scholarly journals Leaf Litter Decomposition of Two Central Himalayan Oaks

2015 ◽  
Vol 10 (2) ◽  
pp. 509-516 ◽  
Author(s):  
Kirtika Padalia ◽  
Rajendra Parihaar ◽  
Nidhi Bhakuni ◽  
Bhawana Kapkoti
Keyword(s):  
Weight Loss ◽  
Leaf Litter ◽  
Rate Coefficient ◽  
Climatic Factors ◽  
Average Weight ◽  
Oak Forest ◽  
Litter Bags ◽  
Litter Bag ◽  
Quercus Floribunda ◽  
Quercus Leucotrichophora

The study was conducted in two natural oak forest of Nainital (Uttarakhand) India, during 2012-2013 to determine the weight loss pattern in leaf litter of two Central Himalayan Oaks (i.e., Quercus leucotrichophora A. Camus. and Quercus floribunda Lindl.) with the help of litter bag technique. The present study concluded that weight loss proceeded throughout the study period and relatively higher within 60 days after the placement of litter bags into the soil. Among these two species, higher weight loss observed in Q. floribunda as compared to Q. leucotrichophora across both the sites. Within 365 days, average weight loss observed about 60% in Q. leucotrichophora and 62% in Q. floribunda. Decay rate coefficient rate ranged from 0.0596- 0.0014 for Q. leucotrichophora while it varies from 0.0558 to 0.0013 for Q. floribunda. The monthly relative decomposition rate (RDR) ranged between 0.0598-0.0014 g/g/day and 0.0208-0.0050 g/g/day for Q. leucotrichophora and Q. floribunda, respectively. Climatic factors (rainfall, temperature and relative humidity) also influenced the rate of decomposition.

Nutrient changes and release during decomposition of leaf litter in a Himalayan oak–conifer forest

1984 ◽  
Vol 62 (9) ◽  
pp. 1824-1831 ◽  
Author(s):  
Uma Pandey ◽  
J. S. Singh
Keyword(s):  
Leaf Litter ◽  
Water Soluble ◽  
Conifer Forest ◽  
Cedrus Deodara ◽  
Litter Bags ◽  
Absolute Increase ◽  
Absolute Mass ◽  
The Absolute ◽  
Nutrient Changes ◽  
Quercus Floribunda

Changes in nitrogen, calcium, water-soluble compounds, and total available carbohydrate in decomposing leaf litter of six tree and one shrub species, enclosed in nylon net bags and placed in a mixed oak conifer forest, were examined for a period of 487 days. The concentration of nitrogen increased during decomposition in all litter species. This increase was up to threefold in Aesculus indica, Quercus floribunda, and Quercus leucotrichophora. In most species the absolute increase in nitrogen mass was observed when decomposition had progressed up to 213 days. However, in Daphne cannabina and Ilex dipyrena, the absolute mass of nitrogen was never greater than the initial mass at any stage of decomposition. The absolute mass of calcium in litter bags generally declined with time. The concentration of water-soluble compounds and of total available carbohydrates varied from species to species; both these constituents, however, continually decreased with the progress of decomposition. Within 1 year, the release of nitrogen, water-soluble compounds, and total available carbohydrates was 100% in D. cannabina, A. indica, and I. dipyrena. In Cedrus deodara, Q. floribunda, and Q. leucotrichophora about 50% of total nitrogen input to the forest floor as litter fall was released by decomposition. In Cupressus torulosa only 14% of nitrogen falling as leaf litter was released during a period of 1 year.

Litter decomposition in a cool temperate deciduous forest

1976 ◽  
Vol 54 (5-6) ◽  
pp. 419-436 ◽  
Author(s):  
J. D. Lousier ◽  
D. Parkinson
Keyword(s):  
Weight Loss ◽  
Leaf Litter ◽  
Dry Weight ◽  
Decay Rates ◽  
Leaf Fall ◽  
Litter Fall ◽  
Litter Bag ◽  
Litter Input ◽  
Mesh Bags ◽  
Tree Leaf

