Plant Health Care – the ®evolution

Cassian Humphrey continues his journey into iCulture and hopes the industry will follow his lead on Plant Health Care.

In a past article I made a play on the word ‘iCulture’, partly reflective of our move into the world of artificial intelligence (AI), but also a reflection on my making the emphasis on the tree – iCulture – as a means to encourage arborists to reflect on their position. Are you an arboriculturist? Or a glorified tree lopper?

Google the actual old English meaning of ‘lop’ before you answer.

I recognise the industry-driven vacuum in mainstream arboricultural knowledge around tree biology, especially at trade base, on understanding how trees function and what actually constitutes their needs. In truth, tree pruning does nothing for woody-plant vitality, and limb removal actually reduces tree life expectancy. Barring volume reductions, the only crown works we can really call treecare involve mechanical support for veteran trees.

Be honest: how many of us are engaged to do that and how often?

Mostly we feed wood-chippers. The great sin of our times is to negate the profession in service to industry, especially when that costs the tree.

Make health food local

My sojourn in arboriculture takes me further and further into education, and my current interest is to reach out to the tree custodians, professional or otherwise, to deliver the message on tree basics: air, water and bio-carbon (biologically activated carbon), because the industry-driven are not listening.

The established Plant Health Care (PHC) movement, mostly in the United States and parts of Europe – I would love to know what’s going on in Japan – is centred on tree longevity, assisting urban trees to last longer in the urban treescape. I liken PHC for trees and gardens as akin to a health-food store for humans. Mainstream agriculture, like Big Pharma, fails to deliver on top-end nutrition for plant or human longevity. With its high environmental and financial costs driven by a global carbon footprint, the health-food store needs to be an intermediary step for humans determined to eat well and be eco-sustainable.

As with traditional times before WW2, the next step is to make health food local. The PHC movement is a critical step in the direction of arboriculture, yet ultimately, as with the traditional garden allotment, we will need local facilities to produce the bio-carbon (or humus) essential for all healthy perennial-plant production.

Figure 2: Northbourne Avenue, CBD Canberra, ACT. Witnessing the central reservation and tramline refurbishment with understorey
planting of grassland species in association with gum trees (since my last 2016 visit) certainly gladdened my heart. This area is kilometres in length and around 40m wide. Many species of eucalypt have naturally evolved in association with uncropped grasses and sedges. Though not as species-diverse as woodland or local grassy-woodland, this kind of environment mitigates people pressure via nutrition and exclusion, with designated pathways that help direct pedestrians where desired. A THC initiative would involve vertical fissuring to decompact soils compacted at turf-removal phase and from past turf/mower maintenance. Green-space initiatives like this greatly support conservation arboriculture in city environments.

Gold standard

My awakening to iCulture in arboriculture commenced in the early 1990s with carrying out revegetation works in association with established trees – a practise catapulted into my understanding with Shigo’s 1997 Arbor Age article Troubles in the Rhizosphere. Coupled to exploration into being a guinea pig for health foods and a study of the nutrient cycle, it led me to understand the role of plants as pumps that drive the web of life. That involved realising the plant-driven unification of the atmosphere and rhizosphere – Heaven and Earth.

At both ends of the tree-pump plants interface on a cellular level with these non-visible ‘spheres’.

I’ve long stood by the image of the figure-eight as a symbol of Shigo’s pump (Ref: page 2 of Modern Arboriculture) as being the perfect symbol of the plant that ‘births’ all life, with plants harvesting inorganic nutrients, embodying them, and making them available organically to all other life. It was this image that spurred me to spend less time in the harness and to get my hands in the soil, culminating in my AAA article The Heart Of Arboriculture 2021.

As an agent for arboriculture, the life journey brought me back to Canberra to work with a highly qualified and experienced contractual/consulting arborist, James Macpehrson. My goal has been to assist him to integrate into his business the conservationarboriculture strategies I promote. Initially planning to run Naturaculture workshops for his staff, we have stepped up to the level of establishing a Gold Leaf Tree Health Care division.

