Apparent controls of mass loss rate of leaf litter on a regional scale

Decomposition of a slow-decaying litter type is expected to be faster in the presence of a nutrient-rich, fast-decaying litter type, but this effect has never been conclusively demonstrated for deciduous leaves. In a Rocky Mountain aspen forest, we followed decomposition of leaf litter of trembling aspen (Populustremuloides), a relatively slow-decomposing, nutrient-poor species, and green alder (Alnuscrispa), a nutrient-rich, faster-decomposing species, as well as a mixture of the two, for 2 years. Mass losses over the first winter were greatest for aspen alone, probably as a result of loss of solubles, but the mass loss rate overall was lowest for aspen (k = −0.191/year) and greatest for alder (k = −0.251/year). Mass loss rate for mixed litter (k = −0.245/year) was much closer to the rate for alder than for aspen, demonstrating a marked acceleration of mass loss rates in the mixed-litter bags. At these rates, 95% mass loss would be achieved by aspen, alder, and mixed litter in 14.5, 11.5, and 11.6 years, respectively.

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Litter mass-loss rates and decomposition patterns in some needle and leaf litter types. Long-term decomposition in a Scots pine forest. VII

Canadian Journal of Botany ◽

10.1139/b91-187 ◽

1991 ◽

Vol 69 (7) ◽

pp. 1449-1456 ◽

Cited By ~ 208

Author(s):

Björn Berg ◽

Gunnar Ekbohm

Keyword(s):

Mass Loss ◽

Leaf Litter ◽

Litter Decomposition ◽

Loss Rate ◽

Mass Loss Rate ◽

Nitrogen Concentration ◽

White Birch ◽

Litter Mass ◽

Mass Losses ◽

Litter Mass Loss

The decomposition dynamics of four types of needle litter and three types of leaf litter were followed for 4 years. Mass losses and certain chemical changes were studied. Most of the nutrient-rich litters appeared to decompose relatively quickly during the first 12–18 months. After 3–4 years, however, their accumulated mass losses were lower compared with litter types that intially had lower rates. Thus the more nutrient-rich litters had considerably lower mass-loss rates in the later stages. This pattern was even more pronouced for extract-free lignocellulose: its mass-loss rate was negatively related to the lignin concentration, which increased progressively as litter decomposition proceeded. During late stages in litter with a high nitrogen content, there was also a clear negative relation between nitrogen concentration and lignin mass-loss rate, as well as between nitrogen concentration and litter mass-loss rate. By extrapolation of measured mass-loss values, maximum values for accumulated litter–mass loss were estimated. A nonlinear statistical model predicted that the proportion of mass lost through decomposition should be 50% for grey alder leaves, 54% for green leaves of white birch, and 57% for brown leaves of white birch. For Scots pine the predicted maximums for accumulated mass loss were 68% for green needles and 89% for brown needles, whereas corresponding values for lodgepole pine needles were 81% (green) and 100% (brown). Lodgepole pine is an introduced species in this system. Key words: litter, decomposition, lignin, nitrogen, maxium mass loss.

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Reaction-to-fire tests. Heat release, smoke production and mass loss rate

10.3403/30282467 ◽

2013 ◽

Keyword(s):

Mass Loss ◽

Heat Release ◽

Loss Rate ◽

Mass Loss Rate ◽

Fire Tests ◽

Smoke Production

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Reaction-to-fire tests. Heat release, smoke production and mass loss rate

10.3403/30354021 ◽

2017 ◽

Keyword(s):

Mass Loss ◽

Heat Release ◽

Loss Rate ◽

Mass Loss Rate ◽

Fire Tests ◽

Smoke Production

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Reaction-to-fire tests. Heat release, smoke production and mass loss rate

10.3403/bsiso5660 ◽

2015 ◽

Keyword(s):

Mass Loss ◽

Heat Release ◽

Loss Rate ◽

Mass Loss Rate ◽

Fire Tests ◽

Smoke Production

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Reaction-to-fire tests � Heat release, smoke production and mass loss rate

10.3403/pdisots5660 ◽

2015 ◽

Keyword(s):

Mass Loss ◽

Heat Release ◽

Loss Rate ◽

Mass Loss Rate ◽

Fire Tests ◽

Smoke Production

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SN 2009ip: CONSTRAINTS ON THE PROGENITOR MASS-LOSS RATE

The Astrophysical Journal ◽

10.1088/0004-637x/768/1/47 ◽

2013 ◽

Vol 768 (1) ◽

pp. 47 ◽

Cited By ~ 42

Author(s):

E. O. Ofek ◽

L. Lin ◽

C. Kouveliotou ◽

G. Younes ◽

E. Göğüş ◽

...

Keyword(s):

Mass Loss ◽

Loss Rate ◽

Mass Loss Rate

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Effect of Sample Width on Downward Flame Spread over Typical Energy Conservation Material at a High Elevation Area

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.664.199 ◽

2014 ◽

Vol 664 ◽

pp. 199-203 ◽

Cited By ~ 1

Author(s):

Wei Guang An ◽

Lin Jiang ◽

Jin Hua Sun ◽

K.M. Liew

Keyword(s):

Mass Loss ◽

Flame Spread ◽

Loss Rate ◽

Mass Loss Rate ◽

High Elevation ◽

Flame Height ◽

Spread Rate ◽

Flame Spread Rate ◽

Sample Width ◽

Downward Flame Spread

An experimental study on downward flame spread over extruded polystyrene (XPS) foam at a high elevation is presented. The flame shape, flame height, mass loss rate and flame spread rate were measured. The influences of width and high altitude were investigated. The flame fronts are approximately horizontal. Both the intensity of flame pulsation and the average flame height increase with the rise of sample width. The flame spread rate first drops and then rises with an increase in width. The average flame height, mass loss rate and flame spread rate at the higher elevation is smaller than that at a low elevation, which demonstrates that the XPS fire risk at the higher elevation area is lower. The experimental results agree well with the theoretical analysis. This work is vital to the fire safety design of building energy conservation system.

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Radio Supernovae as Direct Evidence of Stellar Evolution in Real Time

Highlights of Astronomy ◽

10.1017/s1539299600021171 ◽

1998 ◽

Vol 11 (1) ◽

pp. 367-367

Author(s):

S.D. Van Dyk ◽

M.J. Montes ◽

K.W. Weiler ◽

R.A. Sramek ◽

N. Panagia

Keyword(s):

Mass Loss ◽

Stellar Evolution ◽

Loss Rate ◽

Direct Evidence ◽

Mass Loss Rate ◽

X Ray ◽

Stringent Constraint ◽

Clear Change ◽

Late Stages ◽

Circumstellar Environment

The radio emission from supernovae provides a direct probe of a supernova’s circumstellar environment, which presumably was established by mass-loss episodes in the late stages of the progenitor’s presupernova evolution. The observed synchrotron emission is generated by the SN shock interacting with the relatively high-density circumstellar medium which has been fully ionized and heated by the initial UV/X-ray flash. The study of radio supernovae therefore provides many clues to and constraints on stellar evolution. We will present the recent results on several cases, including SN 1980K, whose recent abrupt decline provides us with a stringent constraint on the progenitor’s initial mass; SN 1993J, for which the profile of the wind matter supports the picture of the progenitor’s evolution in an interacting binary system; and SN 1979C, where a clear change in presupernova mass-loss rate occurred about 104 years before explosion. Other examples, such as SNe 19941 and 1996cb, will also be discussed.

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