In ring-porous species, such as ash, black locust, catalpa, chestnut, elm, hickory, mulberry, and oak, the larger vessels or pores (as cross sections of vessels are called) are localised in the part of the growth ring formed in spring, thus forming a region of more or less open and porous tissue. The rest of the ring, produced in summer, is made up of smaller vessels and a much greater proportion of wood fibers. These fibers are the elements which give strength and toughness to wood, while the vessels are a source of weakness.[citation needed] COUNT 5
QSN1 What species of hardwood are hickory and mulberry trees? ANS1 ring-porous QSN2 In what season do the growth-rings of ring-porous species form with larger vessels localized? ANS2 spring QSN3 In what season does the part of the growth-ring with smaller vessels form in ring-porous species? ANS3 summer QSN4 What fibers does the summer's section of growth-ring have more of? ANS4 wood fibers QSN5 Along with strength, what property do wood fibers lend to wood? ANS5 toughness