Respiratory activity of fungal associations in zones of heart rot and stain in sugar maple

Abstract

Some of the progressive changes in decay in maple trees were studied by comparing total activity of the decay community (as measured by carbon dioxide output of excised samples), water content, pH, and predominant microorganisms (as shown by isolation on malt agar) in zones selected across the pocket of decay.Four trees from which Fomes igniarius were isolated gave consistent results with alkaline pH, high moisture content, and a predominance of imperfect fungi in the zones of incipient decay. Surprisingly, these zones showed the highest rates of carbon dioxide output, though they were only slightly higher than those of the transition zones. The center, severely decayed, parts of the trees were slightly acid, appreciably drier, and contained F. igniarius in abundance. They showed only about half the rate of carbon dioxide production of the outer zones. A section of rot caused by Polyporus glomeratus corresponded in most respects to those with F. igniarius.In samples of two regions from which no basidiomycete decay fungus was isolated, the pattern was completely different. In these the pH was consistently alkaline all across the pocket, exceeding pH 9 in one central area, and was highest in the central zone. The moisture content of these two trees was very high, being highest in the central zones, and the carbon dioxide production was much higher than that of the F. igniarius decays.

Host Attributes Affecting Patterns of Decay in a Regrowth Eucalypt Forest. IV. The Responses of Sapwood to Injury

“…The discolouration of sapwood of these eucalypts is not accompanied by marked increases in moisture content, levels of potassium and pH (Table 2), such äs may occur preceding or during deterioration in deciduous hardwoods (Good et al 1955(Good et al , 1968Hart 1968;Shigo and Sharon 1970;Safford et al 1974). While changes in these properties may not be essential for effective compartmentalisation of deterioration in either the eucalypts or the deciduous hardwoods, they serve äs useful indicators of a host response in the latter woods.…”

Hollows in living trees develop slowly but considerably influence the estimate of forest biomass

“…; Remm & Lõhmus ). Hollows in living trees are formed by micro‐organisms that enter wounds of trunks or large branches and then decompose heartwood consisting of dead xylem cells (Good, Basham & Kadzielawa ; Mackowski ; Cockle, Martin & Robledo ). In some forests, woodpecker excavation, termite attacks, and wind or fire damage initiate or accelerate this process.…”

“…The decomposition rate of tree hollows determines the speed of hollow formation but, except for the measurement of respiration rate of heart rot in sugar maple ( Acer saccharum Marsh.) by Good, Basham & Kadzielawa (), other studies have not considered the rate of hollow formation in estimates of the forest carbon budget. Harmon et al .…”

“…Microbes, particularly fungi, are responsible for wood decomposition including heart rot (Good, Basham & Kadzielawa ; Cornwell et al . ).…”

“…Living hollow-bearing trees occur in forests around the world, mostly in old-growth forests (Lindenmayer et al 1993;Fan et al 2003;Boyle et al 2008;Zheng et al 2009;Remm & Lõhmus 2011). Hollows in living trees are formed by micro-organisms that enter wounds of trunks or large branches and then decompose heartwood consisting of dead xylem cells (Good, Basham & Kadzielawa 1968;Mackowski 1984;Cockle, Martin & Robledo 2012). In some forests, woodpecker excavation, termite attacks, and wind or fire damage initiate or accelerate this process.…”