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Swing Through the Trees, Dive in the Seas: What Technical Diving Can Teach Arborists About Safety

Tree hugging arborist and safety consultant turned tekkie Brad Hughes is applying the lessons of technical diving to improving tree climbing safety. If the power saws don’t get you, the rapid descents will! Pre-climb checks anyone?



By Brad Hughes
Header image courtesy of D. McLaughlin Photography

As many of you scanned the title of this article you were probably thinking, “What does diving have anything at all to do with tree climbing?” You may have added,  “Whoever wrote this is a few split pieces shy of a full chord!”

Despite the naysayers, by the end of this discussion I hope to have convinced you all that, not only are there similarities between diving and tree climbing, but also there is something relevant to be learned from the way technical divers approach safety while operating in high risk environments. I also hope to encourage you to look outside the box to find new and novel ways to improve safety and performance for your organization and the tree care industry as a whole. 

Operating in high risk environments.
Photo by D. McLaughlin Photography.

When I started out in this industry, my job became my hobby, which I am sure is true for some of you as well.  I would climb after work and on the weekends in an effort to move myself up the organizational chart from “Brush Dragger Extraordinaire” to “Guy Who Climbs Too Slow to Be Useful”. Eventually though, after reaching the lofty status of “Knows Enough to be Dangerous”, I started getting a little burnt out and determined I needed something other than work-related activities to occupy my free time. I decided to pursue technical diving, since I was already certified as an entry level diver. Through my experiences and interactions in diving I have been exposed to many diverse ideas that have added to my understanding of operating in high risk environments. I have come to realize there is much to be learned from seemingly unrelated industries and activities, each offering a different perspective and risk analysis.

Through my experiences and interactions in diving I have been exposed to many diverse ideas that have added to my understanding of operating in high risk environments.

Applying The Principals of Technical Diving

Technical diving is a leisure sport, not to be confused with commercial diving, which is a trade similar to rope access. For the purposes of this article, technical diving will refer to any diving in an overhead environment. Overhead environments include caves where there is a physical barrier to the surface and deep diving where an immediate ascent to the surface is not possible due to risk of injury caused by ascending too quickly. Though tree work and diving are vastly different, I began to see similarities between tree care operations and diving. Both divers and climbers operate in high risk environments, use unique technical skills to conduct their operations, and are not easily accessible by rescue personnel in the event of an emergency. 

As in diving, a workable plan, allowing for contingencies, and deploying as a team is what allows for the safe removal of trees in the urban environment. Photo by Brad Hughes.

As I became more involved in diving and started reading training materials, talking with divers and instructors, and investigating accident reports, I realized many diving-related incidents shared common root causes with those that we commonly observe in tree work, including lapses in situational awareness, insufficient training, and a lack of planning and preparation. I began comparing technical dive training and procedures with those commonly employed in the tree care industry to see if I could glean any insights. 

As a result, I have identified areas where safety and performance could be enhanced by implementing the mindset, practices, and procedures that I observed in the technical diving community. Though I cannot relay all of my insights in this article, I will focus on two areas where I see the most immediate benefit for the tree care industry. These specific topics were also chosen due to their familiarity; OSHA and ANSI standards already mandate job training, gear inspection, and job briefings. In many cases, though, these requirements are not being met. My intent is to illustrate how another industry takes a different and possibly more effective approach to a task that is familiar to us as tree care professionals, but I would be remiss if I did not mention the importance of culture. 

Scaling up is not as easy as it seems! As tasks become more complicated and nuanced, experience becomes increasingly critical to positive outcomes. Photo by Brad Hughes.

In the absence of a willing culture, new ideas and perspectives will not flourish. The reason that some tasks—like job briefings and equipment checks—are often omitted can be attributed to a company’s or even an entire industry’s culture. Culture is an umbrella term that encompasses topics like leadership, accountability, attitude, just culture, and employee relations. In this context I am referring to an organization’s emphasis on safety and training. To put it simply, building a better checklist will do no good if it is not used. The technical diving community places an enormous amount of emphasis on safety and training which is reflected by its relatively low incident rate.

Dive Planning/Job Planning

Technical divers plan their activities with exacting precision. Once a dive has begun, it is impractical or sometimes impossible to retrieve a forgotten item, change equipment configurations, or get help in the case of an emergency; therefore, planning for each dive is critical. Technical divers will methodically plan their goals for a dive, assign team members areas of responsibility, calculate maximum amount of time allowed underwater at a given depth, evaluate decompression strategies, determine the amount and type of breathing gas to carry, identify environmental hazards, and complete gear inspections prior to entering the water. By applying this rigorous planning process to tree care operations, I believe that safety, performance, and profitability could be improved. 

