SOME FUNGI IN WOOD.
49
and less frequently on other deciduous trees, has recently
been investigated by Wilkins [36, 37] in lime and has been
found to produce a white rot with black zone lines, which
may result in the complete destruction of the tree. Bulgaria
polymorpha (Ced.) Wett. occurs on felled oak logs, attacking
bark and the more peripheral sapwood: it does not do much
damage. Tabor and Barratt [31] conclude that it is a facultative
parasite on old beeches—primarily as a bark parasite—although
young, healthy trees are not attacked.
Chlorosplenium. Certain fungi belonging to this genus
produce a bright, somewhat bluish green stain in the wood which
they attack.
C. aeruginosum (Ced.) d. Not. occurs in varions hardwoods
and especially in oak, while another species, according to Hubert,
is found in coniferous woods. Decay is very slow, although
finally, according to Eades [9], a stringy rot is produced.
Sap stains. The sap stains in wood, of which mention has
already been made, are due almost entirely to Ascomycetes.
They are dealt with by Hubert [20] in detail, so that they will
receive brief treatment in the present paper. They occur in
timber of both broad-leaved and coniferous trees, and, while
feeding primarily on the cell contents, are known in some
instances to do some damage to the cell walls. The blue sap
stains, which are most important economically, are due to
species of Ceratostomella and several other genera. It has been
claimed that the ambrosia beetles, which bore in the sapwood
of felled timber, assist in the spreading of blue sap stain by
carrying the spores, but spores no doubt also obtain entry into
the wood through minute surface cracks as well. Sap stain
fungi require plenty of warmth and moisture to develop, and
these conditions frequently obtain when summer felled logs are
lying on the forest floor, and in various stages in the manufacture
of prepared wood. The sap stain fungi constitute a serious
problem to the timber manufacturer and shipper; although they
do seem to weaken the wood slightly this diminution in strength
is not usually sufficient to be of consequence, but discoloration
naturally tends to lower the value of wood, especially if it is to
be used without paint, while the presence of a fungus, however
benign it may be, is frequently regarded with suspicion among
buyers of wood.
D