Merbau is a favorite wood for furniture and household projects because of its aesthetic color and durability. Merbau timber weathers well and stands strong against termite attacks. However, high demand for this valuable hardwood drives unsustainable harvesting practices and illegal logging in tropical forests, causing great biodiversity loss. So we had to ask: How sustainable is it to buy products made with merbau wood?

Merbau wood is generally a sustainable wood thanks to its carbon sequestration and storage. However, the high ecological cost of tropical forest deforestation due to logging and the long transporting distances make this tropical timber less sustainable than timber from local, temperate forests.

In this article, we’ll walk you through the life-cycle of merbau wood used for furniture and decking. Then, we evaluate its sustainability, potentials, and shortfalls. And in the end, we’ll show you tips for buying sustainable merbau wood. 

Here’s How Sustainable Merbau Wood Is

Merbau is a type of hardwood desired for outdoor furniture and flooring, especially in outdoor settings. Unfortunately, merbau species are vulnerable to illegal logging and unsustainable harvesting practices in most of their native growing regions. Still, it is important to note that wood is better for the environment than plastic, especially when sourced from sustainably managed forests.

“Sustainable: The ability to be maintained at a certain rate or level | Avoidance of the depletion of natural resources in order to maintain an ecological balance”

Oxford Dictionary

To understand the sustainability of merbau wood, we assess the life-cycle of projects like flooring or decking. This life-cycle assessment (LCA) is a method to evaluate the environmental impacts of each stage in a product’s life-cycle, from the making to the recycling. Over the years, companies have strategically used LCA to research and create more sustainable products. 

We’ll say that it is possible to find sustainable merbau wood for furniture and musical instrument projects. However, the actual environmental impact of a particular product, like garden decking or guitar fingerboard, depends on many factors, especially the forest management practices and the distance and mode of transportation. Let’s dive deeper into each stage and find out how it can be more sustainable. 

How Sustainable Is the Growing Merbau Wood

Growing merbau in its native tropical forests is sustainable because of carbon sequestration and storage in the tree and its rooting system. However, logging practices are a cause for concern because of unsustainable harvesting, illegal logging, and wood originality fraud. 

What Type of Wood is Merbau and What Does This Mean for Sustainability

Merbau trees are hardwood trees of the genus Intsia. Intsia bijuga is the most widely distributed merbau species. They are slow-growing tree species, taking 75 to 80 years to reach maturity. That is much longer than many temperate softwood trees. For example, a pine tree typically reaches maturity (and can be harvested for wood) at 25 to 30 years old. 

How Sustainably Does Merbau Wood Grow

Living merbau trees can mitigate global warming impact through carbon sequestration. However, merbau species are vulnerable to logging, which means harvesting merbau timber is much less sustainable than harvesting, for example, Douglas fir or maple timber. The reasons for merbau’s vulnerability are its slow rate of replacement and low stock in natural forests. 

• A slow rate of replacement: Merbau trees grow sparsely even in rich forests. This means two things. Firstly, the population of old-growth merbau trees is relatively small. Secondly, loggers often end up cutting down many other trees to reach a targeted merbau tree. Once a merbau tree is cut down, the replacement trees, if planted, would take a comparatively long time to reach maturity. During the young and growing stage, these trees are at risk of infection and damage. Together, the low density and the slow-growth rate result in the poor replacement of merbau trees. 

• A diminishing stock in native forests: A Greenpeace report predicts that most of the remaining merbau will be gone by 2043 at the current official rotation cycle for logging. The figure does not consider widespread illegal logging, which exacerbates the rate of destruction and will increase the speed at which merbau disappears. Intsia tree species are listed as “vulnerable” on the IUCN Red List of threatened species as they are considered to be facing a high risk of extinction in the wild.

When merbau trees are grown in sustainably managed forests, the carbon sequestration and carbon storage in tree trunks and roots (as well as in timber and wood products) contribute to its being more sustainable than materials like wood plastic composite.  

• Carbon sequestration: As merbau trees grow, they absorb CO₂ from the atmosphere while releasing oxygen. During their lifespan, they act as a carbon sink. This means that they are taking greenhouse gases out of the atmosphere, helping to mitigate the climate crisis. And they can store a lot because they grow tall and large. In tropical forests, merbau trees can reach 130-200 feet in height and 4-5 feet in trunk diameter.

