1. What is meant by exogenous trees? In what kinds of wood are the annual layers most prominent? Describe the formation of annual layers. What causes the difference in the degrees of hardness of wood? In the color and odor of wood? How may the age of a tree be determined? Are the broadest annual layers found in young or in old trees? From what class of trees does soft wood come? Hard wood?
2. Describe the motion of sap. What forms the sapwood? With what are the cells of the sapwood filled? Compare sapwood and heartwood.
3. Describe the four different tissues in a tree. Describe the inner bark.
4. What are the medullary rays? In what woods are they most prominent? How do they affect the strength of timber?
5. What is the nature of trees which grow in exposed situations? Where are the straightest trees found? Why does the location of a tree affect the grain? What is meant by coarse, fine, straight, and cross-grained lumber?
6. What causes wind shakes? Heart shakes? Star shakes? How may they be distinguished from each other? What causes discolorations? What is the usual character of timber grown upon marshy ground? What woods are adapted to low ground? What sometimes causes spiral growth? What do lumps and excrescences upon a tree generally signify? What causes clefts in trees? What are the results of clefts? Does nature perfectly repair the cleft? What is the usual result of a branch being broken off?
7. What is the per cent of moisture in green wood? Should very young trees be cut? Why? How may the top of a tree show when it should be felled? At what time of year should trees be cut?
CHAPTER II
Lumbering and Varieties of Wood
8. The manufacture of lumber.—(A.) There are two distinct processes in the preparation of lumber for commercial purposes, logging and sawing; the former includes all the steps from felling the tree to the delivery of the logs at the sawmill; there the logs are sawed into boards, planks, and timbers of certain dimensions, which are piled and exposed to the sun and air for a sufficient time to allow a large part of the water in them to evaporate, when the lumber is said to be “weather dried,” and ready for shipment to the consumer.