PREVENTIVK AND COMB ATI VK MKASlliK-. 77 



wound must remain open till completion of occlusion." If we followed 

 this view, then numerous wounds would lie left freely open as entrancee 

 for wound-parasites, and serious loss would result. It is just the num-rou- 

 smaller wounds (e.g. those produced l>y hail), which are the principal pla< - 

 of infection for specie-, of _W<-/ ,-,'/, (.''/<///////.///'', //<///< /<"/// ;,< '>, etc., in 

 fact, they form very convenient places whence a tree may lie easily infect. -d 

 artificially. 



The following points in regard to treatment of branches ma\ 

 be conveniently summarized here. Trees in closed plantations 



are naturally stripped of their branches by these dyinu in con- 

 sequence of deficient illumination; they then break off, and 

 the short stumps are soon occluded or grown over. Ihirinu 

 this process there is always a risk of infection by fungi, and 

 "snag-pruning" 1 is employed to shorten the period of occlusion 

 as much as possible. This at the same time prevents the in- 

 clusion of long branch-stumps in the timber, and reduces the 

 number of knots in sawn boards. Such dead snags or stump- 

 are deficient in nutritive materials and very dry, so that they 

 are less suited for the entrance of wound-fungi than wounds on 

 the living branch. 



The usual process of forest-pruning is necessary to produce 

 dean boles, to increase the illumination for undergrowth, or 

 to utilize the branches so removed. In the operation, all 

 branches should be cut oil' close to the shaft, no snag- .should 

 be left, nor must injury be inflicted on neighbouring bark. 

 Th>' operation is best carried out in autumn or winter when 

 the bark is most adherent to the wood, occlusion then bev,in- 

 with the renewal of vegetative acthitv in .-pring and is well 

 advanced by the time the greatest dispersal of fmi;_:u--spores tak. 

 place. Infect ion by fungi will, bo\\e\er, be rendered quite 

 impos-iMe if wound.- are immediately painted over with tar, or, 

 in the case of -mailer wounds on garden stock, with tree-wax ; 

 these reagents, if applied in winter, will easily penetrate into the 



Wood, and even replace the formation of protective Wolllld-Wood. 



Haiti- says on ibis subject: 2 tarring produces satisfactory 



result- only when pruning has been done in late autumn oi 

 in \\inttT, because it is only then thai the tar is absorbed by 

 llie -url'acf of the wound. Il would appear that the absorption 

 of bar i- due partly to the diminished amount of \\aier in the 



1 Tr<>, U, ii.i-timg. ll.itij. /' / . Kn-li-li K.lit. \>. ! 