Amounts of autumn tree leaf litter fall, understory litter input, tree leaf litter nutrient input, and rates of dry weight loss in decomposing leaf litter were estimated in an aspen woodland (Populus tremuloides Michx. – P. balsamifera L.) site in the Rocky Mountains in southwestern Alberta. Tree leaf litter input amounted to 250 g m−2 and comprised 3.7% of the total organic matter in the ecosystem (1.92 × 105 kg ha−1). The ratio of the weight of aspen leaf fall to balsam leaf fall was about 6:1. The tree leaf litter input and the total litter input figures were similar to those for other Northern Hemisphere aspen forests. The understory litter input in the study plots was measured as 99 g m−2. The importance by weight of some of the nutrients returned to the soil via tree leaf litter fall was Ca > N > K > Mg > P > Zn > Fe > Mn > Na > Cu. The total weight of these nutrients returned to the soil was 116 kg ha−1, with N, Ca, and K comprising 89% and Mg and P comprising 9.8% of the total.The dry weight loss of decomposing aspen and balsam leaves was measured at 1-, 5-, 8-, 12-, 18-, 24-, and 30-month intervals by using 3-mm-mesh litter bags, and at 12-, 24-, 36-, 48-, and 60-month intervals by using 10-mm-mesh bags. Litter-bag mesh size was of little consequence to the rate of dry weight loss for the first 12 months, but subsequent dry weight loss was greater in the 3-mm-mesh bags, which maintained higher, more representative, moisture conditions than did the 10-mm-mesh bags. However, tethered leaves lost 1.7 times more weight over the first 12 months of decomposition than did confined litter. The decay rate decline with time and with the depth of the litter bag in the litter layers, with maximum dry weight loss occurring over the period encompassing the fall freeze, winter, and the spring thaw and runoff. Leaf litter placed on north-facing slopes was characterized by significantly slower decay rates than that on south-facing slopes.The dry weight loss for aspen leaf litter was 26.2 ± 2.0% after 12 months. 40.0 ± 1.6% after 30 months, and 58.7% after 60 months (by regression): for balsam litter it was 21.2 ± 1.9% after 12 months, 37.4 ± 1.7% after 30 months, and 47.9% after 60 months (by regression). The highly leachable component of leaf litter was estimated at 23.1% for aspen and 21.4% for balsam. The time required for 99% decomposition was calculated as about 24 years for aspen and about 27 years for balsam, which gives average annual decay rates of 3.2% for aspen and 2.9% for balsam. The decay rate for Populus leaf litter was lower than that for aspen in Alaska and appeared to fit the range for deciduous leaf litter from some forested IBP Tundra Biome sites.

scholarly journals Diversity of fungi in decomposition process the Avicennia marina leaf litter at various level of salinity

2021 ◽  
Vol 886 (1) ◽  
pp. 012063
Author(s):  
Yunasfi ◽  
Derita ◽  
Ipanna Enggar Susetya ◽  
Rusdi Leidonald
Keyword(s):  
Species Diversity ◽  
Leaf Litter ◽  
Avicennia Marina ◽  
Diversity Indices ◽  
Fungal Species ◽  
Fungal Colonization ◽  
Isolation And Identification ◽  
Litter Bags ◽  
Litter Bag ◽  
Factors Affecting

Abstract Factors affecting the rate of the decomposition are animals and microorganisms such as worms, snails, bacteria, fungi etc. as well as environmental conditions, such as type of soil, pH and salinity of water, etc. This research was conducted at the Deli Belawan River and Forest Cultivation Laboratory, Medan, North Sumatra Sumatera. A study was undertaken to find out the effect of the salinity on : the number of species, the population, the species diversity and the frequency of colonization of the different species of fungi during the process of the composition of the A. marina leaf litter decomposition. The leaf litter of A. marina to be put in a litter bag that is 50 g and it’s 33 litter bags for each level of salinity totally. The level of salinity to be used such as < 10, 10 – 20, 20 – 30 and > 30 ppt. The time series to collect data were 0 (control), 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, and 165 days. The leaf litter of A. marina in a litter bag was taken from each salinity level that was three bags for each time. It was used for isolation and identification of the fungi. There were 21 fungal species isolated from the A. marina leaf litter before being decomposed and from those decomposed at < 10, 10 – 20, 20 – 30 and > 30 ppt. The highest population was found in the leaf litter before being decomposed with an average of 1.6 × 103 cfu/ml. The Species Diversity Indices of the fungi isolated from the leaf litter at < 10, 10 – 20, 20 – 30, and > 30 ppt were 1.96, 1.86, 1.75 and 1,50. The frequency of the fungal colonization ranged from 9.1 to 100 %.

