ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

The galleries, or mines, of wood borers can seriously degrade some products,
primarily peeler grade 1 ogs, but seldom become abundant enough to cause cull before
fungi render the wood useless for lumber (Kirrmey 1955). Wood borers related directly
to the general deterioration of wood in fire-killed trees by providing entrance
holes and galleries through which decay fungi can gain direct and early access to
wood tissues (Elasham 1956; Gardiner 1957; Stevens and Hall 1960; Wallis and others
19747.
"The most destructive wood borers belong to two families of beetles: the
roundheaded borers and the flatheaded borers. Both groups contain a great many
species, some of which are attracted to fire-killed timber even before the fire is
out" (Stevens and Hal 1 1960).
Roundheaded wood borers (Cerambycidae) . --Several species of beet1 es in this
group attack sound heartwood, often of f i re-ki 11 ed or weakened trees. Roundheaded
borers are usually the most important insects to consider in determining the salvabil
ity of fire-injured trees (Kimmey and Furniss 1943). Most heartwood damage to
fire-predisposed trees is caused by a large roundheaded borer, Ergates spiculatus
Leconte (Beal and others 1935). Beetles of this species usually do not become
abundant in fire-killed trees until 5 or 6 years following the fire; beetle attacks
continue as long as the wood remains sound (Kimmey and Furniss 1943).
--f--%--
The roundheaded borer, Crioce ha1 us roductus Leconte, causes considerabl e
damage to the heartwood of Doug as-fir pre isposed by fire (Kimmey and Furniss
1943). Adults of this group attack trees the first year after a fire (Kimmey and
Furniss 1943), often while the trees are still smoldering (Furniss 1937b). By the
third or fourth year after a fire, beetle larvae usually have not penetrated the
heartwood of trees of average to large size, but in the smal ler-to-medium-sized
fire-kil led trees, these borers will have done considerable damage (Furniss 1937b).
Another borer, Leptura obl i terata, along with several other wood-boring species and
their associated fungi, destroy the sapwood and attack the heartwood of some conifers
in the third year after fire has predisposed them to attack (Beal and Kimmey 1935).
Roundheaded wood-boring species of the genus Monochamus a1 so damage fi re-ki 11 ed
conifers by excavating tunnels into the heartwood usually after feeding for a time
on the inner bark and outer layers of sapwood (Gardiner 1957). In a study of Monochamus
damage to three species of fi re-predi sposed pine--eastern white pine, red pine,
and jack pine, Pinus banksiana Lamb. ,--Gardiner (1 957) summarized: 1 ) the effect
of the fire on wood borer damage varies with the tree s ecies; 2) the severity of
the burn governs the spread and nature of the attack; 3 ! the severity of the burn,
which influences the attack pattern,
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indicates when trees should be harvested. In
British Columbia, Monochamus ore onensi s Leconte damage fire-kill ed white spruce (Ross
1960), and in New Hampshire M scute latus Say attacks spruce as severly as it does
pine (Bess 1943).
Flatheaded wood borers (Buprestidae) . --Probably the most notable f 1 atheaded
borers associated with fi re-predi sposed conifers are various species of the genus
Melanophila, or metal1 ic wood borers (fig. 6). A1 though 1 lving, uninjured green
trees are either resistant to (Linsley 1943) or not killed (Furniss 1937b) by Melano-
hila, these beetles are definitely attracted to trees predisposed by wildfirep
Evans 1966, 1971).
F- Perhaps the most interesting relationship between beetles in the genus Melanophila
and fire-predisposed trees is how the insects are attracted to the fire. Some
investigators feel that these beetles are attracted by volatile materials associated
with smoke (Linsley 1943). Recent studies indicate that they are attracted to heat
(Evans 1971), because heat is always a directional stimulus but smoke is affected by
wind and is soon dissipated. Melanophila beetles apparently are able to detect