lOI 



54. Thuja gigantea. 



This arbor vitae shares the same sylvicultural 

 peculiarities as the Lawson cypress, and may be 

 cultivated under identical conditions, bearing, 

 however, in mind that it suffers more than the 

 Lawson cypress from the ravages of the Pesta- 

 lozzi funerea. The suppression of this fungus by 

 means of continually new forming shoots is more 

 difficult it its case, and the future alone can show 

 whether this fungus may not render the cultiva- 

 tion of this species of timber tree altogether 

 impossible. 



55. Tsuga mertensiana. 



This very rapid growing somewhat shade- 

 tolerating tree, with the slender drooping tips 

 of its branches, is exposed to danger from early 

 frosts up to the tenth year of its existence, and 

 from that period onward it seems to be as hardy 

 as the Canadian tsuga, to which it is superior in 

 rapidity of growth. This variety of tree may, 

 therefore, be employed in the same localities as 

 have already been suggested for the Canadian 

 plant. With these may be added two kinds of 

 timber trees which, hitherto, have only been 

 treated in the experimental gardens of Grafrath, 

 namely, the 



