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ŠUMARSKI LIST 11-12/2009 str. 38     <-- 38 -->        PDF

S.Andrašev, M. Bobinac, S. Orlović: DIAMETER STRUCTURE MODELS OF BLACK POPLAR SELECTED ... Šumarski list br. 11–12, CXXXIII (2009), 589-603

height, represented by standard deviation (sd). Its
change depending on plantation age, with a high value
of the correlation coefficient (R=0.74), points to the
differentiation process of the trees in the plantation.

The parameters of the Weibull diameter structure
model (a,b,c) of the study poplar clones, according to
the analysis of variance F-ratio, decrease till the age of
8, and then they increase.Asimilar F-ratio trend was
shown by the stand quadratic mean diameter (dg) and
total basal area per hectare (G), with the minimal F-
ratio at the age of 12.As the parameters describe the internal
plantation structure, the earlier change in
parameters compared to growth elements indicates the
growth changes in the trees of different categories (diameters),
which enables the adequate evaluation of the
plantation state and future development.

The quantification of similatities and differences in
the location, scale and shape of diameter structure during
the development of the plantations of different clones
contributes to the advanced study of plantation
development and can be applied in the construction of
the growth model of selected clones, and their production

The assessment of the effects of clone and plantation
age on diameter structure enables a more reliable
construction and estimation of the future structure, and
also its incorporation in growth models.

6. CONCLUSIONS – Zaključci

Based on the research of 20-year old test plantation
consisting of several newly selected clones of black poplar,
Section Aigeiros(Duby), which are either registered
or are in the selection procedure, we can conclude
as follows:

– there are significant differences in growth elements
(dg, G) between individual clones in the test plantation
at the end of the study period of 20 years, which
provides the basis for their production differentiation;
– periodical measurements of diameters at breast
height showed different growth of the clones depending
on the age: in the initial period of development,
the clonesPopulus deltoidesBartr. ex Marsh. (S ,


NS , PE 19/66, NS , S ) developed more inten

1-3 11-8 6-36

sively than the clone Pannonia (Populus×euramericana(
Dode) Guinier), and later on Pannonia had a
more intensive growth, while the clones ofP.deltoidesBartr.
ex Marsh. showed the differentiation;

– theWeibull distribution model is suitable for diameter
structure modelling of the study poplar clones at
different plantation ages, and the applied method of
predicting the location parameter (a) of theWeibull
distribution model showed that in 90.6 % of the
study sample, the parameter “a”ranged between 50
and 90%, and in 52.4% “a”ranged from 80 to 90%
of the minimal diameter;

– with higher plantation ages, location parameter (a)
and scale parameter (b) also increased with small
oscillations, which was confirmed by the significance
of the correlation coefficient of 0.71 and 0.73
respectively. This was shown by the shift of the
curve of diameter structure model to the right, towards
larger diameters, and in a wider range of diameters
at breast height with a lower relative
frequency of the modal degree;

in the initial period, F-ratio of all three parameters of
theWeibull diameter structure model decreased and
reached the minimal value at the age of eight, and the
predominantly increasing trend started at the age of
twelve, which points to the changes in diameter
structure of the clones depending on the age;

the constructed models of poplar clone diameter
structure show the clone grouping in two groups,
which was confirmed by the non-parametric Kolmogorov-
Smirnov test, the analysis of variance test, and
LSD test for the percentage of the number of trees
with diameters at breast height above 40 cm. This
emphasises the possibility and the need of their grouping
in the definition of management procedures.

7. REFERENCES – Literatura

Anderson,T.W.,D.A.,Darling,1954: ATest of
goodness-of-fit. Journal of theAmerican StatisticalAssociation,
49: 765–769,Alexandria, USA.

Andrašev,S., S.Rončević, M.Bobinac,2003:
Uticaj gustine sadnje na debljinsku strukturu
klonova crnih topola S 6-7 i M-1 (SekcijaAigeiros
(Duby)). Glasnik Šumarskog fakulteta, 88:
7–16, Beograd.

Andrašev,S., M. Vučković, S.Rončević, M.
Bobinac,2004: Mogućnost modelovanja debljinske
strukture i izračunavanje zapremine za

sada klonova crnih topola. Glasnik Šumarskog

fakulteta 90: 37–51, Beograd.

Andrašev,S., M. Vučković, S.Rončević, M.
Bobinac,2006: Modeli rasta stabala crnih topola
sekcije Aigeiros (Duby). Glasnik Šumarskog
fakulteta 94: 81–90, Beograd.

Andrašev,S., 2008: Razvojno proizvodne karakteristike
selekcionisanih klonova crnih topola (sekcija
Aigeiros Duby) u gornjem i srednjem