Question

Diferentiate between hard wood and sap wood

Answer 1

Dear student,

wood is the secondary xylem of seed-plants. As the tree ages, certain permanent changes take place in the wood. The inner parts of the wood become darker. The xylem in this central part is called heartwood (it is not hardwood) or ‘duramen’. The peripheral part of the wood is light coloured and it is called sapwood or ‘alburnum’. The sap conduction occurs through the sapwood. The dark colour of heartwood is due to the accumulation many aromatic substances, pigments and tannins. These changes make the wood more strong and durable and resistant to decay by insect or fungal attacks. The inner heartwood provides the mechanical support.

Major differences are as follows:

Sl. No.HeartwoodSapwood

1	Heartwood occurs in the central portion of an old stem.	Sapwood occurs in the peripheral (outer) portion of an old stem.
2	Cells are comparatively older.	Cells are comparatively younger.
3	Also called as ‘Duramen’	Also called as ‘Alburnum’
4	Heartwood is dark colured	Sapwood is light coloured.
5	It is the dead and nonfunctional part of the secondary xylem.	It is the living and functional part of the secondary xylem.
6	The lumens of vessels and tracheids are plugged due to tyloses formation.	Vessel and tracheid are not plugged. No tyloses formation.
7	Cells store many ergastic substances such as resins and tannins.	Cells do not store any ergastic substances.
8	Cells store many ergastic substances such as resins and tannins. Heartwood is heavier.	Sapwood is light in weight.
9	Heartwood is the durable wood.	Sapwood is not a durable wood.
10	Heartwood is suitable for making furniture	Sapwood is not suitable for making furniture.
11	Wood is resistant to insect and fungal attacks	Wood is susceptible to insect and fungal attacks.