Aspen and pine leaf litter decomposition in laboratory microcosms. I. Linear versus exponential models of decay

1988 ◽  
Vol 66 (10) ◽  
pp. 1960-1965 ◽  
Author(s):  
Barry R. Taylor ◽  
Dennis Parkinson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Populus Tremuloides ◽  
Pinus Contorta ◽  
Exponential Model ◽  
Plant Litter ◽  
Adverse Conditions ◽  
Negative Exponential Model ◽  
Negative Exponential ◽  
Moisture Conditions

Leaf litter of trembling aspen (Populus tremuloides Michx.) and lodgepole–jack pine (Pinus contorta Loud, × P. banksiana Lamb.) was decomposed in laboratory microcosms at 2, 10, 18, or 26 °C and three watering rates (15, 30, or 60 mL∙week−1) for 16 weeks. Aspen litter lost 5.0–37.3% of original mass, and pine litter lost 7.8–14.9%. Decay curves fit a sample linear model equally as well as the negative exponential model regardless of temperature or moisture conditions or species of litter. A general explanation of circumstances promoting apparently linear mass loss from decaying plant litter is derived from these data, a survey of the literature, and the assumption that all decay curves are ultimately curvilinear. Mass loss rates are expected to appear linear from slowly decaying substrates such as bole wood or when decay of rapidly decomposing substrates is not followed past the inflection point of the curve. Climatic variables that favour decomposer activity are hypothesized to increase the concavity of decay curves, while adverse conditions do the opposite.

Decomposition of red spruce and balsam fir boles in the White Mountains of New Hampshire

1982 ◽  
Vol 12 (3) ◽  
pp. 617-626 ◽  
Author(s):  
Jeffrey R. Foster ◽  
Gerald E. Lang
Keyword(s):  
Mass Loss ◽  
High Elevation ◽  
Exponential Model ◽  
Red Spruce ◽  
Balsam Fir ◽  
White Mountains ◽  
A Value ◽  
Negative Exponential Model ◽  
Negative Exponential ◽  
Na Release

Decomposition rates for red spruce (Picearubens Sarg.) and balsam fir (Abiesbalsamea (L.) Mill.) boles on the forest floor were determined for midelevation forests of the White Mountains from a chronosequence of previously logged stands. Density changes in wood and bark were described using a negative exponential model, yielding decay constants of 0.033 and 0.029/year for spruce and fir wood, respectively. The two species were not statistically different in terms of mass loss. Bole diameter had no influence on the decay rate of red spruce. Fir boles in midelevation forests decayed significantly faster than those in high-elevation forests measured in another study. Net accumulation of N, P, Ca, and Mg occurred in the wood of both species. N accumulated in bark, but P, Ca, and Mg behavior was variable. Na and K behavior was similar in the wood and bark of both species, with Na release concomitant with mass loss, while K was lost faster than mass. C:N ratios declined, and N:P ratios converged on a value of ca. 20, in the wood and bark of both species.

APPLICATION OF TWO-LEVEL NEGATIVE EXPONENTIAL MODEL TO CHILDREN'S LEARNING CURVE IN READING

2002 ◽  
Vol 31 (2) ◽  
pp. 279-299 ◽  
Author(s):  
Dung-Tsa Chen ◽  
Wenyaw Chan ◽  
David J. Francis ◽  
Sally E. Shaywitz ◽  
Bennett A. Shaywitz
Keyword(s):  
Learning Curve ◽  
Exponential Model ◽  
Children’S Learning ◽  
Negative Exponential Model ◽  
Negative Exponential ◽  
Children's Learning

scholarly journals A Wave-Spectrum Analysis of Urban Population Density: Entropy, Fractal, and Spatial Localization

2008 ◽  
Vol 2008 ◽  
pp. 1-22 ◽  
Author(s):  
Yanguang Chen
Keyword(s):  
Urban Population ◽  
Population Distribution ◽  
Wave Spectrum ◽  
Spatial Dynamics ◽  
Exponential Model ◽  
Urban Morphology ◽  
Wave Number ◽  
Entropy Maximization ◽  
Negative Exponential Model ◽  
Negative Exponential

