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The effect of thinning on wood quality and solid wood product recovery of regrowth forests:
E. Diversicolor from South West Western Australia
PROJECT NUMBER: PN06.3015 MAY 2009
SUSTAINABILITY & RESOURCES
This report can also be viewed on the FWPA website
www.fwpa.com.auFWPA Level 4, 10-16 Queen Street,
Melbourne VIC 3000, AustraliaT +61 (0)3 9614 7544 F +61 (0)3 9614 6822
E [email protected] W www.fwpa.com.au
The effect of thinning on wood quality and solid wood product recovery of regrowth forests: E. Diversicolor from South West Western Australia
Prepared for
Forest & Wood Products Australia
by
R. Washusen, A. Morrow, T. Wardlaw and D. Ngo
Publication: The effect of thinning on wood quality and solid wood product recovery of regrowth forests: E. Diversicolor from South West Western Australia Project No: PN06.3015 © 2008 Forest & Wood Products Australia Limited. All rights reserved. Forest & Wood Products Australia Limited (FWPA) makes no warranties or assurances with respect to this publication including merchantability, fitness for purpose or otherwise. FWPA and all persons associated with it exclude all liability (including liability for negligence) in relation to any opinion, advice or information contained in this publication or for any consequences arising from the use of such opinion, advice or information. This work is copyright and protected under the Copyright Act 1968 (Cth). All material except the FWPA logo may be reproduced in whole or in part, provided that it is not sold or used for commercial benefit and its source (Forest & Wood Products Australia Limited) is acknowledged. Reproduction or copying for other purposes, which is strictly reserved only for the owner or licensee of copyright under the Copyright Act, is prohibited without the prior written consent of Forest & Wood Products Australia Limited. ISBN: 978-1-920883-64-5 Researcher: R. Washusen CSIRO Materials Science & Engineering Private Bag 10 Clayton Vic 3169 Final report received by FWPA in December, 2007
Forest & Wood Products Australia Limited Level 4, 10-16 Queen St, Melbourne, Victoria, 3000 T +61 3 9614 7544 F +61 3 9614 6822 E [email protected] W www.fwpa.com.au
CLIENT REPORT Client Report No: 1821
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EXECUTIVE SUMMARY Objective The objective was to determine if, after the application of conventional processing methods, there were differences in solid wood quality, recovery, board defects and heartwood colour between E. diversicolor logs obtained from thinned and unthinned native forest regrowth.
Key Results The trial, conducted at Auswest Timbers Pemberton, compared one sample of thinned and two samples of unthinned E. diversicolor logs of similar diameter, grade and length. The logs selected were: • Thinned logs were butt-logs obtained from the Warren Block southwest of
Pemberton, WA. This was 1972 regrowth thinned in 1994. • First unthinned sample were butt-logs also obtained from the Warren Block. This was
1974 regrowth adjacent to thinned forest. • Second unthinned sample were primarily butt-logs obtained from the Shannon near
Pemberton. This sample was older (but of undetermined age) than the Warren Block and was selected by Auswest Timbers to represent normal mill allocations of the log diameter range under investigation (30-45 cm mean diameter).
Following sawing, drying as a single batch (where boards from the three samples had been randomly distributed in drying stacks), skip dressing and grading to meet the requirements of AS 2796, the recoveries and a number of product quality indicators were calculated for all WA FPC Grade 1 logs (118 logs). The main results were:
• Overall product recovery, which included pallet grade and 100 x 25 mm and 75 X 25 mm boards intended for flooring, were similar (not significantly different at p<0.05). Recoveries were 27.6, 27.6 and 28.2 (% log vol) for the thinned logs and unthinned Warren Block and Shannon respectively.
• There were a number of product quality indicators that were significantly different between the samples. The most important were:
o Board end-split severity and spring in sawn boards were more severe in the thinned Warren Block than in (declining order of severity) the unthinned Warren Block and the Shannon samples (significantly different between each sample). This did not appear to impact on recovery because of the severity of other defects.
o The recovery of select grade was 15.5, 11.2 and 7.9 (% log vol) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly different between each sample).
o The recovery of utility and pallet grade combined was 10.3, 14.1 and 16.4 (% log vol) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly different between each sample).
o Product value (using wholesale prices for southwest WA) was 170, 141 and 125 ($ m-3) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly higher for the thinned Warren Block).
CLIENT REPORT Client Report No: 1821
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o The ratio of “white wood” of Grade 4 and 5 (graded on a 1-5 scale darkest to lightest colour) was 0.503, 0.465 and 0.250 (board surface m2 : total m-2) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly lower for Shannon).
o Kino veins, kino pockets and insect damage were all significantly more common in the Shannon logs than the Warren Block. This was the principal reason for recovery and product value differences between the samples.
• There was no significant difference in defects attributed to the drying. Internal checking was rare. Surface checks and undersizing (primarily due to excessive shrinkage or cupping) were evident but they were not major value limiting defects. These latter 2 defects were least common in the thinned Warren Block sample.
Application of Results The results suggest that, with the processing strategies employed by Auswest Timbers, and despite significant differences in board end-splitting severity and board deflection, the thinned sample clearly outperformed the two unthinned samples. Most importantly it can be assumed that faster growth in the younger thinned resource did not contribute to deterioration in wood drying performance, in fact the opposite occurred. This indicates that there may be advantages for industry to process logs from this type of forest, particularly if log lengths were reduced from the 6.0 m lengths used in these processing trials to assist in limiting board distortion.
As with the earlier trial in E. fastigata the younger logs (both samples) had lower incidence of kino and insect damage than logs from the older trees.
One finding of this trial that was not a specific objective relates to the 7.9 (% log vol) recovery of Select grade in the Shannon sample. This is close to industry expectations for WA FPC Grade 1 logs in the diameter range being considered. However, when the Victorian grading method was applied it was found further segregation would produce higher recovery in higher grade logs (B-grade logs). Thus the Victorian grading rules, or similar rules, may be applied in WA to better segregate E. diversicolor logs for processing. For example, from the 40 FPC Grade 1 logs from Shannon, twelve were B-grade and five below D-grade. These produced recoveries of Select grade of 13.4 and 2.4 (% log vol) respectively. Similar improvements were evident in the Warren Block samples.
Further Work As with all of the trails in this series this work was not definitive because of the limitations of the methodologies. Therefore, if processing such thinned resources becomes common, further evaluation taking into account the full tree diameter range and height of the stem may be useful. While variation in sawing and drying methods may contribute to differences in processing performance and prevent certainty in the conclusions, the results will at least be useful in determining the variation in the prevalence of insect damage and kino.
It may be useful to evaluate the application of grading rules similar to those applied in Victoria as a basis for log valuation and sales to improve industry viability in Western Australia.
