Have you ever wondered what kinds of similarities exist between human skin and the bark of a tree?
Trees are subject to major and minor injuries just like humans are. These injuries could be the result of a broken branch, insect infestation, animal damage, fire and human related damages. These kinds of injuries can lead to the infection of a plant which can cause rotting and damage to the transport tissues like phloem (nutrients) and xylem (water) by microorganisms and insects (bacteria, fungi, parasites) (Figure 1).
Fluid excretion in wounds and development of scar tissue
Blood serum is secreted in human wounds, whereas gum and resin type fluids are secreted in various trees (Figure 2 and 3). Serum plays an important role in sterilization of the wound, along with blood coagulation. Defense mechanisms in trees involve excretion of different fluids (resin in needleleaf trees, gum in broadleaf trees) that are synthesized via composition of various chemicals. The most important feature of these fluids is that with their special chemical make up, they can protect the wound from organisms like bacteria, fungi, and insects that are potentially harmful to the tree. These fluids also feature coagulation like the human serum; they congeal and solidify after excretion and trigger a biological healing process while physically covering the wounded area.
Wounds are repaired with new connective tissue cells (fibroblasts) in humans and by callus in trees. Healing of the wound following the coagulation takes place with proliferation of cells in this region (epithelialization). First, epithelial cells wrap the wound via proliferation. New transport tissue is developed during this process. Next, fibroblasts that are in charge of wound repair are transferred into coagulate via this transport tissue. Fibroblasts synthesize collagen protein of the required fiber structure needed for the wound repair. Injured area is woven with these, and recovers its former shape in time depending on the size of the wound.
Healing is granted through timely reproduction, transformation and maturation of paranchimatic cells that make up the callus, when only a portion of tree bark is damaged. Paranchimatic cells are fused side by side and they form a thick elevation of callus tissue around the wound (Figure 4). At the end, these are activated for the development of a new, healthy cambium and bark. Cambium tissue is responsible for vertical and lateral growth of a tree therefore it is vitally important that it does not suffer any damage. This tissue in growth season proceeds from the perimeter of the wound towards the center for a complete healing. The productive efficiency of the tree medium can speed up or slow down the curing process similar to humans.
The reality is that all living things are created with a dress suited for their environments so that their bodies can be protected from negative elements from the outside world. Organisms are armored from many harmful physical (mechanical, extreme temperatures, light etc.) and chemical effects with this perfectly bestowed dress as a manifestation of the divine compassion in the universe just as in the case of the wounds of humans, animals and plants which are subject to the similar laws found in nature.