The method of spectral analysis is employed to research the spatial dynamics of urban population distribution. First of all, the negative exponential model is derived in a new way by using an entropy-maximizing idea. Then an approximate scaling relation between wave number and spectral density is derived by Fourier transform of the negative exponential model. The theoretical results suggest the locality of urban population activities. So the principle of entropy maximization can be utilized to interpret the locality and localization of urban morphology. The wave-spectrum model is applied to the city in the real world, Hangzhou, China, and spectral exponents can give the dimension values of the fractal lines of urban population profiles. The changing trend of the fractal dimension does reflect the localization of urban population growth and diffusion. This research on spatial dynamics of urban evolvement is significant for modeling spatial complexity and simulating spatial complication of city systems by cellular automata.

Decomposition of aspen (Populustremuloides) leaf litter modified by leaching

1990 ◽  
Vol 20 (7) ◽  
pp. 943-951 ◽  
Author(s):  
William F. J. Parsons ◽  
Barry R. Taylor ◽  
Dennis Parkinson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Rocky Mountain ◽  
Exponential Model ◽  
Decay Rates ◽  
Double Exponential ◽  
Exponential Trend ◽  
Aspen Forest ◽  
Double Exponential Model ◽  
Soluble Material

In a Rocky Mountain aspen forest, the detailed pattern of mass loss from decomposing leaf litter of trembling aspen (Populustremuloides Michx.) during the first 6 months of decay was compared with that from aspen leaves modified to produce a more recalcitrant litter type by removal of leachable material (31.7% of original mass). Leaching litter removed substantial quantities of N (24%) and P (54%), but did not change the litter's C/N ratio (77:1); and leached leaves still contained 33% labile (benzene alcohol soluble) material. Decomposition of intact aspen litter was best described by a double exponential model (k1 = −7.91/year, k2 = −0.21/year), except during the first 2 weeks, when an extremely rapid mass loss (14.2%) apparently resulted from leaching. Microbial metabolism was probably responsible for most of the subsequent decay (35% total in 6 months). In contrast, decomposition of leached aspen showed no exponential trend and was best described by a simple linear regression with a slope of −19.7%/year. Additional data from a 2nd year (12–15 months decay) reduced the regression estimates of decay rates but did not alter the best fit models. Fits were improved slightly if temperature sum replaced time in the regressions, especially if 2nd-year data were included.

scholarly journals Fungal Planet description sheets: 1112–1181

2020 ◽  
Vol 45 (1) ◽  
pp. 251-409
Author(s):  
P.W. Crous ◽  
D.A. Cowan ◽  
G. Maggs-Kölling ◽  
N. Yilmaz ◽  
E. Larsson ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Populus Tremuloides ◽  
Pinus Halepensis ◽  
Forest Litter ◽  
Pond Water ◽  
Scale Insect ◽  
Quercus Suber ◽  
Plant Litter ◽  
Cow Dung ◽  
Buxus Sempervirens

