CONTRIBUTORS - WOOD WORKS
The wood properties of the different species of Araucaria are similar and, as an example, the properties of A. angustifolia
are summarised below for the wood enthusiast:
MONKEY PUZZLE: HARD FACTS
Botanical/
scientific name: Araucaria angustifolia (Bertol.) O. Kuntze
Family: Araucariaceae Trade name: Parana Pine. Other names: Brazilian Pine (USA) Origin: Parana Pine is native to southern Brazil, Paraguay
and northern Argentina. It is especially common in the state of Parana,
Brazil.
Conservation
status: Parana Pine is listed by IUCN as critically
endangered in its natural habitat (it is one of the
most important native timber species in Brazil).
Data published in 1995 indicated that a forest
reduction of 97% had taken place due to logging
since the beginning of the 20th century. The fruit and seeds of the tree are also consumed
by humans (3 400 tonnes per annum are
harvested), reducing its ability to propagate in
the wild. The Brazilian Government is promoting
several initiatives to protect Araucaria genetic
resources.
Bole
characteristics: Mature trees reach heights of 25 to 40m and a
trunk diameter of up to 1.5m. In the forest, the bole of the tree is usually
cylindrical and clear of branches, topped by a flat
crown. Clear bole lengths of 20m are obtainable.
Colour: The heartwood is light brownish-tan, occasionally The wood of Parana Pine lacks a strong, resinous
exhibiting vivid, rusty-red streaks. The sapwood is odour and has a slightly lustrous surface.
a light yellowish-cream colour.
Grain pattern: Straight, with a fine and even texture and growth
ring figuring, although not as pronounced as Pine
(Pinus species). Density (at
12% moisture
content): 480-599 kg/m 3 (Ref. 2)
460 (420-500) kg/m 3 (Ref. 3)
540 (500-600) kg/m 3 (Ref. 4) Strength/bending
properties: The wood has medium crushing strength, low
to medium bending strength, low stiffness and
toughness. Janka side grain hardness is soft to medium hard
and shearing strength is low.
Seasoning: Parana Pine is reported to be more difficult to
dry than most softwoods as it often contains
compression wood, which causes drying defects.
The darker coloured wood is prone to splitting and
distortion and dries slowly A prolonged conditioning period and weighted
load is essential to ensure uniformity in drying.
Once dry, the stability of the wood in use is not
outstanding, but acceptable, provided compression
wood is avoided. Movement in use is small to
medium.
Durability and
preservative
treatment: The wood is non-durable and has a low resistance
to fungi and decay. It is moderately resistant to preservative
treatment.
Working and
finishing
properties: The wood saws easily by hand or machine. It has
a slight blunting effect on tools. The wood planes
to a smooth, clean finish. It peels easily for veneer
and construction plywood. The wood nails well and has excellent nail-holding
properties, it has good gluing properties and good
results can be obtained with stains, polishes
and paints.
TIMBER DRYING SCHEDULE FOR PARANA PINE (Araucaria angustifolia).
Supplied by H-P Stöhr, Timber Drying Institute ([email protected])
Dry Bulb temperatures (°C) and Relative Humidity (%) at the following Timber Moisture Contents
Drying schedule no.
5
Green
40%
30%
18% to final
DB RH% DB RH% DB RH% DB RH%
60 59 65 46 65 34 75 38
DB = Dry bulb temperature, RH = Relative Humidity
Please note: Drying schedules only serve as a guide to the kiln operator, with the response of the timber to the drying
condition being the criterion.
52 JUNE / JULY 2017 //