Wood suitable for carpentary and building is known as timber. It is of two types, hardwood (most dicots) and soft wood (gymnosperms and some dicots like Salix; Salmalia and Morus). Heaviest wood is that of Guaiacum officinale but in India, Acacia sundra. Some common timber yielding trees are:
(Sagwan) Tectona grandis. Most durable wood.
(Shisham). Dalbergia sisso (Indian Red wood) Dalbergia latifolia is Indian Rose wood.
(6) Indian Almond:
Mesua ferra (Nagkesar, Nagchampa).
Trees are also planted under social forestry programme on village common land, vacant land along roads and railway embankment. The plants should be fast growing, capable of giving fodder and fuel besides some timber, e.g. Leucaena, Allanthus, Anogeissus. Certain woods are used for specific purposes. For example; wood of Salix alba and Salix purpurea is useful for making cricket,bats. Hockey sticks are prepared from wood of Moras alba.
(1) Plants Used as a Source of Resin:
Alcohol soluble sticky exudation. Pine resin (Pinus roxburghii and other species, gymnosperm) yields turpentine and rosin Damar is obtained from Shorea robusta or Sal.
(2) Plants Used as a Source of Gums:
Gums are sticky exudation of bark which are insoluble in alcohol but form colloidal solution in water.
(I) Kuteera gum-Sterculia urens.
(2) Bengal Kingo gum-Butea monosperma.
(3) Salai-Boswellia serrata.
(4) Dhaora-Anogeissus latifolia.
(5) Gum Arabic-Acasia sapota.
(6) Milky latex of Achras sapota forms chickle gum from which chewing gum is produced.
(3) Plants Used as a Source of Tannins:
These are astringent acidic substances used in preparation of dyes, inks and leather. Acacia nilotica, WalnutJuglans regia, Cesalpinia, Uncania (leaves and young branches).
(4) Plants Used as a Source of Dyes:
(1) Cutch (Kattha): Heart wood of Acacia catechu in betel leaves and colouring textiles.
(2) Henna (Mehndi): Leaves of Lawsonia inermis.
(5) Plants Used as a Source for Insecticides:
Insecticide kill or repel insects. Natural insecticides include
(1) Azadirachta indica (Magosa/Neem)
(2) Boenighauscnia alhiflora.
(3) Peganum harmala.
(4) Derris (rotenone)
(5) Chrysanthemum (Pyrethrum).
First commercial bioinsecticide is sporeine developed in Germany. Synthetic insecticides are organochjorines, organophosphates, carbamates, pyrethroids.