Wood Processing Properties of Plantation- Grown Norway Spruce for Saw Milling in Finland Erkki Verkasalo 1 , Harri Kilpeläinen 1 , Antti Ihalainen 2 , Tuomas Ropponen 2 METLA Finnish Forest Research Institute 1 Metsä Group, Finland 2
http://www.metla.fi/ohjelma/mat/index-en.htm
Wood Materials and Products in the Development of Bioeconomy Thematic structure
MOTIVATION FOR PLANTATION WOOD RESEARCH 1) Wood from planted, in some cases directly sown forests is the solution for increasing wood demand in Europe => Intensive forest management toward larger crops per hectare and shorter rotations is increasingly raising the head - also in boreal regions . 2) Growing biomass seems to be the primary goal in wood production, whereas increasing building and living with wood should suggest more attention to larger-dimensioned, high-quality logs for value adding wood product industries 3) Raw material qualities and their variations are different in cultivated vs. naturally regenerated forests * which end product strategies and development needs in processing technology do the key properties suggest * how the key properties could be upgraded * what is the overall profitability for primary and further wood product industries when using this wood
NORWAY SPRUCE PLANTATIONS IN FINLAND Examples of first final fellings HARTOLA Cultivated abandoned field, high soil fertility, best trees SAARIJÄRVI pruned, age 56 years Regenerated forest site, medium soil fertility, age 70 yrs Photos: Metla/ Erkki Verkasalo
FOREST INVENTORY STUDY METLA (Finland) completed a research project - to map the areas, volumes and tree dimensions of the cultivated forests vs. naturally regenerated forests - by dominant species, geographic region, development class and forest site - based on the data of 10 th Finnish National Forest Inventory (VMI 10) For sample tree data of Norway spruce ( Picea abies ) (and Scots pine ( Pinus sylvestris )) - dimensional measures and factors of the external quality, by dbh class - potential recovery of the most important roundwood assortments and pulpwood , which mirrors the tree quality, using the measured data and bucking-to-value simulation
Note! The following colours denote the types of regeneration in the following graphs Blue = natural Reddish = planted
Commercial forest land area of and growign stock volume of Norway spuce dominated stands by development class and type of regeneration - All Finland Kuusivaltaisten metsien pinta-ala (km 2 ) Kuusivaltaistenmetsien tilavuudet (milj. m 3 ) 16000 350 14000 300 Viljely Luontainen Luontainen 12000 Viljely 250 10000 200 8000 150 6000 100 4000 50 2000 Metla / VMI10 Metla / VMI10 0 0 Pieni taimikko Varttunut Nuori Varttunut Uudistuskypsä Suojus- tai Pieni taimikko Varttunut Nuori Varttunut Uudistuskypsä Suojus- tai taimikko kasvatusmetsä kasvatusmetsä siemenpuusto taimikko kasvatusmetsä kasvatusmetsä siemenpuusto
DBH distributions of Norway spruce sample trees by type of regeneration All Finland South and North Syntytapa Lpmluokka E-Suomi P-Suomi Luontainen <10 1859 611 10-14 1440 520 14-18 1615 515 18-22 1723 437 22-26 1610 313 26-30 1477 214 >30 2447 198 Kaikki 12171 2808 Viljely <10 227 29 10-14 263 9 14-18 320 4 18-22 340 7 22-26 251 2 26-30 120 2 >30 97 1 Kaikki 1618 54
Technical defects in Norway spruce trees of saw log size by dbh class and type of regeneration Total percentage of defected trees South Finland Natural Planted 35 No defects 75,3 75,6 Luontainen Excessive knottiness, sound knots 0,9 0,3 30 Viljely Dead, decayed or spike knots 2,2 1,8 25 Crookedness 15,6 15,1 Sweepness 2,6 2,6 20 Forks 0,6 0,4 15 Stem decay 1,1 1,5 Stem wound or crack 1,5 2,3 10 Other defect or damage 0,3 0,4 5 0 14-18 18-22 22-26 26-30 >30 Kaikki North Finland 100 Natural Planted Luontainen Viljely No defects 55,3 18,2 80 Excessive knottiness, sound knots 1,2 0,0 Dead, decayed or spike knots 0,8 0,0 60 Crookedness 25,9 81,8 Sweepness 7,8 0,0 40 Forks 2,0 0,0 Stem decay 3,3 0,0 20 Stem wound or crack 3,1 0,0 Other defect or damage 0,6 0,0 0 18-22 22-26 26-30 >30 Kaikki
Stem quality class distributions of Norway spruce trees by dbh class and type of regeneration South Finland North Finland LEGEND (starting from the bottom): smal tree (unmerchantable), waste wood, good pulpwood (small-diameter log quality), normal pulpwood, defected pulpwood, prime butt log, normal butt log, secondary butt log, defected butt log, reject saw log (pulpwood)
