Modeling the decay of coarse woody debris in a subalpine Norway spruce forest of the West Carpathians, Poland

2008 ◽  
Vol 38 (3) ◽  
pp. 415-428 ◽  
Author(s):  
Jan Holeksa ◽  
Tomasz Zielonka ◽  
Magdalena Żywiec
Keyword(s):  
Decay Rate ◽  
Norway Spruce ◽  
Residence Time ◽  
Coarse Woody Debris ◽  
Woody Debris ◽  
Subalpine Forest ◽  
Residence Times ◽  
Stem Size ◽  
The Mean ◽  
Total Residence Time

Coarse woody debris (CWD) is an important structural element in forests. Its role depends on the species, size, position, and decay rate. This paper reports an attempt to determine the total residence time of CWD across all decay classes and also within successive decay classes. We simulated the process of CWD decomposition for stem size and position (snags versus logs), using matrices of the transition of CWD between decay classes. The study was based on a sample of 2785 Norway spruce snags and logs measured twice over a 10  year period in a Carpathian subalpine forest. The revealed pattern of decomposition depended highly on CWD size. When log numbers were considered, the mean total residence time increased from 71 years for small logs (diameter < 23 cm) to 90 years for medium-sized logs (23–35 cm), and to 113 years for large logs (>35 cm). In terms of volume, the mean total residence times of logs were 47, 49, and 63 years for the three diameter categories. Still shorter were the mean total residence times for log mass: 34, 41, and 41 years for the three diameter categories. The pattern of decomposition depended highly on the CWD attributes taken into consideration. The differences in decay rate between log diameter categories are considerable when the number of logs is taken into account, but they practically vanish when log mass is considered.

Movement and characteristics of stream-borne coarse woody debris in adjacent burned and undisturbed watersheds in Wyoming

1994 ◽  
Vol 24 (9) ◽  
pp. 1933-1938 ◽  
Author(s):  
Michael K. Young
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Rocky Mountain ◽  
Mountain Streams ◽  
Bank Stability ◽  
Stream Surface ◽  
Riparian Trees ◽  
Mean Diameter ◽  
Debris Transport ◽  
The Mean

Following fire, changes in streamflow and bank stability in burned watersheds can mobilize coarse woody debris. In 1990 and 1991, I measured characteristics of coarse woody debris and standing riparian trees and snags in Jones Creek, a watershed burned in 1988, and in Crow Creek, an unburned watershed. The mean diameter of riparian trees along Jones Creek was less than that of trees along Crow Creek, but the coarse woody debris in Jones Creek was greater in mean diameter. Tagged debris in Jones Creek was three times as likely to move, and moved over four times as far as such debris in Crow Creek. In Jones Creek, the probability of movement was higher for tagged pieces that were in contact with the stream surface. Larger pieces tended to be more stable in both streams. It appears that increased flows and decreased bank stability following fire increased the transport of coarse woody debris in the burned watershed. Overall, debris transport in Rocky Mountain streams may be of greater significance than previously recognized.

scholarly journals Compartment models for estimating attributes of digesta flow in cattle

1988 ◽  
Vol 60 (3) ◽  
pp. 571-595 ◽  
Author(s):  
K. R. Pond ◽  
W. C. Ellis ◽  
J. H. Matis ◽  
H. M. Ferreiro ◽  
J. D. Sutton
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Residence Times ◽  
Age Dependency ◽  
Faecal Excretion ◽  
Compartment Models ◽  
Equal Rate ◽  
Age Dependent ◽  
The Mean ◽  
Age Independent

