The timber of Tasmanian blue gum (Eucalyptus globulus Labill.
subsp. globulus) has been used for general construction, pulp and paper,
rayon, flooring and furniture. If preservative-treated it can be used
for posts, poles, sleepers and fence posts. The species has generally
been used as a green structural timber because of the timber's
susceptibility to surface checking, collapse and warping, particularly
when backsawn (Boland et al. 1984).
Currently there are about 200 000 ha of Tasmanian blue gum
plantations in the south-west of Western Australia on ex-pasture land,
established mainly as a source of woodchips for pulp and paper
manufacture. Almost 60% of the total resource has been planted since
1995 (Department of Fisheries, Agriculture and Forestry--Australia
2001). Some of this resource could be allocated to other end uses, for
example sawn timber, medium-density fibreboard or veneer.
There are an estimated 1080 ha of eucalypts planted and managed for
sawlogs on privately-owned land in Western Australia, of which 640 ha or
60% is Tasmanian blue gum. A further estimated area of 100 ha or 9% of
the privately-grown eucalypts that are managed for sawlogs consists of
Sydney blue gum (Eucalyptus saligna Sm.) (Hingston 2000). The areas
available for sawlog production could be increased by managing already
established stands for sawlogs, using appropriate pruning and thinning
schedules, thereby increasing the area of trees potentially yielding a
sawlog crop (Hingston 2002).
Farm forestry research in Western Australia started in the
mid-1970s, and investigated the growing of pine sawlogs at wide spacing.
Similar trials with eucalypts began in the early 1980s. Many of the
trees in these trials have reached a size suitable for milling and
assessment of their utilisation potential. These studies contribute to
the development of commercial tree crops that can be used by farmers to
provide a range of benefits, such as land protection, salinity control,
shade and shelter, and income from timber.
In 1994 a sawmilling study was conducted at the CALM Centre for
Timber Technology (CTT) and a veneering trial at Wesfi's Victoria
Park plant, using 13-y-old Tasmanian blue gum (Moore et al. 1996).
This paper reports a further sawmilling study begun in October
1998, using trees from an adjoining stand. On-farm milling equipment was
used to break down the logs in the field, followed by re-sawing
resultant flitches with a conventional bandsaw. The purpose of the study
was to assess graded recovery of 17-y-old Tasmanian blue gum timber
milled from pruned trees grown at wide spacing on ex-pasture land.
As density is the best single predictor of strength and hardness,
and these properties have not been assessed for blue gum grown in
Western Australian plantations, we also took the opportunity to evaluate
Materials and methods
Stand management history and study aims
The five Tasmanian blue gum trees used in this study came from a
study site in Vasse Plantation, about 20 km south-west of Busselton. The
trial had been established on an ex-bush site in 1981. At the same time,
pasture was established to build up soil fertility and to graze cattle.
Six different eucalypt species were planted in 7-row belts at 3 m x 2 m
spacing (1666 trees [ha.sup.-1] within the tree belt). The
slower-growing, forked and crooked trees were culled at 3, 5 and 8 y of
age to allow the remaining widely-spaced crop trees to grow with less
competition. The final stocking was 220 trees [ha.sup.-1]. The trees
were pruned at age 3 y to 2.5 m, then at age 5 y and 8 y to about 6 m
and 10 m respectively. Cattle were introduced at year 3 to graze the
pasture. The history of silvicultural treatment and fertiliser
application is given in Table 1.
The stand parameters for the five trees prior to felling the trees
in October 1998 were:
* Stand density: 220 stems ha-1 (within the tree belt)
* Stand mean height: 24.4 m
* Stand mean dbhob: 45.9 cm
* Stand basal area (over bark): 37.6 [m.sup.3] [ha.sup.-1] (within
the tree belt)
* Total tree volume: 306 m3 ha-1 (within the tree belt)
* Mean annual increment (volume over bark): 17.8 [m.sup.3]
[ha.sup.-1] (within the tree belt)
For the five sample trees:
* Total merchantable volume (to 10 cm dbhob): 10.5 [m.sup.3]
* Sawlog volume to 7.5 m: 6.35 [m.sup.3]
* Pulpwood volume: 4.20 [m.sup.3].