Study of the properties larch and larch wood construction materials

2016 ◽  
Author(s):  
М.А. Чубинский ◽  
К.В. Чаузов
Keyword(s):  
Weight Loss ◽  
Urea Formaldehyde ◽  
Construction Materials ◽  
Siberian Larch ◽  
Larix Sibirica ◽  
Average Weight ◽  
Biological Stability ◽  
Laminated Beam ◽  
Coniophora Puteana ◽  
Larch Wood

Несмотря на огромные запасы, древесина лиственницы до сего времени в незначительных объемах используется в строительной индустрии, других отраслях экономики, что связано как с технологическими сложностями ее переработки, так и недостаточной изученностью ее свойств. Одним из уникальных свойств древесины лиственницы сибирской (Larix sibirica) является ее повышенная естественная биостойкость, наряду с максимально высокой среди отечественных хвойных пород прочностью. Стойкость древесины лиственницы (Larix sibirica) к воздействию дереворазрушающих грибов Coniofora puteana значительно превышает стойкость сосны. В среднем потеря массы ядровой древесины лиственницы сибирской под воздействием дереворазрушающего гриба Coniophora puteana составляет 14,84%, снижаясь с увеличением возраста дерева, а контрольные образцы из ядровой древесины сосны в возрасте 90 лет имели потерю массы 57,8%. Возраст дерева является одним из наиболее значимых факторов, влияющих на степень биостойкости древесины. По мере его увеличения значительно повышается устойчивость деструктивному воздействию дереворазрушающих грибов Coniophora puteana. Положение образцов также влияет на степень биостойкости древесины, однако эта зависимость слабо выражена по сравнению с влиянием возраста и плотности древесины. Исследования кинетики разложения древесины лиственницы сибирской и роли экстрактивных веществ в развитии дереворазрушающих грибов позволяют утверждать наличие связи биостойкости и содержания в древесине экстрактивных веществ. Для изготовления клееного бруса из древесины лиственницы предложена клеевая композиция, включающая карбамидомеламиноформальдегидный клей и карбамидоформальдегидную смолу, модифицированную шунгитами. Ее применение позволяет получать клеевые соединения, не уступающие по прочности при скалывании массивной древесине, как по сухому образцу, так и после его вымачивания. Таким образом, клееный брус из древесины лиственницы сибирской характеризуется высокими показателями биостойкости, прочности и водостойкости. Despite vast reserves, larch wood so far in small volumes used in the construction industry and other sectors of the economy, which is connected as the technological difficulties of its treatment, as well as insufficient knowledge of its properties. One of the unique properties of the wood of Siberian larch (Larix sibirica) is its increased natural biological stability (decay resistant), along with the highest among the domestic softwood strength. Resistance Larch (Larix sibirica) to the effects of wood-destroying fungi Coniofora puteana is much higher than pine. The average weight loss of Siberian larch heartwood exposed wood-destroying fungi Coniophora puteana is 14.84%, decreasing with increasing age of the tree, and control samples of heartwood pine at age 90 had a weight loss of 57.8%. Age of a tree is one of the most significant factors affecting the degree of biological stability of wood. With the increase it significantly increases the stability of the destructive effects of wood-destroying fungi and Coniophora puteana. The position of the sample in tree also affects the degree of biological stability of wood, but this dependence is poorly developed in comparison with the influence of age and wood density. Studies of the kinetics of decomposition of Siberian larch wood and the role of extractives in the development of wood-destroying fungi suggest a link, and the decay resistant of the content in the wood extractives. For the manufacture of larch glued laminated beam proposed adhesive composition comprising urea and melamine-formaldehyde glue and urea-formaldehyde resins, modified shungites. Its use allows to obtain the bonds are not inferior in strength at shearing solid wood as dry sample, and after soaking. Thus, glued laminated beam from Siberian larch wood is characterized by high decay resistant, strength and water resistance.

