Decomposition of Douglas-fir and red alder wood in clear-cuttings

1986 ◽  
Vol 16 (4) ◽  
pp. 822-831 ◽  
Author(s):  
Robert L. Edmonds ◽  
Daniel J. Vogt ◽  
David H. Sandberg ◽  
Charles H. Driver
Keyword(s):  
Small Diameter ◽  
Soil Surface ◽  
Douglas Fir ◽  
Dominant Factor ◽  
Minor Role ◽  
Wood Decomposition ◽  
Decomposition Rates ◽  
Red Alder ◽  
A Minor ◽  
The University

Decomposition rates of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) wood (simulating logging residues) were determined in clear-cuttings at the Charles Lathrop Pack Experimental Forest of the University of Washington, which is located approximately 120 km south of Seattle, WA. The influence of diameter (1–2, 4–6, and 8–12 cm), vertical location (buried, on the soil surface, and elevated), season of logging (summer and winter), aspect (north and south), and wood temperature, moisture, and chemistry on wood decomposition rates were determined. Red alder wood decomposed faster (k = 0.035–0.517 year−1) than Douglas-fir wood (k = 0.006–0.205 year−1). In general, buried wood decomposed faster than surface wood, which decomposed faster than elevated wood. Small diameter wood generally decomposed faster than larger diameter wood. Aspect and season of logging had little influence on decomposition rates. Moisture and temperature were the dominant factors related to Douglas-fir wood decomposition, with initial chemistry playing a minor role. Initial wood chemistry, particularly soda solubility, was the dominant factor related to red alder wood decomposition.

Decomposition of logging residues in Douglas-fir, western hemlock, Pacific silver fir, and ponderosa pine ecosystems

1985 ◽  
Vol 15 (5) ◽  
pp. 914-921 ◽  
Author(s):  
Heather E. Erickson ◽  
R. L. Edmonds ◽  
C. E. Peterson
Keyword(s):  
Ponderosa Pine ◽  
Small Diameter ◽  
Soil Surface ◽  
Douglas Fir ◽  
Dry Season ◽  
Western Hemlock ◽  
Dominant Factor ◽  
Silver Fir ◽  
Decomposition Rates ◽  
Residue Decomposition

Logging residue decomposition rates were determined in four conifer forest ecosystems in the State of Washington, U.S.A. (coastal western hemlock, Puget lowland Douglas-fir, high-elevation Pacific silver fir, and eastern Cascade ponderosa pine), by examining wood density changes in a series of south-facing harvest areas with residues of different ages. Decomposition rates were determined for two diameter classes (1–2 and 8–12 cm) and two vertical locations (on and >20 cm above the soil surface). Pacific silver fir and ponderosa pine ecosystems had the lowest k values (0.005 and 0.010 year−1, respectively) followed by Douglas-fir (range, 0.004–0.037 year−1) and western hemlock (range, 0.010–0.030 year−1). Small-diameter residues decomposed at rates significantly slower than large-diameter residues in Douglas-fir and western hemlock ecosystems; this relationship was also implied in the other ecosystems. In all four ecosystems, dry season moisture contents were lower in smaller-diameter residues. Moisture levels associated with small-diameter residues were too low for significant decomposition to occur during the dry summer period and probably contributed to the slow annual decay rates. Residues located above the soil surface decomposed significantly slower than residues on the soil surface only in the Douglas-fir ecosystem. Dry season residue moisture, rather than initial lignin concentration, appeared to be the dominant factor determining residue decomposition rates on exposed harvested areas.

