Decomposition rates of Scots pine needle litter related to site properties, litter quality, and climate

1994 ◽  
Vol 24 (9) ◽  
pp. 1771-1781 ◽  
Author(s):  
Maj-Britt Johansson
Keyword(s):  
Mass Loss ◽  
Scots Pine ◽  
Climatic Factors ◽  
Mass Loss Rate ◽  
Calcium Content ◽  
Organic Chemical ◽  
Litter Mass ◽  
Mass Losses ◽  
Needle Litter ◽  
Wide Range

Decomposition of Scots pine (Pinussylvestris L.) needle litter was studied at 14 sites along a climatic transect through Sweden. The forests encompassed a wide range of the variability in site properties found in the country. The mass loss pattern of litter differed considerably among sites. Mass losses obtained during the 1st year of decomposition varied from 11.1 to 43.7% among sites and showed positive linear correlations with climatic factors as well as site productivity indices. After 2 years, about 60% of the litter mass was decomposed at the majority of sites in the middle and southern parts of the country. Mass losses ranged from 20 to 50% in northern Sweden. During later stages of decomposition, mass losses seemed to be highly dependent on the organic–chemical composition of the litter. For accumulated mass losses up to 65%, the annual mass loss of litter was described as a function of the holocellulose to lignocellulose ratio of the litter. For litter mass losses exceeding 65%, a significant linear relation between litter calcium content and mass loss rate was found. Significant linear relations were also obtained between annual lignin loss and litter calcium content.

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

1991 ◽  
Vol 69 (7) ◽  
pp. 1449-1456 ◽  
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.

Litter mass-loss rates in late stages of decomposition at some climatically and nutritionally different pine sites. Long-term decomposition in a Scots pine forest. VIII

1993 ◽  
Vol 71 (5) ◽  
pp. 680-692 ◽  
Author(s):  
Björn Berg ◽  
Charles McClaugherty ◽  
Maj-Britt Johansson
Keyword(s):  
Mass Loss ◽  
Scots Pine ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Climatic Conditions ◽  
Initial Mass ◽  
Lignin Concentration ◽  
Litter Mass ◽  
Litter Mass Loss ◽  
Loss Rates

The patterns of some chemical changes and litter mass-loss rates were investigated for a variety of types of decomposing litter in pine forests under different climatic conditions and at sites with different nutrient status. A mixed deciduous forest was also compared. In initially chemically identical Scots pine needle litter incubated under different climatic conditions, the lignin concentration increased faster as a function of accumulated mass loss when the climatic conditions promoted a higher initial mass-loss rate. Also under artificially created conditions, e.g., after fertilization and irrigation, the same phenomenon occurred. Litter mass-loss rates decreased during decomposition as lignin concentrations increased. The relative decrease was significantly larger at sites with a climate that promoted an initially higher mass-loss rate. At the same lignin concentration, however, the mass-loss rate was significantly lower in drier and colder conditions, viz. climatic conditions that promote a lower initial mass-loss rate. Nevertheless, at very high lignin concentrations that lignin clearly dominated over climate as a rate-regulating factor. A possible consequence of this observation could be a higher rate of organic matter accumulation at sites that initially promote a high initial mass-loss rate for litter than at sites with conditions that give lower initial rates, at least for a given species of litter. Key words: litter, decomposition, lignin, chemical changes, climatic transect, effect of climate change.

Decomposition of Populustremuloides leaf litter accelerated by addition of Alnuscrispa litter

1989 ◽  
Vol 19 (5) ◽  
pp. 674-679 ◽  
Author(s):  
Barry R. Taylor ◽  
William F. J. Parsons ◽  
Dennis Parkinson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Rocky Mountain ◽  
Litter Type ◽  
Litter Bags ◽  
Mass Losses ◽  
Mixed Litter ◽  
Aspen Forest

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.