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

scholarly journals Incidence and Outcomes of Home Parenteral Nutrition in Patients With Crohn Disease in Olmsted County, Minnesota

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Zeinab Bakhshi ◽  
Siddhant Yadav ◽  
Bradley R Salonen ◽  
Sara L Bonnes ◽  
Jithinraj Edakkanambeth Varayil ◽  
...  
Keyword(s):  
Weight Loss ◽  
Parenteral Nutrition ◽  
Short Bowel Syndrome ◽  
Crohn Disease ◽  
Severe Disease ◽  
Bloodstream Infections ◽  
Home Parenteral Nutrition ◽  
Average Weight ◽  
Olmsted County ◽  
Short Bowel

Abstract Background We sought to estimate the incidence of home parenteral nutrition (HPN) use in a population-based cohort of patients with Crohn disease (CD), and to assess clinical outcomes and complications associated with HPN. Methods We used the Rochester Epidemiology Project (REP) to identify residents of Olmsted County, who were diagnosed with CD between 1970 and 2011, and required HPN. Results Fourteen out of 429 patients (3.3%) with CD received HPN (86% female). Eleven patients (79%) had moderate–severe CD and 12 patients (86%) had fistulizing disease. Thirteen patients (93%) underwent surgery, primarily due to obstruction. Among CD incidence cases, the cumulative incidence of HPN from the date of CD diagnosis was 0% at 1 year, 0.5% at 5 years, 0.8% at 10 years, and 2.4% at 20 years. Indications for HPN included short bowel syndrome in 64%, malnutrition in 29%, and bowel rest in 21%. The median duration of HPN was 2.5 years. There was an average weight gain of 1.2 kg at 6 months, an average weight loss of 1.4 kg at 1 year, and a further weight loss of 2.2 kg at 2 years from the start of HPN. Patients were hospitalized a mean of 5 times after the start of HPN, mainly due to catheter-related bloodstream infections and thrombosis. Conclusions Less than 4% of patients with CD need HPN. Most have moderate to severe disease with short bowel syndrome or malnutrition. Possible reasons for the patients’ weight loss could be noncompliance, and increased metabolic needs because of active disease.

scholarly journals Patterns of Weight Change in Aging and Dying

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 491-491
Author(s):  
Stephen Thielke
Keyword(s):  
Older Adults ◽  
Weight Loss ◽  
Risk Factor ◽  
Weight Change ◽  
Population Level ◽  
Chronological Age ◽  
Average Weight ◽  
Remaining Life ◽  
Entire Cohort ◽  
History Of

Abstract Little research has characterized the natural history of weight change in older adults. Different changes may occur during aging and dying. We analyzed 18 years of weight measures from a cohort of 736,361 Veterans, all of whom had died at age 70 or older. We produced summary measures that accounted for both chronological age and number of years before death. Several clear population-level trends appeared. (1) The average weight of the sample declined across all ages at a rate of about 0.18 BMI points per year. (2) Starting about seven years before death, the amount of loss began to accelerate, reaching a decline of 0.75 BMI points in the year before death. (3) Changes in weight relative to years of remaining life were independent of chronologic age. People who died at age 70 experienced, on average, the same type and duration of terminal decline as did those who died at age 95. (4) The dying process involved a cumulative loss of about 1.3 BMI points. (5) The distribution of weights during advancing age both declined and narrowed. (6) Disproportionate deaths occurred at the lower BMI ranges (below a BMI of 24), and especially below 18, regardless of age. (7) The finding in #5 is explained by the entire cohort losing weight, with death of the thinnest members. These findings argue for examining survival time in studies of weight change. They indicate that weight loss may be a natural part of dying, rather than a risk factor for it.

scholarly journals Post-fire consequences for leaf breakdown in a tropical stream

2019 ◽  
Vol 31 ◽  
Author(s):  
Renan de Souza Rezende ◽  
Cristiano Queiroz de Albuquerque ◽  
Andrezza Sayuri Victoriano Hirota ◽  
Paulo Fernandes Roges Souza Silva ◽  
Ricardo Keichi Umetsu ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Fungal Biomass ◽  
Mesh Size ◽  
Fire Effects ◽  
Dry Mass ◽  
Tropical Stream ◽  
Fire Event ◽  
Litter Bags ◽  
Fine Mesh ◽  
Post Fire Effects