High Hopes

2020 ◽  
pp. 286-301
Author(s):  
Katja Lahikainen ◽  
Timo Pihkala ◽  
Elena Ruskovaara
Keyword(s):  
Regional Policy ◽  
Peripheral Region ◽  
Minor Role ◽  
Regional Impact ◽  
Regional Policies ◽  
A Minor ◽  
Lock In ◽  
The University ◽  
Technological University ◽  
Start Ups

The regional impact of entrepreneurial universities is a well-researched topic, but less attention is paid to the expectations of the regional policy institutes toward the university. This chapter investigates the regional policy expectations toward the university and what the influence of the university to these expectations is. This study is based on a technological university case in a peripheral region in Finland. The results of the study show that the existence of a single university leads easily to a university-dominant policy and thus to a regional policy lock-in. Consequently, the implementation of the regional policies can be in the hands of the university, leaving other regional stakeholders with a minor role. In order to fully utilize the potential of the university to address the specific regional challenges, the university should not only be seen as a locus of new spin-offs and start-ups, but rather as a producer of qualified graduates and future entrepreneurs.

Interaction of Douglas-fir with red alder and salal foliage litter during decomposition

1993 ◽  
Vol 23 (3) ◽  
pp. 358-361 ◽  
Author(s):  
J.W. Fyles ◽  
I.H. Fyles
Keyword(s):  
Mass Loss ◽  
Nitrogen Content ◽  
Litter Decomposition ◽  
Tree Species ◽  
Linear Trend ◽  
Douglas Fir ◽  
Negative Effects ◽  
Decomposition Rates ◽  
Red Alder ◽  
Ericaceous Shrub

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) foliage litter was incubated in the laboratory in 100/0, 75/25, 50/50, 25/75, and 0/100% mixtures with foliage litters from red alder (Alnusrubra Bong.), a nitrogen-fixing tree species, and salal (Gaultheriashallon Pursh) an ericaceous shrub. Mass loss and mineral nitrogen content were measured at eight dates during the 32-week incubation. The occurrence of interaction between litters, observed as deviation from a linear trend across mixtures at each date, was determined by polynomial contrasts. Douglas-fir–red alder mixtures decomposed faster than predicted by mass loss from pure litters throughout the study, apparently because of nitrogen mineralized by the red alder component. Douglas-fir–salal mixtures decomposed more slowly than predicted between 7 and 25 weeks. The study demonstrates the potential for litters to interact with positive or negative effects on decomposition rates and emphasizes the need to examine such interactions if litter decomposition in the field is to be understood.

Basement–cover relationships in the Shaftesbury area of the Wessex Basin, southern England

1994 ◽  
Vol 131 (3) ◽  
pp. 387-394 ◽  
Author(s):  
D. J. Evans ◽  
R. A. Chadwick
Keyword(s):  
Seismic Reflection ◽  
Late Triassic ◽  
Dominant Factor ◽  
Minor Role ◽  
Northwestern Part ◽  
Borehole Data ◽  
Southern England ◽  
Sedimentary Fill ◽  
A Minor ◽  
Carboniferous Limestone

AbstractIn the northwestern part of the Wessex Basin of southern England, interpretation of seismic reflection and recently released borehole data provides detailed information of the major unconformity at the base of the sedimentary-fill. Seismic mapping of the top of Variscan basement reveals a concealed, faulted, dome-like Palaeozoic basement culmination or structural ‘high’ lying within the larger Cranborne–Fordingbridge High, southwest of Shaftesbury. This structure profoundly affected the deposition of the overlying Permo-Triassic sequence. The culmination, composed of Carboniferous Limestone, lies to the south of northwards-throwing, basement-controlled, syn-sedimentary faults which form the southern margin of the Mere Basin. In this area, the main phase of faulting occurred during Permo-Triassic times with little or no faulting during the Jurassic. Triassic strata onlap the basement culmination which was overstepped and finally submerged in late Triassic times. The structure has much in common with the basement ‘highs’ at Bruton and in the Mendips and provides further evidence for the existence of such features close to the main lines of Mesozoic faulting within the Wessex Basin. It is considered that differential subsidence related to syn-depositional normal faulting was the dominant factor controlling development of the highs. The simple infilling of a pre-existing post-orogenic topography played a minor role.

Decomposition rates and nutrient dynamics in small-diameter woody litter in four forest ecosystems in Washington, U.S.A.

