University of Amsterdam PhD Fraanje renewable resources vernieuwbae grondstoffen biobased timber pine wood recycling salvaged wood

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Resources, Conservationand Recycling19 (1997) 21 28
Cascading of pine wood
Peter J. Fraanje*
I V A M Environmental Research, University of Amsterdam, P.O Box 18180,
1001 ZB Amsterdam, The Netherland~
Received 27 December 1995; revised I I June 1996; accepted 3 August 1996
Abstract
Resource-cascading, the sequential exploitation of the full potential of a resource during
its use, is one of the ways to improve efficiency of raw materials use. In this article it is
shown that cascading of the renewable resource pinewood can lead to large savings in
primary resource use. For pine wood a cascade of five or six steps can be set up which
extends the time that the resource is in use from about 75 to more than 350 years. Cascading
also means that, when using wood, the moment that carbon dioxide is emitted, is postponed.
This is interesting in relation to global warming. In the Netherlands, a country where labour
is relatively expensive, parts of this cascade are realised in practice. Until now, however only
a small percentage of the total amount of wood is cascaded. To favour cascading of wood
several options may be considered, such as eco-taxation of resources, prohibition to dump
waste-wood and a 'wood-bank' showing which kind of wood with certain properties is
available at a certain moment. Copyright © 1997 Elsevier Science B.V.
1. Introduction
Since the onset o f the industrial r e v o l u t i o n the use o f virgin n a t u r a l resources has
increased strongly, especially after the second w o r l d w a r ( M e a d o w s , 1972). A large
share o f these virgin resources o r i g i n a t e d in slow geological processes a n d can
therefore be seen as virtually n o n renewable. S o m e renewable resources have been
subject to o v e r e x p l o i t a t i o n . The c u r r e n t intensity o f use o f virgin n a t u r a l resources
* Tel.: + 31 20 5255080; fax: + 31 20 5255850.
0921-3449/97/$17.00 Copyright ~ 1997 Elsevier Science B.V. All rights reserved
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2. 22 P.J. Fraanje / Resources, Conservation and Recycling 19 (1997) 21-28
leads to resource depletion, loss of biodiversity and pollution (Reijnders, 1995).
This is not in line with sustainable development as defined by the UN-Commission
on Sustainable Development (World Commission on Environment and Develop-
ment, 1987).
Based on the concept of sustainability in the Netherlands there is a case for a
reduced use of virgin natural resources and a relative shift from virtually n o n
renewables to renewable resources (Ministerie van VROM, 1989, 1990). An ex-
panded use of renewables following from the replacement of non renewable
resources however ceteris paribus leads to an unacceptable pressure on land
resources. To reduce or rather avoid this pressure, the efficiency of resource-utiliza-
tion should be increased. Similar considerations hold for other industrialized
countries.
Resource-cascading, which can be defined as the sequential exploitation of the
full potential of a resource during its use, is one of the ways to improve efficiency
of the raw materials use. The word cascading originates from the analogy of the
cascade of a (mountain)river, where the water is descending from one level to the
next, towards the sea or a lake (Sirkin and ten Houten, 1993). The concept of
resource-cascading can help designers and policy makers to find ways to a more
efficient use of raw materials.
In this contribution the potential of cascading the renewable resource wood is
discussed. It focusses on the cascading of wood of the pine tree (Pinus Sylvestris).
2. Cascading of renewable resources
In Sirkin and ten Houten (1993) and Sirkin and ten Houten (1994) the theory of
cascading is described extensively. Based on experience with the practical applica-
tion of cascading (Sienknecht and Fraanje, 1992, Fraanje and Lafleur, 1994) a
simplified approach is presented here. Whereas Sirken and ten Houten employ four
dimensions (quality, time, consumption rate and salvageability) I here use two
dimensions, quality and time. A similar simplification has also been suggested by
Sirkin and ten Houten (1994). This simplified approach appears to be suitable to
design a resource conservation policy strategy.
Following this approach cascading is about starting at a high Q (Q -- resource-
quality), increasing AT ( = life time per application) and ZAT (overall life time) and
minimizing AQ (quality loss per application) (see Fig. 1).
The quality of a resource depends on the energy embodied in the resource, its
chemical composition and its organization. For renewable resources a definition of
quality could be the measure in which the original functional properties are present.
In general the dispersion of matter and/or energy and loss of organisation can be
seen as a loss of quality. In case of a renewable resource like wood from a tree,
solar energy, nutrients and water made it possible for the tree to develop a woody
structure with certain properties like strength, durability etc. Some of these proper-
ties can be useful to man. At the moment a tree is cut into pieces its properties
change and certain uses or applications are not possible anymore without invest-

