6 A HANDBOOK OF CONIFERiE 



such ducts are absent. The distinction between spring and 

 autumn wood is usually well marked in trees from temperate 

 regions, but less distinct in species from warmer countries. 

 Heart-wood and sap-wood are not always well defined. 



Economic Uses. 



Many conifers yield timber of very great economic importance, 

 In most cases the wood is strong in comparison to its light weight, 

 straight-grained, easily worked, durable, or easily made so by 

 treatment with preservatives. It takes paint, polish, or glue 

 well, and is suitable for a wide range of work, particularly general 

 carpentry and joinery, pit props, telegraph poles, railway sleepers, 

 paving blocks, and paper pulp. By destructive distillation various 

 tar products, pyroligneous acid, etc., are obtained. Several 

 species yield resin in commercial quantities, which is used in the 

 preparation of paints and varnishes or distilled for the production 

 of turpentine and rosin. From bark-blisters and wood a semi- 

 resinous substance is procured which is used in medicine and for 

 other purposes. Oil obtained by the distillation of leaves, fruits, 

 and wood is used in medicine and perfumery. Fibre from bark 

 and foliage is sometimes used in upholstery ; the seeds of certain 

 species are valuable for food, whilst the bark of others is employed 

 by tanners. Further particulars of the economic uses are given 

 under the respective species. 



Propagation. 



Whenever possible, conifers should be increased by seeds, for 

 seedlings usually form the best trees. Cuttings of various 

 species, particularly of Cwpressus, may be rooted, and this method 

 of propagation is necessary in the case of varieties that do not 

 breed true from seeds. Grafting is also resorted to in such cases, 

 but grafting should not be tried until other means of propagation 

 have been tried and failed. When grafting is practised stocks 

 closely related to the scions should be chosen. Layered branches 

 sometimes take root, but plants raised by this means are often 

 misshapen. A few species (notably Cryptomeria japonica and 

 Sequoia sempervirens) produce coppice shoots from cut-over 

 trees. Seeds may be sown during autumn or early spring (the 

 latter time for preference), the ground chosen being on the light 

 side, well drained, and well worked. For large quantities of seed, 

 beds 4 feet wide, separated bypaths 12-15 in. wide, are most con- 

 venient. The soil should be on the dry side when the seed is 

 sown. The seed should be sown rather thinly, lightly covered 

 with soil and pressed down by means of a light wooden roller. Steps 

 must be taken to protect the seeds from vermin and, when 

 necessary, to shelter seedlings from frost and hot sun. Small quan- 