Where Is Merbau Wood Usually Grown

Merbau trees were originally found in Eastern Africa, Southern India, Southeast Asia, and some Pacific islands. Today, only in Indonesia and Papua New Guinea, merbau trees grow in significant commercial quantities. 

Harvesting merbau wood from natural forests can result in biodiversity loss. One example is when loggers only cut down the biggest and tallest trees. That pattern would cause a reduction in the genetic diversity and quality of the trees within the stand, leading to gradual degradation of tree quality. Clear-cutting a large area of forest to reach a few merbau trees also hurts the forest’s biodiversity. 

Intsia bijuga (a species of merbau) trees make up a core foundation of the mangrove swamps, a unique and highly beneficial ecosystem that is important to Northern Australia and Southeast Asia. Wildlife such as shrimp, crabs, mud lobsters who make their home in those swamps is losing their habitat to timber harvesting. Mangrove swamps protect us from storm surges and tsunamis thanks to their ability to absorb wave energy, and losing them is losing our defense against natural disasters. 

The biggest problem with merbau wood’s sustainability is that illegal logging and fraud trading of the species are widespread and treacherous, driven by poor governance in growing countries and high demand from importing countries like China. Greenpeace estimated that up to 80 percent of logging in Indonesia, the main origin for merbau timber, is illegal. 

The only way for consumers to tackle problems caused by illegal logging is to source sustainable woods. We will point you in the right direction with merbau in a later section. 

In total, logging of forestry products from plantations accounts for 26% of forest loss, which is a combination of deforestation and forest degradation. However, the loss in bio-diverse forests in tropical climates is more significant (and sometimes less properly recorded) than in temperate, well-managed logging forests. 

How Sustainable Is the Manufacturing of Merbau Wood

Turning merbau wood into a product, such as garden decking or a drum, can have a relatively low carbon footprint when wood waste is utilized to make by-products or biomass pellets to offset the carbon emissions during harvesting and processing. Significant reduction in carbon emissions can also come from using fossil-free energy. 

The first step of manufacturing merbau furniture involves cutting down trees and turning them into lumber in a sawmill. Sawing is an electricity-consuming step. 

The next step is to dry lumber and turn it into furniture. Merbau is a slow-drying wood, requiring more energy if using a kiln. However, a significant part of the energy needed for kiln-drying can come from burning wood waste. At least 90% of all thermal energy used for kiln drying in the US hardwood sector comes from such biomass. 

How Sustainable Is the Transportation of Merbau Wood

Transporting is a carbon-intensive stage in the life cycle of merbau furniture due to the emissions associated with operating the hauling vehicles that take timber to sawmills and factories, then furniture to stores.   

As merbau timber in the US would typically come from Southeast Asia, transporting merbau products has a higher carbon footprint than furniture made with regionally available wood, like oak or pine.

The actual emission during the transporting stage depends on the type of vehicles used, the fuel they need, and the distance the wood travels. Calculations made by the Norwegian Forest and Landscape Institute showed that smaller wood hauling trucks emitted more CO₂ per transported cubic meters of timber: 1.25 times more than larger wood hauling trucks, 1.3 times more than sea vessels, and six times more than freight trains. Therefore, the sustainable transportation option would be rail or large trucks running on biofuel. You can check with your wood suppliers how their products are transported to and within the US and opt for the more sustainable option. 

How Sustainable Is the Usage of Merbau Wood

Using merbau furniture can be sustainable thanks to the carbon capture during the products’ long life. 

Merbau is highly durable, thanks to its density and strength. The wood contains natural oil with a high tannin content, contributing to its resistance to weathering, decay, and termites. In terms of lifespan, even outdoor merbau products can last for decades, somewhere between 15 to 40 years.  

When merbau wood is decayed, either naturally in the forest or because of damage caused by usage at home, the carbon stored in the wood is released back to the atmosphere. Therefore, long-lasting furniture can be considered a good way of keeping carbon out of the atmosphere. If the wood is then reclaimed for making another piece of furniture, its positive carbon storage environmental impact is even higher. 

How Sustainable Is the End-of-Life of Merbau Wood

The end-of-life stage for merbau furniture is sustainable when the wood is reused or burned as bioenergy. 

There are a few scenarios for wood products – furniture and other household projects – at the end of their life. 

They can end up in landfills and don’t decompose. In this case, they’d keep their role as carbon storage. 