Resource characterisation may also be further refined with the application of acoustic assessment tools, on both standing trees and harvested logs, to predict the presence of defects such as kino and insect damage.
The high incidence of “white wood” in all samples suggests that processing strategies should also be developed or implemented to reduce colour variation in this species.
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THE EFFECT OF THINNING ON WOOD QUALITY AND SOLID WOOD PRODUCT RECOVERY IN REGROWTH FORESTS: 2. E. diversicolor from southwest Western Australia
R. Washusen, A. Morrow, G. Siemon and Dung Ngo
Table of Contents EXECUTIVE SUMMARY .................................................................................3
Objective ......................................................................................................3 Key Results ..................................................................................................3 Application of Results...................................................................................4 Further Work ................................................................................................4
INTRODUCTION .............................................................................................6 Eucalyptus diversicolor F. Muell. – Background ..........................................7
Silvicultural background............................................................................8 MATERIALS AND METHODS .........................................................................8
Forest and tree selection..............................................................................8 Log preparation sawing and drying ............................................................11
Sawing....................................................................................................11 Kiln drying ...............................................................................................13
Timber grading and final product assessment............................................14 Measuring end-split severity ...................................................................14 Planing, docking defects and grading .....................................................14 Recording defects and wood colour variation .........................................14 Recovery calculations.............................................................................15 Statistical analysis ..................................................................................16
RESULTS AND DISCUSSION.......................................................................17 Log grade and diameter .............................................................................17
Recovery and product value differences between samples....................19 Wood quality differences between samples............................................20 Processing differences between samples...............................................23
REFERENCES ..............................................................................................25 ACKNOWLEDGEMENTS ..............................................................................25 APPENDICES................................................................................................26
Appendix A: Analysis of co-variance and Scheffé test results for recovery and product value variates .........................................................................26 Appendix B: Anova and Scheffé test results for wood quality variates .......27
Information for Ensis abstracting: Contract number FFP 05/237 Report ID number 6296 Products investigated wood quality from thinned native forests Wood species worked on Eucalyptus diversicolor Location Southwest Western Australia
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INTRODUCTION This report is the second in a series of reports prepared for the FWPA that examine the solid wood quality from retained trees in commercially thinned regrowth forests. This research builds on the work conducted by Innes et al. (2005) in the FWPRDC project PN03.1316, which examined the impact of harvesting age and tree size on sawing, drying and solid wood properties of natural forest regrowth eucalypts. The main difference from this earlier work is that in the current project the resources examined were thinned to promote diameter growth rather than examine the general solid wood properties and differences based on tree size. As a consequence the thinned forests produced logs of a suitable size for existing processors at a much younger age than conventional log supplies.
Wardlaw et al. 2004, compared sawn timber recoveries and defect levels from thinned logs than the corresponding unthinned stands, of E. regnans and E. globulus, resulting from a silvicultural intervention at age 7. The current research aimed to compare the sawing and drying performance of wood from logs of similar quality and size from thinned and unthinned forests using a more widely prescribed thinning treatment.
The species examined were selected at the request of industry and the relevant State Forest management agencies. They were E. fastigata from New South Wales, E. seiberi from Victoria, E. regnans from Tasmania and Victoria, and E. diversicolor from southwest Western Australia. In forests set aside for sawlog production these species represent commercially important natural forest species supplying high quality sawlogs to a large and diversified solid wood processing industry. Each of the State Forest management agencies, responsible for management of natural forest, has undertaken experimental thinning programs in an attempt to improve the yield of high quality sawlogs, and hence develop better utilisation strategies for the forests.
The thinned forests are yet to contribute to a significant supply of sawlogs. However, many have produced trees of a harvestable size and are approaching the time when they will produce a substantial supply of logs to the conventional processing industry. Despite the work of Innes et al. and Wardlaw et al. (cited above) little is known about the wood properties that influence processing performance and associated wood quality and value. It will be of benefit to industry to know what differences there are between older conventional unthinned and the thinned forests in determining processing strategies and market potential.
Details will be provided in the individual reports for each species and region on the growth responses to experimental thinning where it is available. However, at the outset it is assumed that the thinning treatment has been responsible for a growth response after thinning that may alter wood properties. While there is evidence suggesting that wood quality may be different in terms of the occurrence of insect damage, decay, kino veins, kino pockets, and the size and condition of knots (Wardlaw et al. cited above), little is known about the performance of logs in mills, and how they behave during sawing and drying and what consequence this has on product quality and value. One of the reasons why this may be the case is that direct comparisons have not been made between logs of the same diameter and grade obtained from older conventional sawlog supplies from unthinned forests and those from younger thinned forests. In the latter case the logs must have a sheath of wood that is produced after thinning that has different wood properties than slower grown conventional resources, which may influence board behaviour during sawing and drying. The magnitude of longitudinal tensile growth stress may be different between resources, impacting on board end-split severity, board deflection during sawing and product undersizing, and as a consequence impact on product recovery and value. During drying the wood may produce different drying performance and influence the commercially important defects of surface and internal checking.
While each project had subtle differences in design, each aimed to understand the effect of growth differences on key economic indicators of wood quality and value. In order to minimise variation in these key indicators, each research trial adhered as near as possible to the following conditions:
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• Samples of logs selected from the thinned and unthinned forests were matched on diameter, length and log grade determined by the respective State forest management agencies.
• Sites selected for harvest had similar topography (primarily slope and aspect), climate and soil types and trees with similar genetic origins.
• During processing, mill staff were employed on one task and normal staff rotations avoided to ensure consistency in processing strategies.
• After coding the logs were randomized before entering the mills to ensure that:
o Identity of the logs was unknown throughout processing
o Logs were processed by identical strategies in the sawmills
o Boards from each sample were randomised within a single drying batch and so were dried with the same schedule, and the position within the kiln was reduced as much as possible as a variable in drying performance.
o During the grading by industry graders resource identity was unknown.
Many of the conditions imposed on the research restricted the size of the project because of the expense in handling and tracking material. However, it was considered imperative that this be done in order to eliminate as many of the variables that may impact on processing performance as possible. These variables included sawing techniques resulting in differences in product orientation and sizing, differences in drying schedules and drying conditions and differences in interpretation of board grade and final product size.
Eucalyptus diversicolor F. Muell. – Background The second of the research trials is the subject of this report. The species is Eucalyptus diversicolor (common name Karri). The karri tall open forest occupies about 300,000 ha of the lower southwest of Western Australia, extending from Nannup and the upper Donnelly River, then southeast to Denmark, with a few outliers e.g. Karridale, Mount Many Peaks, Rocky Gully, and the Porongorup Ranges north of Albany (Boland et al. 1984). The tree can grow to 45 – 70 m, with d.b.h. often 1.5 m to 2.5 m. The occurrence is generally between latitudes 34º and 35º, with altitudes from sea level to about 300 m. Rainfall is between 900-1300 mm yr-1. Karri soils are acidic, and range from fine sands to sandy loams.