Five dominant trees were randomly selected for this study. After
felling, each tree was docked into logs 2.5 m long; the logs were marked
with a branding hammer to identify tree number and butt, mid and crown
logs, then end-sealed with 'Mobilcer' log end sealer. The logs
were taken only from the pruned section of the trees. Although the crown
section was not used for sawlogs, it was assumed to be pulpwood and the
volume was calculated.
Log measurement and yield
After felling, tree height and merchantable height (to 7.5 m) were
measured, together with log lengths, and small and large-end diameters
under bark. Any major log defects, for example large knots, branches or
sweep, were recorded. Log volumes were determined using Smalian's
formula (Carron 1968).
The logs were milled on site in October 1998, using a
'Woodmizer' portable bandsaw with a thin (2.5-3 mm) kerf. Logs
were broken down into flitches using a back-sawing pattern, which
involved cutting on one side of the log, then on the opposite side (at
180[degrees] to the first cut), then backsawing the remainder of the
log. Dimensioned flitches were cut to about a quarter of the log
diameter or until log degrade was encountered, then logs were turned
180[degrees] and further flitches were cut on the opposite side of the
log. The effect of growth stresses (bow and spring) was monitored during
log breakdown. This cutting pattern is similar to one used by CSIRO for
fast-grown eucalypt sawlogs >45 cm mid-diameter (Waugh 1998),
although Waugh recommended turning the logs 90[degrees], not
This pattern, combined with cutting the logs to short lengths 2.5
m), helped to minimise the effects of any growth stresses in the logs.
The resultant flitches had minimal bow and spring following milling.
Each flitch was cut parallel to the bark, that is 'taper
sawn'. This allowed the shorter-length products and residue to come
from the lower-quality knotty core region of the log, rather than from
the more valuable clear wood on the outer parts of the log.
The logs were cut into flitches 25 mm, 38 mm and 50 mm thick which
were identified with a log number, block stacked by log, strapped and
taken to the Centre for Timber Technology (CTT) in Harvey for re-sawing.
During transport the flitches were covered with a tarpaulin to reduce
Milling--re-sawing and docking
At CTT, flitches were stored in a shed with open ends for about two
weeks before re-sawing into backsawn boards with a Jonsereds' band
re-saw. The following widths were cut from each of the different flitch
thicknesses: 50 mm, 75 mm, 100 mm, 125 mm or 140 mm. Priority was given
to boards 100 mm, 125 mm or 140 mm wide, as these sizes are commonly
used by Western Australian furniture manufacturers. At the docking saw,
boards were trimmed to 1.2 m, 1.5 m, 1.8 m, 2.1 m or 2.4 m. The aim of
docking was to produce the longest possible lengths free of faults, for
example brittle heart, decay, excessive knots, kino, wane and end
splits. Boards from each log were identified and individually tallied,
which allowed recovery from individual logs to be calculated.
Boards were then treated with log end-sealer to reduce end
splitting, and block stacked ready for dipping.
Dipping for Lyctus borer attack
The sapwood of Tasmanian blue gum is susceptible to Lyctus borer
attack (Bootle 1983). To prevent attack, the timber was dipped in a 4.5%
borax solution immediately after block stacking. After draining the
excess liquid, the timber was covered completely with a plastic
tarpaulin to prevent drying and to facilitate diffusion of the
preservative throughout the sapwood. The timber remained block stacked
for several months in a controlled high-humidity environment, before
strip stacking and drying by solar kiln. The recommended diffusion time
is 28 days, but the timber remained blocked stacked for several months
until kiln space was available.
Strip stacking and kiln drying
The timber was strip stacked into stacks 2.4 m long for drying,
using standard 19 mm pine strippers. Standard 800 kg weights (400 kg
[m.sup.-2]) were placed on top of each stack to minimise cupping or
twisting during drying. Sample boards located throughout the stacks were
used to monitor moisture content.
