DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 7-8/2006 str. 38 <-- 38 --> PDF |
M. Prka: ZNAČAJKE DOZNAČENIH BUKOVIH STABALA PO VRSTI SIJEKA U SJEĆINAMA ... SUMMARY: The subject of research were absolute and percentage share of assigned trees according to diameter class and type of felling and their influence on assortment structure of particular types offelling. The assigned exemplary trees were categorized according to the most prominent outward features into nine categories. The research was carried out on the total number of 36 areas of the economic unit Bjelovarska Bilogora. In the seeding felling areas data were collected on several occasions (felling). In that way, 2,308 assigned trees were categorized in the total of 46 occasions (felling). All the areas belong to ecological-economical type II-D-11 and structural class BEECH with the rotation of 100 years. The aim of the process was gaining more insight into the factors that influence assortment structure of stands, as well as completing the information on principles and ways of forest management in the past and nowadays. Analysis of the number of trees of particular categories according to the type of felling (stand age) and diameter class was carried out with the aim of finding the answers to questions pertaining to the criteria of assignment of one type offelling, as well as the degree of damage to stands during the exploiting of forest in the area subject to research. The assigned trees of group A (undamaged trees of normal growth) have, on the whole, extremely positive influence on assortment structure of particular type offelling. To these we can, to a certain extent, join pregrowth trees, i.e. group G, whose influence is limited mostly to thinningfelling. Trees of all the other described groups have more or less negative effect on assortment structure of particular type of felling. The influence of suppressed trees (group H) on assortment structure is insignificant, and their importance for successful carrying out of seedingfelling is considerable. Thepercentage of trees with positive influence on assortment structure according to the type offelling, stands about 50 % in thinning and preparatory felling, while in seeding andfinal felling it is about 60 %. Trees of medium diameter and large diameter, i.e. trees of diameter class between 41 cm and 60 cm, and those with breast diameter over 61 cm, have the greatest influence on the whole of tree assortment structure or particular types of felling. The reasonfor that is thefact that only those trees can potentially contain timber assortment of the highest quality (according to Croatian Standards of Forest Exploitation Productsfrom 1995) because of the minimal dimensions prescribed for timber assortments of the highest quality. Percentage of those trees with positive and negative influence on assortment structure is almost identical in case of thinning andpreparatory felling, while in case of seeding andfinalfelling the share of trees with positive effect is considerably higher than the percentage of trees with negative effect on assortment structure. It can be said that the percentage of trees with breast diameter larger than 41 cm, with the positive effect on assortment structure grows from 5.7 % in thinningfelling to 57.5 % infinalfelling. If wefocus on the relation (difference) between the trees with breast diameter larger than 41 cm, with positive and negative effect on assortment structure, we can easily say that this value rangesfrom -2.9 % in thinningfelling to 22.9 % in final felling. Trees damaged as a result of our activities, or human influence, are contained within groups with description marks of C, D, E and I. The percentage of trees damaged by human activity increases from thinning felling to final felling. For thinning felling, this percentage amounts to 11.2 %, for preparatory felling it is 13.1 %, for seeding felling it is 15.8 %, while for final felling it amount % damage The increase in participation of trees ts ss t tto oo 23. 23.23.3 33 o oof ff da aged dd trees treestrees. .. T it damaged in nn tha thathat wa waway yy toward towardtowards ss th ththe ee en enend dd o oof ff rotation can be attributed to intensi Šumarski list br. 7-8, CXXX (2006), 319-329 |