SPRING-WOOD AND SUMMER-WOOD. 15 



Xordlinger termed such woods ring-pored [Fig. 5, //, r, spring- 

 wood with wide pores (sections of vessels), /, d, summer- wood 

 with narrow pores ; between them is the annual ring]. The 

 term ruiy-pored is not happily imagined, as it is doubtful 

 whether some woods are to be termed ring-pored, or not ; 

 the term scattered pores is also unsatisfactory, for the wood 

 of oak and ash also possesses pores, though smaller ones, 

 outside the ring of large pores ; for this reason, in the 

 following attempt to classify woods, the use of these terms is 

 abandoned, though they may be serviceable for descriptions 

 and tables of identification when unaccompanied by plates. 



In some other broadleaved trees, as in elms and cherry- 

 trees, the early wood is richer in pores than the late wood ; in 

 others again, such as beech, birch, lime, etc., there is no dis- 

 tinction between the early wood and late wood in this respect, so 

 that it is more difficult to count their rings. In coniferous woods 

 (Fig. 4) vessels occur only in the medullary sheath, and the 

 annual zone begins with a thin-walled, light-colourecTsoft tissue. 

 which gradually, seldom abruptly, passes over into a thick- 

 walled, dark-coloured, hard, late wood, with narrow lamina. 

 Hence (Fig. 4, //, c) light-coloured soft early wood directly 

 adjoins the hard, dark-coloured late wood of the previous year. 

 In conifers therefore there are fairly recognizable annual rings, 

 which facilitate the determination of the age of the tree. 



Owing to the important bearing of the softer early wood and 

 the harder late wood on the different qualities of wood, attempts 

 have been made to determine more precisely, within the 

 annual zone of wood, the periods which produce these layers. 

 The formation of wood during spring, t>., in Central Europe 

 from about the end of April till the end of May (in northern 

 latitudes or higher altitudes from June), has been termed 

 spring-wood, while the wood formed subsequently during the 

 same year, is termed summer-wood, or autumn-wood. As no 

 wood at all is formed in North Europe during autumn, the 

 latter term must be abandoned. 



With a rapid diameter growth and wide annual zones the 

 soft spring-wood of conifers grows more quickly than the 

 summer-wood; with broadleaved woods, on the contrary, 

 wide annual zones imply hard wood, and narrow zones, soft 



