The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
292 
classification and forest type mapping using hyperspectral 
images. 
2. MATERIALS AND METHODS 
2.1. Study sites 
The test site for this study is located in the research Forest of 
University of Tehran located in Mazandaran province in the 
north of Iran, which is a part of the Caspian forest (figure .1). 
This forest is divided to seven districts with a total area of 
845 ha. 
Figure 1: study site location in the Caspian forest (a), the 
photo of mountainous view of the Caspian forest in study 
area 
2.2. Sample collection 
Species Alder 
Hornbeam 
Beech 
Ironwood 
Oak 
No. of trees j ^ 
sampled 
20 
29 
15 
19 
Altitude(m) ^59 
700-100 
400- 
2200 
400- 
590 
700- 
1320 
DBH (cm) 38-61 
35-68 
40-70 
28-36 
42-70 
Height (m) 27-36 
15-25 
25-38 
15-22 
35-60 
Branch level: 
(3R‘*2S 2 *2E 3 *N 3 ) 
228 
240 
348 
180 
228 
Leaf level: 
(3R*2S*2E *N) 
228 
240 
348 
180 
228 
Twig:(6R*N) 
120 
120 
174 
90 
114 
Branch: (6R*N) 
120 
120 
174 
90 
114 
'R, number of repeats or cut branches 2 -S, leaf surface, 
adaxial/abaxial- 3 E, exposed, illuminated/shaded- 4 N, number of tree 
sample for each species 
Table 1: The attribute table of number of each species and 
some measured characteristics 
To sample a representative set of different types of leaves, 
branches were harvested in two exposed conditions, 
illuminated and shaded leaves, at various levels ranging from 
the upper to the lower position in the canopy. A total of 2448 
spectrum for leaves from 102 samples of five tree species 
were analyzed. The samples were collected at three sites in 
altitude gradient between 400 and 2100m (low, mid and high 
elevation) in August and September 2007. For each species 
the samples were chosen from dominant-stairs trees in 
different DBH (diameter at breast height). Table 1 shows the 
attribute table of number of each species and measured 
characteristics. 
2.3. Spectroradiometry measurements 
Reflectance measurements were done using a ASD Fieldspec 
Pro spectroradiometer (350-2500 nm) in the course of 
summer 2007. The sensor, with a field of view of 25°, was 
positioned 30-40 cm above the samples at nadir position. 
Prior to each three measurement, a white reference panel with 
approximately 100% reflectance was used as a reference 
standard. The measurements were conducted under clear and 
cloudless sky between 10:00 and 14:00 at local time. For 
each tree individual three branches have been cut in shade 
and sun exposed condition. At first, the spectral 
measurements of branch-leaves pile has been done and after 
removing the leaves, spectral leave pile was acquired from 
adaxial and abaxial surfaces. 
2.3. Methods 
Vegetation indices 
A variety of indices related to total chlorophyll changes were 
used to characterize complex spectra and make comparisons 
possible among species and between illumination conditions. 
These indices have been derived from the list that Maire et al. 
(2004) presented based on knowledge of the reflectance 
properties of chlorophyll content described in other literatures. 
Total chlorophyll is correlated with the red edge position 
which is the wavelength X (in nanometers) of the maximum 
slope of the reflectance spectrum at wavelength between 690 
and 740 nm. The depths and widths of pigment absorption 
troughs and the position and magnitude of reflectance peaks 
can be quite different among species (Ustin et al. 1993). 
Vegetation 
index 
Equation 
Reference 
mND 705 : 
modified 
Normalized 
difference 
(R750- 
^-705X( R-750+R705- 
2R445) 
Sims & Gamon 
2002 
Simple Ratio 
R750/R700 
Gitelson et al 
1996 
m SR705l 
modified 
(R75O-R445)/( R705- 
Sims & Gamon 
Simple Ratio 
R445) 
2002 
Vogelmann 
index 
R740/R72O 
Vogelmann et al 
1993 
Datt index 
(R850- 
R-71oV( R-850+R-680 ) 
Datt 1999 
Table 2: Vegetation indices used to estimate chlorophyll 
content at leaf level. 
Variations in chlorophyll content can be caused by structural 
status of the leaves, atmospheric pollution, nutrient 
deficiency, toxicity, plant disease, and radiation stress (Filella 
& Penuelas 1999, Clevers et al., 2005). Although these 
factors influence the chlorophyll content within the species or 
individual trees we hypothesized that the chlorophyll changes