Though we are not bound by the same constraints as divers, taking the time to identify hazards, assign tasks to the crew, create a detailed work plan, develop an equipment list, designate a drop zone and drag path, and plan contingencies will pay dividends overall. How much more efficient would your operations be if your employees were not required to go to the truck to retrieve forgotten equipment or maintain an item that should have been fixed after the last job. Have you ever arrived at a job site and realized that a necessary piece of equipment had been left at the shop? Have you ever climbed half way up a tree only to realize the main stem has a split in it? 

Mastery of fundamental skills allows for the safe execution of the seemingly impossible. Photo by Brad Hughes.

Mistakes like these could be the difference between a job being profitable or not. I decided to try planning my jobs and briefing my crews like I would plan and brief a dive. The crews that I work with are extremely professional, but even so, occasionally items would be overlooked. After implementing an improved planning process, I noticed that small things that were occasionally missed before were now being identified and mitigated before we started. Items like small yard ornaments, sprinkler heads, pre existing property damage, forgotten PPE, and hangers in incidental trees along the drag path were being identified before the job started. 

This might not seem like a meaningful improvement; however, if you consider the implications of a broken sprinkler head, a desecrated pet grave, allowing someone to work without PPE, or an injured employee, you can begin to see the value in a good plan. A mentor of mine once told me “Five minutes twelve times is an hour” in other words, little things add up costing lost time and money. 

A mentor of mine once told me “Five minutes twelve times is an hour” in other words, little things add up costing lost time and money. 


As stated above, technical dive training is rigorous and demanding. Dive training is also progressive, structured, and roughly standardized across the sport. This is something that I believe the tree care industry needs to improve upon if we are to get the most out of our workforce. In the technical dive training curriculum that I am working through, a student starts in a class called Fundamentals and then if they pass would have the opportunity to move onto Cave 1 and so on. In between classes there is a requirement to make a certain number of dives in specific conditions to ensure the student is ready to move onto the next stage of training.

 As a contract trainer, I have worked with companies to help them develop similar standardized training programs for their organizations. There are many benefits to having a structured training program in place. A structured training program provides documentation, which is important if a company were ever to have a serious incident. It is also repeatable. All trainees receive instruction on the same subject matter and are held to the same level of proficiency. This gives crew leaders and owners the ability to quickly evaluate where a particular employee falls on the skills spectrum and make crew assignments accordingly. Crew leaders would be able to immediately assess a crew member’s skill level and make job assignments that are appropriate even if that employee was not a regular member of their crew. 

Training is a continuous process, not an end state. Photo courtesy of Tree Care Industry Association.

If we were able to standardize this across the industry, hiring decisions would be made simpler knowing that a prospective employee had attained a certain level of training, even if at a different organization. I am an advocate for assigning a time frame for an employee to remain in any one category of the training program, allowing them ample time to master the skills required, but also making sure that training remains a priority. There is always more to learn, and I think encouraging people to keep moving forward, and providing the structure to facilitate that, not only benefits them but the organization as well. In the end you will have a more experienced, safe, capable, and professional workforce at your disposal. 

One of the great pleasures of doing what we do, whether below the water or above the ground, is experiencing the unique perspectives that those activities afford us. Photo by Brad Hughes.

My hope is that by sharing my experiences with diving, I will encourage other members of the industry to share their experiences and observations regarding occupations and areas of interest outside of tree care. As a contract climber and trainer, it is my job to continually raise the bar for safety and performance for myself, my clients, and the industry as a whole. I hope that all of you reading this will also heed that calling and add your voice, so at the end of the day we may all walk away. 

Additional Resources

Brad Hughes is the owner of Woodline Tree Care LLC. His company specializes in contract climbing and safety consulting within the tree care industry. Brad holds several credentials including being a Certified Arborist, Certified Tree Care Safety Professional, and an aerial rescue instructor approved by the Tree Care Industry Association. Brad has been involved in presenting and conducting demonstrations at industry events and, as well as conducting training for the National Park Service, OSHA and many others. When not swinging around in trees Brad spends much of his free time pursuing his other passion, diving. Brad was first certified by SDI in 2009 as an open water diver. Brad dove off and on as time allowed until he found GUE in 2017. After being introduced to some GUE divers his passion for diving really took off. Brad took Fundamentals in early 2018, and is currently preparing for Cave 1 in February of 2021.


Brits Brew Beer Booty

What do you get when you combine British divers’ proclivity for shipwreck exploration with their strong affinity for beer? A tasty treasure hunt on the “Wallachia” that resulted in swilling 126-year old reconstituted British beer. GUE Scotland’s detective chief inspector Andy Pilley recounts the tale.




by Andy Pilley
Images courtesy of
A. Pilley

Header Image: GUE Scotland’s brewmeisters enjoying their brew (L to R) Top: Owen Flowers, Andy Pilley, Wayne Heelbeck. Middle: Steve Symington, A. Pilley, O. Flowers, Bottom: W. Heelbeck, Sergej Maciuk, S. Symington

“Give my people plenty of beer, good beer, and cheap beer, and you will have no revolution among them.”

