An Objective Observation of the Chapter on Tree Development and Growth Stages in the European Tree Technician Study Guide (EAC, 2023)

 An Objective Observation of the Chapter on Tree Development and Growth Stages in the European Tree Technician Study Guide (EAC, 2023)

While I do not possess formal scholarly credentials, my passion for tree architecture fuels an ongoing commitment to dynamic learning, ensuring that I remain current with advancements in the field. This feedback is grounded in impartial criteria and established research within the realm of tree architecture, serving as a call for positive change rather than a challenge to the status quo. My aim is to foster progress, inspire introspection, and promote dialogue within the arboriculture community. May this observation prompt a reevaluation of obsolete concepts and outdated practices still prevalent in the management of our arboreal patrimony.

The catalyst for my observation stemmed from a notable assertion in the European Tree Technician Study Guide (EAC, 2023): 

"Depending on the approach and the purpose of the work, many authors identify more stages in the life cycle of a tree, however, the 10-stage model of Pierre Raimbault is currently the best one for arborists" 

– European Arboriculture Council, 2023. Tree Technician Study Guide, Ch1., B.3., Tree Development at Different Life Stages, p.39. 

Let's embark on a collaborative exploration, inviting you—the reader—to critically examine the assertion made in the chapter.

Is it indeed true that Raimbault's '10-stage model' represents the most suitable sequence of tree development, as implied by the text? Does scientific research support this claim, making it the most appropriate framework available to arborists today?

Do we find this assertion compelling, or do we require further investigation into the validity and applicability of the model?

Furthermore, we must question whether this assertion relies on the argument of authority, wherein the opinion of the writers on behalf of the European Arboriculture Council serves as evidence. Alternatively, do we find evidence supporting this claim within the literature cited at the end of the chapter?

I encourage you to exercise critical thinking, analyze scientific research accepted by a global consensus, and, for the moment, set aside opinions to arrive at an accurate conclusion.

What alternative models describing the sequence of tree development are being considered?

It's important to approach this examination with an open mind and consider multiple perspectives, if available, before drawing conclusions. This is essential for achieving a thorough and unbiased understanding. By engaging in this collaborative inquiry process, you—the reader— agree to deepen your understanding of tree development and its implication for arboricultural practice. To determine if Raimbault's '10-stage model' is indeed the most reliable sequence of tree development available today, a thorough study of scientific literature and consultation with scholars and specialists in tree architecture is necessary. This field has been scrutinised for over 60 years (originated by Hallé & Oldeman), making it the most reliable source of information on tree development. This involves examining peer-reviewed studies and academic articles, doctoral dissertations, textbooks, and professional publications that discuss tree architecture (dynamics of growth, stages of development and physiological states).

It is also essential to critically evaluate why Pierre Raimbault's model is considered the best for arborists explicitly, as stated by the writers?

Tree development is governed by an endogenous program, fluctuated by the environment. The plasticity of trees unveils the unavoidable correlation between endogenous processes and exogenous factors. The accuracy of a proposed sequence of tree development cannot be compromised by its application; it is what it is. Is the tree the commander in chief of its intrinsic ontogenetic development.

Scientific theories and scientific models are the culmination of a global consensus of scientists. Empirical observations are gathered, a hypothesis is generated, tested & re-tested, aiming inextricably to falsify it, rather than confirming it. This is how scrupulously honest and rigorous the scientific method is. It seeks to put at risk the hypothesis, unlike confirmation bias pseudoscience. Science therefore does not guarantee 100% certainty, but a scientific theory or a scientific model is the highest probability available, until proven false and rejected or modified. Science is in constant reevaluation of its research and so is tree architecture as a science and discipline.

Raimbault's '10-stage model' lacks the validation of a scientific global consensus. Instead, the community of botanists, scholars and academics engaged in tree architecture analysis have never validated or endorsed it, and, for many arborists today, that once embraced it, like my self, its many inconsistencies with a scientific consensus makes it obsolete. 

Don't get me wrong regarding Pierre Raimbault. There's no intent here to discredit his body of work, which is significant in many respects. This observation only addresses discrepancies in his '10-stage model', and even though it was controversial, it's crucial to acknowledge his legacy. He was the pioneer in the application of tree architecture in arboriculture. . However, the bridge between the scientific theory and popular science was built by Caraglio and Édelin and his scholars (Drénou, Genoyer, Atger and Millet). Not only have they contributed to the evolution of tree architecture as a science and discipline, but they have transposed its methods and accuracy to a more comprehensible and accessible language, available and applicable to arboriculture practitioners.

Raimbault's methodology (An above-ground analysis and diagnosis method, 1993) was acclaimed by the arboriculture community, but rejected by the scientific community right from the start. Having achieved his doctoral dissertation on tree senescence, Christophe Drénou, Ph.D. (1994), was the first to point out inconsistency in Raimbault's methodology (Drénou, 1995). Where Raimbault's 6 original stages (Raimbault, 1990) had become 10—adding 9 & 10. Two phases that are not stages of development, but rather physiological states of reaction to environmental conditions.

Stage 9 (Raimbault, 1993), Crown retrenchment (uppermost crown descent).

Stage 10 (Raimbault, 1993), Dislocation (colony of reiterates-substitute shoots, or to retake David Lonsdale's term used in the chapter, a colony of 'functional units'. The initial individual tree becomes a colony of clones, acquiring a low degree of individuality.

These are not ontogenic stages endogenously programmed in the tree; instead, they are physiological states of reaction that can occur in earlier stages due to external factors.

Raimbault's original 6 stages (1990) placed the senescent tree in stage 5 and the tree after crown retrenchment on stage 6.

Thus, in a way, Raimbault's new stages encouraged fostering scientific research on physiological states of reaction within the arboriculture community—in response to the need for clarification. This effort owes much to the rigorous research and popularization led by Christophe Drénou et al. through the ARCHI Method (ARCHItectural diagnosis of tree vitality).

http://www.arboritecture.org/the-archi-method

REFERENCES CITED

Drénou, C., 1994. Approche architecturale de la sénescence des arbres. Le cas de quelques angiospermes tempérées et tropicales. Thèse de doctorat, Université de Montpellier II - Sciences et Techniques du Languedoc, Montpellier.

Drénou, C., 1995. A propos de la gestion des arbres d'ornement. Revue forestière française, pp.709-710.

European Arboriculture Council, EAC, 2023. Tree Technician Study Guide, Edited by Bregt Roobroeck.

https://www.eac-arboriculture.com/ett-study-guide1.pdfx?forced=true

Mólder, A. and Oetjen, R., 2023. The Theoretical Foundations of Tree Management (Ch.1) In EAC, 2023. Tree Technician Study Guide.

Raimbault, P. and Tanguy, M., 1993. La gestion des arbres d'ornement. 1re partie: Une méthode d'analyse et de diagnostic de la partie aérienne. Revue forestière française, 45(2), pp.97-117.

Raimbault, P., 1990. La taille des arbustes et des jeunes arbres d'ornement (1er partie: Le fonctionnement de l'arbre). CNFPT pp.95.

資料來源:

https://www.linkedin.com/pulse/objective-observation-chapter-tree-development-growth-restrepo-hh4te/