Timber “Wood appropriate for homes or engineering functions is known as timber” Classification of Trees They have pointed leaves, They are tall and cone-formed fruit consequently is known as Conifer. and such sorts of trees Endogenous Trees, Exogenous Trees, Conifers or Evergreen Trees
Classification of Trees:-
>>ON THE BASIS OF MODE OF GROWTH:-
A. Endogenous Trees:-Trees that grow inward by depositing every year of fresh layer internally, instead of on the outside of the tree is known as endogenous ( Example * Bamboo, cane, palm ) They have very restricted Engineering applications. which contain amazing majority of cutting-edge trees (all conifers, and all broadleaf trees), develop with the aid of using the addition of latest timber outwards, without delay below the bark. Endogenous trees, in particular, withinside the monocotyledons develop with the aid of using the addition of the latest cloth inwards.
B. Exogenous Trees:-
- Trees that grow outside from the center by depositing annually a new layer of material between the previous year growth in the bark.
- The cross-section of such a tree is having a series of consecutive concentric rings. These rings are called annual rings and each ring represents the growth of one year.
- Such trees grow bigger in diameter.
- The timber which is mostly used for engineering purposes belongs to an Exogenous tree.
Exogenous trees are further divided into two groups:-
- Conifers or Evergreen Trees ⟹ Classification of Trees They have pointed leaves, They are tall and cone-fashioned fruit therefore is called Conifer. These timber yield softwoods, mild in color, mild in weight, and vulnerable wood. Timber acquired from those timbers is appropriate as anxiety members, as they having immediately grains and awesome annular rings.
Exa:- Deodar, Pine, kail, Chir, spruce.
2. Deciduous trees⟹ They have broadleaf. They encompass all right, maples, and beeches, and that they develop in lots of components of the world. The leaves of those bushes fall in autumn and new ones seem in spring seasons. The wood for engineering paintings is primarily derived from deciduous bushes. Timber acquired from those bushes is strong, durable, darkish in color, heavy, and non-resinous. Example: Teak, Sal, Shisham, Walnut, mahogany, babul, oak, etc. Deciduous bushes are large flowering plants. The phrase deciduous approach to “fall off,” and each fall those bushes shed their leaves. Most deciduous bushes are broad-leaved, with wide, flat leaves.
Commercially trees are also classified as soft and hardwoods Softwood.
Hardwood isn’t always always a tougher material (greater dense) and a softwood isn’t always always a softer material (much less dense).
Different kinds of production tasks name for specific forms of timber, each hardwood and softwood are used for the whole thing from structural to decorative pine, redwood, spruce, and yew. Most hardwoods have a better density than most softwoods..
Softwood and hardwood are prominent botanically in phrases in their reproduction, now no longer via way of means of their end-use or appearance. All bushes reproduce via way of means of generating seeds, however, the seed shape varies.
In general, hardwood comes from a deciduous tree that loses its leaves yearly and softwood comes from a conifer, which commonly stays evergreen. Hardwoods have a tendency to be slower growing and are consequently commonly denser.
Examples of hardwood bushes consist of alder, balsa, beech, hickory, mahogany, maple, oak, teak, and walnut. Examples of softwood bushes are cedar, Stephen A. Douglas fir, juniper, pine, redwood, spruce, and yew. Most hardwoods have a better density than most softwoods.
>>ON THE BASIS OF DURABILITY:-
- Highly durable (avg. life span>10 years).
- Moderately durable (5-10 years).
- Low durable (<5 years).
>>ON THE BASIS OF ELASTIC MODULUS:-
- Group A: E = 12.5 GPa
- Group B: E = 9.8 GPa to 12.5 GPa
- Group C: E = 5.6 GPa to 9.8 Gpa.
>>ON THE BASIS OF EASE OF SEASONING:-
- Nonrefractory (can be seasoned easily)
- Medium refractory (liable to twist and warp)
- Highly refractory (liable to undergo severe damage).