Timber of all sizes was dried using the commercial drying schedules
for marri (Corymbia calophylla (Lindl.) K.D. Hill and L.A.S. Johnson).
These schedules (Glossop and Bishop 1996) recommend increasingly severe
drying conditions as moisture content of the timber decreases. Table 2
gives the drying schedules for 25 mm or 38 mm boards, and 50 mm boards.
Collapse recovery steaming
After kiln drying, cell collapse was observed in some 50 mm boards.
To recover cell collapse, a steam re-conditioning treatment with the wet
and dry bulb temperatures set at 97[degrees]C was applied for 8 h. To
restrain the timbers from twisting, concrete weights of 3.7 t were
placed on top of the bundles. A visual assessment of the timber after
steaming indicated that the boards had recovered from the cell collapse.
Dressing and grading
After kiln drying and reconditioning, boards were pre-dressed and
graded into appearance- or core-grade timber. Appearance grades were
based on the WA Industry Standard (FIFWA 1992) and core grade or
laminated panel core grade (CALM 1989). The core-grade boards are
structurally sound and suitable for filler laminates in panels or panel
products to be used without further manufacture. Boards were graded and
docked to lengths ranging from 0.9 m to 2.4 m (in increments of 0.3 m),
with some 2.5 m lengths, aiming at producing longer lengths in a lower
grade rather than shorter lengths of a higher grade. Reasons for
downgrade, rejection or docking were recorded.
Lengths as short as 0.9 m were permitted because a survey of ten
furniture manufacturers in Western Australia found that while the
maximum length of solid jarrah (E. marginata Donn ex Sm.) timber
required was 2.2 m, 84% of lengths were less than 1.0 m (Challis 1989).
Harris Wood Machining of Busselton dressed a 1 [m.sup.3] sample of
timber into floor boards 12 mm and 19 mm thick. Wood quality and
machining properties were noted. Another sample was given to 12
woodworking students at the South-West Regional College of TAFE to
assess the quality of the timber.
After kiln drying to 12% moisture content, 23 Tasmanian blue gum
boards were randomly selected for assessment of air-dry density. The
air-dry volume was calculated after measuring the width and thickness of
each board with Vernier calipers, and the length with a lineal tape
measure. Mass was determined using digital scales to an accuracy of 0.01
Results and discussion
Log yields and stand management
Table 3 gives the tree dimensions, and sawlog and pulpwood yields,
for the five trees assessed in this study. The mean sawlog and pulpwood
yields were 1.27 [m.sup.3] per tree and 0.84 [m.sup.3] per tree
respectively, with sawlogs making 60.2% and pulpwood 39.8% of the
merchantable tree volume to a 7.5 cm diameter limit. Four trees produced
a higher proportion of sawlogs than pulpwood; tree 3 had 49% of its
volume as sawlogs and 51% as pulpwood.
Moore et al. (1996) estimated a mean sawlog and pulpwood yield of
0.96 [m.sup.3] per tree and 0.36 [m.sup.3] per tree, respectively, at 13
y, giving a total merchantable volume of 1.32 [m.sup.3] per tree. The
sawlog component was 73% and pulpwood 27% of merchantable volume. As
would be expected, the sawlog and pulpwood yields were greater at age 17
y than those reported for 13 y. Any further comparison is unwarranted as
the trees in the earlier study were grown in a different stand and at a
mean stocking of 135 stems ha-1, whereas stocking in this study was 220
Knots and other branch defects
The reasons for downgrading the finished boards, and percentage
(based on board volume) downgraded for each log class, are shown in
Figure 1 for 25 mm and 38 mm boards, and in Figure 2 for 50 mm boards.
