Juvenile Wood Characteristics Quiz

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What are the three distinct surfaces of wood that can be identified?

Cross section, radial, tangential

What parts can be seen within the wood zone in the cross section view?

Heartwood, sapwood, annual growth rings, rays

What features can be observed on the radial surface of wood?

Pith, growth rings, heartwood, sapwood, bark

How is the tangential surface of wood created?

By cutting a tangent to the growth rings Signup and view all the answers

Despite the name, what does the hardness of hardwood not necessarily imply?

Hard, dense, or particularly strong Signup and view all the answers

What are the structural elements of wood tissues?

Wood cells Signup and view all the answers

What are the long and narrow tube-like cells found in softwoods?

Tracheids Signup and view all the answers

What are the hard wood cells called?

Fibres Signup and view all the answers

What is the major component of wood substance?

Cellulose Signup and view all the answers

What helps in conducting sap in trees for wood formation?

Vessels Signup and view all the answers

What is the outgrowth from an adjoining ray into the lumen of a vessel called?

Tylosis Signup and view all the answers

What is the main difference between juvenile wood and mature wood?

Juvenile wood shrinks and swells excessively along the grain as moisture content changes, and its strength is lower than mature wood. Signup and view all the answers

Why is juvenile wood more common in lumber today compared to the past?

Juvenile wood is more common today due to the use of smaller diameter trees for lumber production. Signup and view all the answers

What are the two most troubling characteristics of juvenile wood?

<ol> <li>Shrinks and swells excessively along the grain as moisture content changes. 2. Strength is lower than mature wood.</li> </ol> Signup and view all the answers

What is reaction wood and why is it of interest to wood dealers?

Reaction wood is wood with inferior properties formed in response to stem leaning. It is of interest to wood dealers because its properties are less desirable than normal mature wood. Signup and view all the answers

What is compression wood and in which type of trees is it common?

Compression wood is formed on the lower side of a leaning stem and is common in temperate trees. Signup and view all the answers

What is tension wood and in which type of trees is it common?

Tension wood is formed on the upper side of a leaning stem and is common in tropical trees. Signup and view all the answers

What is the dry basis moisture content of freshly sawn low density sapwood if it contains nearly two and a half times as much water by weight as dry wood?

250% Signup and view all the answers

What is the moisture content of freshly sawn wood?

100% Signup and view all the answers

What is hygroscopicity in relation to wood?

Hygroscopicity is the property of wood to attract moisture from the surrounding atmosphere and to hold it in the form of liquid water or water vapour. Signup and view all the answers

What happens when the same number of water molecules returns to the wood surface as leaves from it?

The wood attains an Equilibrium Moisture Content (EMC). Signup and view all the answers

What occurs if more molecules of water leave than return to the wood surface?

Drying takes place. Signup and view all the answers

When does wetting take place in wood?

Wetting takes place if more molecules of water return to than leave the wood surface. Signup and view all the answers

Why is wood drying necessary to enhance the structural properties of timber for safe construction?

Wood drying is necessary to reduce moisture content and prevent issues like warping, cracking, and decay in timber, ensuring structural stability in construction. Signup and view all the answers

What is hygroscopicity, and why is it a very important property of wood?

Hygroscopicity is the ability of wood to absorb and release moisture from the surrounding environment. This property is crucial as it affects the dimensional stability and performance of wood products. Signup and view all the answers

What is anisotropy in the context of wood, and how does it impact dimensional changes?

Anisotropy refers to the property of wood where it reacts differently to moisture changes along different directions of tree growth. This property causes dimensional changes to occur when moisture content fluctuates, affecting the overall stability of wood. Signup and view all the answers

What factors affect wood shrinkage and swelling, and how do they influence dimensional changes?

Density, structure, extractives, and moisture content influence wood shrinkage and swelling. Higher density and extractive content, along with porous wood, can impact the magnitude of dimensional changes in wood. Signup and view all the answers

What is the simplest method for drying lumber, and how does it work?

Air drying is the simplest method, involving carefully stacking timber outside to allow natural air circulation to reduce the moisture content of the wood. Signup and view all the answers

Three surfaces of wood

Cross section, radial, and tangential surfaces of wood.

Wood zone in cross section

Includes heartwood, sapwood, annual growth rings, and rays.