Fluorescent pseudomonad population sizes baited from soils under pure birch, pure Douglas-fir, and mixed forest stands and their antagonism towardArmillaria ostoyaein vitro

2002 ◽  
Vol 32 (12) ◽  
pp. 2146-2159 ◽  
Author(s):  
R L DeLong ◽  
Kathy J Lewis ◽  
Suzanne W Simard ◽  
Susan Gibson
Keyword(s):  
Douglas Fir ◽  
Fluorescent Pseudomonads ◽  
Dual Culture ◽  
Fluorescent Pseudomonad ◽  
Percent Cover ◽  
Forest Stands ◽  
Mixed Stands ◽  
Relative Population ◽  
Population Sizes ◽  
Paper Birch

The relationship between forest stand composition in southern interior British Columbia and fluorescent pseudomonad bacteria populations was investigated using seedling bioassays. The objectives of this study were to (i) compare the relative population sizes of fluorescent pseudomonads baited from soils in pure paper birch (Betula papyrifera Marsh.), pure Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and mixed stands of the two species and (ii) determine if fluorescent pseudomonads from these soils have inhibitory effects against the root pathogen Armillaria ostoyae (Romagn.) Herink in vitro. Soil from birch stands supported four times more pseudomonads on seedling baits than soil from Douglas-fir stands, with the mixed stands intermediate. Soil from young stands yielded twice as many rhizosphere pseudomonads as soil from mature stands. Pseudomonad population size was positively correlated with percent cover and density of birch, and negatively correlated with basal area of Douglas-fir, percent cover of Douglas-fir, and carbon/nitrogen ratio of the soil. Greater than 50% of the fluorescent isolates reduced radial growth of A. ostoyae by more than 20% and greater than 90% reduced biomass of the fungus in dual culture tests. Cell-free bacterial culture filtrates added to the growth medium also reduced growth of A. ostoyae. This study provides evidence that paper birch provides a more favorable environment for fluorescent pseudomonads than Douglas-fir and suggests a mechanism by which paper birch can positively influence the susceptibility of managed forest stands to Armillaria root disease.

Enhancement of population densities of fluorescent pseudomonads in the rhizosphere of tomato plants by addition of acibenzolar-S-methyl

2002 ◽  
Vol 48 (12) ◽  
pp. 1069-1075 ◽  
Author(s):  
W D Fakhouri ◽  
H Buchenauer
Keyword(s):  
Fluorescent Protein ◽  
Fluorescent Pseudomonads ◽  
Fluorescent Pseudomonad ◽  
Bacterial Cells ◽  
In Vitro Production ◽  
Tomato Plants ◽  
Population Sizes ◽  
Cell Densities ◽  
Green Fluorescent

Fluorescent pseudomonad isolates G309 and CW2, in combination with the resistance inducer acibenzolar-S-methyl (ASM), improved control of fungal and bacterial diseases on tomato plants. The interactions of the bacteria in the presence of ASM showed that in vitro growth of Pseudomonas fluorescens G309 and Pseudomonas sp. strain CW2 was not affected in King's B broth supplemented with 10 and 20 μM ASM. Also, the bacterial cells were not able to utilize ASM as a nutrient source. In vitro production of the two antimicrobial secondary metabolites phenazine-1-carboxylic acid and 2-OH-phenazine by the isolate CW2 was not affected within 3 days from incubation. In contrary, addition of ASM at a concentration of 20 μM to King's B liquid medium significantly increased production of salicylic acid by isolate G309. When roots of tomato plants were treated with G309 or CW2 cell suspensions containing 20 μM ASM, the number of bacterial cells recovered from the rhizosphere was significantly higher in the combined treatments than in the single applications 5, 10, and 15 days after inoculation. However, ASM at a higher concentration (50 μM) did not appreciably enhance the population sizes of either bacterial isolate in the rhizosphere. Enhanced bacterial cell densities in the rhizosphere of tomato plants were also determined following simultaneous treatments of tomato roots with 10 and 20 μM ASM in combination with the transformed isolate G309-384 (mini-Tn5gfp), which encodes the green fluorescent protein.Key words: acibenzolar-S-methyl, fluorescent pseudomonads, green fluorescent protein, tomato.

scholarly journals Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

2021 ◽  
Author(s):  
Kirsten Höwler ◽  
Torsten Vor ◽  
Peter Schall ◽  
Peter Annighöfer ◽  
Dominik Seidel ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Mixed Forest ◽  
European Beech ◽  
Forest Stands ◽  
Species Identity ◽  
Mixed Stands ◽  
Mixed Forests ◽  
Climate Conditions ◽  
Timber Quality ◽  
Positive Effects