1. The basic assumptions involved in one- and two-compartment models with age-independent distributed residence times (exponential, G1) for describing digesta flow are reviewed as the bases for describing families of one- and two-compartment models which assume age-dependent distributions (Gn) of residence times.2. The two-compartment, age-independent model with exponentially distributed residence times (GIGI) yielded estimates of essentially equal rate parameters when fitted to faecal values for all four cows receiving a diet of 500 g coarsely chopped, sodium hydroxide-treated straw /kg and one of four cows receiving the same diet but with ground and pelleted straw. The incorporation of progressively higher orders of age dependency (G2-G6, Gn) into the faster turnover compartment of two-compartment models (GnG1) resulted in a resolution of equal rate parameters estimated by the G1G1 model and a reduction in standard errors for the rate and the initial concentration parameters.3. The occurrence of equal rate parameters in two-compartment models indicated an age-dependent process; a process which could equally well be described by a one-compartment, age-dependent compartment having an order of age dependency equal to the sum of these orders in the two-compartment model with equal rate parameters.4. The age-independent models overestimated time of first appearance in the faeces of a meal's particles. The association of age dependency with the faster turnover compartment resulted in earlier estimates for first appearance of the marked particles; estimates which were more consistent with observed first appearance.5. The faecal excretion pattern from cows fed on the ground and pelleted straw diet exhibited an age-independent distribution of longer residence times which dominated approximately 80% of the later residence times. Age-dependent, one-compartment models gave a poor fit to such data from these cows fed on ground and pelleted straw. In contrast, age-dependent, one-compartment models provided an excellent fit to data from cows fed on chopped straw; data which indicated that age-independent distributions of residence times were much delayed in appearing or were totally absent.6. The mean residence time for the slower turnover, age-independent compartment estimated from faecal excretional of stained particles from either diet was similar to that estimated from duodenal concentrations of the stained particles. This suggests that the slower turnover model compartment was confined to preduodenal sites.7. The mean residence time for the faster turnover, age-dependent compartment estimated from duodenal data was 58–62 % that estimated from faecal data and suggests that the site of this model compartment was both pre- and post-duodenal.8. It is emphasized that the slow and imperfect mixing of particulate matter that occurs in reticulo-rumen digesta is inconsistent with the assumptions of instantaneous and homogeneous mixing made by models having age-independent distributions of residence times. The use of age-dependent distributed residence times can accommodate such imperfect mixing and is consistent with the existence of age-discriminating processes involved in particle flow from the reticulo-rumen. Age dependency also offers improved precision in estimating parameters of digesta flow via processes having inherent uncertainty in their mixing and age-discriminating mechanisms.

scholarly journals Habitat Preference of Auriscalpium vulgare Gray Inhabiting Slash and Burn Affected Khasi Pine Cones of India

Our Nature ◽  
1970 ◽  
Vol 7 (1) ◽  
pp. 32-38 ◽  
Author(s):  
P. Das ◽  
A. Chettri ◽  
H. Kayang
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Northeast India ◽  
Land Use Pattern ◽  
Slash And Burn ◽  
Pine Cone ◽  
Predominant Form ◽  
The Mean ◽  
Pine Cones ◽  
Khasi Pine

Slash and burn shifting cultivation or jhum is the predominant form of land use pattern in the hilly terain of northeast India. Impact of jhum practice on Auriscalpium vulgare growing on the female Khasi pine cone was studied. The period of mature cone falling proceeds after the slash and burn activity, hence only 1:3 escapes the burning practice. During the assessment, burned and unburned cones were assigned to coarse woody debris (CWD) and classified into three girth classes: small (≤10 cm), intermediate (>10 to ≤13 cm) and large (>13 cm). The mean number of basidiocarps in burned cones was significantly higher than unburned ones (p<0.00001). A significant linear relationship between girth size of burned cones and number of basidiocarps was observed (r = 0.736; p<0.01). The study reveals that maximum number of fungi thrives on the burned cones (anthropogenically disturbed) of pine and girth size affects the number of basidiocarp. Key words: burned and unburned pine cones; coarse woody debris (CWD); Khasi pine; slash and burnDOI: 10.3126/on.v7i1.2551Our Nature (2009) 7:32-38

Contribution of tissue lipid to long xenon residence times in muscle

1993 ◽  
Vol 74 (5) ◽  
pp. 2127-2134 ◽  
Author(s):  
J. A. Novotny ◽  
E. C. Parker ◽  
S. S. Survanshi ◽  
G. W. Albin ◽  
L. D. Homer
Keyword(s):  
Gas Exchange ◽  
Residence Time ◽  
Compartment Model ◽  
Canine Model ◽  
Inert Gas ◽  
Relative Dispersion ◽  
Residence Times ◽  
Single Compartment ◽  
Single Compartment Model ◽  
The Mean