Bootle (2005) describes the wood as prone to only slight collapse. As the botanical name implies the wood of E. diversicolor exhibits considerable variation in colour, ranging from red, reddish brown through to pink and light brown, with withish wood in the sapwood region. Although there is a tendency for the sapwood zone to darken to pink and reddish tones with the transition of extractives to heartwood, age alone is not a reliable indication of wood colour. The grain is often interlocked and the air-dry density is around 900 kg m-3. The sapwood is reported by Bootle (2005) to be resistant to Lyctid borer attack.
Karri is the second most important commercial timber species in Western Australia and was, before World War II, exported in large quantities for use as building timbers, flooring and guides or sliding beams in mines. Larger lengths are also available for this species than from any other hardwood. Karri is also used for plywood, which is especially favoured for concrete formwork and truck flooring. Cull karri logs are used in the pulp and paper industry. This information is very similar to that in; Forestry in Western Australia’, a 1971 publication of the Forests Department WA. Additional details in the latter include use as slats in refrigerated rail-cars in the USA, wine vats and casks, and wood pipes and flumes. In later years the species was used for power poles after CCA-treatment, but had a propensity to barrel-check while being air-dried before treatment.
The karri sawmilling industry commenced in the 1880s in two coastal regions, near Denmark and Augusta, which had port access (Bradshaw 1999). Mills were established by M.G. Davies at Karridale and Denmark, but harvesting of the main karri belt commenced in 1912 when sawmills were established to mill sleepers for the Trans Australia railway. The original intention was that cleared land would be used for agriculture. After about seven years the
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Forests Act 1918 was proclaimed and the first karri dominant areas were reserved as State Forest (marri dominant areas were cleared for farming).
Silvicultural background Trends in silvicultural practices in Western Australian native forests were discussed by Bradshaw (1999). Silvicultural treatments in the karri forest have been modified over the decades. Karri forest is best regenerated using clear fall methods with a few seed trees retained per hectare, and after clearing and burning to promote regeneration the seed trees are harvested. As with the ash-type eucalypts native to south-east Australia, this is the most efficient method for regeneration.
Early regrowth stands, from 1929 to 1938, were produced using this method (Forests Department 1971), but Bradshaw (1999) reported that by 1940 about half of the areas were selectively cut with gaps less than one hectare. However, smaller immature trees were wasted and the seed trees were actually non-commercial and were ringbarked after seeding rather than utilised.
The ‘Australian Group Selection System’ was then practiced, in which both over-mature and mature trees were removed for use as sawlogs, while trying to minimise damage, and under the direction of a Forest Officer. Standard tree-marking procedures were introduced about 1949, in which the Forest Officer marked the trees to be harvested. This created a ‘two-tier’ stand, and the practice was continued until 1967.
In 1968 the system reverted to an even-aged stand system, similar to the 1929-1938 procedures, but by now a market had developed for smaller dimensioned timber that could be milled from smaller more immature trees. The major advantages were considered to be simplified management and protection, more efficient extraction and less complex regeneration procedures. One major difference was that now high quality trees were retained to use as seed trees, and these were harvested after regeneration.
Changes in Government policy and the 2004-2013 Forest Management Plan reduced the allowable harvest of first and second grade karri logs (all from regrowth forest) from 186,000 m3 to 54 000 m3. Large areas of both mature and regrowth karri forest are now in conservation areas or National Parks. The FPC’s Annual Report provides information on the areas of karri forest that were either clear-felled and regenerated, partially cleared, or thinned. Consequently there are large areas of regrowth forest that have been thinned. As karri provides high quality woodchips that are exported for pulp and paper manufacture, there are significant areas of even-aged regrowth that are suitable for thinning. However, it is difficult to provide figures on the total area of thinned forest that is now suitable for harvesting over the next few years.
MATERIALS AND METHODS Forest and tree selection Three samples were selected for the trial. Two were selected from the Warren Block (Figure 1) about 15 km south-west of Pemberton. This area comprises wet sclerophyll forest with low fire risk, and the area had not been burnt since the original regeneration burn in 1972. Regeneration followed the clear fell system recommenced in 1968. This produced a single age class forest. In 1994 part of the area was commercially thinned by a local sawmiller (Gandy Timbers), using a Bell 3-wheeled harvester and Timberjack forwarder.
One sample was selected from the thinned area and the second from an adjacent unthinned area of Warren coupe 2. This ensured that the site characteristics were similar. Individual trees were selected to produce a log mean diameter range of approximately 30-45 cm in the lower 6.0 m of the stem and similar log quality indicated by surface features of the trees. Harvesting was conducted with a track excavator harvester and Timberjack forwarder and 6.0 m long bush logs from the butt end of the stem were transported to Auswest Timbers, Pemberton.
This site was a production forest that did not have an inventory plot so no information is available on the growth response following thinning.
At the request of Auswest Timbers an additional sample of unthinned logs was included in the trial. These were sourced from the log yard in Pemberton by Auswest Timbers to approximately match the diameter range of the logs from the Warren Block. These logs originated from Shannon and were of undetermined age. While most were butt logs some were from higher in the stem.
Figure 1. Regional map of Warren Forest Block
Log preparation and grading At the mill the bushlogs were debarked and where required cross-cut to produce a uniform sawlog length of 6.0 metres for each sample of logs. This length was the maximum length possible on the small log line and was selected by Auswest Timbers to deliberately test the board and log performance during sawing. In total, there were 45, 36 and 42 logs from thinned Warren Block, unthinned Warren Block and the Shannon respectively.
In order to have uniform samples for comparison each log was graded using FPC and Victorian log grading rules. The rules applied are summarised in Figure 2 and Figure 3 respectively.
The Victorian grading rules applied are much stricter on surface defects (log end defect, sweep, branches on the log surface and other surface defects such as bumps and insect, fire and harvesting damage) than the FPC rules. This potentially enables the selection of more uniform quality samples.
In this case the Victorian rules were applied using the defect on the worst end (as is the case with the FPC grading rules) to grade the 6.0 m length as a single grade A, B, C, D or reject. This is a variation on the way current log grading is conducted in Victoria, where logs greater than 5.4 m long may be graded on both ends and where applicable produce two grades of logs, each a minimum of 2.7 m in length. Also under current arrangements A-grade logs do not exist.
The application of both of these grading methods allowed an assessment of the effectiveness of the WA Forest Products Commission Grading rules. While not an original element of this project proposal this was included after a specific request was made by Auswest Timbers.
