The Submerged Timber Diver

The Submerged Timber Diver

Timber! Divers coming...

As divers, we all know how much history is buried under the surface. We may think about the history of wrecks, caves, mines or even how marine life evolves... but what about the mysteries and treasures of submerged timbers?  

Historically, in Canada, logging is part of the economy and until about 30 years ago, log diving was considered a highly skilled job. For nearly 2 centuries, logging companies used the waterways to transport all the wood to mills downstream until it became forbidden in 1996, due to the high level of pollution of that activity. During all that time, many lakes were covered by woods at a point that even sometimes you couldn’t see the water anymore.  This might sound like an old-time story that can only be remembered with the elders or archive pictures but…now we know that among all the timbers that traveled on the surface of rivers and lakes for nearly 2 centuries, at least 15% just simply sank to the bottom of all those bodies of water. For decades, all the submerged wood just sat there, at the bottom of lakes and rivers without being remembered, until some people decided to do something about that pristine and well-preserved wood that could eventually be used.  



How much wood is there?

What kind of effect does it have on the environment and what is going to happen if we remove the logs?

Is it worth it, both economically and ecologically

So many questions had to be answered! I wanted to explore to better understand the effects of the top industry for so many years. But first, I really wanted to go underwater and see with my own eyes what was left from the amazing time of the timber diver. So I transformed myself into a timber diver and traveled to different areas in Quebec to see what was going on.

First of all, for once, I will not have to go deep. This will change my diving. No need to carry tons of bail out with my CCR. I would just need a single tank, a dry suit, my camera and a couple of lights to let me witness trees that are lying down for so many years. I suspected sediments would be a challenge and logs might be buried under them. 

Like in most lakes, visibility is not the best. Just a couple of minutes after I started my dive, I was confused, I found an unknown structure made of perfectly vertical wood pole without bark on them. As I look closer, no marks, no nails, no mortise, no nothing. I plunge to the bottom to see how that wood is attached and what its purpose might be.  As I put my face just inches above the sediment, I can see the perfect saw cut on the wood. I put my hand on it and gently push it just to see how strong it is. It started to move. Really! That piece of wood is a log that is still standing up straight as if it was just standing to be removed.  



As I dive more and more navigating among the wood logs, I can see how differently they evolve. Some of them are still standing; some of them are free of their bark, some of them covered with sediment or even plants and algae. It was time for me to talk to my friends at the University and at Parks Canada. 

For the past 20 years, a big restoration project is taking place in La Mauricie National Park.  It is one of the most affected areas of wood logging. Removing logs from the bottom of the lakes and their shores help to restore the natural water level and the natural ecosystem. Still, fish need to be reintroducing like native brook trout that nearly disappeared. The accumulation of sediment and deterioration of the shoreline habitats damaged the reproduction and rearing grounds for brook trout. On top of the wood industry, the venue of fishing club and extensive fishing with baitfish, introduced non-native species. These exotic species compete with or prey on the brook trout. This story, kind of, sounds familiar with what is going on nowadays...but it happened starting in 1883.   

It looks like we are not always learning from the past.   

The number of structures, more specifically the splash dam to redirect the logs had an effect on the water regime. At that stage, archeological work needed to be done before dismantling structure. One of the 100-year-old structures is still in place in one of the lakes and I could do the photogrammetry of it.  

Luckily, with this technology we can see them way better than with our eyes. 

If the restoration of the lake is important, what can we learn for the logs themselves? It was time for me to go up north and dive with the scientists at the UQAT University.   

I had to go back on the road and drive up north 600 km. As I was getting close to the spot, I could see the sky getting yellowish. A color, that unfortunately, we get accustomed to in Canada, due to wildfires. I park my van on the side of the lake, preparing my equipment with the song of the loons as my music background. I must admit this is one of the great benefits of those exploration in the woods, waking up early with the sun and getting to bed with the song of nature.  



The next morning, researchers and log divers arrive with their boats and equipment. Time to document the evolution of the lakes and the work of the log divers. 

A small efficient team of 4 people go every morning on the lake once it is free of ice to harvest the wood. A diver, in a wetsuit and equipped with a Shearwater dive computer, jump in with a rope that it will attach on the log. At the end of it a float will be released so the log can be lifted to the working barge. The diver takes the next rope for the next log and so on until he or she has enough air in their tank. The more you do on a single dive, the better it is. At the end of the summer they hope they can remove more than 4000 logs to be milled and then sold for high end furniture or construction. The quality of log is higher than the trees cut now.   

During my dives, I can film the before and after of log removing. I was amazed by the depth of sediment and bark left on the bottom of the lake and how after a couple of months you couldn’t see the trace of the logs anymore, as if they were never there. But still, the impact of removing logs on the ecosystem needs to be studied to qualify and quantify the impactHow bad will the aquatic invertebrates be affected when we remove the wood debris and on the other end how will oxygenation improveFor this multi-layer project, university programs in ecology, dendrochronology, and forestry are partnering with a wood log diving companies. Wood logs can tell us about the past of the unique old-growth forests that do not exist anymore. We will be able to learn about fires, epidemics and provenance of the trees and companies who harvested themThis will help us to better understand climate change and how we can protect the forest in the future.  



Working on this project has a unique meaning this year, as Canada reports its worst wildfire season on record. In 2023, over 14 million hectares of land burnt. Not only are we losing forest but as they burn, water sources get polluted, people lose their homes, air quality gets bad with the release of carbon dioxide and wildlife is getting more and more endangered. 


Written by Nathalie Lasselin


Nathalie Lasselin is a multi-award winning underwater cinematographer. As a technical diver and instructor, she has filmed and explored deep wrecks, caves and body of water in more than 50 countries including the Arctic. Nathalie pursues better understanding of our planet through documentation and shares her concern for our fresh water resources through her films and as a public speaker. Her drive is to bring people together and empower them through better relations with their own environment and ultimately for a higher quality of life. Her latest project Urban Water Odyssey embraces all her goals and philosophy.