Panels & Furniture Asia March/April 2024

ENVIRONMENTAL REPORT
Fig. 1
Calculating the carbon storage is
simple with PEFC’s calculator. There
are two ways to go about it, as shown
in Fig. 1: The first way is to measure
the length, width and thickness of
the furniture. This probably has
to be done multiple times for the
various parts of a furniture item,
since different parts have different
measurements and might be made
of different materials. The second
way is to determine the volume of
the furniture item. This is more for
irregularly shaped furniture.
Other values that need to be keyed
in include the material type and
the wood density. The material
is subcategorised to solid wood,
plywood, particleboard, oriented
strand board (OSB), medium- or
high-density fibreboard (MDF or
HDF).
For wood density, the PEFC has
provided a reference list, but
they encourage manufacturers
or consumers to check the data
sheet that wood suppliers provide,
that should contain the density
information of the wood. Otherwise,
manufacturers or consumers can
calculate the density themselves.
Also, in general, the higher the
density, the higher the amount of
carbon stored in the wood.
HOW DOES IT WORK?
There is a specific formula to
calculate the carbon stored in
wooden furniture. This formula is the
basis behind PEFC’s calculator, with
some preset values.
The carbon stored in wood (CO2
in kilograms) is equivalent to the
multiplication of the fraction of
carbon in the wood (f c), the weight
of a carbon atom in a CO2 molecule
(3.67) and the total weight of oven-dry
wood, as seen in Fig. 2. The weight
of oven-dry wood can be calculated
using the values of the wood density
(kg/m 3 ), the volume of wood (m 3 ),
the moisture of wood content in
percentage (u/100), and the fraction
of wood in the wood-based product
(f w).
Although the calculator uses
preset values, which might lower
the accuracy, the results obtained
from the calculator are still reliable,
according to PEFC. They have
determined 0.5 to be the carbon
fraction in wood as an average
for the calculator. There are more
detailed values based on the wood
species and provenance, which
can be found online. The fraction
of wood in solid wood products is
1, while other products made with,
for example, MDF or OSB varies
because of the presence of glue and
depending on the manufacturing
process. Estimates are incorporated
into the online calculator.
Moisture content in solid wood is
roughly 12%, and 10% for engineered
wood products; although in theory,
the moisture content varies
according to the humidity in the
air, geographical location, seasons,
building type, and more. Water does
not contain carbon, and hence has to
be removed from the equation.
Fig. 2
CIRCULAR ECONOMY
It is important to note that carbon
storage is merely a subset of carbon
footprint. Carbon footprint refers to
more than just the carbon stored in
furniture, but also considers emissions
generated from the manufacturing
process, the logistical aspects like
transportation, and more.
To calculate the carbon footprint,
a lifecycle assessment (LCA) of
the product is needed, more than
just a carbon storage calculator.
Furthermore, for a product to truly be
carbon neutral — which is to say, for the
carbon to be off-set — it has to store
carbon for at least 100 years, according
to PEFC. This a lifetime which most
furniture items rarely achieve.
Even so, understanding how much
carbon is stored in a product is still
key to lowering the global carbon
footprint, especially in an attempt to be
carbon neutral or net zero by 2050, as
stipulated by the Paris Agreement.
While carbon storage in forest is
dynamic and changes over time,
carbon storage in furniture is static,
remains in the product throughout its
lifecycle, and only gets released into
the atmosphere when it is burned.
Prolonging the product’s lifetime
therefore helps the carbon footprint,
since it delays the carbon from being
released. As the PEFC noted in their
booklet: “The [cascading use of wood]
aims to prolong the permanence of
wood biomass within a given system,
based on various strategies that
include extending the service life
of wood products, and reusing and
recycling them”.
More importantly, for all these
calculations on carbon storage to really
contribute to the larger picture, the
furniture has to be manufactured with
MARCH / APRIL 2024 | PANELS & FURNITURE ASIA 17