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Figure 2. Victorian log grading card used to grade logs in the Auswest Timbers trial.
Figure 3. Summary of the WA FPC log grading rules.
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Log preparation sawing and drying
Sawing In preparation for sawing, the three samples of logs were randomised and sequentially colour coded on the butt end (Figure 4) to enable logs to enter the mill at random. The colour coding allowed each board to be tracked back to the log of origin throughout the trial and subsequent calculation of product recoveries and quality on an individual log basis.
The logs were sawn using predominantly normal practice at Auswest Timber’s Pemberton mill for processing E. diversicolor into flooring, tile battens and pallet grade products. This included break-down on the twin McKee band saw (Figure 5) which incorporates a chipper reducer, followed by resawing cants and slabs on a multi-saw, and where product quality was poor, resawing cants on a single circular bench re-saw to produce recovery products (tile battens and pallet grade boards). Target product sizes for flooring were nominal 75 x 25 and 100 x 25 mm and nominal sizes for recovery products were 38 x 25 mm for tile battens and 75 x 25, 100 x 25, 75 x 50 and 100 x 50 mm.
The only modification to normal processing was to the docking procedures. In order to retain board colour code on the board ends the trim saw and docking saws were not used for boards of appearance sizes. These boards were allowed through the trim saw without docking. As pallet grade boards constitute a large volume of material from small diameter E. diversicolor, much of this material is normally segregated and docked on the green chain and tallied separately to other products. This meant that it was not possible to track these boards beyond the trim saw where they were cut to length and diverted from the conveyor. To enable pallet grade recoveries to be accurately tallied for each log it was necessary to tally pallet grade boards on the green chain prior to the trim saw. This was done by identifying pallet grade sizes and recording the board total length (minus end-splits and highly degraded material) and the log sequence and colour code. Where the pallet size was the same as the appearance size, the boards were graded and marked for docking to pallet lengths before they entered the trim saw. Where a board had >1.8 m of Standard grade or better, but still a length of pallet grade, it was allowed through the trim saw at full length. This pallet grade material was tallied at completion of drying.
This procedure meant that Standard grade or better lengths of <1.8 m on a board that was otherwise pallet grade ended up being tallied as pallet. Also there was a large volume of pallet grade wood on boards that were to be dried.
As this procedure was adopted for pallet grade boards, tile battens were also tallied on the green chain prior to the trim saw so they could be docked to length without the need for double handling.
After the sawing and drying the pallet grade and tile batten recoveries were tallied after allowing for docking to the correct lengths. Tile batten lengths were 1.8, 2.1, 2.4, 2.7, 3.0, 3.6, 4.2, 4.8, 5.4 and 6.0 m and pallet grade lengths were 1.5 m for 75 x 50 mm boards (Figure 6) and 1.2 all other sizes.
To capture the colour coding information all of the remaining sawn boards were numbered on the face with water proof pens at the end of the green chain where it was possible to do so safely. At this point the length of end-splits was also marked on both board ends and then immediately racked out for air-drying (Figure 7). As the logs had been randomly allocated to sawing, the boards from each log sample were randomly distributed throughout the drying stack.
Figure 1. Randomised colour-coded logs ready for sawing
Figure 2. Back-sawn processing strategy used to produce boards
Figure 6. Pallet produced in the green mill from the central cant or highly defective outer material
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Figure 7. Sawn boards ready to enter pre-drier
Kiln drying The wood was dried in the Auswest Timbers kilns, using a schedule developed by drying personnel (Table 2). Table 2. Drying schedule used by Auswest Timbers to dry boards
Phase Type Time Dry bulb (°C )
Wet bulb (°C )
Wet bulb depression
(°C )
Equilibrium moisture
content (%)
Relative humidity
(%)
Fan Speed (rpm)
1 Heat 1 day 38 35.5 2.5 17.1 85 50 2 Time 4 days 38 31.8 6.2 11.2 65 50 3 Time 7 days 38 29.7 8.3 9.3 55 50 4 MC2 6 days 38 29.4 8.6 9.1 53 50 5 Time 8 hours 85 81.1 3.9 12.9 85 15 6 Cool 2 hours 38 28.6 9.4 8.5 50 50 7 MC 10 days 38 23.4 14.6 5.5 29 50 8 Wait 1 hour 38 23.4 14.6 5.5 29 0
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Timber grading and final product assessment
Measuring end-split severity At the completion of drying, end-split lengths on each end of the dried boards were recorded along with the width, thickness and length given docking of the end-splits. This information was used to calculate the volume of material lost due to end-splitting as a ratio of the volume pre-docking.
Planing, docking defects and grading Prior to planing the board colour and sequence code written on the board face was transferred to the board edge in at least two positions. The boards were skip-dressed on the face and back to 21 mm thickness with a Weinig Powermat 500 high speed moulder. Defect docking and product grading was conducted by Auswest Timbers staff in accordance with normal practice at the mill. All boards would meet the requirements of AS 2796. The boards were graded as Select grade (Prime grade), Standard grade (Medium feature grade) and a Utility/pallet grade. The utility / pallet grade was a combined grade because the mill did not dock out material to differentiate these grades.
Recording defects and wood colour variation At conclusion of grading, defects present on the graded faces were recorded when present. The most common of these were knots, tight kino veins, insect damage, kino pockets, surface checks and undersized sections (identified as skip usually due to cupping or excessive shrinkage and occasionally sawing inaccuracy). Spring was recorded over the full length of graded boards and internal checks when present on docked board ends (very uncommon).
In addition, for this project the predominant colour of each board was recorded. To achieve this a colour grading method was developed as shown in Figure 8. Each board was allocated one colour grade.
The information recorded for each board was used to calculate a number of wood quality variates (descriptors) for comparisons between the log samples. The variates are listed in Table 3 with a description and method of calculation.
Grade 1 Grade 2 Grade 3 Grade 4 Grade 5
Figure 8. Colour grades used to record predominant colour of each board
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Table 3. Wood quality variates calculated for each log for assessment of variation between samples. Wood quality variates attributed to processing End split severity (docked m3 : total board m3)
Volume of wood docked to remove end splits divided by the total volume of boards pre-docking.
Mean spring (mm m-1) Total spring per metre length of individual boards divided by the number of boards ( Mean spring log-1 ).
Surface check (mm m-2) Aggregate length of surface checks on the graded face divided by total surface area of boards.
Under-sizing (m3 m-3) Volume of affected board divided by total board volume
General wood quality variates
Knots (m m-1) Length of boards where knots were present on graded face divided by the total length of boards.
Kino veins (m m-1) Length of boards where tight kino veins were present on graded face divided by the total length of boards.
Kino pockets (m m-1) Length of boards where kino pockets were present on graded face divided by the total length of boards.