1987 ◽  
Vol 17 (6) ◽  
pp. 499-509 ◽  
Author(s):  
Robert L. Edmonds
Keyword(s):  
Nutrient Dynamics ◽  
Forest Ecosystems ◽  
Small Diameter ◽  
High Elevation ◽  
Silver Fir ◽  
Decomposition Rates ◽  
Red Alder ◽  
N Release ◽  
Woody Litter ◽  
Western Washington

Decomposition rates and nutrient dynamics in small-diameter woody litter (twigs, cones, and branches) were studied in four ecosystems in western Washington: high elevation Pacific silver fir (Abiesamabilis (Dougl.) Forbes) and low elevation Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and red alder (Alnusrubra Bong.). Conifer twigs decomposed faster (k = 0.14–0.24 year−1) than cones (k = 0.09–0.12 year−1) and branches (k = 0.03–0.11 year−1). Decomposition constants were related better to initial lignin/initial N ratios (r = −0.64) than initial lignin concentrations. N was generally the least mobile nutrient while K was the most mobile. Many nutrients were strongly immobilized in conifer fine woody litter, including N, Mg, Mn, and Ca. There was little immobilization of N in red alder branches. N release from decomposing woody litter appears to be controlled by a critical C/N ratio. This critical C/N ratio, however, was not constant and increased as the substrate decomposition rate increased.

scholarly journals Veteran trees have divergent effects on beetle diversity and wood decomposition

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248756
Author(s):  
Ross Wetherbee ◽  
Tone Birkemoe ◽  
Ryan C. Burner ◽  
Anne Sverdrup-Thygeson
Keyword(s):  
Small Diameter ◽  
Decay Rates ◽  
Wood Decomposition ◽  
Decomposition Rates ◽  
Anthropogenic Landscapes ◽  
Hollow Trees ◽  
Unique System ◽  
Veteran Trees ◽  
Experiential Design ◽  
Southern Norway

Veteran hollow trees are keystone structures in ecosystems and provide important habitat for a diverse set of organisms, many of which are involved in the process of decomposition. Since veteran trees are ‘islands’ of high biodiversity, they provide a unique system in which to study the relationship between biodiversity and decomposition of wood. We tested this relationship with a balanced experiential design, where we quantified the taxonomic and functional diversity of beetles directly involved in the process of decomposing wood, and measured the decomposition of experimentally added bundles of small diameter wood around 20 veteran trees and 20 nearby young trees in southern Norway. We found that the diversity (both taxonomic and functional) of wood-decomposing beetles was significantly higher around the veteran trees, and beetle communities around veteran trees consisted of species with a greater preference for larger diameter wood. We extracted few beetles from the experimentally added wood bundles, regardless of the tree type that they were placed near, but decomposition rates were significantly lower around veteran trees. We speculate that slower decomposition rates around veteran trees could have been a result of a greater diversity of competing fungi, which has been found to decrease decay rates. Veteran trees provide an ecological legacy within anthropogenic landscapes, enhance biodiversity and influence wood decomposition. Actions to protect veteran trees are urgently needed in order to save these valuable organisms and their associated biodiversity.

scholarly journals Bryosphere Loss Impairs Litter Decomposition Consistently Across Moss Species, Litter Types, and Micro-Arthropod Abundance

Ecosystems ◽  
2021 ◽  
Author(s):  
Roger Grau-Andrés ◽  
David A. Wardle ◽  
Paul Kardol
Keyword(s):  
Litter Decomposition ◽  
Boreal Forests ◽  
Terrestrial Ecosystems ◽  
Minor Role ◽  
Decomposition Rates ◽  
Moss Species ◽  
Key Driver ◽  
A Minor ◽  
Positive Effect ◽  
Arthropod Abundance

