DIGITALNA ARHIVA ŠUMARSKOG LISTA
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|ŠUMARSKI LIST 1-2/1966 str. 96 <-- 96 --> PDF|
Thus it will be possible to utilize in practice the results of the experiment
without depending on the preservation of the original stands from which the
seeds have been collected.
The 7 X 7 m. or 6 X 6 m. arragement spacings will permit the delimitation
of a surround in case the neighbour effect is severe. For the first period of
the experiment until the trees come into crown contact with each other and a
cleaning is necessary, it will be possible to eliminate from the analysis of data
either one or for pine species even two rows of surround trees, leaving at least
9 trees as the plot proper.
During the ticket stage (15—20 years) there will be about 1/2 of the
original number of trees per plot, as a result of the removal at the cleanings.
The border trees in a plot could still be considered as an isolation strip, leaving
at least 8 trees inside the plot, to be treated as the plot proper. At later stages
of the experiment it will be necessary to consider the whole plots, and it will
not be possible to eliminate the neighbour effect.
From the above discussion it will be seen that by basing the experiment
on minimal conditions it will be possible to satisfy all requirements specified
for provenance experiments at the beginning of this paper. Minimization of
the conditions is not a popular practice with biological research workers, but
it is the only way in which all requirements can be fulfilled.
A lay-out for provenance experiments is proposed, which will comprise
49 pine trees and 36 spruce trees per plot, i.e. 8 replicates within a complete
The plots will be rectangular for pine (4,20 X 8,40 m.) with the trees
planted at 0,60 X 1,20 m. spacing, and square for spruce (6X 6 m.) at 1 X 1
m. spacing, both cultivated according to the standard practices for Central
This type of lay-out will make possible:
1) treatment of marginal trees as a surround for 15—20 years;
2) measurement of productivity per unit area at an age of 33—40 years;
3) establishment of a seed orchard from 40 clones per provenance at an
age of 40—50 years, thus preserving the genetically valuable populations;
4) maintainance of at least one tree per plot until rotation age, to permit
the establishment of juvenile-mature correlations;
5) inclusion of about 170 provenances in an experimental area of 5 ha.
It is suggested that when the requirements placed before the provenance
experiments are minimized to the extreme limit, they can all be satisfied by the
POKUSI PROVENIJENCIJA I NJIHOVO PRILAGOĐIVANJE NAJEFIKASNIJOJ
SELEKCIJI I OČUVANJU POŽELJNIH ŠUMSKIH POPULACIJA
Predlaže se osnova za postavljanje pokusa s provenijencijama koji će obuhvatiti
49 borovih i 36 smrekovih stabala po pokusnoj plohi, tj. 8 replika (ponovljenja) unutar
plana pokusa po shemi potpunog bloka (grupe).