30 THE REDWOOD. 



The brown wood is very brittle and has all the properties of char- 

 coal. Under a little pressure it will crumble into a line powder. As 

 the wood decays, it shrinks considerablj^ This reduction hi volume 

 causes large cracks to appear in the brown wood, and in some 

 instances the diseased wood separates entirel}^ from the sounder wood 

 and lies loose in the pocket. 



The decay starts in the inner rings of the heartwood and extends 

 outward gradually until all the heartwood is pitted (PI. X, figs. 1 

 and 2). Several instances have been found where small pockets had 

 formed in the sap wood. The brown rot starts at the ground and 

 extends from the roots upward into the trunk for distances varying 

 from 3 to 50 feet, and in some cases probably higher. As a rule, 

 though, it does not go farther than 10 to 15 feet in the butt, so that 

 by cutting off a butt log of about that length sound wood can gener- 

 ally be reached. The brown rot is found in older trees only, so far as 

 observed by the writer, and seems to develop very slowly. 



At present no one fungus can be determined to be the cause of this 

 disease. Under the best conditions it is a matter of great difficulty to 

 ascertain the cause of a disease which affects the roots and butts of 

 trees; but in the case of the Redwood the immense size of the tree 

 and its thick bark and formidable buttresses render an accurate 

 determination of the disease which affects it impossible without long 

 study. There are many saprophytic fungi which grow on the dead 

 bark and in and about the roots of the Redwoods, but in the present 

 incomplete state of our knowledge it would be hazardous to connect 

 any one of them with this disease. 



Reference may be made to the close resemblance of the brown rot 

 to the pin rot of Libocedras decurrens. The diseased wood of the 

 Incense Cedar is filled with brown pockets which closely resemble 

 those of the Redwood. These pockets occur in the tops of the trees, 

 however. The fungus causing this disease is Polyporus lihocedris^^ 

 so far found only on Libocedrus. It may be that it causes the rot of 

 the Redwood. The fact that the Redwood disease occurs in the base 

 of the trees ought to furnish no objection to such an assumption, since 

 there are other cases where the same fungus attacks one tree in the 

 crown and another nearer the ground — Trametes pini^ for instance, 

 which causes the disease of most of the pines in the tops of the trees, 

 attacks Plnus monticola very close to the ground. 



The brown rot has so far been reported as rather prevalent in north- 

 ern California. Near Fort Bragg and Crescent City the writer found 

 it in a good many old trees. It probably occurs throughout the Red 

 wood belt. 



Brown rot is not so serious as to cause alarm; it does practically lit- 



«von Schrenk, H. A disease of Taxodium known as Peckiness; also a similar dis- 

 ease of iyi6ocec?ni.s d^ecwrren-s-. Rep. Mo. Bot. Garden, 11:2, 8, 1900. 