In the mid and crown logs, knots and the combination of knot and checks
were the major reason for downgrading boards. For example, in the 25 mm
and 38 mm boards the fraction downgraded from Prime Grade to Standard
Grade was 3% for mid logs and 5.1% for crown logs. The fraction
downgraded from appearance grade to Core Grade or below was 8.4% for mid
logs and 14.9% for crown logs. For the 50 mm boards, knots did not
result in any mid-log boards being downgraded from Prime Grade to
Standard Grade, but knots caused 9.3% of the board volume cut from crown
logs to be downgraded. For all timber thicknesses, the overall fraction
downgraded from appearance grade to Core Grade or below was 7.7% for
mid-logs and 11.0% for crown logs. This indicates that some boards from
the mid and crown logs were cut from the knotty core section of the
[FIGURE 1 OMITTED]
[FIGURE 2 OMITTED]
Wide-spaced trees produce large branches, which result in large
knots that downgrade sawn timber products. Pruning at an early age, as
occurred in this trial, is essential where the aim is to produce
appearance-grade products, as it reduces the size of the knotty core and
knot size in sawn timber, and restricts the development of loose knots
which can result from encased dead branches. If pruning is timed to
coincide with the period of most rapid diameter growth, branch stubs
will be rapidly occluded, minimising the likelihood of infection by
Mechanical pruning (1) was in three lifts: at age 3 y to 2.5 m,
then at ages 5 y and 8 y to about 6 m and 10 m respectively. The higher
proportion of knots in the mid and crown logs would have resulted from
pruning at either age 5 or 8 y. Pruning to 6 m or 10 m at an earlier age
may result in fewer knots in the mid and crown logs, but the loss of
overall leaf area and its effect on tree growth must also be considered.
Pinkard and Beadle (1998) found that removing 50% of the lower green
crown in E. nitens ((Deane and Maiden) Maiden) had no impact on height
or diameter increment in the two years following treatment, but removal
of 70% of the length of the lower crown resulted in significant
decreases in both height and diameter increment.
In comparison, a milling study using 15-y-old unpruned E. globulus
also found that knots were the major factor causing boards to be
downgraded from select-grade products (Washusen et al. 2000b). In those
unmanaged trees, decay and kino appeared to be associated with branches
and were a serious problem, but those defects can be reduced with
mechanical pruning. In our study knots were a common cause of downgrade
in the mid and crown logs, but not to the same extent as reported in the
unpruned trees. We found no decay associated with knots, and kino caused
only a very small proportion of the boards to be downgraded from
appearance grade to below grade (Figs 1 and 2), indicating rapid branch
This study has shown that mechanical pruning will improve wood
quality. Good silvicultural practice--early thinning and mechanical
pruning as in this example--produces a healthy stand, reduces branch and
knot size and results in rapid branch occlusion, which reduces the
chance of fungal and insect attack. Efficient stand management improves
overall wood quality.
Milling, drying and processing
In this trial minimal splitting of log ends was observed when the
logs were cut to length. Applying a water-resistant log end sealer
immediately after felling and docking reduced the amount of drying from
the log ends and helped reduce end splitting. Bow and spring of flitches
and board was not a problem during milling and drying. Cutting logs into
short lengths and using a backsawing cutting pattern assisted in
reducing the amount of bow and spring. Storing logs under water spray
for up to six months before milling can also assist in relieving growth
stresses in fast-grown eucalypts (Brennan et al. 1990).
The 17-y-old Tasmanian blue gum boards were dried under mild
conditions in a solar kiln, using commercial drying schedules developed
for marri. These schedules recommend increasingly severe drying
conditions as the moisture content of the timber decreases. The drying
rates for the 25 mm and 38 mm boards could have been increased, as
minimal drying degrade occurred on these boards. Some cell collapse
occurred in the 50 mm boards when dried under these mild conditions, but
this was recovered in a steam re-conditioning treatment. Further
research is required to develop efficient drying schedules for the three
board thicknesses studied.
