Illustrated Theatre Production Guide, 2nd Edition

226 Illustrated Theatre Production Guide 2 ed

TREES AND WOOD

Softwoods are coniferous trees that have a needle-like

leaf structure. The most common varieties in North

America are pine, spruce, redwood, cedar, and fir. Fir,

pine, and spruce are the three types of wood most often

used to produce lumber. There are many different vari-

eties of pine trees, but they can be separated into two

main types, yellow and white. Stage scenery has tradi-

tionally been constructed of white pine. White pine is

an extremely workable wood for building scenery, as it

is soft and easy to cut, it has a straight grain pattern,

and it is widely available at a reasonable price. Yellow

pine is much heavier and is more susceptible to splitting.

Fir is quite often used to make interior trims and

moldings.

At least a cursory understanding of the mechanics

of how trees grow can help you understand how wood

will react when it is used for building stage scenery.

Because trees grow naturally, they are prone to quirks

that cannot be entirely eliminated by the lumber milling

process.

Many people seem to think that trees grow upward

out of the ground, but this is not the case. In reality,

they grow from the top up and from the outside out,

and not from the center or bottom. Tree bark protects

an interior layer of fibers known as the cambium or

sapwood. The cambium layer of a tree is the area where

growth rings originate. Everyone has seen growth rings,

which are evident when looking at a cross section of a

tree trunk. These rings are added to from the outside,

which is to say that each year’s growth ring, provided

by the cambium layer, is added to the outside of the

tree trunk, just under the bark. Bark is very much like

skin for a tree and protects the cambium layer from

weather and disease. Bark is rough because it must con-

stantly expand as the tree grows.

The cambium is responsible for transporting water

and nutrients from the ground to the leaves. It is really

a mass of tiny tubes much like blood vessels. These

fibers are very strong and pliable along their length, but

they are not bound together all that well. It is possible

to strip the fibers from some trees into long strings. This

works with other plants as well. Hemp fibers are stripped

from the stalk of that plant and then twisted into rope.

You may think of a stalk of celery as being indicative of

the mechanics of the structure of a tree. The stalk will

bend along its length, but will easily snap across its

width. After it does, the stringy fibers that make up the

stalk are plainly visible.

Celery grows to its full size in one season, so there

is no division of growth rings. A tree can grow over

hundreds of seasons, and the heartwood, or interior of

the trunk, is the remaining evidence of many years’

cambium layers. The heartwood is the rigid material

that gives the tree its strength and ability to remain

erect.

The way a tree grows means that objects on the

outside of the tree trunk will eventually be enveloped

by it. If a sign is nailed to the exterior of a tree trunk,

some years later the tree will have grown around it,

causing the sign to eventually disappear. The same thing

can happen to wire fences and other manmade objects

in the forest.