3. P.J. Fraalz/e .; Resources, Consert:ation amt Recycling 19 (I 997) 21- 28 23
meat of (non renewable) energy and materials. The joist which is made out of a
piece of roundwood has not the original strength of the trunk anymore. Only with
the input of additional energy and materials it is possible to restore the loss of
functional properties.
The actual use of resources is often in contrast with the ideas of cascading: wood
with good (construction)qualities is made to pulp (in Fig. 1 this can be shown as a
lower Q as the potential). Crops are often used partly (e.g. only the seeds) and often
only used for low quality applications, with a short life span. Therefore currently
the area (A) under the curve is usually relatively small (see Fig. 1), this in opposite
to the area under the curve when cascading.
The nodes shown in the graph represent the moments where concious choices
should be made. The utilization time of the resource in a certain application can be
extended at cost of investing (non renewable) energy and other resources. Another
possibility is to find a next application and thereby minimize the loss of quality. To
optimize the environmental choice, at every node the decisionmaker should study
which is the best solution. In doing so one should think ahead. Some choices block
other applications in the future. In practice the differences between the options will
often be clear and if not, determination of the parameters energy and (other)
resource-use can be helpful.
Q
Convert- ~, t t
"J U / / / / U / L
/ L J
//,//////T *, • , ,, ,
Z~T ~l T
Fig. 1. A resource cascade and conventional resource use in industrial countries (Fraanje and Lafleur,
1994). Q = resource-quality; T = utilization time; AT= life time per application: EAT = overall life
time; AQ = quality loss per application.

4. 24 P.J. Fraanje / Resources, Conservation and Recycling 19 (1997) 21-28
The principles of (renewable) resource cascading are:
(1) appropriate application (high Q).
Appropriate application means that the resource is applied on the basis of its
(typical) properties, at the highest quality level that is possible. In this view one
should not make pulp out of tree directly, but first profit by specific qualities of
massive wood (like strength). When making paper directly from vegetable
resources, one should rather use flax or hemp, instead of wood. Appropriate
application has reference to the whole resource. A tree consists of more than a
trunk. In case of for instance a cork-oak the wood and the cork find both their
useful applications; for both the wood and the cork seperate cascades can be
made. In case of vegetable renewables whole crop use should be the starting
point for cascading.
(2) life time extension (increase AT and ]EAT).
The AT (life time per application) can be extended through: - optimal design
of the product: in case of production of a window frame for instance, it should
be designed in such a way that water cannot easily stay on it, thereby
preventing rot; - optimal application of the product: this aspect is less strongly
related to the product, but can be influenced by giving prescriptions or
conditions for application. For instance in case of the window frame it means
that the building in which it is placed should preferably be designed in such a
way that the frames are protected against weathering; - good maintainance of
the applicated product, aimed at postponing the replacement of the product by
using small quantities of energy and raw materials (cleaning, painting and so
on).
Increasing ZAT (accumulated life time of all applications) may be helped by
increasing the number of steps in the cascade. If maintainance cannot meet the
technical requirements anymore, if too much energy and materials are required,
or if such a measure brings about too much pollution, then one may look for
an application lower in the cascade, for example using pieces of massive wood
in board.
(3) quality-conservation (minimise AQ)
For a next step in the cascade, a next application should minimize quality-
loss. An example of this principle is that a discarded large dimensioned window
frame can be processed into a window frame with smaller dimensions, instead
of being pulped or burnt, which would result in a greater quality loss.
3. Pine-wood
Commissioned by WWF Holland a study (Fraanje and Lafleur, 1994) has been
executed how to use wood in a more sustainable way. Except for reduction of the
woodconsumption, the total amount of primary wood used in the Netherlands can
be further decreased by cascading wood. In this report with the (translated) title
"Sustainable use of wood in the Netherlands", four examples are given of cascading
the renewable resource wood (Fraanje and Lafleur, 1994).

