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...chive a higher [[accuracy and precision|precision]] with the same [[sample size]]. Beside statistical issues there are further arguments for stratification *Tree sociological classes,

...y interested in estimating variables of [[Forest Definition|forests]] or [[Tree Definition|trees]]. Nevertheless the sampling frame is rarely the set of al In contrast to the infinite size of the sample frame one obviously can only observe a discrete number of tre

...[[Lecturenotes:population|population]] in which sampling is conducted. The size of the polygons is an expression of the [[inclusion probability|selection p This article describes, how jigsaw puzzles can be created from a map with tree locations in ArcGIS.

...rces available to measure <math>n=10</math> sample plots. The small sample size led to a fairly high value of the estimated [[error variance]]. ... 25 m x 25 m out of each original plot. By that, you increase the [[sample size]] to the fourfold and, thus, reduce the error variance.

There are target objects in [[forest inventory]] which are rare, such as rare tree or shrub species. They are sparsely distributed over the population of inte ... that specific topic. Often, the simplest solution is to increase [[sample size]] in order to increase the probability to encounter the rare objects; howev

...e points laid out over an area of interest; or the selection of every 10th tree in an alley; or parallel transects. ... immediate conclusion is that systematic sampling is obviously a sample of size <math>n = 1</math>. The “plot” that is being laid out then is a large [

...plots; here, the ratio estimator may be applied for estimation using plot size as co-variable (DeVries 1986<ref>de Vries, P.G., 1986. Sampling Theory fo ...h>k^{th}</math> tree. Depending on the distance to the <math>k^{th}</math> tree, these circle plots will have very different sizes: in parts of the forest

...erent crown cover was deemed to be an efficient sampling approach. But the tree cover was so irregular in its spatial distribution that it appeared impossi ... the entire area of interest. In any case, the error of estimating stratum size was small in this case.

...robability that element ''i'' is eventually (or included) in the sample of size ''n''. The [[Horvitz-Thompson estimator]] bases on the inclusion probabilit ... to a meaningful variable. Imagine e.g. different plot sizes for different tree dimensions. If bigger trees are observed in larger plots and smaller trees

Total tree bark volume is a variable that cannot easily be directly measured. The “ ...node) to the next – except for the bottom and top sections at which the tree begins and ends, respectively. From this set of N sections we would then

...ity. Importance sampling is applicable to continuous populations where the size attribute is a function from which a probability density function is derive Typical application in forestry is estimating individual tree volume by sampling the [[Stem_volume#The_taper_curve|taper curve]]: we imag

...right|thumb|300px|'''Figure 1''' Illustration of inclusion proportional to size (basal area) in Bitterlich sampling (Kleinn 2007<ref name="kleinn2007">Klei ...ub-plots]] was introduced because we wished to have a balanced number of [[Tree Definition|trees]] in all dimension classes; that is, we wanted to assign a

...on a plot). Nevertheless we need to know the inclusion probability of each tree to derive an unbiased estimate for the target variable. This probability is To determine the inclusion probability of a single tree, one has to know the relative share of all possible sample point locations

... determined. In order to illustrate the effect of minimum crown cover and size of the reference area on forest area estimates, let’s have a look at the ...6.png|right|300px|thumb|'''Figure 2''' Subdivision of a region into equal size cells for forest cover estimation (Kleinn 2000<ref name="kleinn2000a">Klei

...eters]] but also for the measurement of [[Measuring slope|slope angle]], [[tree height]] and other variables. A micro-scale in the device does automaticall ...any other lower diamater that can be measured directly. If, for example, a tree has a dbh of 60 cm and we count 6 relascope units when aiming with the rela

...orrelated with the growth of the tree as the tree crown is the part of the tree, which contains the photosynthesizing tissue, absorbs radiation and produce ...lated, such as [[Tree diameter|diameter]], [[Tree height|height]], [[crown size]], [[Stem volume|bole volume]], etc. The most common attributes of crown us

...growth and increment of trees and [[Forest Definition|forest stands]], the tree attributes need to be measured in time intervals. The difference between th ...ainable [[harvesting plan]]. Diameter increment shows the growth rate of a tree and can thus be used in planning the harvesting rotation year.

...s can visually usually not be recognized. Depending on the stem shape, the tree [[Stem volume|volume]] may be very different for one and the same [[Diamete ...e which is much higher than the tree volume. Then, in order to come to the tree volume, we need to introduce a reduction factor, which reduces the cylinder

...]]'', some times in combination with other variables such as [[Tree height|tree height]] or an [[:Category:Upper stem diameter|upper stem diameter]]. Befor ...to adjust to changing ''dbh''-height relationships as they occur in medium size<br>forest inventories such as [[forest enterprise inventories]] or [[forest

...ether they are in or not and that implies usually additional [[Distance to tree|distance]] measurements which are not required for the other trees. ... small plots, again the cost will be much higher; the decision on [[Sample size]] is again a compromise between practical (cost) criteria and statistical (