Queen Victoria

I never thought when I started diving 10 years ago, that one day I would be able to sit down for a pint of beer with the team from GUE Scotland recreated from a brew that has been hidden under the waves for 126 years. Let me explain.

The Wallachia was a single screw cargo steamer that was owned by William Burrell & Son of Glasgow, and employed on regular trips between Glasgow and the West Indies. On 29th September, 1895 she left Queen’s Dock, Glasgow at 10am bound for Trinidad and Demerara. On board was a valuable general cargo including whisky, gin, beer, acids, glassware, and earthenware plus building materials and footwear. By 1pm that afternoon she had settled on the seabed of the Clyde Estuary after colliding with another ship in a fog bank, she was forgotten until 1977 when a local sub-aqua club rediscovered the wreck site.

The wreck of the Wallachia lies on an even keel in approximately 34 metres of water on a sandy seabed. The wreck itself is largely intact and has six holds in total, three forward and three aft. In the rearmost hold there are thousands of bottles of beer, some still inscribed with the name of the maker, McEwans of Glasgow. This is where myself and the team from GUE Scotland enter the story.

The Wreck of the Wallachia 

The Wallachia is one of the more accessible sites on the west coast of Scotland, where we carry out most of our diving. Depending on weather and tidal conditions, visibility on the wreck can be +10m/33 ft on a very good day or less than 2m/6 ft if there has been a lot of rain due to the amount of particulate in the water. Other elements to consider are the tide as this can vary in its intensity, as well as surrounding boat traffic. The wreck lies in close proximity to a ferry route and care must be taken not to dive when the ferry is closeby. However despite the challenges, the wreck is very rewarding and offers a diver plenty of places to explore and items to look at. 

The main point of interest for most has been the rearmost hold, where the bottles of whisky and beer were stored. The majority of the whisky was removed in the 1980’s however a few bottles can be found on occasion, depending where you look. What remains are thousands of bottles of beer, still with the corks and contents intact. Over the course of 2018 & 2019, the team at GUE Scotland dived on the wreck and recovered a number of bottles from the hold. 

After a chance discussion with a friend at dinner one night, I was given contact details for a company called Brewlab, which is based in Sunderland in the north east of England. Brewlab specialise in the provision of specialist brewing training, as well as laboratory services such as quality assurance, product development, chemical/microbiology testing as well as long term research options. I made contact with Keith Thomas, the Director of Brewlab, to discuss whether he would be interested in analysing the beer and investigating whether it could be recreated. Needless to say the proposal piqued his interest and arrangements were made for the bottles to be shipped to his lab.

Unbeknownst to me, the recovery of historical beers is rare, due to various sources of degradation/contamination which can affect any residual microbial cells and chemical components left in the beer that were used as part of the brewing process. So these samples are a valuable source of information on past brewing and microbiology. Over the course of 2019/2020, Keith and I kept in regular contact over the progress of the investigations and the full analysis of the beer has recently been published.

A Brewing Interest

Between 1850 and 1950, the application of scientific principles to brewing was becoming increasingly prevalent and microbiology was playing an increasingly important role. A pertinent issue in brewing microbiology around 1900 was the application of pure Saccharomyces yeast cultures developed by Hansen at the Carlsberg laboratory in 1888. These were readily adopted by continental breweries as providing more controlled production and purer beers. Application to UK brewing was, however, less positively received, in part because of the belief that British beers possessed particular flavours arising from mixed yeast cultures and, specifically, the involvement of Brettanomyces species. This was especially believed to be essential for the character of ‘stock’ ales which were matured for extended periods.

While a number of breweries did try pure culture yeasts, UK brewing was resistant to change and, with the intervention of World War I, retained its indigenous yeast cultures. Since the 1940’s a more biotechnological approach to fermentation demonstrated the value of pure culture and was progressively applied to the larger breweries developing at that time. 

During the formative period of brewery microbiology after Pasteur, brewing yeast were identified as Saccharomyces species based on morphological features of shape, filamentous propensity and spore characteristics. Non brewing, ‘wild’ yeast was recognised and termed ‘Torula’ if non-sporulating. Of these Brettanomyces strains were identified as contributing important character to stock ales. It is also clear from brewing texts that bacteria were recognised as spoilage organisms in beer, as had been initially demonstrated by Pasteur in 1863. These species were mostly categorised as bacilli and typically portrayed as rods and associated with sarcina sickness – generally producing sourness. Some studies, nevertheless, identified lactic acid bacteria as indigenous components of standard beers.