Novel species of fungi described in this study include those from various countries as follows: Australia, Austroboletus asper on soil, Cylindromonium alloxyli on leaves of Alloxylon pinnatum, Davidhawksworthia quintiniae on leaves of Quintinia sieberi, Exophiala prostantherae on leaves of Prostanthera sp., Lactifluus lactiglaucus on soil, Linteromyces quintiniae (incl. Linteromyces gen. nov.) on leaves of Quintinia sieberi, Lophotrichus medusoides from stem tissue of Citrus garrawayi, Mycena pulchra on soil, Neocalonectria tristaniopsidis (incl. Neocalonectria gen. nov.)and Xyladictyochaeta tristaniopsidis on leaves of Tristaniopsis collina, Parasarocladium tasmanniae on leaves of Tasmannia insipida, Phytophthora aquae-cooljarloo from pond water, Serendipita whamiae as endophyte from roots of Eriochilus cucullatus, Veloboletus limbatus (incl. Veloboletus gen. nov.)onsoil. Austria, Cortinarius glaucoelotus onsoil. Bulgaria, Suhomyces rilaensis from the gut of Bolitophagus interruptus found on a Polyporus sp. Canada, Cantharellus betularum among leaf litter of Betula, Penicillium saanichii from house dust. Chile, Circinella lampensis on soil, Exophiala embothrii from rhizosphere of Embothrium coccineum. China, Colletotrichum cycadis on leaves of Cycas revoluta. Croatia, Phialocephala melitaea on fallen branch of Pinus halepensis. Czech Republic, Geoglossum jirinae on soil, Pyrenochaetopsis rajhradensis from dead wood of Buxus sempervirens. Dominican Republic, Amanita domingensis on litter of deciduous wood, Melanoleuca dominicana on forest litter. France, Crinipellis nigrolamellata (Martinique) on leaves of Pisonia fragrans, Talaromyces pulveris from bore dust of Xestobium rufovillosum infesting floorboards. French Guiana, Hypoxylon hepaticolor on dead corticated branch. Great Britain, Inocybe ionolepis on soil. India, Cortinarius indopurpurascens among leaf litter of Quercus leucotrichophora. Iran, Pseudopyricularia javanii on infected leaves of Cyperus sp., Xenomonodictys iranica (incl. Xenomonodictys gen. nov.) on wood of Fagus orientalis. Italy, Penicillium vallebormidaense from compost. Namibia, Alternaria mirabibensis on plant litter, Curvularia moringae and Moringomyces phantasmae (incl. Moringomyces gen. nov.) on leaves and flowers of Moringa ovalifolia, Gobabebomyces vachelliae (incl. Gobabebomyces gen. nov.) on leaves of Vachellia erioloba, Preussia procaviae on dung of Procavia capensis. Pakistan, Russula shawarensis from soil on forest floor. Russia, Cyberlindnera dauci from Daucus carota. South Africa, Acremonium behniae on leaves of Behnia reticulata, Dothiora aloidendri and Hantamomyces aloidendri (incl. Hantamomyces gen. nov.) on leaves of Aloidendron dichotomum, Endoconidioma euphorbiae on leaves of Euphorbia mauritanica , Eucasphaeria proteae on leaves of Protea neriifolia , Exophiala mali from inner fruit tissue of Malus sp., Graminopassalora geissorhizae on leaves of Geissorhiza splendidissima, Neocamarosporium leipoldtiae on leaves of Leipoldtia schultzii, Neocladosporium osteospermi on leaf spots of Osteospermum moniliferum, Neometulocladosporiella seifertii on leaves of Combretum caffrum, Paramyrothecium pituitipietianum on stems of Grielum humifusum, Phytopythium paucipapillatum from roots of Vitis sp., Stemphylium carpobroti and Verrucocladosporium carpobroti on leaves of Carpobrotus quadrifolius, Suttonomyces cephalophylli on leaves of Cephalophyllum pilansii. Sweden, Coprinopsis rubra on cow dung, Elaphomyces nemoreus fromdeciduouswoodlands. Spain, Polyscytalum pini-canariensis on needles of Pinus canariensis, Pseudosubramaniomyces septatus from stream sediment, Tuber lusitanicum on soil under Quercus suber. Thailand, Tolypocladium flavonigrum on Elaphomyces sp. USA, Chaetothyrina spondiadis on fruits of Spondias mombin, Gymnascella minnisii from bat guano, Juncomyces patwiniorum on culms of Juncus effusus, Moelleriella puertoricoensis on scale insect, Neodothiora populina (incl. Neodothiora gen. nov.) on stem cankers of Populus tremuloides, Pseudogymnoascus palmeri fromcavesediment. Vietnam, Cyphellophora vietnamensis on leaf litter, Tylopilus subotsuensis on soil in montane evergreen broadleaf forest. Morphological and culture characteristics are supported by DNA barcodes.

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