The local wood machining company which dressed the 1 [m.sup.3]
sample of timber into floor boards compared the sample to standard
timbers they process. No collapse or surface checking was observed when
the timber was dressed, while end splits were minimal and did not
significantly affect recovery. Any knots were generally tight and did
not cause problems when dressing the timber. Planing and sanding the
boards did not result in any lifting grain. The timber colour was a
consistent light yellowish-brown, similar to Victorian ash and Tasmanian
oak (P. Harris, Harris Wood Machining, Busselton, pers. comm.).
Woodworking students at the South-West Regional College of TAFE
provided a positive assessment of the quality of the timber, most
finding it very easy to machine and work, and sanding and polishing to a
smooth finish. A sample of flooring has been placed in service, and
stability and performance will be monitored.
Recovery of appearance-grade and laminated-panel-core-grade
The recovery of appearance-grade and laminated-panel-core-grade
products, based on log volume and dry dressed board volume, is given in
Table 5. Thirty percent of the log was recovered into appearance-grade
products, with a further 2.2% suitable for filler laminates in panels or
panel products. Of the total volume of the dried and dressed boards, 85%
of the volume was recovered in appearance-grade timber, and a further
6.3% could be used for filler laminates (Table 5). Moore et al. (1996)
also reported high recoveries as appearance-grade products for 13-y-old
Tasmanian blue gum.
The major reasons for downgrading boards from Prime Grade to
Standard Grade, and from appearance grade to laminated panel core grade,
were knots and the combination of knots and surface checks (Fig. 3). The
major reasons for downgrading to a category below these grades were end
splits and knots. End splits were generally less than 100 mm long and
did not significantly affect recovery. In this trial, boards were
end-sealed, which restricted end splitting during drying.
The figures for recovery of appearance-grade products from butt and
mid logs were similar, and higher than those for crown logs. Crown logs
produced a greater volume of laminated panel core grade than did butt
and mid logs, as some of the boards from crown logs did not meet the
specifications of an appearance product but were structurally sound and
suitable for laminated panel cores.
The results in this study are considerably better than those
reported by Washusen et al. (2000a,b), who found low recoveries of
select grade or better from logs from an unpruned 15-y-old Tasmanian
blue gum stand from a medium-rainfall area in the southern
Murray-Darling Basin. The low recoveries in the latter studies were
largely due to knots, decay, kino and drying degrade, which is partly
caused by the presence of tension wood cells. The present study had
substantially less of these inherent characteristics, resulting in a
recovery of 30% of log volume into appearance-grade products and a
better overall wood quality.
Air-dry density was assessed when the timber dried below 12% MC.
The mean air-dry density was 680 kg [m.sup.-3], with standard deviation
[+ or -]65 kg [m.sup.-3] and range 525-780 kg [m.sup.-3]. Kingston and
Risdon (1961) quoted a mean air-dry density of 790 kg [m.sup.-3] (before
reconditioning) and 727 kg [m.sup.-3] (after re-conditioning) for
17-23-y-old Tasmanian blue gum. In comparison, Bootle (1983) quoted a
mean air-dry density of mature Tasmanian blue gum of 900 kg [m.sup.-3].
As expected the 17-y-old material had a lower density than wood from
mature trees, because wood density increases with tree age; it can also
be influenced by the combination of environmental and genetic factors
and in some cases growth rate.
[FIGURE 3 OMITTED]
Brennan et al. (1992) assessed density of Tasmanian blue gum from
the Manjimup area. The mean basic density of 8-y-old ex-pasture grown
trees was 525 kg [m.sup.-3], and of 10-y-old ex-bush grown trees, 470 kg
[m.sup.-3]. Bishop and Siemon (1995) assessed the air-dry density of
13-y-old Tasmanian blue gum from the same trial as the 17-y-old trees
assessed in this trial, and reported a mean value of 640 kg [m.sup.-3].
