Good News: Coffee Waste Helps Forest Trees’ Growth

Photo by Karolina Kołodziejczak from Unsplash

We’ve recognized how getting that caffeine buzz helps us be adults and accomplish our daily tasks. In fact, you may be sipping on a cup of joe right about now.

But who knew that trees could also benefit from coffee?

In a research report published by the British Ecological Society journal, Ecological Solutions and Evidence, results suggest that using coffee waste enables tropical forest recovery.

Why Use Coffee Waste?

Now, this is not a new thing at all. Reforestation communities are aware that using organic waste can accelerate forest succession. That is, making degraded land healthy again and enabling new tree species to grow on it.

The soil used in previous pastures often becomes degraded due to compaction and loss of nutrients. Aside from that, invasive grasses could take root. All these factors prevent new-planted trees from growing robust.

Enriching the soil with organic material can potentially overcome these challenges to forest recovery.

But why coffee waste in particular?

For one, it’s something that’s readily available. Coffee is among the largest manufactured products globally, with over 60 countries producing it.

To get coffee-fueled adults like us functioning, processors must get the coffee beans. They separate the seed from the fruit, pulpy parts, and other filmy bits. The seeds are then dried and roasted.

Processing coffee leaves a lot of waste – almost 50% the weight of an entire coffee harvest. To get an idea, a million 60-kg bags of dried coffee beans generates over 218,000 tons of pulp and gooey mucilage.

These byproducts are actually nutrient-rich, containing carbohydrates, protein, and lignin – prime for composting.

But even if this is the case, coffee waste is only seldom used for farming. The pulp is typically discarded or minimally processed.

Coffee Waste: A Resource for Forest Trees’ Growth

In the study, researchers from ETH-Zurich and the University of Hawaii used 30 dump truck loads of coffee byproducts on a 35 x 40m area in southern Costa Rica.

The land was a former coffee farm now being used for conservation. The region has been described as being moderate to highly degraded in terms of soil condition.

To compare the results, a control land area with a similar size was also observed.

So what happened?

Researchers report that within just 2 years, there were striking differences between the soil enriched with the coffee pulp and the control area.

Photo Source: Coffee pulp accelerates early tropical forest succession on old fields

The area treated with coffee waste turned into a small forest in such a short time! Meanwhile, the control plot remained dominated by non-native pasture grasses.

Tree growth also improved significantly. The treated area had a canopy cover that’s four times taller than that of the control land.

These results suggest that adding half-a-meter deep of rich organic material changed the soil chemistry for the better. Aside from that, the coffee waste changed the forest floor. It prevented invasive grasses from competing with the plants.

What’s Next

While the study had positive results, the researchers are keen to note that much work still needs to be done.

This is just a single case study. It remains to be seen if using coffee waste can be replicated in other land areas, with a broader range of conditions.

And the recorded observations were in a span of two years. The team wants to observe the land longer, to find out if there are any long-term effects that may be detrimental to the land.

There were also other caveats.

While raw coffee waste benefited the forest trees, it’s still that: waste. It contains organic pollutants that may be hazardous to human health. For example, traces of pesticides used in farming coffee could impact water systems, causing excess algae.

Putting truckloads of coffee waste in a big patch of land will also make the area pretty stinky. It will attract a lot of flies and pests.

Therefore, one big consideration is that the land in which it will be spread should not have any residential or water systems nearby.

Researchers advised that like in the study, the land used must be relatively flat and bare, so there will be a lower risk of contamination. Their future research will also look at the potential impact on surrounding areas.

Caveats aside, these latest findings illustrate how coffee waste can significantly support reforestation, specifically on tropical lands. It’s an exciting prospect to utilize waste to help the environment.