When people stroll through a forest, they often overlook the seemingly inconspicuous pieces of dead wood scattered across the forest floor. Little do they know that these logs play a crucial role in providing habitat for arthropods and fungi, and contribute significantly to the forest’s nutrient cycling. In this post, I share my journey into the heart of the tropical forest, hauling hundreds of dead wood pieces to explore their impact on ecological interactions.
Beetles, termites, ants, and more, occupy these logs using them as a nesting spot or as a place to find food. Fungi withdraw nutrients from various components of dead wood, including cellulose and hemicellulose, and use them to grow. Anthropogenic disturbances such as deforestation decrease dead wood amounts on the forest floor. And yet, the recovery of this forest component through strategies like restoration is rarely studied in the tropics where it is typically harvested for fuel.
Due to its pivotal role as a habitat and its influence on nutrient cycling, my goal was to assess the possibility of restoring ecological interactions between dead wood and its inhabitants. Specifically, I aimed to investigate how both active and passive restoration methods influenced the recovery of insect-mediated dead wood decomposition.
The focus of this post is the often-untold stories behind the scenes of scientific research—fieldwork. While peer-reviewed papers seldom delve into these narratives, fieldwork is the stage of science filled with anecdotes, adventures, camaraderie, and hard work. I will be sharing the study’s results in an upcoming post.
A Resplendent Quetzal, watching from its nest inside a standing dead woody debris piece.
Preliminary design – Control and caged dead wood
To establish my experimental setup, I obtained approximately 300 logs of uniform size from the Inga edulis species. This abundance of logs provided good statistical power, and using the same species ensured proper replication. Since the study aimed to examine both decomposition and the influence of arthropods, it needed various treatments, including caging a subset of logs to prevent arthropod colonization.
After securing a farmer’s permission to cut Inga trees at a reasonable price, we started our work at a coffee farm near Las Cruces. It took approximately four round trips to fill Juan Abel’s truck with logs for temporary storage in Las Cruces before introducing them into the field
The pieces of dead wood that we cut at a coffee farm near Las Cruces. It took us around four round trips to fill our truck truck with logs to bring them to Las Cruces for temporary storage before introducing them in the field.
Upon cutting the logs, the challenge arose of affixing them to the ground, especially on steep sites. In Costa Rica, where bamboo is versatile for various purposes, we obtained stakes from Roy, a local landowner. These stakes, crafted from bamboo, served to prevent our dead wood from rolling down the hills.
One of our control logs in an old-growth forest site. We later nailed numbered aluminum tags to our logs for easy identification.
Crafting cages for the logs proved to be a more intricate undertaking, but thanks to the construction skills of my field assistant, Johan, we developed a design that seamlessly combined effectiveness and durability. Originally, I had envisioned a somewhat rudimentary “sausage” device utilizing aluminum mesh to enclose our logs. However, Johan’s ingenious suggestion involved cutting and bending aluminum curtain rods, which we affixed to the structure. This modification served the dual purpose of reinforcing the cage and preventing potential damage from falling branches. The assembly process involved securing the aluminum rods to the net with fisherman’s thread, a method that was not only efficient but also robust. The successful outcome of our design can be observed in the image below showcasing both a test cage and an in-situ cage.
Our log caging design. Left: a visual of the caged and control logs in a restoration plantation. Right: a close view from one of our cages.
Introducing logs inside restoration sites
With logs secured and insects excluded, the formidable task of introducing all 300 logs into 15 restoration plots began. Control logs were introduced with minimal effort since they only needed staking. Cages took longer, requiring the assembly of components on-site. Our transportation methods for the logs varied depending on the topography of the restoration sites. For flatter sites with road access or well-established trails, we efficiently used a wheelbarrow. In instances where sites were more challenging to reach, we employed two large duffle bag backpacks, each accommodating approximately four logs along with the necessary materials. For the farthest sites, a routine of hauling logs back and forth into the forest twice a day ensued, resulting in a daily trek of around 12 kilometers. The physical toll was palpable, leaving a lasting impression on my legs. The entire process, from daily field trips to introducing the logs—staking and cage construction included—spanned roughly three months. Subsequently, we left the logs to decompose and be colonized by arthropods over the course of a year.
Left: Me pushing the wheelbarrow up the hill to bring logs to our closest site, Julio Gonzales. Right: our wheelbarrow in the middle of an old-growth forest trail. That was as far as we could take it. We hauled logs in our arms from that point.
Final Remarks
Overall, this was probably one of the toughest field seasons I have had. Not only was I constrained due to my project being concomitant with the covid pandemic, but the physical work was demanding. And yet at the same time, this was one of the best field experiences I’ve had. We spent large amounts of time walking up and down trails, during a time when barely anyone was visiting the forest. This quiet period allowed us to see lots of birds and fauna that were uncharacteristically visible, unencumbered by the usual human-induced noise. Below, I’m sharing pictures of some of our findings. One time, a group of Capuccin monkeys tried to steal our lunch bags. When we caught them in fraganti, they started throwing branches and yelling at us from the safety of the trees – Truly, a gem of a moment which will linger in my memory.
The spot where Johan and I rested halfway through our backpack-laden trek, listening to the rain and the soothing sounds of the river
The forest’s symphony of cicadas singing in unison around noon provided a poignant backdrop to our fieldwork. The cacophony, at times drowning out our voices, served as a reminder of the beauty of nature and the tranquil moments experienced at Las Cruces.