multispectral scanning data, the SPOT HRV data, and 
the Landsat-TM data. Some bands, of these three 
remotely sensed data were close related with vegetation 
condition. For example, in the visible and infrared 
regions, the forest crown closure is strongly correlated to 
the dry matter accumulation of trees. Green leaves of 
trees absorb red light and reflect the near-infrared 
radiation strongly. The red light is used in the 
photosynthesis as a catalyst for the conversion of water 
and carbon dioxide into sugars and hence all organic 
matter. So, the photosynthesis is direct related to tree 
biomass accumulation. In other words, the spectral 
reflectance in the visible and near-infrared regions can 
be used to estimate forest crown closure and stand 
volume. 
The author would like to express his appreciation to the 
National Science Council of the Republic of china for 
providing the financial aid (contract NSC-83-0409- 
B002-304). 
MATERIALS AND METHODS 
].The study site 
This study was conducted in the Chi-tou district of the 
Experimental Forest of National Taiwan Universing in 
the central portion of Taiwan. The study area covers a 
5,000 ha. section of national forest land with elevations 
ranging from 750m to 1,800m. The annual precipitation 
of this arca is about 2,500mm and the humidity 8596. 
There are 1,500 ha. Man made plantations with ages 
from 1 to 80 years old. The others were covered by 
natural hardwoods and bamboos. In this long-time 
managed area, basic data of trees such as tree species, 
height, crown diameter, crown closure, growth situation 
and volume were available. 
2.Data Utilized 
These three remotely sensed data used in this study were 
adopted from the author's past study "A Study of Using 
Spectral Reflectance to Estimate Forest Crown Closure". 
In the above mentioned paper, the airborne multispectral 
scanning data were acquired by a DS-1260 airborne 
MSS system with 11 channels on April 10, 1987. A 
Computer Compatable Tape (CCT) containing airborne 
MSS data in band 1 to band 11 except band 7 were used 
in data processing. The SPOT data (band XS, ^ XS» 
and XS3)were acquired on December 10, 1986. It was 
raw level-1 images recorded in multispectral mode. The 
Landsat-TM data were acquired by Landsat-5 on 
January 17, 1987 with path/row annotation of 117/44. 
All six reflective TM bands were utillized in this study. 
The thermal infrared data which have 120m spatial 
resolution were not used (Table 1). 
Table 1 » Remotely Sensed Data Used in This Study 
  
Sensor Recording Date 
Band Wavelength 
interval (um) 
  
Airborne 
multispectral 04/10/87 
scanner 
0.38-0.42 
0.42-0.45 
0.45-0.50 
0.50-0.55 
0.55-0.60 
0.60-0.65 
0.70-0.79 
0.80-0.89 
0.92-1.10 
8.50-13.0 
— [oO [ooo [Ow [t^ |- [JW IS | 
  
SPOT-HRV 12/10/86 
0.50-0.59 
XS2 0.61-0.68 
0.79-0.89 
X 
= 
X 
n 
[90 
  
Landsat-TM 01/17/87 
— 
0.45-0.52 
0.52-0.60 
0.63-0.69 
0.76-0.90 
1.55-1.75 
2.08-2.35 
- [tA [4 | [IN 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996 
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