Dynamic stratification for estimating pointwise forest characteristics.
1996
Mozgeris, Gintautas | The Finnish Society of Forest Science | Suomen metsätieteellinen seura | Finlands Forstvetenskapliga Samfund
This paper deals with the testing of dynamic stratification for estimating stand level forest characteristics (basal area, mean diameter, mean height and mean age) for a 117 ha study area in Finland. The results do not show possibilities to achieve more accurate estimates using only Landsat TM principal components as auxiliary data opposed to static stratification. It was found that in dynamic stratification non-measured observations should be assigned the mean characteristics of the measured observations that belong to the same cube (class) instead of randomly selected ones. Stratification errors tend to decrease with the lessening of stratification variable classes until a certain limit. If only one principal component is used the number of classes has however little influence. Low field values are overestimated and high values underestimated. The only successful results were obtained using two variables of different origin – the qualitative development stage class and the quantitative 1st principal compund. The lowest root mean square error in estimating basal area was 6.40 m2/ha, mean diameter 3.34 cm, mean height 2.65 m and mean age 14.06 years. This increase of stratification accuracy is mainly resulted by the use of development stage class as an auxiliary variable.
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