(1) 
(2) 
en 
(3) 
(4) 
ing 
($5) 
(6) 
Dees, Matthias 
  
2 1 2 > 2 
V(R uU) 7 zou * Roa. 
y,strat strat strat 
strat 
OR Vu 
strat ^ y,strat ) 
  
(8) 
with 
Himp2i (LN y, In y H 2.9, Ce 7. In) 
S: tra = [+ Es > S: tra = [^^ E ] 
pem 2. d t n,—1 RT 2. n, 2. n, -1 
H 2m Oz Wn) 
S = Y[— k=1 k=1 ] 
yz,Strat 
h=1 D kzi n, —1 
where 2 is defined according to S , (derived from Sárndal et al. (1992), equation. 5.6.10). The sampling errors 
can be derived by taking the square root of the variances of the estimates. 
3.3 Results and Conclusions 
For the establishing of strata, a partitioning was selected that enables a reduction of the estimation errors both for the 
estimates according to age groups and according to tree type. Every one of the stands has a main tree type. All stands 
are assigned to a stratum using the main tree type and the age group of the main tree type. First, the main tree type 
assignments were made: class 1 'oak' ; class 2 'other broad-leaf tree species"; class 3 'coniferous species'. Within each of 
these classes, three age classes are defined according to table 2, resulting in 9 strata. The entire area of 2268,3 ha was 
divided into these 9 strata, which covered proportions of the entire area from 7.1% to 18.7%. 
  
  
  
  
  
  
  
age group 1 age group 1 age group 1 
class 1 'oak’ <= 60 years <= 40 years <= 40 years 
class 2 ‘other broad-leaf tree species’ 61 — 120 years 41 - 80 years 41 - 80 years 
class 3 'coniferous species’ > 120 years > 80 years > 80 years 
  
  
  
Table 2. Definition of the strata 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Attribute Estimate with Estimate with Potential to reduce the 
absolute sampling | absolute sampling sample size using stratified 
error, stratified error, simple random sampling (main- 
sampling random sampling taining the sampling error) 
in [%] for the single 
attributes 
Standing cross volume [m?] 631495 + 9754 | 630587 + 11342 26 
Standing commercial volume [m°] 484509 + 7712 | 483148 + 9073 26 
Oak, standing cross volume [m°] 214581 +7032 | 216623 + 10661 56 
Beach, standing cross volume [m°] 148800 + 8393 | 142449 + 8846 8 
Spruce, standing cross volume [m°] 69183 +6124 |. 75031 +7712 38 
Oak, relative area [%] 34,2 +0,9 34,6 +1,5 60 
Beach, relative area [%] 18,2 +1,1 17,4 +11 8 
Spruce, relative area [%] 9,9 +08 10,7 x10 40 
Standing cross volume per forest 253,8 +43 253,9 +48 23 
area [m°/ha], main stand 
Oak, standing cross volume per 271,09 +59 2714 +6,6 23 
beech area [m?/ha], main stand 
Beech, standing cross volume per 300,9 $10.5 299,9 +110 9 
beech area [m3/ha], main stand 
Spruce, standing cross volume per 299,3 + 14,1 301,3 + 15,3 7 
spruce area [m*/ha], main stand 
  
  
  
  
  
Table 3. Estimates, errors and potential to reduce the sample size for main attributes 
(main stand: stand without reserving of standards and undergrowth) 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 359