5. P.J. Fraan/e / Resources, Conservation and Re~3,clmg 19 (1997) 21 28 25
Some possible uses o f the pine tree as a whole
pine tree (alive) pine tree (when cat)
needles insulation material
needle-wool
flowers pine bee-honey
pine apples energy
gum-resin turpentine
kolphonium
bark energy
footpaths
top-wood fertilizer (in the forest)
energy
pulpwood
branch-wood fertilizer
energy
pulpwood
trunk column
floor-joist
floor-plank
window- frame
Fig, 2. Some possible uses of the pine tree as a whole.
In this contribution the pine tree (Pinus Silvestris) is subject of research. The tree
is quite abundant (at about a quarter of the whole Dutch forest area) in the
Netherlands. In Fig. 2 the possible uses of the whole pine tree are shown. For every
application of a part of the tree a cascading strategy can be formulated.
If, as in this case, the resource is defined as wood of the pine tree, it is important
to find an application which is in accordance with the typical properties of pine
wood. For a high quality application it is necessary to know what size (length,
diameter) and qualities of pine wood are available. Here attention is focussed on
the wood derived from the trunk of the pine tree, pine wood. In Fig. 3 one of the
possible cascades for such pine wood is shown.
When exploiting the full potential of cascading, the total using-time of pine wood
(EAT) can be expanded from about 75 years to more than 350 years. In the
Netherlands, a country where labour is relatively expensive, parts of this cascade
are realised in practice.
Step 1 could be normal practice in the Netherlands, but as the Dutch pine forest
is relatively young there is not much pine wood available with large diameters. The
second step in the cascade (see Fig. 3, step 2) is put into practice by a specialized
demolition firm located near Utrecht. Floorboard is made out of old floorjoists (de
Weert, 1992), (Fraanje and Lafleur, 1994). The floorjoists measure 0.75 × 0.20-0.25
m average and are at about 4.5 m long. After the removal of the 75-100 year old
beams with special equipment, the joists are made nail-free by hand and controlled
with a metal-detector. Nothing is thrown away, as the nails go to a company
recycling old metal. After that, the joists are planed and often it is necessary to cut
of the ends that were in contact with the wall. Then the beam is sawn in floorboards
of 2.5 cm thickness, with tongue and groove joints. In case of average quality some

6. 26 P.J. Fraanje / Resources, Conservation and Recycling 19 (1997) 21 28
8 planks, 0.7 m wide and at least 4 meters long, can be produced out of one beam.
About 75% of the old beam is used for floorboard. The rest is used in other
applications such as wood with smaller dimensions, pile caps (pieces of wood of bad
quality, often the unusable ends of the old beams) and for fibreboard. For every
seperate application, a new cascade can be made. For pile caps for instance it will
be a very short cascade, as they are used once or twice and than burned, but for wood
of certain measures the cascade can be much longer. The manager told that the
demand for old floorboards appears much bigger than that the company can produce.
The Dutch consumer appreciates such planks, because they are worked out, they are
wider than the new planks and the quality of the old wood is better (probably due
to slower rotation in production-forests) (Fraanje and Lafleur, 1994).
As a floorcovering the floorboards produced by the company involved can start
a second life (step 3) and easily a third by planing them once more. Other companies
in Holland sell second hand floor planks too (step 3). The only processing these
companies are doing is making the old floor board nail free and plane them. Since
wooden floors are more popular, second hand floorboard is almost a common product
in the Netherlands.
When a floorplank is worn out it could be used in a jointed wooden frame (step
4 in Fig. 3). For such a frame pieces of at least a length of 0.20 m are required;
technically it is possible to build up such a frame out of very thin layers, but the thinner
the layer (in this case it would be at about 20 cm, a normal thickness is 3-4 cm), the
more glue is needed.
Q
resource
qu~lity
1
3
floorjoist
floor
board
floor f l ~ 4 5
board
(
jointed) I '
window- flake ! i,~ fibreboard
frame board I ~"
i
7
I jinc!nera-
I
I t~on
1
I
75 75 75 75 75 30 • time T (years)
Fig. 3. A possible cascade for wood of the pine tree.