Colour variation (m2 m-2) Ratio of surface area of board with ascribed colour grade divided by the total surface area of boards
Insect damage (m m-1) Length of boards where kino pockets were present on graded face divided by the total length of boards.
Other defects For minor defects, severity was recorded on graded face as the length of boards affected divided by the total length of boards.
Recovery calculations Two measurements of diameter for each log end and log length recorded during log preparation were used to calculate log volume using equation 1:
(1) LDDDDV ×⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎠⎞
⎜⎝⎛ ×
+++=
2
21
44321π
Where: V = log volume (m3); D1= log small end diameter 1 (m); D2 = log small end diameter 2 (m); D3 = log large end diameter 1 (m); D4 = log large end diameter 2 (m); L = log length (m)
Nominal board dimensions were used to calculate recovery.
Product recoveries were calculated for each log and expressed either as a percentage of log volume or percentage of select grade as indicated below:
All boards (% of log volume); all boards after docking end-splits (includes some reject lengths).
• Select grade (% of log volume)
• Standard grade (% of log volume)
• Pallet and utility grade (% of log volume)
• Select <1.8 m length (% of select grade)
• Mean product value ( $ log-1)
• Mean product value ( $ m-3 of log input)
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Product value was calculated from wholesale prices at May 2007 (Table 4) applicable to karri in southwest Western Australia. The prices are mill door, free of GST, and based on the nominal dry dimensions indicated.
Table 4. Wholesale prices for karri skip dressed appearance products, tile battens and a combined utility / pallet grade used to calculate product value.
WHOLESALE PRICES (MAY 2007) for graded karri boards
Width (mm)
Thick (mm)
Select ($ m-3)
Standard ($ m-3)
Tile battens and Utility / pallet grade
($ m-3)
38 25 - - 250
75 50 - - 250
100 50 - - 250
75 25 880 700 300
100 25 880 700 300
Statistical analysis Initially to determine which were the most appropriate log groups to compare initially, an analysis of log diameter and recoveries for the FPC Grade 1 and 2 logs and Victorian A, B, C, D and reject logs was undertaken. This indicated that the analysis was best undertaken on FPC Grade 1 logs only. It was also determined that there was a diameter difference between samples for FPC Grade 1 logs. As a consequence statistical analysis was conducted with STATISTICA software using the following procedures:
• Pearson and Spearman correlation matrices were calculated to assess the relative importance of all variates.
• In the case of the wood quality variates multivariate analysis of variance were calculated using the One-way Anova module of STATISTICA. Grouping variables (factors) were the log samples. Dependant variables of importance were detected from the correlation matrices and subsequent univariate analysis of variance after tests were conducted for heteroscedasticity. Where heteroscedasticity was detected the data was transformed by the square root.
• For recovery and product value, diameter was significantly correlated and so an Analysis of Covariance was calculated specifying log sample as the grouping variable, recovery and product value as dependant variables and diameter as covariate.
• For significant sources of variation post hoc analyses were conducted with Scheffé tests to determine significant differences between samples.
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RESULTS AND DISCUSSION Log grade and diameter A summary of log quality differences, recovery and product value for the three samples and for the Victorian and FPC log grades are given in Tables 5 and 6.
The most important points from the two tables are:
• In total there were 36, 45 and 42 logs from the thinned Warren block, the unthinned Warren block and the unthinned Shannon respectively. Of these 36, 42 and 40 (respectively) were FPC Grade 1 logs.
• There was a range of Victorian log grades within each sample. Most notably there were 7 logs below D-grade in the sample from Shannon.
• There were increasing trends in the recovery of select grade, product value and mean log diameter, and declining trends in the recovery of utility / pallet grade and recovery of select grade <1.8 m in length, as the log quality improved (indicated by Victorian log grade). This is consistent with results in southeastern Australia, where the Victoria grading rules are applied, suggesting that a graduated grading system may also be appropriate in E. diversicolor regrowth in Western Australia.
• In the order of unthinned Shannon, unthinned Warren and thinned Warren there were increasing trends in the recovery of select grade, product value and mean log diameter, and declining trends in the recovery of utility / pallet grade and recovery of select grade <1.8 m in length. This trend was evident within each Victorian log grade, all Victorian in-grade logs and FPC Grade 1 logs. These differences are the subject of the statistical analysis to follow.
• In the Shannon sample the recovery of select grade was 7.9% (rounded to 8% in Table 6) in FPC Grade 1 logs. This is close to recovery of 7.0% expected by Auswest Timbers for FPC Grade 1 logs of the diameter range used in this trial (personal communication, Steve Fisher, Auswest Timbers). This could almost be doubled if logs delivered to the mill from Shannon were Victorian B-grade.
• Overall the recovery of utility / pallet grade appears to be very high. One log of FPC Grade 1 from Shannon produced only pallet or chip in the green mill.
• Despite the differences in grading methods there was consistency in recovery, product value, diameter between all Victorian in-grade logs and FPC Grade 1 (in bold type in Table 6). As the FPC Grade-1 category produced the largest number of logs it was subsequently used for comparison between the three samples (to provide adequate sample sizes for statistical analysis). As diameter appeared to be associated with recovery and product value the statistical analysis aimed to remove the diameter effect where appropriate. This was done through analysis of covariance where mean log diameter was the covariate in the model.
Table 5. Log volumes, numbers, mean diameter and Victorian and FPC grades for the three log samples.
Log Numbers
Log
volu
me
(m-3
)
Mea
n di
amet
er (c
m)
Vict
oria
n A
-gra
de
Vict
oria
n B
-gra
de
Vict
oria
n C
-gra
de
Vict
oria
n D
-gra
de
Vict
oria
n R
ejec
t
FPC
Gra
de 1
FPC
Gra
de 2
Thinned Warren 28.4 40.4 1 13 16 6 0 36 0
Unthinned Warren 29.4 36.9 0 7 16 21 1 42 3
Unthinned Shannon 25.7 35.4 0 12 7 16 7 40 2
Table 6. Mean log diameter, recovery of select grade, recovery of utility / pallet, select grade boards <1.8 m in length and product value per log grade.