AbstractResearch on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on the effects of tree species mixing on timber quality. In particular, it is still unclear whether the numerous positive effects of mixed forests on productivity and stability come at the expense of timber quality. In this study, we used photographs of sawn boards from 90 European beech (Fagus sylvatica L.) trees of mixed and pure forest stands to analyze internal timber quality through the quality indicator knot surface that was quantitatively assessed using the software Datinf® Measure. We observed a decrease in knot surface with increasing distance from the pith as well as smaller values in the lower log sections. Regarding the influence of neighborhood species identity, we found only minor effects meaning that timber qualities in mixed stands of beech and Norway spruce (Picea abies (L.) H. Karst.) tended to be slightly worse compared to pure beech stands.

scholarly journals Influence of trees and associated variables on soil organic carbon: a review

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Angom Sarjubala Devi
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Significant Negative Correlation ◽  
Mean Annual Temperature ◽  
Forest Stands ◽  
Mixed Stands ◽  
Silt Fraction ◽  
Different Types ◽  
Soil Climate ◽  
Associated Variables

AbstractThe level of soil organic carbon (SOC) fluctuates in different types of forest stands: this variation can be attributed to differences in tree species, and the variables associated with soil, climate, and topographical features. The present review evaluates the level of SOC in different types of forest stands to determine the factors responsible for the observed variation. Mixed stands have the highest amount of SOC, while coniferous (both deciduous-coniferous and evergreen-coniferous) stands have greater SOC concentrations than deciduous (broadleaved) and evergreen (broadleaved) tree stands. There was a significant negative correlation between SOC and mean annual temperature (MAT) and sand composition, in all types of forest stands. In contrast, the silt fraction has a positive correlation with SOC, in all types of tree stands. Variation in SOC under different types of forest stands in different landscapes can be due to differences in MAT, and the sand and silt fraction of soil apart from the type of forests.

Competition theory — science and application in mixed forest stands: review of experimental and modelling methods and suggestions for future research

2013 ◽  
Vol 21 (2) ◽  
pp. 71-84 ◽  
Author(s):  
Guy R. Larocque ◽  
Nancy Luckai ◽  
Shailendra N. Adhikary ◽  
Arthur Groot ◽  
F. Wayne Bell ◽  
...  
Keyword(s):  
Mixed Forest ◽  
Single Species ◽  
Experimental Designs ◽  
Competitive Interactions ◽  
Future Research ◽  
Relative Importance ◽  
Forest Stands ◽  
Management Scenarios ◽  
Mixed Stands ◽  
Individual Tree

Competition in forest stands has long been of interest to researchers. However, much of the knowledge originates from empirical studies that examined the effects of competition. For instance, many studies were focused on the effects of the presence of herbaceous species on the development of tree seedlings or the decrease in individual tree growth with increases in stand density. Several models that incorporate competitive effects have been developed to predict tree and stand growth, but with simplified representations of competitive interactions. While these studies provided guidance useful for forest management, they contributed only partially to furthering our understanding of competitive mechanisms. Also, most competition studies were conducted in single-species stands. As competitive interactions occurring in mixed stands are characterized by a higher degree of complexity than those in single-species stands, a better understanding of these mechanisms can contribute to developing optimal management scenarios. The dynamics of forest stands with at least two species may be affected not only by competition, but also by facilitation or complementarity mechanisms. Thus, knowledge of the mechanisms may provide insight into the relative importance of intra- versus inter-specific competition and whether competition is symmetric or asymmetric. Special attention to the implementation of field experimental designs is warranted for mixed stands. While traditional spacing trials are appropriate for single-species stands, the examination of competitive interactions in mixed stands requires more complex experimental designs to examine the relative importance of species combinations. Forest productivity models allow resource managers to test different management scenarios, but again most of these models were developed for single-species stands. As competitive interactions are more complex in mixed stands, models developed to predict their dynamics will need to include more mechanistic representations of competition.

scholarly journals Production potential of Douglas fir at mesotrophic sites of Křtiny Training Forest Enterprise

2008 ◽  
Vol 54 (No. 7) ◽  
pp. 321-332 ◽  
Author(s):  
P. Kantor
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Production Potential ◽  
European Larch ◽  
Mixed Stands ◽  
Production Parameters ◽  
Breast Height ◽  
The Mean ◽  
The One ◽  
Mature Stands

: The study evaluates production parameters (height, diameter at breast height, volume) of Douglas fir (<I>Pseudotsuga menziesii</I> [Mirb.] Franco) at mesotrophic sites of the Křtiny Training Forest Enterprise in mature stands. In total, 29 mixed stands were assessed with the registered proportion of Douglas fir at an age of 85 to 136 years. Comparing the 10 largest Douglas firs with the 10 largest spruces or larches higher, and as a rule markedly higher, production potential of introduced Douglas fir was found in all assessed stands. There were also groups of trees where the volume of Douglas fir was twice to 3 times higher than the volume of spruce or larch (see Tabs. 5 to 10). For example, in stand 177B11, the mean volume of 9.12 m<sup>3</sup> was recorded in the 10 largest Douglas fir trees but the volume of spruce reached only 3.17 m<sup>3</sup> and the volume of larch was 3.70 m<sup>3</sup>. Differences in mensurational parameters of Douglas fir found on the one hand and of Norway spruce (<I>Picea abies</I> [L.] Karst.) or European larch (<I>Larix decidua</I> Mill.) on the other hand compared by ANOVA tests were statistically highly significant. Annual ring analyses have shown that at present the volume increment of particular Douglas fir trees ranges from 0.12 to 0.16 m<sup>3</sup> per year in mature stands (i.e. about 1.5 m<sup>3</sup> every 10 years).