7. P.J. Fraan/e / Resources, Conservation amt Rec:veling 19 (1997) 21 28 27
Step 4 (see Fig. 3) is put into practice by a Dutch firm that makes, depending on
the size of the wood, floorjoists or window frames out of second hand pine wood.
The company sells window frames of this pine wood as an alternative for tropical
hardwood.
After use of the jointed window frame the wood can be used as a resource for
board production (step 6). In the end this board can be burned in combination with
energy-recovery (step 7 in Fig. 3). These steps are quite common, though often
immediate incineration also occurs. In theory before the application of wood in
fibre board there could be another step (step 5): application in flake-board. Flakes
measure at about 6.5 × 2.5 cm. Now European flake board is made of fresh sawn
pine-wood pieces, but probably such a process can be adapted for secondary wood.
4. Discussion
Though parts of the wood cascade are a proven possibility, until now, in the
Netherlands only a small percentage of the total amount of wood follows (parts of)
the cascade as shown in Fig. 3. This leads to the unnecessary waste of valuable
natural resources. Thus measures to increase cascading are well advised. For such
measures several options may be considered:
eco taxation which means a shift of the tax burden from labour to resources,
which is expected to make resources relatively more expensive, probably stimu-
lating the efficient use of raw materials;
deposit money on newly built houses, to make a more sophisticated demolition
economically possible;
regulations which allot more responsibility to producers for post-consumer waste
(Reijnders, 1993);
prohibition to dump waste-wood (Lafleur and Fraanje, 1995);
a digital wood-bank showing which kind of wood with certain properties is
available at a certain moment, to prevent unnecessary low quality application of
wood as a result of inadequate communication (Fraanje and Lafleur, 1994).
The last two options will be probably introduced in the Netherlands on a short
term and are expected to have a positive influence on the efficient use (including
cascading) of the raw material wood. Recently deposit money on new cars is
succesfully introduced in the Netherlands to make disassembly of old cars econom-
ically possible. It may be an effective measure for houses too, with a positive effect
on the labourmarket. The third option may not be easily applicable for building
materials which have a long life time. It can be complicated to make arrangements
or give garantees for an action which takes place in the far future, e.g. after 50
years. The first option can be effective, but only if the eco-taxation on raw materials
is substantial.
One remark should be made on differences in quality of pine wood. In the
Netherlands in the past most of the pine wood was imported from the Baltic, where
pine trees where growing relatively slow and regularly in a continental climate, in
contrast with pines growing in the Netherlands. Pine wood which was harvested

8. 28 P.J. Fraanje / Resources, Conservation and Recycling 19 (1997) 21-28
and applied a hundred years ago and now appears as second hand wood on the
market is different, often better, in quality than that of new pine wood.
5. Conclusion
In this article it is shown that cascading of the renewable resource wood can lead
to large savings in primary resource use. Applicated on a large scale, cascading of
renewable resources can make a greater share of renewable resources in the total
resource use a distinct possibility.
Cascading can increase the overall life time of the resource wood strongly. For
pine wood a cascade of five or six steps can be set up, which extends the using time
from about 75 to over 350 years. By cascading resources the efficiency of resource
use increases significantly.
Cascading of wood on a large scale can also be interesting as a means of limiting
the amount of carbondioxide emitted. The carbon which is locked up in the wood
stays there for a longer time and CO2 emissions are postponed. In a cascading-strat-
egy, incineration is often the last step, but before that 'second hand' wood can have
many other applications.
Acknowledgements
The author thanks Professor Dr. U Reijnders of the Interfaculty Department of
Environmental Sciences (IDES) of the University of Amsterdam for his comments
and contributions and the companies Bevers in Harmelen, TASB in Beverwijk and
Norbord Industries in Zaandam for their cooperation and information.
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