Almost everything we do is based on response. In this sense, arborists and trees and plants in general are very similar. I recently read in the ISA’s Arborist Certification Study Guide that “Plant systems, like all living organisms, respond to environmental stimuli,” which is what prompted this discussion. We respond to our clients, to our own personal situation, to the atmosphere on a job site and beyond. Arborists are constantly responding to their environmental stimuli just like the plants we look after. But what makes for a favorable response?

If we look at plant function, you soon realize how interconnected biological processes are. Let us consider the leaf itself, which seems appropriate with the brilliant Fall season almost upon us. Our trees will turn deep red and orange and yellow as the nights cool and lengthen. So just in this small description, it seems almost obvious that response requires change. But only on the surface.

Response arises from solid structure. Consider the cross section of a leaf. With any sort of imagination, you’ll realize this image looks more like a stonewall than anything organic. That’s because, like a well built stone wall, the biological arrangement of the leaf needs to be sturdy. If we start at the base of the wall, you’ll see the guard cells like drainage exits on the foundation. Specialized regulators. And all around those, the lower epidermis, big meaty boulders weighing down the bottom of the leaf. Next, the spongy layer which houses the vascular tissue of the leaf. You may know them as veins. Moving upward on the leaf structure, vertically arranged like fenceposts, is the palisade layer. There is a certain rigidity exemplified in this cell layer, and firmly capping off the whole structure is the upper epidermis and the famous cuticle.

There is no doubt this sound structure arises out of the necessity to support the main function of the leaf, which is the ever-famous physiological process of photosynthesis. Vitally critical to tree life.

But what about that famous fall color, that delightful and glowing response that reminds us to give thanks? Sugars start to become way overstocked, and just as if it were a grocery market, the manager is forced to order less chlorophyll. Luckily for the casual onlooker, chlorophyll isn’t the only pigment in the leaf. And finally, after being draped by green for most of the season, the anthocyanins and carotenoids are revealed, like a Monet, or a Dali, or a Rembrandt.

I think of the new Ascent Event at the tree climbing competitions as a response, mainly to changing techniques in regards to ascending trees. The modern arborist is changing. Or is it that our understanding of the arborist is changing?

While on the topic of tree climbing competitions, I also think of the aerial rescue event, which is held in high regard for many competitors. Much like a biological system, good response in a state of emergency can be handled quite calmly and routinely; but only if the right structure is in place. Basic training and research certainly gives us the tools we need, but how to we get comfortable in highs-stress scenarios? The competitive experience supplements this, I think. A highly beneficial experience from the AR event is this simulated pressure to respond from stressful stimulus in our environment, on which we are scored. Therefore, we can constantly work on getting better at our responses.

Response requires change, but it also requires a reliable and familiar foundation to support that cycle of change experienced. Good response comes from sound action in the face of elevated challenges in the environment. Good response comes from the foundation of the past, strength and focus in the present, and from things remembered that never go away.