Manganese dynamics in decomposing needle and leaf litter — a synthesis

2013 ◽  
Vol 43 (12) ◽  
pp. 1127-1136 ◽  
Author(s):  
Björn Berg ◽  
Björn Erhagen ◽  
Maj-Britt Johansson ◽  
Lars Vesterdal ◽  
Mikaeel Faituri ◽  
...  
Keyword(s):  
Mass Loss ◽  
Norway Spruce ◽  
Scots Pine ◽  
Deciduous Species ◽  
Limit Values ◽  
Litter Mass ◽  
Litter Mass Loss ◽  
Species Groups ◽  
Mn Concentration ◽  
Mn Concentrations

The aim of the present synthesis paper was to determine whether concentration changes and net release of manganese (Mn), as related to accumulated litter mass loss, are related to initial Mn concentration, mean annual temperature (MAT), mean annual precipitation (MAP), and tree genus or species. We also examined whether limit values for decomposition are related to initial litter Mn concentration, MAT, and MAP. We compiled 84 foliar litter decomposition studies, conducted mainly in boreal and temperate forest ecosystems, for which Mn dynamics had been well documented. Manganese concentration and amount were related to accumulated litter mass loss at each sampling time for each single study, as well as for (i) all studies combined (n = 748) and (ii) for species groups viz. Norway spruce (Picea abies (L.) Karst.) (n = 284), pine (Pinus) species (n = 330), and deciduous species (n = 214). The changes in Mn concentration with accumulated mass loss followed quadratic functions showing significantly higher Mn concentrations for Norway spruce vs. Scots pine (Pinus sylvestris L.) (p < 0.0001) and vs. deciduous species (p < 0.01), as well as significantly higher for deciduous species vs. Scots pine (p < 0.0001). Manganese release rates were different among the three species groups (p < 0.001). Still, rates were related to initial Mn concentrations (p < 0.001) for all litter types combined and for the three species groups. Norway spruce released Mn more slowly than pine and deciduous species. Rates were related to climatic factors for litter of Norway spruce and deciduous species. Limit values for all litter and for pine species separately were related to Mn (p < 0.001) and MAT (p < 0.001). For Norway spruce, limit values were related to MAT (p < 0.001) and MAP (p < 0.01). It appears that Norway spruce litter retains Mn more strongly in the litter structure, producing humus richer in Mn than does litter of pine and deciduous species.

Decomposition of needle litter and its organic chemical components: theory and field experiments. Long-term decomposition in a Scots pine forest. III

1984 ◽  
Vol 62 (12) ◽  
pp. 2880-2888 ◽  
Author(s):  
Björn Berg ◽  
Göran I. Ågren
Keyword(s):  
Chemical Composition ◽  
Mass Loss ◽  
Scots Pine ◽  
Field Experiments ◽  
Average Rate ◽  
Chemical Components ◽  
Organic Chemical ◽  
Labile Fraction ◽  
Lignin Fraction ◽  
Scots Pine Forest

Scots pine needles were collected and field incubations were begun in the autumn of 6 consecutive years. The incubated needles were sampled three times a year and analysed for mass loss and chemical composition. The longest incubation time obtained was 1825 days. Four series of needles from a nutrition experiment (three levels of nutrient application and one control) sampled at one occasion were followed in the same way for 1448 days. The logarithm of remaining mass versus time of the pooled samples fits a linear regression well (average rate constant = 0.286 year−1, r2 = 0.963, n = 75). A higher resolution shows, however, that the decay rate decreases with time as the chemical composition changes. To better understand the decomposition process we have formulated a mathematical model for the course of mass loss as a system consisting of two fractions, a readily decomposable (labile) one and a refractory one. The mass loss from the two fractions can be direct or mass can be transferred from the refractory to the labile fraction. The model allows us to calculate the variation of the refractory fraction with time (generally there will always be some labile material in the system) and the decrease of the decomposition rate as a function of time or as a function of the concentration of the refractory fraction. We have found it possible to identify the refractory fraction both as the lignin fraction and as the nonsoluble fraction of the needles. The first identification yields a long transient response, whereas the second gives a system rapidly reaching a steady state. In both cases, the decay of the refractory material results in transfer of material to the labile fraction.

scholarly journals OH masers in oxygen-rich late-type stars

2002 ◽  
Vol 206 ◽  
pp. 319-322
Author(s):  
Sandra Etoka ◽  
A.M. Le Squeren
Keyword(s):  
Mass Loss ◽  
Radio Telescope ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Monitoring Programme ◽  
Late Type ◽  
Wide Range ◽  
Ir Stars ◽  
Circumstellar Shell

We present here some noteworthy results of two related studies on oxygen-rich late type stars. The aim of this work was to study the OH circumstellar shell properties in terms of evolution. These studies are based on an OH monitoring programme carried out with the Nançay Radio Telescope. The first study concerns seven Miras distributed along the colour-colour diagram. They were observed at two or three different epochs covering one to seven cycles over a period from 1980 to 1995 at 1612, 1667 and 1665 MHz in both circular polarizations. The second study concerns thirty objects covering a wide range of mass loss rate from Miras to OH/IR stars. They were observed in 1994 at 1665 & 1667 MHz in both circular polarizations.

