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Wood - Biodetrioration


Quiz Questions

1.The principal organisms that can degrade wood are fungi, insects, bacteria, and marine borers.
True
False
2. Termites are the major insect enemy of wood, but on a national scale, they are a less serious threat than fungi.
True
False
3.Bacteria in wood ordinarily are of little consequence, but some may make the wood excessively absorptive. In addition, some may cause strength losses over long periods of exposure, particularly in forest soils.
True
False
4.Marine borers are a fourth general type of wood-degrading organism. They can attack susceptible wood rapidly in salt-water harbors where they are the principal cause of damage to piles and other wood marine structures.
True
False
5.Fungus damage to wood may be traced to some general causes:
Lack of suitable protective measures when storing logs or bolts;
Improper seasoning, storing, or handling of the raw material produced from the log
Failure to take ordinary simple precautions in using the final product
All of the above
6.The incidence and development of molds, decay, and stains caused by fungi does not depend on temperature and moisture conditions.
True
False
7.Molds and fungus stains are confined to a great extent to sapwood and are of various colors. The principal fungus stains are usually referred to as sap stain or blue stain.
True
False
8.What does figure 13-1 illustrate about?
(Refer Pg 13-2)

Climate index for decay hazard
Molds and Fungus Stains
Decay Cycle
None of the above
9.Under favorable moisture and temperature conditions, staining and molding fungi may become established and develop rapidly in the sapwood of logs shortly after they are cut.
True
False
10.Non-microbial or chemical stains are easy to control and represent substantial loss in wood quality.
True
False
11.Serious decay occurs only when the moisture content of the wood is above the fiber saturation point (average 30%).
True
False
12.Typical or late stages of decay are easily recognized, because the wood has undergone definite changes in color and properties, the character of the changes depending on the organism and the substances it removes.
True
False
13.Decay initially affects toughness, or the ability of wood to withstand impacts. This is generally followed by reductions in strength values related to static bending. Eventually, all strength properties are seriously reduced.
True
False
14.The wood species, geographic region, and time of the year determine what precautions must be taken to avoid serious damage from fungi in logs, poles, piles, ties, and similar thick products during seasoning or storage.
True
False
15.Wood should also be protected from rain during construction. Protection from rainwater or condensation in walls and roofs will prevent the development of decay.
True
False
16.Subterranean termites are responsible for most of the termite damage done to wood structures in the United States.
True
False
17.Moisture condensation on the floor joists and subflooring, which may cause conditions favorable to decay and contribute to infestation by termites, can be avoided by covering the soil below with a moisture barrier, maintaining adequate ventilation, and assuming proper drainage of rainwater away from all sides of a structure.
True
False
18.What does figure 13-9 illustrate about?
(Refer Pg 13-10)
Types of insect damage most likely to occur in a building
Molds and Fungus Stains
Decay Cycle
None of the above
19.When wood is to be used in salt water, avoidance of cutting or injuring the surface after treatment is even less important than when wood is to be used on land.
True
False
20.Wood barges have been constructed with planking or sheathing pressure-treated with creosote to protect the hull from marine borers, and the results have been favorable.
True
False