- Tytuł:
-
Ocena dokładności obrębowej metody inwentaryzacji lasu opartej na losowaniu warstwowym
Assessment of the accuracy of the forest district inventory method based on the stratified sampling - Autorzy:
-
Bruchwald, A.
Miścicki, S.
Dmyterko, E.
Stereńczak, K. - Powiązania:
- https://bibliotekanauki.pl/articles/988954.pdf
- Data publikacji:
- 2017
- Wydawca:
- Polskie Towarzystwo Leśne
- Tematy:
-
lesnictwo
miazszosc drzewostanow
inwentaryzacja lasu
metoda obrebowa
losowanie warstwowe
dokladnosc
auxiliary variable
dominant tree species
sample allocation
stratum - Opis:
- The aim of the research was to assess the accuracy of the stratified sampling method used to estimate the standing volume of a forest district and to compare it with the accuracy of simple random sampling methods. The paper presents the variability of the variables affecting the accuracy of the stratified sampling method. We attempted to find the ways to increase this accuracy. The research was based on the empirical material collected on approximately 42,000 sample plots with a size of 50−500 m², and with an average of 737 plots per forest district. The standard deviation of the merchantable volume of trees on sample plots ranged from 87 to 213 m³/ha, with an average of 128 m³/ha. The coefficient of variation ranged from 5.3 to 28.5% (the average 40.8%). Using a simple random sampling method, the standard error of the volume ranged from 3.3 to 10.0 m³/ha (the average 4.8 m³/ha) and the relative error – from 1.01 to 3.41% (the average 1.55%). The absolute error of the stratified sampling method under which strata are formed on the basis of the main tree species and its age ranged from 2.9 to 7.4 m³/ha, the average 4.2 m³/ha, and the relative error ranged from 0.65 to 1.95%, 1.02% on average (tab.). The accuracy of the stratified sampling method was by 15% higher than that of the simple random sampling method. We found that the relationship between the volume of a sample plot and the main tree species and its age measured by the correlation coefficient was 0.453 on average. For the relationship between volume and age of stands this coefficient was on average 0.422, while between volume and main tree species – only 0.118. Stand age – as an auxiliary variable in formation of strata – proved to be of moderate usefulness resulting from a small difference in the standing volume of stands in older age classes. Main tree species turned out to be of slight usefulness in formation of strata, therefore it seems reasonable to find some other auxiliary variables to replace it.
- Źródło:
-
Sylwan; 2017, 161, 11; 909-916
0039-7660 - Pojawia się w:
- Sylwan
- Dostawca treści:
- Biblioteka Nauki
Artykuł