What is the outermost layer of stems and roots of woody plants called?
The outermost layer of stems and roots of woody plants is called bark. This tissue covers all living parts outside the vascular cambium.
Questions about Bark (botany)
Short answers, pulled from the story.
How does bark form in young trees as they mature?
As the plant matures, the epidermal layer gets replaced by a secondary covering known as the periderm. The periderm forms from cells called the cork cambium or phellogen which divide to produce new layers of cork on the outside and phelloderm on the inside.
Why do some trees like oaks not heal bark wounds rapidly?
Some plants produce callus growth that heals over wounds rapidly but oaks do not produce extensive callus repair for similar injuries. Sap sometimes seals damaged areas against disease and insect intrusion instead.
Which historical societies used pine bark as food during famine periods?
Hunter-gatherer societies harvest inner bark as a food source during times of famine. Pine bark served as emergency food in Finland during civil war periods ending in 1918 while Sami people use large sheets of Pinus sylvestris bark as staple food resources.
What chemical components make up between 10 and 20 percent of woody vascular plants by weight?
Bark tissues make up between 10 and 20 percent of woody vascular plants by weight. They consist of various biopolymers including lignin, suberin, tannins, and polysaccharides with up to 40 percent of the bark tissue made of lignin.