Experiments demonstrate that the mean residence time of an inert gas in tissue is longer than that predicted by a single-compartment model of gas exchange. Also the relative dispersion (RD, the standard deviation of residence times divided by the mean) is 1 according to this model, but RDs in real tissues are closer to 2, suggesting that a multiple-compartment model might be more accurate. The residence time of a gas is proportional to its solubility in the tissue. Although the noble gases in particular are 10 times more soluble in lipid than in nonlipid tissues, models of gas exchange generally do not incorporate measurements of the lipid in tissue, which may lead to error in the predicted gas residence times. Could a multiple-compartment model that accounts for the lipid in tissue more accurately predict the mean and RD of gas residence times? In this study, we determined the mean and RD of Xe residence times in intact and surgically isolated muscles in a canine model. We then determined the lipid content and the perfusion heterogeneity in each tissue, and we used these measurements with a multiple-compartment model of gas exchange to predict the longest physiologically plausible Xe residence times. Even so, we found the observed Xe mean residence times to be twice as long as those predicted by the model. However, the predicted RDs were considerably larger than the observed RDs. We conclude that lipid alone cannot account for the residence times of Xe in tissue and that a multiple-compartment model is not an accurate representation of inert gas exchange in tissue.

Modeling dead wood in Fennoscandian old-growth forests dominated by Norway spruce

2004 ◽  
Vol 34 (5) ◽  
pp. 1025-1034 ◽  
Author(s):  
Thomas Ranius ◽  
Bengt Gunnar Jonsson ◽  
Nicholas Kruys
Keyword(s):  
Norway Spruce ◽  
Residence Time ◽  
Tree Mortality ◽  
Woody Debris ◽  
National Forest Inventory ◽  
Mortality Data ◽  
Negative Exponential Distribution ◽  
Computer Simulation Program ◽  
Number Of Stems ◽  
Negative Exponential

If equilibrium is assumed in unmanaged forests, the volume of coarse woody debris (CWD), VCWD, may be calculated from (i) the volume of living trees, Vliving, (ii) average volume of a dead stem in relation to when it was alive, k, (iii) tree mortality rate, m, and (iv) residence time of CWD, t, by the equation VCWD = Vlivingkmt. We parameterized this equation with data from Norway spruce (Picea abies (L.) Karst.) dominated forests in Fennoscandia. The Vliving was assumed to be directly proportional to forest productivity. Tree mortality data were from the National Forest Inventory, while it was difficult to find quantitative data on k and t. The predicted amounts (74–138 m3/ha, with larger amounts in the south) and size distribution (a negative exponential distribution of the number of stems) of CWD corresponded fairly well to averages from field inventories. By using a computer simulation program, the variability in tree mortality, density of living trees, and residence time of CWD were considered. In the simulations, the amount of CWD varied widely between 1-ha plots, especially for individual decay classes. Therefore, this model could be used to predict averages from larger landscapes unaffected by large disturbances, while no model can predict the amount of CWD at individual plots.

scholarly journals Stand and coarse woody debris dynamics in subalpine Norway spruce forests withdrawn from regular management

2010 ◽  
Vol 67 (8) ◽  
pp. 803-803 ◽  
Author(s):  
Renzo Motta ◽  
Roberta Berretti ◽  
Daniele Castagneri ◽  
Emanuele Lingua ◽  
Paola Nola ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Coarse Woody Debris ◽  
Woody Debris ◽  
Spruce Forests

Macroinvertebrates on coarse woody debris in the littoral zone of a boreal lake

2009 ◽  
Vol 60 (9) ◽  
pp. 960 ◽  
Author(s):  
Patricia N. Glaz ◽  
Christian Nozais ◽  
Dominique Arseneault
Keyword(s):  
Coarse Woody Debris ◽  
Temporal Dynamics ◽  
Woody Debris ◽  
Macroinvertebrate Community ◽  
Macroinvertebrate Communities ◽  
Boreal Lake ◽  
The Mean ◽  
The 19Th Century ◽  
Regular Practice ◽  
Main Factor

Logging activity was a regular practice in the boreal forest of Quebec during the 19th century and may have had an impact on the temporal dynamics of aquatic coarse woody debris (CWD) and associated organisms. The dynamics of white cedar (Thuja occidentalis) CWD inputs from the riparian environment in a boreal lake in Eastern Quebec, Canada, over the past 350 years were reconstructed and differences in the macroinvertebate communities according to CWD age, season of sampling (spring, summer and autumn), depth and site were investigated. It was hypothesised that CWD macroinvertebrate community structure would change with CWD age, season and depth, but not among sites. No significant correlation was found between CWD age and macroinvertebrate densities and taxa number. The macroinvertebrate community was highly variable in space and time. Season was the main factor influencing taxa composition and the relative densities of individuals. The mean density was more than twofold greater in autumn than in spring and summer (1046, 1049 and 2335 individuals m–2 in spring, summer and autumn respectively). Density and taxa number decreased with depth, but site did not appear to influence the community. As CWD inputs increased during the log-driving period, impacts on macroinvertebrate communities were likely to be important and should be documented across the boreal zone.

