Superior processing of small diameter hardwood

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2 Introduction The portion of hardwood is increasing in Austria (figure 1 shows the changes in soft- and hardwood stocks within a 10 years trend) annual increase annual decrease Changes in wood distribution in Austria Hectares Softwood Hardwood Figure 1: Changes in wood distribution in Austria Small diameter hardwood is often not supplied nor graded regarding wood quality for any superior wood processing, rather qualified as industrial wood or fuelwood due to its dimensions.

3 Introduction Industrial assortments are generally low priced with varying proportions of probably potential wood relating to total quantity. Raw material out of superior use and high-potential wood provide a kind of technological added value overlapping area. Guidelines for grading the logs and the timber of small diameter hardwood, together with recommendations for its use should be developed. Various conventional mechanical tests should show the potentials and encourage the use of common used hardwood thinnings native in Central Europe. Process and value chains are investigated to show possible alternatives for processing small diameter hardwood.

4 Work areas

5 Siviculture Management concepts for high value hardwood timber Determination of potential amounts of SDH from broadleaved and mixed forests based on regional forest inventory data Sample plots: diameter distribution, quality classification Management concepts for broadleaved and mixed forests in the context of SDH: regeneration, tending, thinning Recommendations for multi-functional use of broadleaved and mixed forests and high-value SDH Mittendurchmesser mit Rinde (cm) Mittendurchmesserverteilung (cm) Ahorn Eiche Esche Rotbuche Anzahl der Bloche

6 Processing und products 122 trees were harvested for the project Harvesting time was winter and the logs had been cut in May One log from each tree was taken for further investigation In general the bottom log was chosen, but 21 trunks had to be trimmed due to root collars, warping, cracks,... The grading of the round wood and the sawn timber was carried out following the grading rules of OEHHU, except of the grading criteria diameter laufende Nummer Baumart Betriebsnummer Versuchsflächennummer Baumnummer Baumartennummer Mittendurchmesser (cm) mr Blochlänge (m) vom Fällschnitt entfernt Ahorn 20 3,0 1, Ahorn 26 2,5 1, Ahorn 16 3,0 1, Rotbuche 32 3,0 2, Rotbuche 21 3,0 1, Rotbuche 26 3,0 1, Rotbuche 29 3,0 2, Rotbuche 22 2,5 kein Erdstamm Rotbuche 24 3,0 3,0 kein Erdstamm Rotbuche 27 3,0 0, Rotbuche 31 3,0 1, Rotbuche 31 2,5 3,0 kein Erdstamm Rotbuche 30 2,5 1, Rotbuche 28 3,0 1, Eiche 30 3,0 1, Eiche 30 2,5 1, Eiche 28 2,5 1, Eiche 24 3,0 1, Esche 18 3,0 0, Esche 19 3,0 0, Esche 18 2,5 0,5

7 Grading of round wood Grading classes A, B, C Distribution of grading classes (A, B, C) Number of logs maple oak ash beech 17 A B C Wood species

8 Grading of round wood Diameter classes versus grading classes diameter versus grading class Number of logs A B C b 2a 2b 3a

9 Grading of sawn timber The through and through sawing of the logs was carried out at the sawmill Frey-Amon, Hetzmannsdorf, Lower Austria using a band-saw. Being cut, the boards were marked and stacked for kiln drying. The marking of the samples was carried out as shown in figure 2. The dried boards were graded as one piece without partitioning them into sections (figure 3). The medium face width and the length due to end cracks were determined and the resulting board was graded.

10 Grading of sawn timber Grading classes I, II, III; x = rejections Distribution of grading classes (I, II, III, x) Numbers of boards Maple Oak Ash Beech I II III x Wood species

11 Grading of sawn timber Grading classes I, II, III; x = rejections Distribution of grading classes (I, II, III, x) Numbers of boards Maple class B grading classes of boards 63due to their 48 position within the log 100% % % 70% % % 40% % Maple Oak Ash Beech 20% 10% Wood species 0% a b c d e f g I II III x x

12 Superior processing Oakof class B small grading classes diameter of boards due hardwood to their Grading of sawn timber Grading classes I, II, III; x = rejections Numbers of boards Distribution of grading classes (I, II, III, x) % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% position within the log a b c d e f g Maple Oak Ash Beech Wood species x I II III x

13 Yield The total cut of 20.5 fm of wood resulted in 10.6 m³ of kiln dried and sawn timber in different qualities which equates a yield of app. 52 %. The average yield for the hardwood industry is app. 55 to 60 %. The yield of maple was 67 %, of ash about 52 %, of beech about 45 % and of oak about 41 %. The low yield of beech and oak are due to red heartwood in beech and the high portion of sapwood of oak. yield of kiln dried timber [m³] volume sawn timber [m³] maple oak ash beech overall 4,210 2,163 1,795 2,460 10,63 volume round wood [fm] maple oak ash beech overall 6,26 5,30 3,453 5,51 20,52 yield [%] maple oak ash beech average 67,28 40,84 51,99 44,66 51,81