Log Sample
Vict
oria
n A
-gra
de
Vict
oria
n B
-gra
de
Vict
oria
n C
-gra
de
Vict
oria
n D
-gra
de
Vict
oria
n R
ejec
t
Vict
oria
n A
ll in
-gra
de
FPC
Gra
de-1
FPC
Gra
de-2
Thinned WarrenNumber of logs 1 13 16 6 36 36Mean log diameter (cm) 31 46 39 35 40 40Mean reco select (% log vol) 10 20 14 11 16 16Mean reco utility / pallet (% log vol) 19 9 10 14 10 10Select boards <1.8m length (% select grade) 19 18 28 27 24 24Log value ($ m-3) 131 201 160 132 170 170Unthinned WarrenNumber of logs 7 16 21 1 44 42 3Mean log diameter 45 37 35 31 37 37 37Mean reco select (% log vol) 16 14 8 6 11 11 9Mean reco utility / pallet (% log vol) 10 12 18 26 14 14 24Select boards <1.8m length (% select grade) 21 22 25 11 24 23 23Log value ($ m-3) 174 152 122 124 141 141 141Unthinned ShannonNumber of logs 12 7 16 7 35 40 2Mean log diameter 44 35 32 29 37 36 29Mean reco select (% log vol) 13 7 6 2 9 8 2Mean reco utility / pallet (% log vol) 10 16 22 21 17 17 28Select boards <1.8m length (% select grade) 26 37 40 40 31 36 50Log value ($ m-3) 160 119 118 80 133 126 87
18
Results of statistical analysis Statistical analysis was conducted only on FPC grade 1 logs. Two separate analyses were conducted to detect significant sources of variation between the three samples using analysis of variance for; (i) product recovery and value variates; and, (ii) all wood quality variates. This was done because one log from Shannon did not produce boards for drying so no board quality data was collected for this log.
The means for all variates for the two separate analyses are given in Table 7 and 8.
Table 7. Means for all recovery and log value variates and log numbers for each resource for FPC grade-one logs.
Rec
o se
lect
(% lo
g vo
l)
Sta
ndar
d gr
ade
+ (%
log
vol)
Rec
o ut
ility
/ pa
llet (
% lo
g vo
l)
Rec
o al
l (%
log
vol)
Sel
ect +
<1.
8m (%
rec
over
y)
Val
ue ($
log
-1)
Val
ue ($
m-3
)
Num
ber
of lo
gs
RESOURCEThinned Warren logs 15.5 1.0 10.3 27.6 23.8 138 170 36Unthinned Warren logs 11.2 0.9 14.1 27.6 23.4 94 141 42Unthinned Shannon logs 7.9 1.8 16.8 28.2 32.0 84 126 40 Table 8. Means for all quality variates and log numbers for each sample.
Log
mea
n di
amet
er (m
)
knot
(m m
-1)
Kin
o ve
in (m
m-1
)
Kin
o po
cket
(m m
-1)
Inse
ct d
amag
e (m
m-1
)
Sur
face
che
ck (m
m m
-2)
Und
ersi
zing
(m3 m
-3)
Mea
n sp
ring
(mm
m-1
)
End
spl
it (m
3 m-3
)
Col
our
1 to
3 (m
2 m-2
)
Col
our
4 an
d 5
(m2
m-2
)
Num
ber
of lo
gs
RESOURCEThinned Warren logs 0.404 0.022 0.348 0.022 0.352 15 0.055 3.343 0.056 0.495 0.503 36Unthinned Warren logs 0.369 0.045 0.398 0.063 0.440 43 0.141 2.856 0.038 0.535 0.465 42Unthinned Shannon logs 0.357 0.032 0.570 0.170 0.586 51 0.186 2.189 0.025 0.750 0.250 39
Recovery and product value differences between samples The results of the analysis of covariance and Scheffé tests are given in Appendix A. There were significant differences found for all of the calculated variates except Recovery of all boards (Reco all). The means and significant differences (at p<0.05) are shown in Figure 9 a-f and the results are also summarised as follows:
• Overall board recovery was similar for each sample (not significant at p<0.05). Recoveries were 27.6, 27.6 and 28.2 (% log vol) for the thinned Warren block, the unthinned Warren Block and Shannon respectively.
• Recovery of select grade was 15.5, 11.2 and 7.9 (% log vol) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly different between each sample).
• Recovery of standard grade was 1.0, 0.9 and 1.8 (% log vol) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly higher for Shannon). This difference is of little consequence because of the very low recovery recorded.
19
20
• Recovery of utility and pallet grade combined was 10.3, 14.1 and 16.4 (% log vol) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly different between each sample).
• Product value per log was 138, 94 and 84 ($ log-1) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly higher for the thinned Warren Block)
• Product value was 170, 141 and 125 ($ m-3) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly higher for the thinned Warren Block).
Wood quality differences between samples The results of the multivariate and univariate one-way Analysis of variance for significant wood quality variates and the post hoc analysis using Scheffé tests is given in Appendix B. There were significant sources of variation for kino veins, kino pockets, insect damage, spring, end-split severity and colour as Grade 1-3 and 4-5 combined. The results are shown in Figure 10 a-g. For kino veins, kino pockets and insect damage the data shown is the data transformed by the square root because of heteroscedasticity. The results are also summarised as follows:
• Board end-split severity and spring in sawn boards were more severe in the thinned Warren Block than in (declining order of severity), the unthinned Warren Block and the Shannon samples (significantly different between each sample). This did not appear to impact on recovery because of the severity of other defects.
• Percentage of “white wood” of Grade 4 and 5 (graded on a 1-5 scale darkest to lightest colour) was 0.503, 0.465 and 0.250 (board surface m2 : total m-2) for the thinned Warren Block, the unthinned Warren Block and the unthinned Shannon logs respectively (significantly lower for Shannon).
• Kino veins, kino pockets and insect damage were all significantly more common in the Shannon logs than the Warren Block. This was the principal reason for recovery and product value differences between the samples.
(a)
Thinned Warren Unthinned Warren Unthinned Shannon25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
Rec
o al
l (%
log
vol)
(b)
Thinned Warren Unthinned Warren Unthinned Shannon4
6
8
10
12
14
16
18
20
Rec
o se
lect
(% lo
g vo
l)
(a)
(b)
(c)
(c)
Thinned Warren Unthinned Warren Unthinned Shanon0.2
0.3
0.4
0.5
0.6
0.7
Inse
ct d
amag
e (m
m-1
)1/2
(a)
(a)
(b)
(d)
Thinned Warren Unthinned Warren Unthinned Shannon6
8
10
12
14
16
18
20
Rec
o ut
lilty
/ pa
llet (
% lo
g vo
l)
(a)
(b)
(b)
(e)
Thinned Warren Unthinned Warren Unthinned Shannon60
70
80
90
100
110
120
130
140
150
160
Valu
e ($
log
-1)
(a)
(b)
(b)
(f)
Thinned Warren Unthinned Warren Unthinned Shannon100
110
120
130
140
150
160
170
180
190
200
Valu
e ($
m-3
) (a)
(b)
(b)
Figure 9. a-f. Means and 95% confidence limits for significant variates from the analysis of co-variance. Signifcant differences from Scheffé tests are given; ‘a’ is significantly different to ‘b’ and ‘c’ at p <0.05; and, ‘b’ is significantly different to ‘c’ at p<0.05.
