Istraživanjem se nastojao izna}i prijedlog za poboljšanje postojećih modela procjene drvnih sortimenata koje koristi šumarska operativa. Poticaj istraživanju te tematike bili su česti navodi iz šumarske operative o neslaganju planskih vrijednosti sortimenata sa vrijednostima sortimenata ostvarenim u proizvodnom
procesu (po kolićini i kvalitetnoj strukturi). U radu su istraženi međuodnosi planiranih količina drvnih sortimenata (po Hs-PPI programu) i procijenjenog obujma sortimenata od strane procjenitelja [umarskog instituta, Jastrebarsko te od
strane šumarijskih djelatnika, na uzorcima s pet istraživanih lokaliteta. Istraživanim lokalitetima zahvaćene su četiri šumske zajednice, tri različita ekološko-gospodarska
tipa šuma u V. dobnom razredu. U proredama na svih pet lokaliteta
kori{tena je sortimentna metoda pri sječi i izradi drva.
Temeljem rezultata koji ukazuju na zna~ajne korelacije izme|u obujma pojedinih sortimentnih klasa oblikovani su uvjeti za isklju~ivanje "nepravih nula" iz podataka uzorka prije regresijske analize obujma sortimentnih klasa. Analizom
varijance triju varijabli "lokalitet", "način procjene" i "interakcija lokalitet način procjene", ustanovljeno je kako je "lokalitet" najutjecajnija varijabla na varijabilnost obujma sortimentnih klasa.
Od ispitivanih matematičkih modela, model naziva "VD1" najpouzdanije opisuje razvoj obujma različitih sortimentnih klasa po debljinskim stupnjevima. Temeljem rezultata istraživanja, predlo`ena su pobolj{anja postoje}ih modela procjene
drvnih sortimenata u primjeni, u vidu novih koeficijenata modela. Za preciznije i pouzdanije rezultate procjene obujma sortimenata na razini lokaliteta (sastojina/grupa stabala) nu`na su dodatna istraživanja.The paper presents a way to determine a proposal for improving existing models for
evaluation of timber assortments, which are used by forestry operative units. The incentive
for the investigation of this theme were the frequent reports from forestry operative units on
inconsistency of the planned values of assortments with the values of assortments realised
in the process of production (according to the amount and quality of the assortment structure).
The paper examines the mutual relations of the planned amounts of timber assortments
(according to Hs-PPI programme) and the estimated volume of assortments on the
part of the estimator from Forest Research Institute, and the forestry employees, on samples
from five investigated localities. The localities investigated covered four forestry communities,
three different ecological-managerial forest types (EMFT) and 5 age class. In thinnings
on all five localities an assortment method during logging was utilised.
On the basis of the obtained results which indicate significant correlations between the
volume of certain assortment classes, conditions were formed for exclusion of "unreal zeros"
from the sample data prior to regression analyses of the volume of assortment classes. By
analysis of variance of three variables "locality", "method of evaluation" and "interaction locality
* method of evaluation" it was established that "locality" is the most influential variable
on the variability of the volume of assortment classes.
Of the tested mathematical models, model called "VD1" (VONDRA 1991) most reliably
described the development of the volume of different assortment classes. On the basis
of the results of the research, improvements in the existing models of evaluation of timber
assortments were proposed, with regard to new model coefficients. Additional more investigations
are necessary for more precise and reliable results of evaluation of the volume of assortments
at the level of locality (stand/group of trees)