Figure 3: A fairy-ring fungi, quite possibly Clitocybe nebularis. If so, this is another cosmopolitan European fungi bought in by historic plantations such as York Park Canberra, where I photographed it. In greater Brisbane we commonly have a similar fairy-ring species, Chlorophyllum molybdites, originally from North America. The fungi are as cosmopolitan as we humans.

Like minds

Already having a repertoire on the science and biological inputs behind the soil-food-web, and already being in dialogue with one of Australia’s first true conservation-arboriculturists – I’m very excited to know microbiologist Katia Plouznikoff – I was grateful to introduce Gold Leaf to the company that supports her, Heritage Tree Care, in Sumner, west of Brisbane. Katia works with the company’s agronomist and head of her division, Andrew McLennan. These allied professionals work for another key arboricultural entrepreneur, the CEO of Heritage, Gavin Rowan, another individual I pay homage to. Without the arb entrepreneurs financing new ventures we would be stuck.

It has been a great joy for me to cultivate a connection with Katia, a true specialist in arboriculture, not just for the professional association, but because in her I met an ally who operates beyond the confines of ego. This makes interaction energising, seamless and exceptionally productive.

I can say the same of the Gold-Leaf CEO.

Figure 4: A classic weeping elm – Ulmus sp – at Rodney’s Plant Nursery in Canberra, surrounded by hard landscape. Even through bitumen or bricks, with aeration and fissuring in mind, this is the perfect candidate for THC.

Good people

Heritage Tree Care is an important conduit for the promotion of PHC.

As a business with the longest established PHC division in Australia – five years – the division is now also responsible for the marketing and distribution of the latest machine to grace the world of modern arboriculture. To be truthful, Andrew McLennan gets the acknowledgment for that.

Before I launch into this piece I’ll discuss and honour some history.

Another important pioneer in the field of Queensland arboriculture is a man who you may meet at conferences, who quietly seems to work on the sidelines, yet is actually in the front-line of the evolution and revolution of our profession: Queensland consulting arboriculturist, researcher, project-developer and project-manager, Daniel Oaten.

I’ve crossed paths with Daniel a number of times in my own evolution. Born of a similar generation, we have been driven by the same thirst for the iCulture that is missing from Australian Arboriculture. Though I have never had the opportunity to work with Daniel, I have long known and respected him. At a similar time I was the senior consulting arboriculturist (Co-founder of the Energex VTA Program) with Utility Arb company ETS (2004-2012), he was in the same kind of position with Treescape. It was there he founded a PHC division for greater Brisbane, and it was from that experience that he went on to found the PHC division in Heritage Tree Care, the management team proactive there today he bought together. Daniel, brother, for your hard yards work in Tree Health Care I salute you and pray that in time Arboriculture Australia erects a statue in honour of your contribution.

As discussed in past publications, my recipe for what I call holistic Tree Health Care (THC) involves establishing ecosystems. Diverse plant-species and nutrient-bed establishment invites in the organisms that make up the tree ecosystem that evolved to interface with the tree. The smaller ecological associations deliver far more in resilience and information back to the soil-food-web and the tree than we lumbering human arborists can know. Though I have no doubt making multiple vertical fissures for planting tube-stock associated vegetation in support of trees assists with aerating soils, I have long known that in light of heavy compaction this was not enough. With my consideration of nature’s action on soils, I knew fissuring via plant growth, and the impact of environmental/climatic factors, naturally have an influence on soil aeration. But I realised that with heavy compaction we needed mechanical intervention.

Figure 5: The Bavarian VOGT Geoinjector-Max, a new kid on the block Downunder, gaining attention from savvy local-government arboriculturists. It’s a specialist tool to enable soil restoration around street trees, parks trees, in service to botanical gardens, parklands…anywhere there are trees, gardens and open space. The mix of good timing, education
bridging the gap between people and trees with input from the head of Heritage PHC’s Andrew McLennan, and bringing in a new tool to assist us to deliver on plant nutritional needs, this is a solid sign of the times as we shift into New Earth ventures.