Interaction between decomposing litter and soil fauna of the Betula ermanii forest floor of the Changbai Mountains, China

2014 ◽  
Vol 44 (12) ◽  
pp. 1507-1514 ◽  
Author(s):  
Xiaoqiang Li ◽  
Xiuqin Yin ◽  
Zhenhai Wang ◽  
Weihong Fan
Keyword(s):  
Mass Loss ◽  
Forest Floor ◽  
Loss Rate ◽  
Soil Fauna ◽  
Mass Loss Rate ◽  
Changbai Mountains ◽  
Mixed Species ◽  
High Quality ◽  
Litter Mass ◽  
Litter Mass Loss

Soil fauna play a key role in litter decomposition as they influence the litter mass loss rate in terrestrial ecosystems. However, the interaction between decomposing litter and soil fauna has not been adequately addressed. We examine the interaction between different types of decomposing litter and soil fauna on the Betula ermanii Cham. (BE) forest floor of the Changbai Mountains, China, by measuring the mass loss of six litter species groups using litterbags with two sizes of mesh (4 mm and 0.01 mm) during a yearlong experiment. Soil fauna were identified at the order level. We found that soil fauna have a limited effect on litter mass loss at the initial stage of the experiment. Its positive effect became apparent at month 12 of the experiment. After 1 year, soil fauna increased the litter mass loss rate of the high-quality litter of Parasenecio komarovianus (Pojark.) Y.L. Chen (PK) by 7.02% and of the low-quality litter of Rhododendron aureum Georgi (RA) by 25.26%. BE + PK litter was associated with a significantly higher abundance of soil fauna at months 8 and 10 of the experiment and also with a significantly higher richness of soil fauna at month 10 of the experiment. At the end of the experiment, however, the Shannon–Wiener diversity index of soil fauna was not necessarily higher in mixed-species litter. Litter mixing did promote the abundance, richness, and diversity of soil fauna during the warm season in the high-quality litter substrate of BE + PK. Our results illustrate that the impact of soil fauna on the litter mass loss of both single- and mixed-species litterbags ranges from a limited impact to a positive impact as litter mass loss advances. The soil fauna contribute more to the litter mass loss of the low-quality litter with higher C to N ratios than to those with a low C to N ratio. The promoting effect of litter mixing on the soil faunal community composition is only short term and is dependent on substrate quality.

Litter mass-loss rates in late stages of decomposition in a climatic transect of pine forests. Long-term decomposition in a Scots pine forest. IX.

1995 ◽  
Vol 73 (10) ◽  
pp. 1509-1521 ◽  
Author(s):  
Maj-Britt Johansson ◽  
Björn Berg ◽  
Vernon Meentemeyer
Keyword(s):  
Mass Loss ◽  
Scots Pine ◽  
Actual Evapotranspiration ◽  
The Arctic ◽  
Decomposition Rates ◽  
Lignin Concentration ◽  
Arctic Circle ◽  
Litter Mass ◽  
Litter Mass Loss ◽  
Loss Rates

We investigated rate-regulating factors for decomposition rates of Scots pine needle litter at 22 sites over a 2000-km long transect ranging from the Arctic Circle in Scandinavia to northern continental Europe. We found very different patterns for rate-regulating factors in the early stages of decomposition as compared to later stages (> 20% accumulated mass loss). The initial decomposition rates (measured over the 1st year) ranged from about 10.9%/year close to the Arctic Circle to about 43.7%/year in south Sweden. The dominant rate-regulating factor was climate (average annual temperature, and actual evapotranspiration), and none of the substrate-quality factors was significant. In the later stages, the annual mass loss varied from 2.2%/year to 41.5%/year. The rate-regulating factors were climate and the litter's concentration of lignin. We found that the effect of lignin concentration on litter mass-loss rate varied with site and this relative effect was negatively related with actual evapotranspiration. The effect of lignin concentration on mass-loss rates near the Arctic Circle was thus low (at low values for actual evapotranspiration) whereas in Southern Sweden and on the continent the rate-regulating effect of lignin was higher. Key words: foliar litter, decomposition, lignin, climatic transect, rate-regulating factors, climate change.

