Plywood consists of an odd number of thin wood veneer sheets with formaldehyde glue sticking them together. Pressure and heat are applied to the wood veneers to stick them together and create durable plywood sheets. These sheet materials can be used in many applications, including building and furniture construction.

Lighter and less dense than natural wood, plywood sheets can nonetheless look like solid wood and can be customised with various types of wood as the top face. Panels of plywood are vital because the wood grain is alternated on each layer (cross-graining) to create a more robust material that is less likely to warp. 

Plywood is a versatile material which can be used for a wide range of different projects. Different types of plywood lend themselves to various uses, such as roofing, furniture making, and flooring. 

For example, panels of softwood plywood (made from pine, cedar, spruce, fir, or redwood timber) are ideal for construction and packaging. Meanwhile, hardwood plywood (made of mahogany, birch, poplar, beech, or oak timber) is a more robust and durable material used for factory walls, floors, or heavy-duty containers. 

Another type of plywood is marine plywood because it can be used for boats or wet environments. Marine plywood is highly durable and resistant to water, so it can be used for these applications.

One way to determine whether a material is sustainable for our planet is by looking closely at how it is made. 

The process of manufacturing plywood products begins with cutting down trees. This may conjure images of machines tearing down the forests but don't worry -- this timber can be gathered sustainably from well-managed woodlands. In these cases, there are limits on the number of trees cut down to protect the forest's natural resources. The organisation will also plant new trees to keep the forest healthy and sustainable.  

The next step is to strip the branches and bark off the trees. This waste can be recycled for other purposes or used as biomass fuel. The remaining hardwood or softwood logs are chopped up, heated, and soaked in water. Next, super thin veneers are peeled off the logs, ranging from around 1.5mm to 4mm in thickness.

The dried veneers are glued together with their grain at right angles using glue with heat and pressure. This lamination process gives the engineered wood strength and helps protect it from warping or shrinkage.

While plywood is generally reasonably good for the planet, some plywood is better environmentally than others. 

Birch plywood is the best type for sustainability. Birch is a hardwood that is great for plywood production for several reasons:

1. Birch trees are abundant in the planet's northern hemisphere, proliferating for sustainable logging.
2. They support natural wildlife when managed as a sustainable forest resource, meaning they contribute to the forest's natural biodiversity without disrupting it.
3. Almost every part of the hardwood tree can be used, including the twigs and bark.

Even waste timber at plywood mills is recycled for use in other materials and purposes. 

Another factor that makes plywood score high on sustainability is its long-lasting and durable nature. This means that things made from plywood -- furniture, flooring, home bars, for example -- will last a long time without needing to be replaced. This means that less material is being sent to landfill in the long run. As a result, plywood is an intelligent option for the environmentally-conscious professional

If you no longer want your plywood furniture or materials, recycling or reusing them is possible. Because plywood is often used as sheets or panels, you can easily reuse it for future projects after trimming off any damage and flattening the material if it warped. Cheaper and more environmentally friendly than buying new sheet materials, reusing your old plywood panels is a great way to be sustainable and save some cash in the process! Or, if you have no use for the sheet materials anymore, you could donate or sell them to someone else who can use them. 

Recycling plywood is a little more complicated, but don't let that put you off. Technically, plywood is a class B wood that has been treated, so it is recyclable but has to be recycled separately from class A untreated timber. Most places do not allow you to put wood and timber in household recycling bins, so you will have to hire a skip or take it to drop it off at a recycling centre. Here, it will be turned into recycled materials such as animal bedding alongside other old wood. 

Recycling your wood means it doesn't end up in a landfill and can be used sustainably for other purposes. Remember that the phrase 'reduce, reuse, recycle' is listed in order of importance. If it's possible to reuse your leftover or old plywood for another purpose, this is usually better than recycling it.