Some Common Hardwoods, 411 



was found that a portion of a sapling 1^ in. in diameter and 

 6 ft. H in. long had 31 vessels as ^long as the piece itself. This 

 result is not as good as some given by Professor Ewart in AnnaU 

 of Botany, 1910, but it is very likely that even these results could 

 be beaten by Mountain Ash. The length of the vessels, their large 

 size, and their even distribution over the annual ring will prob- 

 ably limit the application of Mountain Ash for certain purposes. 



The second element of importance is the libriform fibres. They 

 are elongated and sliarply pointed. They average about 1 mm. 

 in length. It would appear that the fibres formed during the 

 sapling growth are slightly longer than those formed in later 

 years. Hal:»erlandt states that the reverse is the case for tracheides 

 in conifers. 



The rays are uniseriate and very numerous. In the rays in the 

 centre of old mature trees nuclei are very frequemt. These have 

 been traced almost up to the central ring, so that they must be 

 considerably over a century old. No trace of starch has been 

 found in these central ray cells. In conjunction with this 

 phenomenon is the fact that this central wood has a higher moisture- 

 content than tlie rest of the M'ood. This high moisture content 

 accounts for the enormous shrinking and warping that takes place 

 when this central wood or '' heart " dries. This large percentage 

 of moisture in the centre, together with the imperfect lignification 

 of tlie fibres predisposes the central portion to decay. By good 

 forestiAi tlie amount of this immature w^ood formed could probably 

 be lessened. 



Tyloses have frequently been found associated with the nuclei 

 near the centre of the big timber. Tyloses have also been abun- 

 dantly found in Messmate (E. obliqua), right up against the 

 cambium. These facts are conflicting, and at present no explana- 

 tion can l)e given. 



Mountain Ash when green is a softwood, but when seasoned is a 

 hardwood, and this must be kept in mind if this wood is to l>e 

 pulped. A very objectionable feature to its use for pulp is the 

 presence of tannin. 



I wish to express my thanks to the various sawmilh'rs and bush- 

 workers who have kindly afforded opportunities for carjying out 

 these investigations. My thanks are especially due to the manager 

 of Powell town. 



Tlie work was carried out in connection with tlie Botanical 

 LaVjoratoi-y, MellKJurne rniversity. with the aid of a Government 

 Research Grant. 



8 