AbstractThe bryosphere (that is, ground mosses and their associated biota) is a key driver of nutrient and carbon dynamics in many terrestrial ecosystems, in part because it regulates litter decomposition. However, we have a poor understanding of how litter decomposition responds to changes in the bryosphere, including changes in bryosphere cover, moss species, and bryosphere-associated biota. Specifically, the contribution of micro-arthropods to litter decomposition in the bryosphere is unclear. Here, we used a 16-month litterbag field experiment in two boreal forests to investigate bryosphere effects on litter decomposition rates among two moss species (Pleurozium schreberi and Hylocomium splendens), and two litter types (higher-quality Betula pendula litter and lower-quality P. schreberi litter). Additionally, we counted all micro-arthropods in the litterbags and identified them to functional groups. We found that bryosphere removal reduced litter decomposition rates by 28% and micro-arthropod abundance by 29% and led to a colder micro-climate. Litter decomposition rates and micro-arthropod abundance were uncorrelated overall, but were positively correlated in B. pendula litterbags. Bryosphere effects on litter decomposition rates were consistent across moss species, litter types, and micro-arthropod abundances and community compositions. These findings suggest that micro-arthropods play a minor role in litter decomposition in the boreal forest floor, suggesting that other factors (for example, micro-climate, nutrient availability) likely drive the positive effect of the bryosphere on decomposition rates. Our results point to a substantial and consistent impairment of litter decomposition in response to loss of moss cover, which could have important implications for nutrient and carbon cycling in moss-dominated ecosystems.

scholarly journals Spread of infectious disease through clustered populations

2009 ◽  
Vol 6 (41) ◽  
pp. 1121-1134 ◽  
Author(s):  
Joel C. Miller
Keyword(s):  
Infectious Disease ◽  
Growth Rate ◽  
Significant Contribution ◽  
Dominant Factor ◽  
Disease Models ◽  
Minor Role ◽  
Rate Heterogeneity ◽  
A Minor ◽  
The Impact ◽  
Infectious Disease Models

Networks of person-to-person contacts form the substrate along which infectious diseases spread. Most network-based studies of this spread focus on the impact of variations in degree (the number of contacts an individual has). However, other effects such as clustering, variations in infectiousness or susceptibility, or variations in closeness of contacts may play a significant role. We develop analytic techniques to predict how these effects alter the growth rate, probability and size of epidemics, and validate the predictions with a realistic social network. We find that (for a given degree distribution and average transmissibility) clustering is the dominant factor controlling the growth rate, heterogeneity in infectiousness is the dominant factor controlling the probability of an epidemic and heterogeneity in susceptibility is the dominant factor controlling the size of an epidemic. Edge weights (measuring closeness or duration of contacts) have impact only if correlations exist between different edges. Combined, these effects can play a minor role in reinforcing one another, with the impact of clustering the largest when the population is maximally heterogeneous or if the closer contacts are also strongly clustered. Our most significant contribution is a systematic way to address clustering in infectious disease models, and our results have a number of implications for the design of interventions.

PLANE AND SPHERICAL TRANSIENT VOIGT WAVES

Geophysics ◽  
1970 ◽  
Vol 35 (5) ◽  
pp. 745-761 ◽  
Author(s):  
A. H. Balch ◽  
F. R. Smolka
Keyword(s):  
High Speed ◽  
Seismic Wave Propagation ◽  
Dominant Factor ◽  
Symmetric System ◽  
Finite Difference Schemes ◽  
Minor Role ◽  
Infinite Body ◽  
Noticeable Effect ◽  
Pressure Impulse ◽  
A Minor

The combination of high‐speed digital computers and recursive finite difference schemes has become a powerful tool in the theoretical analysis of seismic wave propagation. Using this tool, we have obtained solutions to the viscoelastic, or Voigt, wave equation under the following conditions: First, a pressure impulse is applied to the surface of a spherical cavity in a spherically symmetric system; and, second, an arbitrary function is applied to the surface of a semi‐infinite body in a rectangular system. At and near the cavity wall, the cavity radius appears to be the dominant factor in determining the wavelet shape. The viscosity of the medium plays a minor role. At large distances from the cavity, the pressure impulse response of the medium is controlled by the viscosity. Poisson’s ratio has a small but noticeable effect on the wavelet shape near the source. In the plane‐wave case, our results are in good agreement with those given by Collins (1960) near the source and those of Ricker (1943, 1953) at large distances from the source.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

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