Northway and Blakemore (1996) estimated the basic density of 24-y-old
Tasmanian blue gum growing in south-eastern Gippsland in Victoria as 590
There is now a project in Western Australia to grow eucalypts for
sawlogs. In 2001 and 2002 about 650 ha were planted on cleared farmlands
in water recovery catchments (2) to produce high-grade timber and to
improve water quality (Moore and Buckton 2002). The long-term aim is to
develop a new industry--using cleared private land in the 450-650 mm
annual rainfall zone--delivering multiple benefits for landcare and
regional development. The planting will also assist the protection and
recovery of biodiversity and water resources threatened by salinity. The
species planted are Tasmanian blue gum and Sydney blue gum on the better
soils and in the wetter end of the rainfall range, and spotted gum (E.
maculata Hook.) and sugar gum (E. cladocalyx F.Muell.) on the poorer
soils at the drier end of the range.
Further studies are required of the milling and drying of the
remaining trees at the Vasse trial and of trees from other trials.
Results of the present and future studies will provide basic information
for growers and timber processors involved with the new eucalypt sawlog
industry, so they can have more confidence in using Tasmanian blue gum
timber from trees grown at wide spacing.
Revised manuscript received 4 June 2004
Bishop, D.W. and Siemon, G.R. (1995) Drying Tasmanian blue gum
boards using a conventional batch kiln. Department of Conservation and
Land Management, Timber Technology, unpublished report.
Boland, D.J., Brooker, M.I.H., Chippendale, G.M., Hall, N., Hyland,
B.P.M., Johnston, R.D., Kleinig, D.A. and Turner, J.D. (1984) Forest
Trees of Australia. Thomas Nelson Australia and CSIRO.
Bootle, K.R. (1983) Wood in Australia--Types, Properties and Uses.
McGraw-Hill Book Company, Sydney.
Brennan, G.K., Glossop, B.R. and Mathews, L.R. (1990) Stockpiling
of Regrowth Jarrah and Karri Logs Using Different Watering Schedules.
Department of Conservation and Land Management WA, Wood Utilisation
Research Centre Report No. 16, 27 pp.
Brennan, G.K., Hanks, W.R. and Ward, S.L. (1992) Processing
Plantation-Grown Tasmanian Blue Gum. Department of Conservation and Land
Management WA, Wood Utilisation Research Centre Technical Report No. 41,
CALM (1989) Grading criteria for laminated panel core material.
Department of Conservation and Land Management, Western Australia.
Carron, L.T. (1968) An Outline of Forest Mensuration with Special
Reference to Australia. Australian National University Press, Canberra.
Challis, D.J. (1989) Survey of Solid Wood Sizes Used by the
Furniture Industry in Western Australia. Department of Conservation and
Land Management Western Australia, Wood Utilisation Research Centre
Report No. 9.
Department of Agriculture, Fisheries and Forestry--Australia (2001)
Plantations of Australia 2001. National Forest Inventory, Bureau of
Rural Sciences, Canberra, 172 pp.
FIFWA (1992) Industry Standard for Seasoning, Sawn and Skip-Dressed
WA Hardwoods. Forest Products Federation (WA), Perth.
Glossop, B.R. and Bishop, D.W. (1996) Drying marri boards using a
conventional batch kiln. Department of Conservation and Land Management
Timber Technology, Western Australia. Unpublished report.
Hingston, R.A. (2000) Review of pruning eucalypts for clearwood in
Western Australia. Paper presented at Pruning Workshop, Launceston,
Tasmania March 2000. (Available from author.)
Hingston, R.A. (2002) High-grade eucalypt sawlogs--silviculture and
markets for farm forestry. Paper presented at Australian Forest Growers
Conference, Albany, Western Australia, 13-16 October 2002. (Available
Kingston, R.S.T. and Risdon, C.J.E. (1961) Shrinkage and Density of
Australian and other South-West Pacific Woods. CSIRO Division of Forest
Products, Technological Paper No. 13.
Moore, R.W. and Buckton, M. (2002) Eucalypts for high-grade timber
--building a new industry centred on farmland. Paper presented at
Agroforestry Expo, Mt Barker, Western Australia, 13 October 2002.