scholarly journals Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust

2019 ◽  
Vol 628 ◽  
pp. A62 ◽  
Author(s):  
S. Massalkhi ◽  
M. Agúndez ◽  
J. Cernicharo
Keyword(s):  
Mass Loss ◽  
Gas Phase ◽  
Mass Loss Rate ◽  
Carbon Star ◽  
High Mass ◽  
Agb Stars ◽  
Dust Grains ◽  
Fractional Abundance ◽  
Wide Range ◽  
Loss Rates

Aims. We aim to determine the abundances of CS, SiO, and SiS in a large sample of carbon star envelopes covering a wide range of mass loss rates to investigate the potential role that these molecules could play in the formation of dust in the surroundings of the central AGB star. Methods. We surveyed a sample of 25 carbon-rich AGB stars in the λ 2 mm band, more concretely in the J = 3−2 line of CS and SiO, and in the J = 7−6 and J = 8−7 lines of SiS, using the IRAM 30 m telescope. We performed excitation and radiative transfer calculations based on the large velocity gradient (LVG) method to model the observed lines of the molecules and to derive their fractional abundances in the observed envelopes. We also assessed the effect of infrared pumping in the excitation of the molecules. Results. We detected CS in all 25 targeted envelopes, SiO in 24 of them, and SiS in 17 sources. Remarkably, SiS is not detected in any envelope with a mass loss rate below 10−6 M⊙ yr−1 while it is detected in all envelopes with mass loss rates above that threshold. We found that CS and SiS have similar abundances in carbon star envelopes, while SiO is present with a lower abundance. We also found a strong correlation in which the denser the envelope, the less abundant are CS and SiO. The trend is however only tentatively seen for SiS in the range of high mass loss rates. Furthermore, we found a relation in which the integrated flux of the MgS dust feature at 30 μm increases as the fractional abundance of CS decreases. Conclusions. The decline in the fractional abundance of CS with increasing density could be due to gas-phase chemistry in the inner envelope or to adsorption onto dust grains. The latter possibility is favored by a correlation between the CS fractional abundance and the 30 μm feature, which suggests that CS is efficiently incorporated onto MgS dust around C-rich AGB stars. In the case of SiO, the observed abundance depletion with increasing density is most likely caused by an efficient incorporation onto dust grains. We conclude that CS, SiO (very likely), and SiS (tentatively) are good candidates to act as gas-phase precursors of dust in C-rich AGB envelopes.

Changes in organic chemical components of needle litter during decomposition. Long-term decomposition in a Scots pine forest. I

1982 ◽  
Vol 60 (8) ◽  
pp. 1310-1319 ◽  
Author(s):  
Björn Berg ◽  
Kai Hannus ◽  
Thomas Popoff ◽  
Olof Theander
Keyword(s):  
Scots Pine ◽  
Chemical Components ◽  
Organic Chemical ◽  
Pinus Silvestris ◽  
Steryl Esters ◽  
Needle Litter ◽  
Field Incubation ◽  
Scots Pine Forest ◽  
Soluble Components

The decomposition and organic chemical changes in Scots pine (Pinus silvestris) needle litter were studied for a period of 5 years and until 75% weight loss was reached in field incubation. The changes in components such as various groups of lipophilic extractives, low-molecular carbohydrates, cyclitols, phenolic glycosides, polysaccarides, and lignin were followed. There was a great drop of sugars, steryl esters, and triglycerides during the 1st year of decomposition. Some isoprenoid alcohols, sterols, and some acids belonged to the most stable of the soluble components. Of the solid residue the arabinans decomposed rapidly, the cellulose decomposed somewhat faster than the hemicelluloses as a group, and the lignin decomposed rather slowly (about 48% in 5 years).

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