Wood products can also be upcycled and reused, extending their role as carbon storage and reducing the fossil CO₂ emitted as much as four times when comparing, for example, a recovered hardwood flooring with a new one. New wood products often travel much further to their markets, compared with recovered wood products. The latter is typically made in urban centers and sold locally, which lowers the transportation environmental burdens. 

In another end-of-life scenario, products like a merbau table can be burned for biomass energy displacing coal or natural gas in generating electricity.  

With smaller items, like a guitar fingerboard, the offset won’t be as high as there is much less waste for burning. However, if such products are made from wood waste as by-products, their carbon footprint is minimal. 

How Can You Buy Merbau Wood More Sustainably

The key to sustainably buying any wood is to check on relevant environmental and original certifications. Reliable certifications for sustainable woods are: 

• Forest Stewardship Council: 

An FSC certification ensures that the merbau wood comes from responsibly managed forests that provide environmental, social, and economic benefits.

• Program for Endorsement of Forest Certification: 

PEFC’s approaches to sustainable forest management are in line with protecting the forests globally and locally and making the certificate working for everyone. Getting a PEFC certification is strict enough to ensure the sustainable management of a forest is socially just, ecologically sound, and economically viable but attainable not only by big but small forest owners. 

Because there is a high risk of illegal and unsustainable logging for merbau timber, make sure you only buy merbau furniture with an FSC or PEFC certification.

Why Is It Important to Buy More Sustainable Wood

Buying sustainable wood also means helping to prevent illegal or unsustainable logging, which harms the forests’ biosystems and accelerates climate change. 

Logging of forestry products from plantations accounts for 26% of forest loss. Cutting down trees for wood has a lesser impact on carbon storage than digging up the whole forest floor and turning it into farms or mines. However, if logging is not sustainably managed, it can badly damage wildlife.

When logging happens in tropical forests – the bio hotspots of our planet – the biodiversity loss can be much more damaging. Subtropical and tropical forests are packed with unique wildlife – endemic mammals, birds, and amphibians. The displacement of such wildlife during poorly managed logging would be a major contributor to global biodiversity loss. 

Sustainable management of forests also means that trees are cut down for timber only when they are mature. These trees will then be able to regrow and eventually replace the loss of canopy, absorb carbon from the atmosphere and reduce the effect of climate change. 

Final Thoughts

You can buy sustainable furniture and flooring made with merbau wood as long as the material comes from sustainably managed forests. However, because merbau is an imported tropical wood, it has a higher transportation carbon footprint than hardwoods from temperate forests in the US or even South America. If you decide to use merbau for any wood project, make sure to use it for as long as you can, upcycle the material to extend its usage, and arrange for it to be recycled fully.

Stay impactful,

Sources

• Reuters: Ditch metal and plastic and turn to wood to save the planet, says U.N.
• Science Direct: Life-cycle assessment (LCA)
• MIT SMR: Strategic Sustainability Uses of Life-Cycle Analysis
• TRAFFIC: REVIEW OF TRADE IN MERBAU FROM MAJOR RANGE STATES
• Impactful Ninja: How Sustainable Is Pine Wood? Here Are the Fact
• Impactful Ninja: How Sustainable Is Douglas Fir Wood? Here Are the Facts
• Impactful Ninja: How Sustainable Is Maple Wood? Here Are the Facts
• NexGENDECKING: Merbau Decking – it’s TIme to Rethink
• Greenpeace: Shut the door on illegal merbau
• IUCN: IUCN Red List of Threatened Species
• OKLAHOMA STATE UNIVERSITY: What is Wood Plastic Composite?
• THE WOOD DATABASE: MERBAU
• Research Gate: The Asian Tsunami: A Protective Role for Coastal Vegetation
• Our World in Data: Deforestation and Forest Loss
• Tropix: MERBAU
• American Hardwood: Environmental Life Cycle Assessment
• Impactful Ninja: How Sustainable Is White Oak Wood? Here Are the Facts
• Science Norway: Larger logging trucks give less CO₂ emissions
• Build.com: Merbau decking and pergolas
• Softwoods.com: Merbau decking: All you need to know
• Research Gate: Life cycle primary energy and carbon analysis of recovering softwood 
• Impactful Ninja: What Is the Carbon Footprint of Biomass Energy? A Life-Cycle Assessment
• Forest Stewardship Council
• Program for Endorsement of Forest Certification
• Our World in Data: Epidemic Mammal Species