A challenge and an answer

The major challenge I have faced with the process of decompacting soils involves tool selection to best enable the vertical-fissuring. Though I have had great success with narrow augers and a range of powerheads that drive them, the issue can involve auger bits sticking and powerhead kickback, though this is manageable with sensitivity (many people should not ride motorbikes or handle chainsaws).

I have been looking for other options, and over the years I have also manned airspades and high-pressure water jets and not been as satisfied as I am with the use of augers. Then, through sharing from Katia Iast year, I heard about the VOGT Geoinjector range, the latest advance in soil-decompaction technology. It’s a tool for vertical and horizontal fissuring, or, as described by the German company that makes it (amongst a range of high-pressure tools), the Geoinjector combines soil aeration with soil-injection technology. Operating since 1992 VOGT is based in Bavaria South Germany, and now equips arboriculturists with these units throughout Europe.

Buckle your seatbelt, Dorothy! The age of iCulture the tree has finally arrived.

Figure 6: Katia directing the Heritage crew in the field, an image I took on a recent Brisbane trip to see and try the unit in the field myself as part of the conservationarboriculture system I follow. I am glad to back Gold Leaf in the purchase of this the VOGT Geoinjector-Max.

Serious about aboriCulture

But don’t hold your breath. Verticalfissure works on their own are not enough. Without top-end carbon resources, the bio-carbon as compost, compost tea and mulch (not that green, cooked, inert, dead stuff most of us pedal), the organic/inorganic mineral and probiotic inputs, the associate understorey vegetation, and the means to mitigate soil compaction, the result is likely to be retarded (weed response following treatment is an indicator of that). When I consider all I have integrated in the realm of THC and continue to learn as I professionally support the launch of the Gold Leaf Tree Health Care division, I realise a detailsfocussed mind is essential. THC or PHC (with a broad application) is only for the truly arboriculturally minded. Until mainstream arboricultural education embraces the theory behind the micro, as arborists we will be very limited to incorporate it into the macro.

I will be co-authoring a future article with Katia as we at Gold Leaf prepare to receive our Geo-injector-Max and receive her with an essential educational course to prepare us for the many detailed variables for our management team.

The big news for we who prescribe to being at the top end of our profession is that already one Queensland landscape company has initiated a PHC division and taken ownership of a VOGT. It is time for arborists to get serious about the iCulture or be left behind when it comes to practising arboriCulture in name.

In closing, I just have one more past figure to honour: a great holisticarboriculturist and friend as early as 2006, Steven Richards, I thank you for bringing me to the work of Dr Elaine Ingham, and the soil-food-web. For our many good contacts, I salute you.

Figure 7: In this image I’m squatting before Gold Leaf’s new VOGT unit. Heritage Tree Care already runs three units in service to its local government contracts, as well as being agents for the machine and its spare-parts on behalf of VOGT Germany. Heritage has sold a number of these units Australiawide. Standing is agronomist and division head Andrew McLennan (left), and Heritage’s Frenchborn microbiologist Katia Plouznikoff. As well as developing and monitoring the biological product for soil injection, she is responsible for research, development, presenting, educating and project management. How apt it is to take a soil scientist like her to give (mycorrhizal) balls to the Australian arboricultural profession.

I love how science – let’s call it ‘creation’ – is helping us (who love to short-cut) to be on the straight and narrow. There is no room here for industry-driven tick-and-flick education to understand the science and application of PHC. It takes in-depth study and practise. It’s one thing to integrate a Cert 3 in Arb, or even a diploma, yet in light of all I have learned, I can clearly see a Cert 4 in Tree or Plant Health Care, probably as well suited to horticultural education as arboriculture. I can now see the perfect nudge for arboriculture and horticulture to be interfaced as the one entity it started off as, tree and garden care, one system management akin to managing an ecosystem. Elitism separated the two, largely by arborists who get paid to destroy rather than care for trees, and new generation horticulturists who never learned how to prune to a node. Truly this is the time for arboriCulture, and the VOGT is a powerful catalyst.

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