Arthur,
Your asking all of the right questions and what your really getting at is the importance of life cycle assessment as a decision making tool for AEC professionals. I've done a lot of work performing life cycle assessments for buildings and my short answer to the question of "is wood good" would be
sometimes. The real answer is that it depends on a lot of variables that you hinted at such as forest harvest practices, transportation, alternate comparisons and end of life assumptions.
Your also correct that certainly not
all wood is good. For instance, if you were to compare worst case scenario wood (poorly harvested, shipped long distances, and landfilled or incinerated at end of life) to best case scenario concrete (low cement content, high quality aggregate, hyper local, and recycled at end of life) it would be relatively easy to prove through a life cycle assessment that wood would actually emit more carbon through it's life-cycle than the concrete alternative. However, if you start to tweak some of those variables wood can quickly prove to be the more environmentally friendly option.
Unfortunately there is no one-size-fits-all answer to your question. Wood certainly has the potential to be the more eco-friendly option, but it really depends on forestry practices. I'd encourage you to check out a few different resources:
- Open Letter for Climate Smart CLT
- A great summary of the concerns about the mass timber trend and recommendations for navigating it.
- Carbon Leadership Forum
- University of Washington collaboration dedicated to reducing embodied carbon in buildings. Lots of tools, resources, and network links.
- Embodied Carbon Network
- Knowledge network platform under the umbrella of the Carbon Leadership Forum. Endless ways to get involved, ask questions, find events, and get connected on all things embodied carbon.
Hope this helps!
------------------------------
Brad Benke AIA
Seattle WA
------------------------------
Original Message:
Sent: 06-12-2019 11:15
From: Arthur Adams
Subject: Is Wood Good?
Wood is great stuff, it is a natural product, renewable, can be shaped, fabricated in many useful objects, and it can become Art.
But is it environmentally responsible to use it to build large buildings?
Here on the east coast of the United States many multistory multifamily buildings have been built in recent years utilizing wood almost exclusively as structural members. The international press has carried news stories describing a number of ground breaking multi-story mid-rise buildings recently utilizing wood with many more in the planning stages. When these buildings reach the end of there useful life will the wood materials be recycled? What will be the cost to remove the wood from a large building? - will the wood still be useful? What is the total embodied environmental and energy cost utilized in transportation, fabrication, and construction when utilizing wood? If consideration is made for the amount of carbon a tree will extract from the environment over its lifetime what is the cost in terms of the carbon cycle and balance sheet if the wood is not recycled? Are we just crating a large problem for future generations by using wood? How will they recycle or dispose of it?
Wood initially is inexpensive - the alternatives steel and concrete are initially more expensive and have higher carbon footprints related to there initial raw material extracting and manufacturing processes. Steel can be recycled and remanufactured efficiently and economically today. Concrete can be recycled. Given the amount of energy (carbon) expended over a lifetime of recycling do these materials provide less of a carbon footprint that cutting large amounts of trees, fabrication of structural and standardized building elements, and construction for wood buildings? There have been press reports for recent advances in reducing the amount of energy (carbon) to manufacture concrete, its carbon footprint is being significantly reduced. Given the carbon cost and the initial energy expended to manufacture steel and concrete are they less expensive compared to the cost of wood if those materials can be recycled and wood cannot over time?
The question is "Is the race to use wood good"?
Arthur Hall Adams/ARCHITECT/AIA/LEED AP
AHAdams&Company
PO Box 1166
309 Davisville Road
Willow Grove, Pennsylvania 19090
p215.659.8844
f215.659.8873
www.ahadamsco.com
P Please consider the environment before printing this email
Confidentiality Notice: This email is for the use of the intended recipient(s) only. If you have received this email in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not keep, use, disclose, copy or distribute this email without the author's prior permission. We have taken precautions to minimize the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. The information contained in this communication may be confidential and may be subject to client privileges. If you are the intended recipient and you do not wish to receive similar electronic messages from us in future then please respond to the sender to this effect.