Finland Erkki Verkasalo 1 , Harri Kilpelinen 1 , Antti Ihalainen 2 , - - PowerPoint PPT Presentation

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

HARTOLA SAARIJÄRVI

Cultivated abandoned field, high soil fertility, best trees pruned, age 56 years Regenerated forest site, medium soil fertility, age 70 yrs

Examples of first final fellings

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 10th 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

Blue = natural Reddish = planted Note! The following colours denote the types of regeneration in the following graphs

Kuusivaltaisten metsien pinta-ala (km2)

Viljely Luontainen

Commercial forest land area of and growign stock volume

• f Norway spuce dominated stands by development class

and type of regeneration - All Finland

50 100 150 200 250 300 350

Luontainen Viljely

Kuusivaltaistenmetsien tilavuudet (milj. m3)

DBH distributions of Norway spruce sample trees by type of regeneration

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

All Finland South and North

Technical defects in Norway spruce trees of saw log size by dbh class and type of regeneration

South Finland

Natural Planted No defects 75,3 75,6 Excessive knottiness, sound knots 0,9 0,3 Dead, decayed or spike knots 2,2 1,8 Crookedness 15,6 15,1 Sweepness 2,6 2,6 Forks 0,6 0,4 Stem decay 1,1 1,5 Stem wound or crack 1,5 2,3 Other defect or damage 0,3 0,4

North Finland

Natural Planted No defects 55,3 18,2 Excessive knottiness, sound knots 1,2 0,0 Dead, decayed or spike knots 0,8 0,0 Crookedness 25,9 81,8 Sweepness 7,8 0,0 Forks 2,0 0,0 Stem decay 3,3 0,0 Stem wound or crack 3,1 0,0 Other defect or damage 0,6 0,0

Total percentage of defected trees

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

14 14

Variable Dbh class, cm 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 defect-free trees 67 72 74 75 77 76 77 74 74 76 Saw and plywood log % 1 2 28 34 49 57 59 69 71 80 Total log % 62 61 52 59 58 66 65 76 73 82 Saw and plywood log reduction % 86 78 46 35 34 25 30 19 22 13 Total log reduction % 4 7 38 29 34 25 28 18 21 13

Summary of tree characteristics of planted and naturally regenerated Norway spruce by breast height diameter class (dbh class).

SAWN TIMBER FROM PLANTATION-GROWN NORWAY SPRUCE - APPEARANCE

Centre yield 44 * 215

Resin leaks Small cracks from knots Looks good for knottiness and grain texture Larger ring width (here 7 mm) Juvenile wood Warping (twist)

Live-sawn boards 30 mm

• left: unpruned
• right: pruned

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 regeneration Number of stands and trees Tree age, years Tree height, m Dbh, cm (over bark) Stem volume, dm3 (over bark) Planted 14 / 70 63 23.4 26.3 673 Naturally Regenerated 20/ 100 93 23.2 27.6 704

• 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

Value calculations

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, m3 (over bark)

47.1 70.4 Sawn timber, m3

• Center yield, %
• Side and surface boards, %

22.9 87.2 12.8 33.5 87.8 12.2 Sawn timber yield, % ‒ Log consumption, m3 / m3 54.4 ‒ 1.84 52.8 ‒ 1.90 Knottiness distribution of sawn timber, %

• Center yield: sound knotted ‒ dry knotted
• Boards: sound knotted ‒ dry knotted
• All: sound knotted ‒ dry knotted

44.6 ‒ 42.7 1.8 ‒ 10.9 46.4 ‒ 53.6 38.7 ‒ 49.1 1.3 ‒ 10.9 40.0 ‒ 60.0 Nordic timber grade distribution of sawn timber, %

• A
• B
• C
• D

54.4 31.6 10.3 3,7 51.2 36.3 9.2 3.2 Net value of sawn timber, €/m3

• Value per sawn timber volume
• Value per log volume (over bark)

154.60 84.10 155.70 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/m3

• Butt logs
• Upper logs

358.1 (39.8) 357.8 (34.3) 380.4 (40.2) 379.1 (33.3) Ring width, mm

• Butt logs
• Upper logs

3.1 (0.9) 3.3 (0.9) 2.1 (0.7) 2.5 (0.8) Compression wood content, %

• Butt logs
• Upper logs

7.6 (6.6) 5.6 (5.8) 8.3 (6.4) 5.9 (5.7) Heartwood content, %

• Butt logs
• Upper logs

41.8 (9.0) 31.6 (11.1) 41.6 (10.8) 34.7 (10.0) Thickness of sapwood, mm

• Butt logs
• Upper logs

85.0 (30.3) 81.9 (20.8) 85.5 (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

• n 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

• n the product qualities is not possible.

4) Planted forests may provide 20% to 30% of saw and plywood logs of spruce already in 2020’s, if we count roundwood potential from final cuttings and advanced thinnings together. 5) Planted spruce forests generally provide a lower log percentage at a given stage of diameter than naturally regenerated forests, albeit the smaller difference in the observed occurrence of technical defects. The younger generations of planted spruce show a better potential in this respect. 6) Logs from first-generation plantations of spruce seem to provide at least as high a yield of sawn timber as the logs that saw mills are used to process. High yield of sound-knotted timber especially in centre yield seems also a clear advantage, but the range of variation in the appearance quality is larger. 7) In all, the net value of sawn timber from plantation logs was higher per log unit volume but slightly smaller per sawn timber unit volume.

8) The lower density of planted spruce, along with larger ring width, indicated lower mechanical properties, less dimension stability and more warp for wood products. This sawn timber is eventually stress graded to lower grades of structural sawn timber or glue-laminated timber than the current spruce timber from Finland. The problems concern also plywood and LVL, maybe not so much CLT. 9) The material of this study showed a ring width of 3-4 mm only, however, typical values of 5-8 mm were observed recently in the spruce forests planted during 1970’s or later. This probably leads to a larger decrease in the density, strength and stiffness in the future. Low density may be considered valuable in new building materials where light weight or good thermal insulation properties are aimed. 10) Technical problems in wood drying, machining and end-uses due to compression wood may become smaller when using planted

• spruce. Similar heartwood/sapwood relationship may also indicate

as good stability and moisture resistance as in natural spruce.

FINALLY

• It is a strategic issue for the wood product industries to position

their products into the future market segments and implement new technology, innovation and marketing strategies, matching the available raw material with the product palette.

• There is a need to identify and develop technically appropriate

and cost-competitive products from the raw materials like planted spruce

• There is a need to develop the sorting of spruce timber for both

appearance products and structural products to match the customer requirements, develop pricing of spruce logs according to processing value and improve planning and control

• f log procurement to appropriate uses.
• Wood machining, drying, gluing, treatments and other further

processing technologies need to match to the raw material, as well.

Thank you so much!

Authors