (1 st type) had minor role. The resulted, classified 
spectral data could be applied as a spectral library, which are 
suitable for the detailed examination of plant physiology and 
spectral data. The optimal climatic conditions for pear are 
generally cooler and humid, with at least 65% of relative air 
humidity. There is a lack of these conditions in Ujfeherto at the 
30-40% in a year. At the examined site, pear species with large 
biomass concerned as those species which had major tolerance 
against drier and unfavourable environmental conditions. These 
genetic properties could be very important in the frame of the 
potential climate change. Stress, caused by the relative water 
lack, evolves in a short term physiological process. The first 
symptoms of water stress are often not visually observed, 
although those have negative effect on the yield quantity and 
quality. The conventional invasive measurements can hardly be 
reproduced, because of the sampling (cut) of the vegetation 
tissue (i.g. leaf, shoot) or only few cm 2 of leaf area is measured, 
which limits the representative sampling. The airborne 
hyperspectral remote sensing data eliminate these 
disadvantages, since it can provide detailed spectral data from 
the whole canopy. 
In Figure 2 the continuum removed spectra of Bajai, KorteB/3, 
Szentendrei csaszar, Verteskozmai pear species are shown 
descending order of biomass. Continuum Removal is to 
normalize reflectance spectra to compare individual absorption 
features from a common baseline. The continuum is a convex 
hull fit over the top of a spectrum using straight-line segments 
that connect local spectra maxima. The first and last spectral 
data values are on the hull; therefore, the first and last bands in 
the output continuum-removed data file are equal to 1.0. The 
resulting image spectra are equal to 1.0 where the continuum 
and the spectra match, and less than 1.0 where absorption 
features occur. 
Figure 2. The pear species have species specific spectral 
properties 
Based on the horticultural data, the four biomass segments 
showed strong correlation with the water stress tolerance. The 
pear tree species were grafted to the same wild pear rootstock, 
thus there were no differences in the water consumption root 
zone. In accordance with the spectral data, the “Bajai” species 
produced large canopy with 5.7 m height and large yield 
quantity (Figure 3).