21
(a)
Thinned Warren Unthinned Warren Unthinned Shannon0.2
0.3
0.4
0.5
0.6
0.7
Kin
o Ve
in (m
m-1
)1/2
(a)
(a)
(b)
(b)
Thinned Warren Unthinned Warren Unthinned Shannon-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Kin
o po
cket
(m m
-1 )1/
2
(a)
(a)
(b)
(c)
Thinned Warren Unthinned Warren Unthinned Shanon0.2
0.3
0.4
0.5
0.6
0.7
Inse
ct d
amag
e (m
m-1
)1/2
(a)
(a)
(b)
(d)
Thinned warren Unthinned warren Unthinned Shannon1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
Mea
n sp
ring
(mm
m-1
) (a)
(b)
(c)
(e)
Thinned Warren Unthinned Warren Unthinned Shannon0.01
0.02
0.03
0.04
0.05
0.06
0.07
End
split
all
(m3
m-3
) (a)
(b)
(c)
(f)
Thinned Warren Unthined warren Unthinned Shannon0.3
0.4
0.5
0.6
0.7
0.8
0.9
Col
our g
rade
s 1
to 3
(m
2 m
-2)
(a)(a)
(b)
(g)
Thinned Warren Unthined Warren Unthinned Shannon0.1
0.2
0.3
0.4
0.5
0.6
0.7
Col
our g
rade
s 4
and
5 (m
2 m-2
)
(a)(a)
(b)
Figure 10 a-g. Means and 95% confidence limits for significant variates from the one-way ANOVA. Signifcant differences from Scheffé tests are given; ‘a’ is significantly different to ‘b’ and ‘c’ at p <0.05; and, ‘b’ is significantly different to ‘c’ at p<0.05.
22
Processing differences between samples It has already been discussed that spring and end-splitting were of greater severity in the thinned Warren Block sample than the unthinned Warren Block and unthinned Shannon.
The other processing attributes measured were surface checking, internal checking and undersizing.
Of these three potential defects internal checking as indicated earlier was rare and so was not analysed. Undersizing was more common but still only a minor defect and was least common in the thinned Warren Block (not significant at p<0.05) (Table 8).
The remaining defect of these three is surface checking. This warrants special attention because there were comparable levels of surface checking as the previous trial in this series in E. fastigata (Washusen et al. 2007). However, on this occasion surface checking was relatively rare in the thinned Warren block and progressively worsened in the unthinned Warren Block and Shannon. For the thinned Warren Block there was a mean of 15 mm of surface checking on the graded face per m2 of graded surface area. This indicates that surface checking was relatively uncommon in this sample. In comparison the unthinned Warren Block and Shannon had 43 and 51 mm m-2 respectively. In the E. fastigata project surface checking was more common and displayed the opposite trend with 82 and 73 mm m-2
for the unthinned log sample and the unthinned log sample respectively.
As with the E. fastigata, no significant differences were found for surface checking despite what appears to be considerable differences between the samples. Once again this is because many boards did not have surface checking so that normal parametric statistical analysis could not detect differences even after transformations of the data. This is shown in Figure 11 where the data is displayed non-parametrically by giving the median, quartiles and minimum and maximum values. The median value in each sample was 0 indicating that surface checking was not detected in at least 50% of the logs in each sample.
Median 25%-75% Min-Max Thinned Warren
Unthinned WarrenUnthinned Shannon
0
100
200
300
400
500
600
Surf
ace
chec
ks (m
m m
-2)
Figure 11. Plot of median and maximum and minimum values of surface checking for the three log samples.
23
24
RECOMMENDATIONS AND CONCLUSIONS The results indicate a considerable difference in wood quality between the three log samples. The thinned logs had overall better wood quality, recovery of select grade and total product value and value per cubic metre of log. This was due primarily to differences in the incidence of kino veins, kino pockets and insect damage that were more prevalent in both unthinned log samples. This was also the case in the first of this series of reports on E fastigata. As with the E. fastigata it is not possible to say if this was a direct consequence of the silvicultural intervention or simply differences in forest health between trees in the three coupes logged for the trial. It would be useful for industry to know if this were the case and research established to investigate this further.
There were some differences in processing performance between the three log samples which were matched on length and reasonably well matched on diameter. Despite a slightly larger diameter, the thinned logs had the most severe spring and board end-splitting. However, this did not affect recovery and simply shortening logs in commercial operations may solve this problem. It should be noted that the log lengths processed were at the maximum length possible for this mill in order to test this performance characteristic.
Other processing characteristics were relatively minor. Internal checking was rare, undersizing a minor problem and surface checking was found to be minor and least common in the thinned logs. This generally goes against the conventional thoughts of industry where it is often felt that faster growth and younger age leads to processing difficulties. On this occasion and to some extent in the earlier E. fastigata trial it appears that thinning has quite the opposite effect.
However, care should be taken in extrapolating these results into the broader forest. It appears reasonably clear that there are no major problems when it comes to processing such logs as were used in these trials from thinned forests, and in this case the results suggest industry may derive some benefit in taking on this resource. However, the results are only relevant to logs of the specific quality and diameter range used in the trials. It would therefore be useful to undertake further trials to assess the processing performance and wood quality from the thinned forests.
It would also be useful to develop some projections of log volumes of the size and quality used in the trials that may potentially be harvested from the thinned forests over the medium term.
Further work should also investigate the application of alternative log grading methods in Western Australia. It is clear from this trial that recoveries of high quality wood can be very low from some logs in the FPC Grade 1 category and there is evidence here that further segregation will produce higher recoveries and therefore potentially improve the viability of the sawmilling industry in southwest Western Australia. Coupled with this it may be useful to experiment with log acoustics in order to fine tune log grading by detecting logs with hidden decay, kino pockets, kino veins and insect damage.
25
REFERENCES Boland, D.J., Brooker, M.I.H., Chippendale, G.M., Hall, N., Hyland, B.M.P., Johnston, R.D., KLeing, D.A and Turner, J.D. (1984). Forest trees of Australia. Nelson CSIRO. Bootle, K.R. (2005). Wood in Australia. Types, properties and uses. McGraw-Hill Book Company, Sydney. pp443.
Bradshaw, F.J. (1999). Trends in silvicultural practices in the native forests of Western Australia. Australian Forestry 62(3): 255-264. Forests Department of Western Australia (1971). Forestry in Western Australia. Third edition. Government Printer, Perth. Innes, T., Armstrong, M. and Siemon, G. (2005). The impact of harvesting age/tree size on sawing, drying and solid wood properties of key regrowth eucalypt species. Project No. PN03.1316, Forest and Wood Products Research and Development Corporation, Melbourne. pp 99.