Timber assortment distribution of Norway spruce trees by dbh class and type of regeneration Southern and Central Finland
Summary of tree characteristics of planted and naturally regenerated Norway spruce by breast height diameter class (dbh class). Dbh class, cm Variable 14-18 18-22 22-26 26-30 30+ Pl. Nat. Pl. Nat. Pl. Nat. Pl. Nat. Plan. Nat. Age, years 36 63 40 72 43 77 47 83 54 90 Percentage of 67 72 74 75 77 76 77 74 74 76 defect-free trees Saw and plywood 1 2 28 34 49 57 59 69 71 80 log % Total log % 62 61 52 59 58 66 65 76 73 82 Saw and plywood 86 78 46 35 34 25 30 19 22 13 log reduction % Total log reduction % 4 7 38 29 34 25 28 18 21 13 14 14
SAWN TIMBER FROM PLANTATION-GROWN NORWAY SPRUCE - APPEARANCE Centre yield 44 * 215 Looks good for knottiness and grain texture Live-sawn boards 30 mm left: unpruned - right: pruned - Resin leaks Small cracks from knots Larger ring width (here 7 mm) Juvenile wood Warping (twist) Photos: Metla/ Erkki Verkasalo
SAW MILLING STUDY We compared in a master’s thesis study - basic density, ring width, compression wood content and heartwood content in the logs from planted and naturally regenerated trees, and - the simulated yield and value of sawn timber according to the Nordic cant sawing procedure and NT grading. We studied the sources of variation in the value of logs by linear mixed modelling and in the sawn timber yield, ring width and basic density by analysis of covariance (ANCOVA).
Empirical data – experimental stands and sample trees Type of Number of Tree age, Tree height, Dbh, cm Stem volume, dm 3 stands and years m (over bark) regeneration trees (over bark) Planted 14 / 70 63 23.4 26.3 673 Naturally Regenerated 20/ 100 93 23.2 27.6 704 Value calculations • Average unit prices of the products and production costs of four Finnish spruce sawmills during 2006-2008 (Ropponen 2010) • Sawn goods prices: EXW prices of export dried (14-18% MC) whitewood sawn timber and saw mill chips, saw dust and bark according to the prevailed domestic market prices
Sawn timber yield, grade distributions and net value for the entire lots of planted and naturally regenerated Norway spruce. Both conventional and small-diameter logs are considered. Variable Planted Naturally regenerated Conventional and small-diameter logs, m 3 (over bark) 47.1 70.4 Sawn timber, m 3 22.9 33.5 - Center yield, % 87.2 87.8 - Side and surface boards, % 12.8 12.2 Sawn timber yield, % ‒ Log consumption, 54.4 ‒ 1.84 52.8 ‒ 1.90 m 3 / m 3 Knottiness distribution of sawn timber, % - Center yield: sound knotted ‒ dry knotted 44.6 ‒ 42.7 3 8.7 ‒ 49.1 - Boards: sound knotted ‒ dry knotted 1.8 ‒ 10.9 1.3 ‒ 10.9 - All: sound knotted ‒ dry knotted 46.4 ‒ 53.6 40.0 ‒ 60.0 Nordic timber grade distribution of sawn timber, % 54.4 51.2 - A 31.6 36.3 - B 10.3 9.2 - C 3,7 3.2 - D Net value of sawn timber , €/m 3 - Value per sawn timber volume 154.60 155.70 - Value per log volume (over bark) 84.10 82.20
Wood properties in the butt logs and upper logs of planted and naturally regenerated Norway spruce: means (standard deviations). Variable Planted Naturally regenerated Basic density, kg/m 3 - Butt logs 358.1 (39.8) 380.4 (40.2) - Upper logs 357.8 (34.3) 379.1 (33.3) Ring width, mm - Butt logs 3.1 (0.9) 2.1 (0.7) - Upper logs 3.3 (0.9) 2.5 (0.8) Compression wood content, % - Butt logs 7.6 (6.6) 8.3 (6.4) - Upper logs 5.6 (5.8) 5.9 (5.7) Heartwood content, % - Butt logs 41.8 (9.0) 41.6 (10.8) - Upper logs 31.6 (11.1) 34.7 (10.0) Thickness of sapwood, mm - Butt logs 85.0 (30.3) 85.5 (20.8) - Upper logs 81.9 (20.8) 75.4 (17.9)
CONCLUSIONS 1) The VMI approach provides useful overall information on the current and 10- 30 years’ timber supply and the location of timber resources, considering the dimensions and (external) quality as well as the roundwood product strategies. 2) Combining measurements of large empirical data and simulation of tree bucking (with the value optimisation) is an efficient method for product-oriented analysis of forest resources. 3) However: 1) generalisation of results suffers from small data on large-dimensioned (=older) trees from cultivated stands; 2) relationships of product quality/internal wood quality vs. external wood quality are obviously different in naturally regenerated and cultivated timber stands, hence conclusions on the product qualities is not possible.
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