Decomposition of Nothofagus wood in vitro and nutrient mobilization by fungi

Abstract

The role of fungi in determining rates of wood decomposition and nutrient release in forest ecosystems is poorly understood. The decomposition of wood from three species of Nothofagus by 12 species of widely occurring New Zealand wood-decay fungi was investigated in vitro under standardized conditions. Wood mass loss varied strongly among fungal species and to a lesser extent with the species of wood. The species of fungi in this study were divided into three groups based on the extent of mass loss after 15 weeks: (1) rapid (>65% reduction in mass, Fomes hemitephrus , Pleurotus purpureoolivaceus , Trametes versicolor , and Ganoderma cf. applanatum), (2) intermediate (15%–30%, Phellinus sp., Schizopora radula , Phellinus nothofagi , and Skeletocutis stramenticus ), and (3) slow (<10%, Armillaria novaezelandiae , Postia pelliculosa , Australoporus tasmanicus , and Laetiporus portentosus ). For several fungal species, the final contents of nitrogen, phosphorus, and calcium in the remaining wood exceeded the initial nutrient contents in the wood, indicating that nutrient sequestration from the supporting soil matrix occurred during decomposition. Nutrient dynamics during decomposition varied with wood species, but the variation among different fungal species was much greater, indicating that fungal diversity is an important factor in determining nutrient flux in decaying wood.

Wood Decay Fungi Restore Essential Calcium to Acidic Soils in Northern New England

“…The variation in decay rate was consistent with laboratory decay tests using various species of fungi. Spruce wood decayed by nine different wood-decay fungi for eight months in vitro had a range of mass loss of 2%-69% with an average of 28% ± 20% [20]; southern beech wood decayed by 12 different wood-decay fungi for four months had a range of mass loss of 0-90% with an average of 35% ± 22% [22]. Variation due to environmental conditions was likely to make a minor contribution to variation in decay rates once the wood-decay fungi and associated microorganisms colonized the wood.…”

“…Microcosm tests demonstrated movement of Ca during wood decay of both conifers [20,21] and hardwoods [22]. Long-term field studies were established in New Hampshire at the Bartlett Experimental Forest (BEF) in 1995 and in Maine at the Penobscot Experimental Forest (PEF) in 1996 and 1997 to investigate the role of the decay process in the cycling of calcium and other essential bases [23].…”

Phosphorus and base cation accumulation and release patterns in decomposing Scots pine, Norway spruce and silver birch stumps

“…The amounts of nutrients in CWD may (1) decrease through mineralisation and leaching (Hafner et al, 2005;Kuehne et al, 2008), (2) remain constant due to immobilisation by microbes (Laiho and Prescott, 1999), or (3) increase through fungal translocation from soil (Wells and Boddy, 1995;Connolly and Jellison, 1997;Lindahl et al, 2001;Clinton et al, 2009) and atmospheric deposition (Harmon et al, 1986). Potassium (K) is usually released from CWD in the early stages of decomposition because it is water soluble and easily leachable (Grier, 1978;Fahey, 1983;Sollins et al, 1987;Arthur et al, 1993;Holub et al, 2001), whereas the release of nitrogen (N), phosphorus (P), calcium (Ca) and magnesium (Mg) is generally slow.…”

“…Fungal translocation likely mediates most of the nutrient accumulation in CWD (Laiho and Prescott, 2004), particularly in northern European boreal forests where nutrient input by deposition is low (Helmisaari, 1995;Ruoho-Airola et al, 2003;Piirainen et al, 2004). Wood-decaying fungi are capable of transporting significant quantities of nutrients, especially P, as well as base cations (K, Ca, and Mg) between soil and decaying wood through their mycelial cord and rhizomorph systems (Wells and Boddy, 1995;Connolly and Jellison, 1997;Lindahl et al, 2001;Clinton et al, 2009). Nutrient transportation from soil to decaying wood is promoted by the suboptimal initial nutrient content of wood for fungal growth Boyle, 1998).…”

Bees of Maine, with a State Species Checklist

“…Root-available Ca is replaced in depleted sites by the action of wooddecay fungi that both release the solar energy stored in cellulose and lignin, the two most abundant organic substances in nature, and enrich the decayed wood residue with Ca from external sources. Microcosm tests demonstrate movement of Ca into decaying wood of conifers (Connolly et al 1999, Ostrofsky et al 1997) and hardwoods (Clinton et al 2009). Many of the fungi that decompose wood are large, long-lived organisms that produce extensive mycelial networks, including cords and rhizomorphs, which move essential elements for many meters through the forest floor in and out of decaying wood (Boddy and Watkinson 1995, Connolly and Jellison 1997, Lindahl et al 2001.…”