Contemporary breweries are increasingly interested in using novel microbiology, either unconventional yeast strains or mixes of species and strains for sour and natural products. Identifying the specific strains and species of yeast and bacteria present in Victorian and Edwardian beers is directly relevant to this and has particular value if cultures of authentic microorganisms can be retrieved. Reports of retrieved historic brewery microbiology are limited but hold interesting promise for identifying novel microorganisms.

The specific parameters of the analysis are contained in a published research paper, Preliminary microbiological and chemical analysis of two historical stock ales from Victorian and Edwardian brewing.”

As I mentioned, the primary objective of the analysis was to confirm whether detail could be provided on the original brewing ingredients and the fermentation microbiology. The analysis confirmed the use of Brettanomyces/Dekkera bruxellensis and Debaryomyces hansenii, which are brewing and fermentation yeasts respectively. The presence of Debaryomyces is interesting as this genus has not been noted as a historic feature of historic brewing, but has been identified in spontaneous fermentations, for example in Belgian lambic beers. Although the strain was reported to the brewing industry in 1906, it has not featured as a major contributor to beer fermentations since.

The analysis has also provided relevant information of the beer character and has confirmed that the beer recovered from the Wallachia was a stout, close to style expectations of the time and had an alcohol content of c. 7.5%. The colour gravity was high, resulting in a much darker beer however a much lower level of bitterness. Again this was typical style of the time and differs from other modern stouts.

More interestingly is the presence of various types of bacteria, which will likely have been picked up during the brewing process. The table below lists these for reference. Needless to say, historic brewing was not a sterile process in comparison to modern methods!

Bacillus licheniformisPlant and soil bacterium
Finegoldia magnaCommensal skin bacterium
Fusobacterium sp.Possible pathogenic bacterium
Kocuria roseaPossible urinary tract pathogen
Mogibacterium pumilumPossible oral cavity bacterium
Shigella sonneiEnteric pathogen
Staphylococcus epidermidisCommensal skin bacterium
Stenotrophomonas maltophiliaSoil bacterium
Varibaculum cambriensePossible pathogenic bacterium

Table 1: The bacteria found in the Wallachia beer bottles

Due to the relatively stable conditions on the wreck, being in near darkness and at a relatively cold temperature (between 6º–14ºC/43º-57ºF depending on the time of year), the live yeast structures within the beer were protected from sources of stress and allowed them to survive over the past 126 years. Luckily, Keith was able to extract these samples and begin to recultivate the yeast, specifically the Debaryomyces, with the hope of being able to rebrew the beer.

Cheers Mates

Just before Christmas, I finally received word from Keith that he had completed a trial brew and seven bottles of the brew were on their way to me. A few excitement laden days later and a nondescript box arrived at my office with the beer inside. I called the guys on our Facebook group chat to show them the case and got each bottle packaged up and sent out to them. 

A few days later, once everyone had received their sample we got together again to try the samples. There was an air of excitement after the two years it had taken us to get to this point, the most anticipated pint ever! I’m no expert in the flavour profiles of beer so you will have to forgive me for my relatively basic analysis. In summary, I got flavours of coffee and chocolate and there was a relatively low level of carbonation, which made it very drinkable. The rest of the team got similar flavours, the only complaint being there wasn’t more to try!

There will of course be slight differences in flavour since we don’t normally add the bacteria listed above as ingredients. However, the recipe we have is as close as we can make it to the original stock version.

The next steps for the project are to carry out further investigation on the characteristics of the Debaryomyces yeast strain in order to determine their suitability for fermentation and potential use in future brewing production. We are making approaches to various commercial breweries in order to discuss future commercialisation of the recipe and produce the brew on large scale. With the story behind the original recipe, we’re hopeful that the provenance would be a key selling point to consumers. It is my hope that the recovery of these samples will open up new possibilities for different types of beers to be developed, and offer something different for beer enthusiasts to try.

I have also found out that there are other types of beer to be found on the wreck, specifically an IPA style. Once we’re allowed to begin diving again, I am hoping to return to the Wallachia and recover some of these bottles so we can carry out the same analysis and keep the project moving forward.

In the mean-time, cheers!

Additional Resources:

The Brewlab Podcast, Episode 2 (March 30, 2021): Lost Beers Recreated from Shipwreck Bottles

GUE Scotland vlog -Episode 1

Andy Pilley is a Chartered Surveyor, team member of GUE Scotland, passionate wreck & cave diver and Ghost Fishing UK team diver. Andy started diving with the Scottish Sub-Aqua club in 2011 and began diving with GUE in 2018. Andy dives on the east and west coasts of Scotland where there is a rich maritime history and an abundance of wrecks to be explored. He has a passion for project diving and is developing objectives for a number of sites with the GUE Scotland team. He hopes to assist on the Mars Project and with the WKPP in the future.

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