Original scientific paper
Structure Comparison of Technical Roundwood in Even-Aged Beech Cutblocks by Assortment Tables with Application of Standards HRN (1995) and HRN EN 1316-1:1999
Marinko Prka
orcid.org/0000-0001-8869-1835
; Hrvatske šume Direkcija Zagreb
Tomislav Poršinsky
; Šumarski fakultet Sveučilišta u Zagrebu
Abstract
This paper deals with research and comparison of technical roundwood structure in assortment tables compiled in accordance with the requirements of the Croatian standards for forest harvesting products of 1995 and the Croatian Standard Hardwood round wood - Qualitative classification - Part 1: Oak and Beech HRN EN 1316-1:1999. The research was carried out in the Management Unit "Bjelovarska Bilogora", Forest Office Bjelovar, Forest Administration Bjelovar. All investigated compartments pertain to ecological management type II-D-11 and management class BEECH with a 100-year rotation. The age of the investigated cutblocks ranged between 59 and 91 with thinning, between 94 and 110 with preparatory cut, between 100 and 112 with seed cut and between 98 and 114 with final cut. The group of sample trees was formed by random selection of approximately 10% of marked trees. The sample for compiling assortment tables in accordance with the requirements of the Croatian standards for forest harvesting products of 1995 involved 3001 sample trees (table 1), and assortment tables were compiled in accordance with the requirements of the Croatian standard HRN EN 1316-1:1999 based on 3082 sample trees (table 2). Share tables of wood assortments determined in accordance with these two standards were developed, for various reasons, separately for thinnings and preparatory felling, and separately for seeding and final felling. By processing sample trees in accordance with the requirements of the Croatian Standards for Forest Harvesting Products of 1995, 10,098 pieces of technical roundwood were obtained, whose total volume was 4,337 m3 (without bark). In accordance with the requirements of this Standard, total processed and classified net volume of all sample trees was 7,469 m3. By bucking sample trees in accordance with the requirements of the Croatian Standard Hardwood round wood - Qualitative classification - Part 1: Oak and Beech HRN EN 1316-1:1999, 13,507 pieces of technical roundwood were obtained, whose total volume was 6,010 m3 (without bark), and in accordance with the requirements of this Standard, the net volume of all sample trees was 8,931 m3. Due to substantial differences, structural comparison of technical roundwood classified in accordance with the requirements of these two standards is more simple and adequate for wood assortments of the best quality, veneer logs - A quality class (Fig. 1) and assortments of the lowest quality class, 3rd class sawlogs - D quality class (Fig. 4). The comparison is much more difficult with other quality classes of technical roundwood, logs for rotary cutting - 1st quality class sawlogs - B quality class (Fig. 2), 2nd class sawlogs - C quality class (Fig. 3), due to even more significant differences between standard requirements with respect to dimensions, range of timber defects, and number of quality classes. Differences between the Croatian standards for forest harvesting products (1995), still applied in Croatian forestry and international standards Hardwood round wood - Qualitative classification - Part 1: Oak and Beech EN 1316-1:1999 are numerous and significant. Differences are related to the number of quality class, prescribed minimum dimensions, range of roundwood defects along with way of measurement of technical roundwood and they reflect to different share of wood assortments (quality classes) determined in accordance with the requirements of individual standards. However, the key difference between these two standards lies in the fact that according to the "old" Croatian standards technical roundwood was classified by purpose, and according to the "new" Croatian standards technical roundwood is classified by quality, therefore avoiding to define its future purpose. Consequently, the comparison of percentage shares of wood assortments in the assortment tables is difficult, and defining unambiguous conclusions (except for assortments of technical roundwood of the highest and lowest quality) is questionable. Differences in contents between international standards and standards currently in use in Croatian forestry shall necessarily bring operational changes in bucking, scaling, classifying and marketing of forest products. Operational changes (partly conditioned by the acceptance of international laws and regulations) shall also be accompanied by certain changes in relationships within the forestry sector.
Keywords
assortment tables; Croatian standards of forest harvesting products 1995; Croatian Standard HRN EN 1316-1:1999; even-aged beech stands
Hrčak ID:
34236
URI
Publication date:
28.2.2009.
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