Trees absorb CO2, and one hectare of pine forest can produce between 2 and 10 cubic meters of wood per year. But is that enough to consider wood as an ecological material? What is the function of forests: to produce wood for our use, or to harbor life and serve as a home for living things other than ourselves?
Wood is probably the most beautiful and versatile of all materials, but asking the right questions is crucial to designing most smartly and sustainably.
From pine, oak, walnut, walnut, beech, mahogany, teak, or cedar. There are as many types of wood as there are types of trees, and at the moment there are at least 70,000 species. To say wood is a generic term because each type has its characteristics. More resistant, softer, more rigid, and stable, or the opposite and something quite important, with a differentiated growth time and coming from different ecosystems. These conditions mean that their use and their environmental impact are radically distinct.
So wood can either represent the ultimate green material or become an unforgivable environmental crime.
So planting trees in deforested areas is surely a good option, and obtaining low carbon footprint materials after a few decades is a strategy in line with sustainable development goals. However, cutting down primary tropical forests can never be an option. Or worse, introducing alien species in monoculture and FSC-certifying industrial exploitation, thus implying the sustainability of the process when it is not sustainable at all.
Trees are the longest-living things on earth. They grow very slowly and at their maturity form the characteristic trunk made of a superbiomaterial composed of cellulose and lignin that we call wood.
Historically, wood has been the most fundamental material for humanity, and without its presence, it would have been impossible to imagine the evolution of people as we know it.
Houses, transport, furniture, even fire itself... The material basis of all societies is in one way or another related to wood. Its significance as a material can be found in its etymology. Wood comes from the Latin "materia" and at the same time, "materia" comes from mater, mother. Wood is a generic material and material as the mother of humanity. The fact is that ancient societies expanded all over the planet thanks to the fact that wood could float and allowed the manufacture of precarious rafts. And they transported goods and people effortlessly over great distances thanks to the wheel made of wood. They heated and cooked food thanks to the calorific power of the wood that fed the fire.
Wood is strong and does not require large machines to work it, nor heat treatment. It is accessible, nearby, and if sourced correctly, it can be inexhaustible. It grows without energy, emits no fumes, and the green of its leaves always feels good. But trees are not factories. Trees are part of the forest, and the forest is home to other life forms, animals, plants, and microorganisms essential to keeping the planet alive and healthy. Forests are ecosystems rich in biodiversity that regulate the planet's climatic conditions, filter air, regulate humidity, keep the soil healthy, and so many other functions. However, as a material, it undoubtedly has a low environmental impact if its production is properly managed. It is widely argued that making the forest productive improves its maintenance and growth. The fact is that in the world's temperate zones, where the original forests such as Europe and North America no longer exist, woodlands are growing so fast. It is all the result of human action. However, in the tropical belts, where the primary forests and jungles are concentrated, the ecosystem is in decline because of the same human action.
The great lungs of the world, the great reservoirs of biodiversity, are diminishing, and this is as serious a threat to the planet's stability as, if not more dangerous than, the rising temperatures of climate change.
The thousand materials of wood: derivatives and cascading utilization
Wood is like they say about pigs: everything is used. And there is a regulated form of what is known as the cascading use of forest products. This is a planning process in which the remains of one process are fed for the next. For example, to obtain solid wood lumber, a waste stream of branches and bark is generated, which is used for bioenergy, livestock farming or composted to produce fertilizer for agriculture. The bark is left over, chipped, and used in the board industry, while the sawdust can be used for paper pulp or bioenergy. Once the wood is used in formats such as treated, varnished, or painted wood panels or strips, it is hard to recycle because of the glues and products added. On the other hand, untreated wood, such as that used in pallets or industrial bins, can be transformed into new materials such as chipboard, which contains at least 30% recycled material from precisely these sources.
Wood as a renewable material and the risks of the nice press
A product made of wood that lasts less than the time it took for the tree to grow should not be considered sustainable.
It is so simple. If we cut down more trees than grow, the resource starts a decline in the stock. So there must be a harmonisation of the rate of pressure on the resource about its natural renewability. There are some super-fast-growing species like poplar used in panel production that take about 15 years to mature, but others such as beech or oak need at least 100 years to be transformed into their precious wood. Therefore, wood can be the most efficient and environmentally friendly material in architectural design with a decades-long life span. During the lifetime of a house, the forest regenerates again. However, in other applications like vegetable crates with a function that does not last more than a week, there are severe doubts that it is environmentally a good choice. When contemplating sustainability, it cannot be forgotten that the time factor is as important as any other pollutant.
To say that using wood in a piece of furniture makes it sustainable is pure greenwashing.
Whereas in the 1980s and 1990s, the use of wood was directly associated with deforestation and met head-on with incipient environmentalism, today the idea of wood as synonymous with green has become established. The argument that it is the "age of wood" and that our world will be sustainable if we make it out of wood, is a simplification that a priori presents some problems. Firstly, one-size-fits-all solutions are never good advisors. Secondly, it depends. Wood, like everything else in life, has its virtues and its defects depending on its context. Let us celebrate diversity, also in materials, and let us be aware that a sustainable material is sustainable according to its application, its use, and its design, and not only by its nature.