As the colder weather sets in, the need for heavier outerwear in panhandle Florida becomes quickly obvious for most warm-blooded creatures, people included. Nature provides for the forest animals through them instinctively growing additional fur and feathers as the temperatures dip.
Reptiles, insects and amphibians retreat to secure locations with enough protective insulation to wait out the ebb and flow of daily chills. Trees, which provide some of the overwintering sites for those needing it, have their own protective layer which defends against the environment year-round.
Bark, the hard layer on the exterior of trees, begins out of sight as a single layer of cells which produces structural support and acts as the first line of defense against the attacking elements. Known as the cambium, it initiates the tissues which ultimately becomes the wood and the bark.
Starting as a single layer of cells called the cambium, bark provides protection and structural support throughout the life of the tree.
The cambium’s outer side quickly becomes the phloem, commonly known as the inner bark layer. This fibrous stratum is moist and flexible to the touch.
Its function is to serve as the downward portion of the tree’s vascular system. The sugars and amino acids produced by the leaves during photosynthesis are transported to the roots through the phloem.
The nutrient flow slows in the autumn as the leaves of deciduous trees change colors and ultimately detach. The nutrient stream suspends during the leafless winter months.
In pines and cedars, along with those trees which retain their leaves in the winter, photosynthesis is reduced in the shorter days. The nutrient flow is reduced to a minuscule trickle.
As the tree grows, the phloem layer continues to be increased by the cambium so that the expanding girth of the trunk and limbs can effectively function. Ultimately, the outer surface of the phloem dies and becomes the outer bark.
The thickness of the outer bark varies by both the species of the tree and an individual tree’s age and health. Most local pines are an example of trees with a thick outer bark which flakes off as the tree matures.
Sometimes lichens will grow on the exterior surface of bark. In many cases they are just opportunistic feeders on the byproduct of naturally decaying bark on healthy trees, but not always.
Lichens are composed of algae and fungi living together in a symbiotic fashion which is beneficial to both organisms. By working together, albeit unconsciously, both are able to prosper in environments where they would individually fail.
The fungi accelerate outer bark decomposition, resulting in nutrient recycling. They are responsible for the breakdown of dead organic materials, converting them into a form useable by other living creatures.
The algae process atmospheric carbon dioxide into organic carbon sugars to supply nutrients for both organisms.
Healthy trees have outer bark which provides a protective barrier and resists the roots of lichens. A dense population of lichens is usually an indication of failing tree health.
While bark provides minimal heat retention features for the tree, it is still the best outerwear regardless of the season. Missing bark on the pines, oak and other trees is far worse than no fleece-lined jacket on these frosty mornings.
No matter the season, bark on trees is always needed.
Leave a Reply