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Index of Subjects --Apple-Mail-19--662945661 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi Peter, Hmm ... I guess this depends on how you define "soon." ;-> In my experience dead trees do not develop fungi on their bark soon at all. From my study of wood decay (principally from an insect perspective) I can say the following. Very soon (within days or weeks, depending on the time of year - in the fall and winter these processes move more slowly) of say, a windblown tree falling over in the forest, the suite of cambium-eating insects that colonize such environments (longhorn beetles (Cerambycidae), jewel beetles (Buprestidae), bark beetles (Scolytinae), and others) arrive. The larvae of these beetles tunnel under the bark of trees eating the cambium (eggs are normally laid in the spring and early summer). Depending on the size of the tree, its location, species, the local environment, etc., with 18-24 months all the cambium there has been consumed and or degraded. This means that a very considerable amount of subcortical space is available for colonization, and indeed much of that area is soon filled by various kinds of fungal hyphae. There are groups of fungi collectively called "brown rot" and "white rot" (including genera such as Dacromyces and Zygosaccharomyces spp.) as well as the blue-stain (Ophiostoma and Ceratocystis spp.) and brown stain (Trichosporium spp.) fungal groups. This process is actively abetted by so-called "ambrozia" beetles (in this region, bark beetles (Scolytinae) of the genera Tripodendron, Xyloterinus, Xyleborinus, Xyleborus, and possibly others) that carry fungal in so-called "mycetangia," which are pits on various portions of their body. These have the effect of innoculating the wood with fungal spores which soon grow into mats of mold/mildew which are then eaten by the adults and larvae of these species. In any event, all this activity opens up the subcortical space for the colonization of many kinds of fungi, which then extend their hyphae under the bark and into the wood and finally produce the fruiting bodies (polypores, a.k.a. bracket fungi and other groups of fungi which we associate with decaying wood) that "appear" protruding through the bark. I'm not certain what the timelines on this are, but its my impression that wood has to be dead for 2-3 years before such epi-cortical "tree mushrooms" become evident. Hope this helps. Cheers! Chris On 19-Dec-06, at 9:39 PM, Peter Payzant wrote: > Here's a question for the plant biologists: A dead tree soon > develops a garden of various kinds of fungi on its bark. This > doesn't happen to living trees, as far as I know (although lichens, > liverworts etc. do attach to them). > > The outer surface of the bark of a tree appears to be made up of > dead tissue. How is the tree able to fight off infection by > external fungi when it is more or less surrounded by dead material? > Is it perhaps a matter of attacking the fungal "roots" when they > penetrate the park to the living tissue? > > Peter Payzant > > > _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. Christopher Majka - Nova Scotia Museum of Natural History 1747 Summer Street, Halifax, Nova Scotia, Canada B3H 3A6 (902) 424-6435 Email <c.majka@ns.sympatico.ca> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. --Apple-Mail-19--662945661 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <HTML><BODY style=3D"word-wrap: break-word; -khtml-nbsp-mode: space; = -khtml-line-break: after-white-space; ">Hi Peter,<DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV><SPAN = class=3D"Apple-style-span">Hmm ... I guess this depends on how you = define "soon." ;-> In my experience dead trees do not develop fungi = on their bark soon at all. =46rom my study of wood decay (principally = from an insect perspective) I can say the following. Very soon (within = days or weeks, depending on the time of year - in the fall and winter = these processes move more slowly) of say, a windblown tree falling over = in the forest, the suite of cambium-eating insects that colonize such = environments (longhorn beetles (Cerambycidae), jewel beetles = (Buprestidae), bark beetles (Scolytinae), and others) arrive. The larvae = of these beetles tunnel under the bark of trees eating the cambium (eggs = are normally laid in the spring and early summer).=A0</SPAN></DIV><DIV><BR= class=3D"khtml-block-placeholder"></DIV><DIV><SPAN = class=3D"Apple-style-span">Depending on the size of the tree, its = location, species, the local environment, etc., with 18-24 months all = the cambium there has been consumed and or degraded. This means that a = very considerable amount of subcortical space is available for = colonization, and indeed much of that area is soon filled by various = kinds of fungal hyphae. There are groups of fungi collectively called = "brown rot" and "white rot" (including genera such as <I>Dacromyces</I> = and <I>Zygosaccharomyces</I> spp.) as well as the blue-stain = (<I>Ophiostoma</I> and <I>Ceratocystis</I> spp.) and brown stain = (<I>Trichosporium</I> spp.) fungal groups.=A0</SPAN></DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV><SPAN = class=3D"Apple-style-span">This process is actively=A0abetted by = so-called "ambrozia" beetles (in this region, bark beetles (Scolytinae) = of the genera <I>Tripodendron, Xyloterinus, Xyleborinus, Xyleborus</I>, = and=A0possibly others) that carry fungal in so-called "mycetangia," = which are pits on various portions of their body. These have the effect = of innoculating the wood with fungal spores which soon grow into mats of = mold/mildew which are then eaten by the adults and larvae of these = species.=A0</SPAN></DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>In any event, all this = activity opens up the subcortical space for the colonization of many = kinds of fungi, which then extend their hyphae under the bark and into = the wood and finally produce the fruiting bodies (polypores, a.k.a. = bracket fungi and other groups of fungi which we associate with decaying = wood) that "appear" protruding through the bark. I'm not certain what = the timelines on this are, but its my impression that wood has to be = dead for 2-3 years before such epi-cortical "tree mushrooms" become = evident.</DIV><DIV><BR class=3D"khtml-block-placeholder"></DIV><DIV>Hope = this helps.</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Cheers!</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Chris</DIV><DIV><BR><DIV><DIV= >On 19-Dec-0