Callous & Callus
On a recent hike on the anniversary of a day significant to me for the trauma I experienced on that day I was thinking a lot about scars.
5 years ago, to the day on this day of my hike, I learned that you can feel your heart break. This may sound insane to some people and lucky you for not knowing or not having had the experience. Those of us who have experienced this we know it certainly is a thing. And while I do not know if my heart looks any different from when it did before that moment (I suspect not, but still I wonder), I feel like there is a scar there along the place where it broke. My heart physically feels like it changed forever, but I know it continues functioning and supporting me, still able to love, forgive and care and still moving blood and oxygen around this body.
As I traveled along the trail I started noticing scars on trees. As I have mentioned, you cannot always see the damage a tree (or a person) is dealing with from the outside. But sometimes, you can.
I noticed, like us, they have scars for two types of wounds – the intentional and the accidental. Like us, regardless of how the wound got there, the tissue created to protect and heal the wound is the same.
Callous can describe a person. It certainly can describe the person who caused this heartbreak. This usually means they are insensitive or unfazed by emotions, empathy or sentiment. I think of it as meaning that they are hardened from these emotions, perhaps because of something that happened to them, perhaps because they never witnessed those emotions in action or felt those emotions personally, who knows.
Completely healed tree wound 
Completely healed tree wound
Callousness can be a protection from getting too close, from feeling emotions.
A callous can also be a protection. You may know the raised, hardened bumps of skin on palms and fingers that speak to the work you do and the hobbies you have. I have callouses from splitting firewood, from raking leaves, from shoveling snow, from gardening and from kayaking. These callouses form over time after repeated damage or irritation to protect the skin in the future.
Though spelled differently, callus wood forms on trees as protection.
Trees naturally compartmentalize damage to prevent it from spreading to the rest of the tree. Part of this process is the creation of callus tissue, the process of which begins the moment the tree is damaged. These undifferentiated cells, called parenchyma cells, grow quickly and spread to cover the wound before insects or diseases can enter. These are also the cells that create burls on trees. Eventually as these cells grow, woundwood forms and covers the wound like a scab covers and protects the wound.
Large sycamore (Platanus occidentalis) with completely healed wound 
The difference between the woundwood and surrounding tissue is evident on this healed wound
In order for the process to work, the area of the tree that forms the cells to create callus tissue must not be damaged. If it is damaged, incomplete healing occurs ensuring continued damage to the tree.
We can think of callus wood on a tree like scar tissue, a different, smoother type of tissue than the surrounding tissue. Like scar tissue which is stronger because the arrangement of cells is more dense and arranged in a way that makes it strong but less flexible.
When a surgeon operates on us, the cuts are intentional and created to heal as well and as fast as possible with little scarring and complete healing. When our wounds result from unintentional accidents or are the result of the callousness of another human the scarring may be worse, the wound longer to heal and in some cases may not heal at all.
The same is true of trees, when storms damage trees the callus and woundwoond may not be able to form, leaving the tree susceptible to further damage. If a well trained and knowledgeable arborist is pruning a tree, they know to cut properly so the wound can heal completely.
I suppose when our hearts break there is no way to know if we heal completely. I like to think that my heart has healed completely. While I do not know if there is physical evidence of the damage, I know I will never forget the feeling, and I am certain it is vulnerable to being broken again, but it is stronger and different and functioning just fine, despite the damage.
Wounds are an inevitable part of a tree’s life, just as they are an inevitable part of ours. How we, and they, heal from them depends as much on the circumstances that created them as the tools within to heal.
HORT travels 