conks not good
Various fungi especially Polyporus and Fomes spp.
Common Host: All Hardwoods
Significance:
Wood decay and heart rots of hardwoods are extremely common in all parts of the world. Diseases of this type are often highly visible, not necessarily because of the decayed or rotted wood, but by virtue of the various and conspicuous conks or sporophores (fruiting bodies) produced by the pathogens on decaying or rotting stems and branches. Losses to wood decay and heart rots can be significant in terms of timber degrade or culls; decayed wood isn't worth much. In addition, trees with advanced or extensive decay represent aesthetic and safety liabilities from the standpoint of branch or stem breakage.
Recognition:
The presence of various types of fungus conks or sporophores on the stems and branches of hardwoods is often a good indicator of wood decay or heart rot. Conks appear in various colors, and are bracket or shelf-like, hoof-shaped, or flattened to the stem, and are often porous on their lower, spore-bearing surfaces (hymenia, sing., hymenium).
The spore-bearing surfaces of other wood decay fungi are smooth (Stereum spp., etc.), gilled (Lenzites spp., Etc.) or toothed (Irpex spp., Etc.) on their spore-bearing surfaces. Conks frequently occur on dead branches or branch stubs and at or near wounds. Sometimes conks appear on the surface of stems or branches that appear normal. Some conks may appear for a short time and disappear; others remain attached to infected trees for years.
Those of Polyporous spp. are typically annual, appearing and disappearing the same year, and are usually fleshy, spongy, corky, leathery, or rubbery in texture. Conks of Fomes spp., on the other hand, are characteristically perennial, and are hard and woody in texture.
Internally, wood infected with decay or heart rot fungi is initially discolored or stained. As decay progresses, infected wood becomes progressively softer and punky, and breaks, crumbles, or shreds easily when examined.
Infection Biology:
Infections occur when spores, aerially disseminated spores from conks of the various decay fungi, are deposited on or near wounds, pruning scars, fire scars, or dead branch stubs of susceptible hosts. Moisture and temperature conditions permitting the spores germinate, and the fungi grow slowly into the vulnerable wood tissues. Some fungi produce predominantly or solely heart rot, invading only the tree's central column of physiologically inactive (nonliving) heartwood. Heart rot fungi are common on old, mature to over-mature trees, especially if they have sustained significant branch or stem injury during their lifetime. Other fungi called sap rotters typically decay the outer layers of weakened or dead sapwood associated with wounds, broken branch stubs, and the like. Rarely do wood decay fungi invade healthy, uninjured wood tissues. Following sufficient development in infected wood tissues, a process sometimes taking years, the decay fungi produce their characteristic conks on the tree's external surfaces.
Control:
No effective or practical control measures exist for treatment of existing heart rot or decay. Prevention of decay by avoiding injuries to trees is the most effective method of minimizing damage. Healthy, vigorously growing trees are usually capable of "compartmentalizing" (walling off) decay in wood tissues present at the time wounds are sustained. Thus, promoting the vigor of trees through timely fertilization and irrigation enhances their ability to compartmentalize decay. (Fertilizing and watering has the added benefit of enhancing the structural strength of wounded or damaged trees by stimulating the growth of a new decay-free wood tissues). Compartmentalization is further enhanced by proper pruning of branches and dead branch stubs, a practice that facilitates the tree's natural callusing and wound closure processes. When pruning branches and branch stubs, make clean cuts immediately outside the swollen or callused branch collars at the base of branches or stubs being removed. Do not injure branch collars in the pruning process as these collars are healthy, growing wood tissues, and wound closure is more rapid if these tissues are left intact. Broken or otherwise projecting branch stubs (poorly pruned branches, etc.) inhibit wound closure, and therefore often provide decay organisms with easy and prolonged access to vulnerable wood tissues and/or a ready supply of necessary air and moisture. Trunk and major branch wounds callus over and close faster and more effectively if the surrounding, damaged bark is carefully scribed in the shape of vertical ellipse (like a blunt football standing on end). Badly decayed branches and trees with extensive heart rot in urban settings should be removed since they often represent safety hazards.
No effective or practical control measures exist for treatment of existing heart rot or decay. Prevention of decay by avoiding injuries to trees is the most effective method of minimizing damage. Healthy, vigorously growing trees are usually capable of "compartmentalizing" (walling off) decay in wood tissues present at the time wounds are sustained. Thus, promoting the vigor of trees through timely fertilization and irrigation enhances their ability to compartmentalize decay. (Fertilizing and watering has the added benefit of enhancing the structural strength of wounded or damaged trees by stimulating the growth of a new decay-free wood tissues). Compartmentalization is further enhanced by proper pruning of branches and dead branch stubs, a practice that facilitates the tree's natural callusing and wound closure processes. When pruning branches and branch stubs, make clean cuts immediately outside the swollen or callused branch collars at the base of branches or stubs being removed. Do not injure branch collars in the pruning process as these collars are healthy, growing wood tissues, and wound closure is more rapid if these tissues are left intact. Broken or otherwise projecting branch stubs (poorly pruned branches, etc.) inhibit wound closure, and therefore often provide decay organisms with easy and prolonged access to vulnerable wood tissues and/or a ready supply of necessary air and moisture. Trunk and major branch wounds callus over and close faster and more effectively if the surrounding, damaged bark is carefully scribed in the shape of vertical ellipse (like a blunt football standing on end). Badly decayed branches and trees with extensive heart rot in urban settings should be removed since they often represent safety hazards. In forest stands, care should be taken to minimize injuries to residual trees during harvest or timber stand improvement operations. In addition, timber losses can be minimized by harvesting damaged, mature or over-mature timber before it is prohibitively degraded by wood decay organisms. Sound fire control measures are also in order since fire-damaged trees often fall victim to wood decay organisms.