Wardlaw T.J., Plumpton B.S., Walsh A.M. and Hickey J.E. (2004). Tasforests Volume 15 June 2004
Washusen, R., Morrow, A., Linehan, M., Bojadzic, M., Ngo Dung and Tuan, D. (2007). The effect of thinning on solid wood quality and solid wood product recovery of regrowth forests: 1. E. fastigata from southern New South Wales. Ensis Report for the FWPRDC (unpublished).
ACKNOWLEDGEMENTS We are grateful for the assistance of Robert Mills and the staff of Auswest timbers, Pemberton who availed themselves and their mill during the trial in a way that assisted the collection of the large amounts of data produced during the trial. We are also grateful to the steering committee for this project, who provided advice when needed.
The steering committee included:
Graeme Mann, Blue Ridge Hardwoods
Alan Richards, Blue Ridge Hardwoods
Larry Henderson, FIAT, FWPRDC HWAG
Dr Chris Lafferty, FWPRDC
Martin Linehan, Forests NSW
Michael Ryan, Vic Forests
Robert Mills, Auswest Timbers
Dr Graeme Siemon, Forest Products Commission
Dr Tim Wardlaw, Forestry Tasmania
Dr Bruce Greaves, Forest Industries Association of Tasmania
Daniel Tuan, Forests N.S.W.
APPENDICES Appendix A: Analysis of covariance and Scheffé test results for recovery and product value variates Tables A1. Multivariate results from analysis of covariance with significant variates MULTIVARIATE Test Value F Effect df Error df p-valueIntercept Wilks 0.096 145.317 7 108 <0.0001Diameter Wilks 0.096 144.841 7 108 <0.0001Resource Wilks 0.673 3.374 14 216 <0.0001
Tables A2. Results of post hoc analysis with Scheffé tests for significant dependant variables Scheffe test results - Recovery and log value variates
Thin
ned
War
ren
Unt
hinn
ed
War
ren
Unt
hinn
ed
Sha
nnon
Means 27.6 27.6 28.2Thinned WarrenUnthinned Warren NS allUnthinned ShannonMeans 15.5 11.2 7.9Thinned WarrenUnthinned Warren <0.01Unthinned Shannon <0.0001 <0.05Means 1 0.9 1.8Thinned WarrenUnthinned Warren NSUnthinned Shannon <0.05 <0.01Means 10.3 14.1 16.8Thinned WarrenUnthinned Warren <0.05Unthinned Shannon <0.001 NSMeans 137.5 94.3 84.03Thinned WarrenUnthinned Warren <0.0001Unthinned Shannon <0.0001 NSMeans 169.5 140.5 125.6Thinned WarrenUnthinned Warren <0.05Unthinned Shannon <0.001 NS
Rec
over
y ut
ility
/ pa
llet
Val
ue
($
log-1
)V
alue
($ m
-3)
Rec
over
y al
lR
ecov
ery
sele
ctR
ecov
ery
Sta
ndar
d
26
Appendix B: Anova and Scheffé test results for wood quality variates Tables B1. Results of multivariate and univariate one-way analysis of variance for significant wood quality variates MULTIVARIATE TEST
Test Value F Effect df Error df p-valueIntercept Wilks 0.000 1061481 7 108 <0.0001Resource Wilks 0.467 7.143 14 216 <0.0001
UNIVARIATE TESTS
KINO df SS MS F p-valueIntercept 1 22.448 22.448 470.28 <0.0001Resource 2 1.047 0.523 10.97 <0.0001Error 114 5.441 0.048Total 116 6.488
KINO POCKET df SS MS F p-valueIntercept 1 0.837 0.837 26.79 <0.0001Resource 2 0.442 0.221 7.08 <0.0001Error 114 3.562 0.031Total 116 4.005
INSECT DAMAGE df SS MS F p-valueIntercept 1 24.566 24.566 465.05 <0.0001Resource 2 1.061 0.530 10.04 <0.0001Error 114 6.022 0.053Total 116 7.083
SPRING df SS MS F p-valueIntercept 1 910.874 910.874 1540.00 <0.0001Resource 2 25.279 12.640 21.37 <0.0001Error 114 67.428 0.591Total 116 92.707
END-SPLIT df SS MS F p-valueIntercept 1 17.981 17.981 404.55 <0.0001Resource 2 1.769 0.885 19.90 <0.0001Error 114 5.067 0.044Total 116 6.836
COLOUR 1 to 3 df SS MS F p-valueIntercept 1 41.003 41.003 1054.29 <0.0001Resource 2 1.435 0.717 18.45 <0.0001Error 114 4.434 0.039Total 116 5.868
(g)COLOUR 4 and 5 df SS MS F p-valueIntercept 1 19.226 19.226 493.56 <0.0001Resource 2 1.433 0.716 18.39 <0.0001Error 114 4.441 0.039Total 116 5.874
(d)
(e)
(f)
(a)
(b)
(c)
27
Tables B2. Results of post hoc analysis with Scheffé tests for wood quality significant dependant variables
Thin
ned
War
ren
Unt
hinn
ed
War
ren
Unt
hinn
ed
Sha
nnon
Means 0.348 0.398 0.57Thinned WarrenUnthinned WarrenUnthinned Shannon <0.001 <0.05Means 0.022 0.063 0.17Thinned WarrenUnthinned Warren NSUnthinned Shannon <0.05 <0.05Means 0.352 0.44 0.586Thinned WarrenUnthinned Warren NSUnthinned Shannon <0.001 <0.05Means 3.343 2.856 2.189Thinned WarrenUnthinned Warren <0.05Unthinned Shannon <0.0001 <0.001Means 0.555 0.375 0.248Thinned WarrenUnthinned Warren <0.05Unthinned Shannon <0.0001 <0.05Means 0.495 0.535 0.75Thinned WarrenUnthinned Warren NSUnthinned Shannon <0.0001 <0.0001Means 0.503 0.465 0.25Thinned WarrenUnthinned Warren NSUnthinned Shannon <0.0001 <0.0001
Kin
o
(m
m-1
)
Kin
o po
cket
(m m
-1)
Col
our
4
and
5
Inse
ct
dam
age
(m
m-1
)
Spr
ing
(mm
m-2
)E
nd s
plit
(m3
m-3
)C
olou
r
1 to
3Scheffe test results - quality variates
Disclaimer: The opinions provided in the Report have been prepared for the Client and its specified purposes. Accordingly, any person other than the Client, uses the information in this report entirely at its own risk. The Report has been provided in good faith and on the basis that every endeavour has been made to be accurate and not misleading and to exercise reasonable care, skill and judgment in providing such opinions. Neither Ensis nor its parent organisations, CSIRO and Scion, or any of its employees, contractors, agents or other persons acting on its behalf or under its control accept any responsibility or liability in respect of any opinion provided in this Report by Ensis
28