(Available from author.)
Moore, R.W., Siemon, G.R., Eckersley, P. and Hingston, R.A. (1996)
Sawlogs from 13-year-old Eucalyptus globulus--management, recovery and
economics. In: Investing in the Future. Proceedings of the Australian
Forest Growers Conference, Mt Gambier, South Australia, pp. 219-231.
Northway, R.L. and Blakemore, P.A. (1996) Evaluation of drying
methods for plantation-grown eucalypt timber: sawing, accelerated drying
and utilization characteristics of Eucalyptus globulus. Client report
No. 117, CSIRO Forestry and Forest Products. Forest and Wood Products
Research and Development Corporation, Melbourne.
Pinkard, E.A. and Beadle, C.L. (1998) Effects of green pruning on
growth and stem shape of Eucalyptus nitens (Deane and Maiden) Maiden.
New Forests 15, 107-126.
Washusen, R., Blakemore, P., Northway, R., Vinden, P. and Waugh, G.
(2000a). Recovery of dried appearance grade timber from Eucalyptus
globulus Labill. grown in plantations in medium rainfall areas of the
southern Murray-Darling Basin. Australian Forestry 63, 277-283.
Washusen, R., Waugh, G., Hudson, I. and Vinden, P. (2000b)
Appearance product potential of plantation hardwoods from medium
rainfall areas of the southern Murray-Darling Basin. Green product
recovery. Australian Forestry 63, 66-71.
Waugh, G. (1998). Sawing of young, fast-grown eucalypts. CSIRO
Division of Forestry and Forest Products. (Available from author, at The
Institute of Land and Food Resources, The University of Melbourne,
Parkville, Vic 3052.)
(1) The removal of unwanted shoots or branches from a tree to
improve its form and wood quality using mechanical equipment, for
example small hand shears and saws, long-handled shears or light-weight
(2) Catchments recognised by the WA Government as being of high
priority for protection and rehabilitation by revegetation with trees
and other woody perennials. This will improve the quality of water from
the catchments and protect biodiversity.
G.K. Brennan [1,2], R.A. Hingston  and R.W. Moore 
 Department of Conservation and Land Management, PO Box 1693,
Bunbury, Western Australia 6231, Australia
 Email: email@example.com
 Trees South West, PO Box 1231, Bunbury, Western Australia 6231,
Table 1. History of the Tasmanian blue gums growing at Vasse,
Year Operation Fertiliser application
0 Trees planted at 3 m x 2 m Aerial application of 416 kg
spacing in belts of 7 rows ha-1 Super Copper Zinc
(1666 trees [ha.sup.-1]) * Molybdenum No. 1 applied with
pasture establishment; 100 g
Agras No. 1 (18% N, 7.6% P,
0.17 S, 0.06% Zn) applied to
each tree at planting
1 480 kg [ha.sup.-1] of Super
Copper Zinc Molybdenum applied
to increase pasture and tree
3 Culled to 675 trees 200 kg [ha.sup.-1] of
[ha.sup.-1] *. Crop trees superphosphate applied
pruned to 50% of tree height annually in years 3 to 10
(about 2.5 m).
5 Culled to 220 trees See above for year 3
[ha.sup.-1] *. Crop trees
pruned to 50% of tree height
(about 6.0 m).
8 Crop trees pruned to 50% of See above for year 3
tree height (about 10.0 m)
11 240 kg [ha.sup.-1] of
superphosphate (9% P) applied
13 55 trees harvested for milling 150 kg [ha.sup.-1] of
and veneer study (Moore et al. superphosphate (9% P) applied
15 200 kg [ha.sup.-1] of super
and potash (3:1) applied to the
16 pasture strips only
17 5 trees harvested for this
The annual applications of fertiliser were to increase pasture growth,
but would have also benefited the trees.
* tree density within the tree belt.