14 Costs The medium diameter of the logs was 26 cm. The medium diameter in the hardwood industry is around 40 cm. The smaller diameter results in higher processing costs for small diameter hardwood using the same sawing technology. The major costs result from overall longer loading times, as the set up is generally independent from log diameter. Reducing costs calls for higher processing speed or alternative processing technologies like chipper or circular saws or alternative value process chains. Kosten Schnittholz EUR/m³ Rundholz Klasse B Rundholz Klasse C Eiche Rotbuche Eiche Rotbuche (Ahorn, Esche) Rundholzpreise [ /fm] Einschnittkosten [ /fm] Trocknungskosten [ /m³] Schnittholzkosten [ /m³] Rundholzpreise proholz Sterimark, 1.Q.2008

15 Value process chains Definition of small-diameter hardwood value chains for Lower Austria Process description, material flow from inventory data Sustainability Impact Assessment (SIA) of regionalized value chains Economic, social, environmental sustainability indicators Comparative SIA of alternative value chains (baseline: energetic use vs. material use of SDH) Analysis of regional resource conflicts arising from diversified use of SDH Lindner et al., 2008

16 Regional value process chain for Lower Austria FM broadleaved and mixed forests Thinning Remaining stand Forwarding/sorting Truck transport Mobile cutting Holzhof Saw mill/saw chain Drying Storage SDH assortment Standard assortment Oak: parquet/long strip planks Beech: solid chairs Maple: solid tables Ash: interior doors

17 Drying Experiments Fagus sylvatica L. Fraxinus excelsior L. Quercus spp. Acer pseudoplatanus L. Drying schedule con.* acc.* con.* acc.* con.* acc.* con.* acc.* Drying time [d,h,min] 35d 19h 58min 15d 08h 44min 30d 03h 55min 16d 04h 30min 72d 13h 54min 29d 10h 36min 27d 17h 06min 11d 14h 19min Temperature range [ C] Equilibrium Moisture Content [%] Air velocity during drying [m/s] > 2 > 2 > 2 > 2 > 2 > 2 > 2 > 2 *con. [conservative drying schedule] *acc. [accelerated drying schedule] 17

18 Results Medium 3-point-bending strength: bending strength [N/mm²] species beech ash maple oak beech [Kollmann 1982] ash [Kollmann 1982] maple [Kollmann 1982] oak [Kollmann 1982] drying conservative accelerated Beech: N/mm² Kollmann: N/mm² Ash: N/mm² Kollmann: N/mm² Maple: N/mm² Kollmann: N/mm² Oak: N/mm² Kollmann: N/mm² Medium modulus of elasticity in 3-point-bending: modulus of elasticity [N/mm²] Encircled values according to Kollmann 1982 Beech: N/mm² Kollmann: N/mm² Ash: 15341,31 N/mm² Kollmann: N/mm² Maple: N/mm² Kollmann: N/mm² Oak: N/mm² Kollmann: N/mm² 18

19 19 Results Medium compression strength parallel to the grain: Beech: N/mm² Kollmann: N/mm² Ash: N/mm² Kollmann: N/mm² Maple: N/mm² Kollmann: N/mm² Oak: N/mm² Kollmann: N/mm² Medium compression strength perpendicular to the grain: Beech: N/mm² Kollmann: 9.32 N/mm² Ash: N/mm² Kollmann: N/mm² Maple: N/mm² Kollmann: - Oak: N/mm² Kollmann: N/mm² beech ash maple oak beech [Kollmann 1982] ash [Kollmann 1982] oak [Kollmann 1982] species conservative accelerated drying compression strength normal [N/mm²] compression strength parallel [N/mm²] Encircled values according to Kollmann 1982

20 20 Results Medium Brinell hardness depending on wood density: Beech: N/mm² Kollmann: N/mm² Ash: N/mm² Kollmann: - Maple: N/mm² Kollmann: N/mm² Oak: N/mm² Kollmann: N/mm² Medium wood density [ovendry]: Beech: kg/m³ Kollmann: kg/m³ Ash: kg/m³ Kollmann: kg/m³ Maple: kg/m³ Kollmann: kg/m³ Oak: kg/m³ Kollmann: kg/m³ beech ash maple oak beech [Kollmann 1982] maple [Kollmann 1982] oak [Kollmann 1982] species conservative accelerated drying density [kg/m³] Brinell hardness [N/mm²] Encircled values according to Kollmann 1982

21 Process and products Reconsidering production systeme.ch/html/produkte/tisch+bank/massiflex.html

22 Superior processing of small diameter hardwood New products

23 Process and products Rethinking material use in construction work with short ends

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25 Process and products - Use hardwood for building constructions System developed by bernath+widmer architects together with Hermann Blumer, Michael Koller, Bergauer Holzbau GmbH, Heidi Bührer.

26 Project Partner: Wood K plus - Competence Center of Wood Composites and Wood Chemistry DendroLight Holzwerkstoffe GmbH Institute of Silviculture, University of Natural Resources and Applied Life Science Institute of Wood Science and Technology Fachverband der Holzindustrie Österreichs Österreichische Bundesforste AG timberfreaks Holztechnik GmbH Holzwerbefonds der NÖ Landwirtschaftskammer, Forstabteilung Forstverwaltung Grafenegg Forstbetrieb Stift Klosterneuburg Funded by:

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