A Robust Procedure for Estimating Salmon Escapement based on the Area-Under-the-Curve Method

1992 ◽  
Vol 49 (10) ◽  
pp. 1982-1989 ◽  
Author(s):  
K. K. English ◽  
R. C. Bocking ◽  
J. R. Irvine
Keyword(s):  
Residence Time ◽  
Theoretical Basis ◽  
Area Under The Curve ◽  
Residence Times ◽  
Survey Area ◽  
Independent Estimate ◽  
Coastal Streams ◽  
Curve Method ◽  
Total Residence Time ◽  
Survey Effort

Salmon spawning escapements are estimated using the area-under-the-curve (AUC) method by dividing the integral of the escapement curve by the average residence time of fish in the survey area. We present two forms of the basic AUC method which differ in the procedure used to estimate residence time from the observations of tagged fish during stream surveys. AUC estimates based on "observed residence times" were sensitive to variability in survey timing, observer efficiency, and tag detection, while those based on "total residence times" were more robust. For two coastal streams, escapement estimates based on "observed residence times" were between 1.1, and 6.8 times larger than an independent escapement estimate (from fence counts and mark–recapture data), while estimates based on "total residence times" were generally closer to the independent estimate (0.74–1.51 times the estimate, and within 26% six times out of seven). The consistency of our results under a wide variety of survey conditions, combined with their strong theoretical basis, indicates that an AUC method based on annual estimates of total residence time and observer efficiency is robust. However, the level of survey effort required for these methods would limit their application to high-priority streams or populations.

scholarly journals Changes in plant debris and carbon stocks across a subalpine forest successional series

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Zhihui Wang ◽  
Lianjun Zhao ◽  
Yi Bai ◽  
Fei Li ◽  
Jianfeng Hou ◽  
...  
Keyword(s):  
Coarse Woody Debris ◽  
Carbon Stock ◽  
Woody Debris ◽  
Carbon Stocks ◽  
Subalpine Forest ◽  
Plant Debris ◽  
Successional Stage ◽  
Successional Series ◽  
Successional Forests ◽  
Shrub Forest

Abstract Background As a structurally and functionally important component in forest ecosystems, plant debris plays a crucial role in the global carbon cycle. Although it is well known that plant debris stocks vary greatly with tree species composition, forest type, forest origin, and stand age, simultaneous investigation on the changes in woody and non-woody debris biomass and their carbon stock with forest succession has not been reported. Therefore, woody and non-woody debris and carbon stocks were investigated across a subalpine forest successional gradient in Wanglang National Nature Reserve on the eastern Qinghai-Tibet Plateau. Results Plant debris ranged from 25.19 to 82.89 Mg∙ha− 1 and showed a global increasing tendency across the subalpine forest successional series except for decreasing at the S4 successional stage. Accordingly, the ratios of woody to non-woody debris stocks ranged from 26.58 to 208.89, and the highest and lowest ratios of woody to non-woody debris stocks were respectively observed in mid-successional coniferous forest and shrub forest, implying that woody debris dominates the plant debris. In particular, the ratios of coarse to fine woody debris stocks varied greatly with the successional stage, and the highest and lowest ratios were found in later and earlier successional subalpine forests, respectively. Furthermore, the woody debris stock varied greatly with diameter size, and larger diameter woody debris dominated the plant debris. Correspondingly, the carbon stock of plant debris ranged from 10.30 to 38.87 Mg∙ha− 1 across the successional series, and the highest and lowest values were observed in the mid-coniferous stage and shrub forest stage, respectively. Most importantly, the carbon stored in coarse woody debris in later successional forests was four times higher than in earlier successional forests. Conclusions The stock and role of woody debris, particularly coarse woody debris, varied greatly with the forest successional stage and dominated the carbon cycle in the subalpine forest ecosystem. Thus, preserving coarse woody debris is a critical strategy for sustainable forest management.

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