Table 2. Drying schedule for Tasmanian blue gum boards 25 mm or
38 mm thick, and 50 mm thick
MC at change (%) DBT ([degrees]C) WBD ([degrees]C)
stage 25/38 mm 50 mm 25/38 mm 50 mm 25/38 mm 50 mm
1 Green 30 20 1.5 1.0
2 60 60 30 25 2.0 1.5
3 45 45 40 30 3.0 2.0
4 35 35 45 40 4.5 3.0
5 30 30 50 45 5.0 4.5
6 25 25 50 50 8.0 5.0
7 20 20 55 50 10.0 8.0
8 15 15 60 60 15.0 15.0
9 12 12 60 60 5.0 5.0
RH (%) EMC (%) (m [sec.sup.-1])
stage 25/38 mm 50 mm 25/38 mm 50 mm 25/38 mm 50 mm
1 89 91 19.6 20.9 0.5 0.5
2 86 88 18.0 19.3 0.5 0.5
3 82 86 16.0 18.0 0.5 0.5
4 78 82 14.2 16.0 0.5 0.5
5 75 78 12.8 14.2 0.5 0.5
6 62 75 9.9 12.8 0.5 0.5
7 57 62 8.6 9.9 0.5 0.5
8 43 43 6.4 6.4 0.5 0.5
9 77 77 12.7 12.7 0.5 0.5
MC = moisture content; DBT = dry bulb temperature; WBD = wet bulb
depression, i.e. the difference between the dry bulb and wet bulb
readings; RH = relative humidity; EMC = equilibrium moisture
Table 3. Tree dimensions and sawlog and pulpwood yield for
the five 17-y-old Tasmanian blue gum trees assessed
Tree Dbhob Total Pruned
no. (cm) height (m) height (m)
1 60.6 26.5 10.5
2 55.6 25.5 10.0
3 56.4 23.6 9.1
4 52.2 24.0 10.2
5 52.0 22.3 9.5
Mean 55.4 24.4 9.9
Sawlog, pulpwood and merchantable volume ([m.sup.3])
no. Butt log Mid log Crown log
1 0.65 0.51 0.43
2 0.57 0.41 0.37
3 0.46 0.30 0.24
4 0.61 0.34 0.29
5 0.48 0.36 0.32
Mean 0.55 (43.6) (a) 0.38 (30.3) (a) 0.33 (26.1) (a)
Sawlog, pulpwood and merchantable volume ([m.sup.3])
no. Total sawlog Pulpwood merchantable
1 1.59 0.92 2.51
2 1.35 0.88 2.23
3 1.00 1.04 2.04
4 1.25 0.62 1.87
5 1.16 0.74 1.90
Mean 1.27 (60.2) (b) 0.84 (39.8) (b) 2.11
(a) mean volume in each sawlog category as a percentage of mean
total sawlog volume, and
(b) mean volume of (total) sawlog and pulpwood as a percentage
of mean (total) merchantable volume for all trees
Table 5. Mean diameter and mean recovery of green sawn, appearance
grade and laminated panel core grade wood from 17-y-old Tasmanian
blue gum (based on volume of log and dry dressed boards), by log
position. (LPCG = laminated panel core grade)
of log Fraction of volume of log
volume recovered in appearance
recovered grades (%)
Log Sedub of sawn wood Prime Standard
position logs (cm) (%) grade grade Total
Butt 45.6 46.8 30.7 0.3 31.0
Mid 42.4 50.6 31.2 1.1 32.3
Crown 39.3 49.9 25.4 1.3 26.7
Overall1 42.4 48.8 29.2 0.9 30.1
Fraction of dry
of volume dressed
Log Fraction of volume of dry of log boards
position dressed boards recovered recovered recovered
in appearance grades in LPCG in LPCG
(%) (%) (%)
grade grade Total
Butt 86.3 0.7 87.0 1.6 4.5
Mid 82.5 3.0 85.5 2 5.1
Crown 74.4 4.6 79.0 3.6 10.8
Overall1 82.6 2.4 85.0 2.2 6.3
(1) Overall mean recoveries are based on total volume