Abstract Aim Wildfire is a natural pulsed disturbance in landscapes of the Savannah Biome. This study evaluates short-term post-fire effects on leaf litter breakdown, the invertebrate community and fungal biomass of litter from three different vegetal species in a tropical stream. Methods Senescent leaves of Inga laurina, Protium spruceanum and Rircheria grandis (2 ± 0.1 g dry mass) were individually placed in litter bags (30 × 30 cm: 10 mm coarse mesh and 0.5 mm fine mesh) and submerged in the study stream before and after fire. Replicate bags (n = 4; individually for each species, sampling time, fire event and mesh size) were then retrieved after 20 and 40 days and washed to separate the invertebrates before fire event and again immediately after fire. Disks were cut from leaves to determine ash-free dry mass, while the remaining material was oven-dried to determine dry mass. Results The pre-fire mean decomposition coefficient (k = -0.012 day-1) was intermediate compared to that reported for other savannah streams, but post-fire it was lower (k = -0.007 day-1), due to decreased allochthonous litter input and increased autochthones production. Intermediate k values for all qualities of litter post-fire may indicate that fire is equalizing litter quality in the stream ecosystem. The abundance of scrapers was found to be more important than fungal biomass or shredder abundance, probably due to their functioning in leaf fragmentation while consuming periphyton growing on leaf litter. Conclusions Theses results indicate that fire can modify the relationships within decomposer communities in tropical stream ecosystems.

Weight loss trajectories and related factors in a 16-week mobile obesity intervention: A retrospective observational study (Preprint)

2021 ◽  
Author(s):  
Ho Heon Kim ◽  
Young In Kim ◽  
Andreas Michaelides ◽  
Yu Rang Park
Keyword(s):  
Machine Learning ◽  
Weight Loss ◽  
Effect Size ◽  
Weight Change ◽  
Average Weight ◽  
Learning Approach ◽  
Obesity Management ◽  
Significant Difference ◽  
Machine Learning Approach ◽  
Cluster 2

BACKGROUND In obesity management, whether patients lose 5% or more of their initial weight is a critical factor in their clinical outcome. However, evaluations that only take this approach cannot identify and distinguish between individuals whose weight change varies and those who steadily lose weight. Evaluation of weight loss considering the volatility of weight change through a mobile-based intervention for obesity can facilitate the understanding of individuals’ behavior and weight changes from a longitudinal perspective. OBJECTIVE With machine learning approach, we examined weight loss trajectories and explored the factors related to behavioral and app usage characteristics that induce weight loss. METHODS We used the lifelog data of 19,784 individuals who enrolled in a 16-week obesity management program on the healthcare app Noom in the US during August 8, 2013 to August 8, 2019. We performed K-means clustering with dynamic time warping to cluster the weight loss time series and inspected the quality of clusters with the total sum of distance within the clusters. To identify the usage factors to determine clustering assignment, we longitudinally compared weekly usage statistics with effect size on a weekly basis. RESULTS Initial Body Mass Index (BMI) of participants was 33.9±5.9 kg/m2, and ultimately reached an average BMI of 32.0±5.7 kg/m2. In their weight log, 5 Clusters were identified: Cluster 1 (sharp decrease) showed a high proportion of weight reduction class between 10% and 15%—the highest among the five clusters (n=2,364/12,796, 18.9%)—followed by Cluster 2 (moderate decrease), Cluster 3 (increase), Cluster 4 (yoyo), Cluster 5 (other). In comparison between cluster 2 and cluster 4, although the effect size of difference in the average meal input adherence and average weight input adherence did not show a significant difference in the first week, it increased continuously for 7 weeks (Cohen’s d=0.408; 0.38). CONCLUSIONS With machine learning approach clustering shape-based timeseries similarity, this study identified 5 weight loss trajectories in mobile weight management app. Overall adherence and early adherence related to self-monitoring emerged as a potential predictor of these trajectories.

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