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0 x : i i i EU ue MN 
06. 09 25 08 30 01" 07. 18 
Jul Aug Apr Jun Jul Jul Jul Aug 
91 92 94 94 94 95 95 95 
  
Recultivation areas reforested with pine 
  
  
  
00 i ly i ud rir! 
06. 09. 25. 08. ‘30 01 ‘07 18 
Jul Aug Apr Jun Jul Jul Jul Aug 
91 92 94 94 94 9595 
Fig. 7a,b: NDVI-development of selected recultivation 
areas (area numbers see Fig. 2) 
has to be made inherently to the different categories of 
data and must consider the actual physico-geographical 
conditions. Though the formation of indices has already 
led to a certain amount of normalization, systematic dis- 
crepancies have been found by both sensor inherent as 
well as seasonal and annual specific influences. Therefo- 
re data normalization was performed on the basis of 
reference areas. Because of their relative stability 10 pine 
forest stands located in the surroundings of the opencast 
mine were selected. As examples, Fig. 7a and b show 
some appropriately corrected mean values of the NDVI 
for selected cropland and reforested areas. 
It can be demonstrated that the agricultural areas cultiva- 
ted with alfalfa have followed a typical annual variation 
which must be considered appropriately in trend analysis. 
Furthermore strong and area independent variations of 
vitality have been detected during the vegetation stages 
in summer which resulted from different kinds of agricul- 
tural treatments, e.g. harvest, of the areas at different 
times. In general, those kinds of variations do not exist 
for pine reforested areas. However, young pine trees 
which are still in development can undergo a strongly 
short-term increase of vitality during the end of 
May/begin of June, which is linked to fresh may sprouts 
(area numbers 10, 11). If an increase of vitality can be 
detected over a longer time period in spring and summer, 
then it can be ascribed to weeds and scrubs growing on 
the area. 
Based on the corrected data of the areas mid- and short- 
term trends can be derived permitting an assessment of 
the development of the area concerned to be made du- 
ring a certain time period. Table 1 shows the data for the 
recultivated areas of the Welzow-Süd dump from 1991 to 
1995. Comparing the results between cropland and refo- 
rested areas, significant differences have been detected. 
Eee a is ai rta ei HE nee c tee M cR REDEEM 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Area Absolute values 7/91 | Trend 91-95 (per year) 
No. NDVI VM2 NDVI VM2 
1 - 0,02 0,77 + 0,138 + 0,502 
2 0,348 2,24 - 0,016 - 0,091 
3 0,091 0,98 * 0,051 + 0,139 
A 0,658 6,60 - 0,050 - 0,401 
5 0,606 5,68 - 0,013 - 0,390 
6 0,491 3,26 * 0,005 * 0,030 
7 0,206 1,36 + 0,071 + 0,316 
8 0,358 2,08 + 0,057 + 0,294 
9 0,068 0,96 + 0,029 + 0,020 
10 0,171 1,27 + 0,050 +0172 
11 0,041 0,88 + 0,031 + 0,046 
12 0,129 1,16 + 0,036 + 0,085 
13 0,170 132 + 0,026 + 0,055 
14 0,256 1,71 + 0,034 + 0,172 
15 0,136 1,18 +0,036 * 0,087 
16 0,162 1,28 * 0,031 * 0,083 
17 0,090 0,99 + 0,031 + 0,065 
18 0,258 1,73 + 0,016 + 0,051 
19 0,236 1,56 + 0,029 + 0,132 
20 0,124 1,09 + 0,027 + 0,061 
21 0,347 2,29 + 0,011 + 0,031 
  
  
Table 1: Vitality indices NDVI and VM2 
areas (above) and reforested areas (below) 
for cropland 
  
Depending on the start of the reforestation, the reforested 
areas have shown more or less a steady increase of 
vitality, indicating a corresponding continuous develop- 
ment of the plantations over several years, whereas the 
cropland areas cultivated with alfalfa can be described as 
very heterogenous. For area 1 which did not belong to 
the recultivation zone in 1991, a sharp increase of vitality 
can be observed from the start of cultivation. The same 
behaviour however was not found for the areas 2,4 and 5 
which were already in recultivation in 1991. In these 
Recultivation areas at the 8th of Oct. 1993 
10096 j 
    
    
    
  
     
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& 8096 4 D cool 
5 60% | | 1} C) medium 
O | ; "n 
9 4096 | : | | Btepid 
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$ 20% III IE 
< THE ll [ Bi hot 
0% HE SEL 
1.3 5 79 11131547 1921 
Area No. 
Recultivation areas at the 8th of June 1994 
10096 4 
8096 | 
60% | 
40% À 
20% 1 
0% | 
Area percentage 
  
Area No. 
Fig. 8 a,b: Relative temperature distribution of recultiva- 
ted areas, a: 1993, b: 1994 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996