Forest Inventory Glossary
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Revision as of 09:45, 30 March 2011
Content A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
A
- Areal sampling frame
- The sampling frame or continuum (area) from which dimensionless samples points are selected.
B
- Basal area
- Sum of the cross sectional areas (in 1.3 meter height) of all trees per hectare (in m2/ha).
- Bitterlich sampling
- Or: "Angle count sampling", "relascope sampling", "point sampling". An unequal probability sampling approach (or plot design). Trees are included in a sample, if they appear bigger that a defined opening angle.
C
- Cluster plot
- Sample plot that is composed of unconnected sub plots. As the subplots are not selected independently, a cluster gives only one observation.
- Concentric circular sample plots
- See: Nested plots.
D
- DBH
- Diameter at breast height (1.3 meter above ground).
E
- Expansion factor
- Reciprocal of the inclusion probability. The factor with which observations have to be multiplied to derive an estimate of the total (or per hectare).
F
- Fixed area sample plots
- sample plots with defined area size.
G
H
I
- Inclusion probability
- Probability that a single population unit is included in a sample based on the actual plot design.
J
K
L
- Line intersect sampling
- A sampling design in which lines serve as observation units. Total length of linear features is estimated based on the number of intersections with sample lines.
- Line intercept sampling
- A sampling design with lines as observation units. Relative proportions of land use classes are estimated based on the length of sample lines (proportion) that comes to lie in a target area class.
M
N
- Nested plots
- Nested sub-plots of different size at one sampling location for the separate assessment of e.g. different diameter classes.
O
P
R
S
- Sample plot
- A certain area or "decision rule", defining which population units are to be included at each sampling location.
- Sampling design
- The statistical framework or design that describes how sampling locations are selected (e.g. simple random sampling or systematic sampling).
- Sampling intensity
- Proportion of the population that is been sampled. In forest inventories the area proportion that was observed in the sampling study (e.g. 3% of the total area).
- Sample size
- Number of samples drawn from a defined sample frame.
- Selection probability
- Probability that a unique set of k population units is selected as sample based on the actual plot design. In case that k=1 similar to the inclusion probability.
- Spatial autocorrelation
- Or: "Self-correlation" describes the relationship between two observations of the same variable, taken at two different objects or times.
- Standard Error
- Standard deviation of the sample means.
- Stratification
- A sampling technique based on the partitioning of the total population (or area) in more homogeneous sub-populations (strata) that can improve precision.
T
- Total
- Aggregate value of the quantitative characteristic of interest in the entire population (e.g. total volume in the area of interest).