During the 7th century the power of the Eastern Roman (Byzantine) Empire was challenged by the Sassanids of Persia, who invaded Egypt in 616. They were expelled again in 628, but soon after, in 642, the country fell to the Arabs, who brought with them a new religion, Islam, and began a new chapter of Egyptian history.
the bark protcts the zylem and the phloem fron infection.bark is like our skin and if we cut off some of it and didnt keep it clean it would become infected.you could shave off a couple of inches and a tree may live depending on its age but if its a sapling and about 3 to 5 inches in diameter it would die eventually.
15. The vascular cambium is the secondary meristematic tissue that forms the vascular tissues (xylem and phloem) of the plant in roots and in the stem. Usually, the outer side of the vascular cambium produces a layer of phloem and the inner (more central) side of the tissue produces a layer of xylem.ateral, or secondary, meristems, consist of the cambium and the phellogen (also known as cork cambium). These are tissues in the stem, branches and roots that generate other tissues via mitosis. These tissues participate in the secondary growth of plant, that is, in the thickening of the stem, branches and roots.