Estimating structural attributes of Douglas-fir/western hemlock forest stands from landsat and SPOT imagery

1992 ◽  
Vol 41 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Warren B. Cohen ◽  
Thomas A. Spies
Keyword(s):  
Douglas Fir ◽  
Western Hemlock ◽  
Forest Stands ◽  
Spot Imagery

Sitka alder, a candidate for mixed stands

1982 ◽  
Vol 12 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Constance A. Harrington ◽  
Robert L. Deal
Keyword(s):  
Organic Matter ◽  
Head Start ◽  
Growth Curves ◽  
Poor Quality ◽  
Height Growth ◽  
Douglas Fir ◽  
Nitrogen Fixing ◽  
Mixed Stands

Juvenile height growth of Sitka alder (Alnussinuata (Regel) Rydb.), a nitrogen-fixing shrub, was examined on eight sites. The potential compatibility of mixed stands of Sitka alder and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was then assessed by comparing height-growth curves of the two species at early ages. Based on Sitka alder's low height and early slowdown in height growth, it appears to be a reasonable candidate for mixed stands on sites where additions of nitrogen or organic matter are desirable. On poor quality Douglas-fir sites, however, Douglas-fir should be given a head start to insure that it is not suppressed.

Molecular and Metabolic Typing of Resident and Transient Fluorescent Pseudomonad Flora from a Meat Mincer

1997 ◽  
Vol 60 (12) ◽  
pp. 1515-1519 ◽  
Author(s):  
CHRIS W. MICHIELS ◽  
MIA SCHELLEKENS ◽  
CARINE C. F. SOONTJENS ◽  
KRISTEL J. A. HAUBEN
Keyword(s):  
Carbon Sources ◽  
Fluorescent Pseudomonads ◽  
Fluorescent Pseudomonad ◽  
Raw Meat ◽  
Homogeneous Cluster ◽  
Predominant Type ◽  
Biolog System ◽  
Working Day ◽  
Endemic Flora ◽  
Cleaning And Disinfection

Nine spots on a meat mincer in a large catering facility were sampled four times over a three-month period after routine cleaning and disinfection. Spot 2 carried a significantly higher average microbial load than the other spots and was the only spot with a persistent population of fluorescent pseudomonads. The predominant type of fluorescent pseudomonads produced a yellow diffusible pigment and were always found in turkey meat. Since turkey was also the last type of meat minced on each working day, it was considered the likely source of these bacteria on the mincer. Sixty-three yellow-fluorescing pseudomonad strains from un-minced turkey and 17 strains from mincer spot 2 after mincing, cleaning, and disinfection were subjected to fingerprint analysis by random amplification of polymorphic DNA (RAPD) and by analysis of the assimilation patterns of 95 carbon sources using the Biolog system. Cluster analysis of the RAPD and the metabolic fingerprints revealed that all the mincer strains formed a homogeneous cluster, exclusive of all the turkey strains which displayed a higher degree of heterogeneity. Six strains isolated 1 week earlier and six strains isolated 11 weeks earlier from spot 2 were also subjected to RAPD analysis. Their fingerprints fell within the existing cluster of 17 spot 2 strains. These results suggest the existence on mincer spot 2 of an endemic flora of fluorescent pseudomonads, probably in the form of a biofilm. The genetic and physiological homogeneity of this flora, as opposed to the heterogeneity of the raw meat flora, indicates that only a fraction of the raw meat population of P. fiuorescens is successful in forming biofilm in this environment.

Comparing productivity of pure and mixed Douglas-fir and western hemlock plantations in the Pacific Northwest

2006 ◽  
Vol 36 (6) ◽  
pp. 1484-1496 ◽  
Author(s):  
M M Amoroso ◽  
E C Turnblom
Keyword(s):  
Pacific Northwest ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Mixed Stand ◽  
Mixed Stands ◽  
Individual Tree ◽  
The Pacific ◽  
Increase In Productivity

We studied pure and 50/50 mixtures of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) plantations to compare attained total yields between mixed-species stands as opposed to monocultures of equal densities. Whether overall stand density influences this outcome has not been adequately investigated, and to address this we included three density levels (494, 1111, and 1729 trees/ha) in the analysis. At age 12, as components of the mixed stands, Douglas-fir exhibited greater height, diameter, and individual-tree volume than western hemlock at all densities. At 494 and 1111 trees/ha the monocultures had a higher volume per hectare than the mixed stand, but at 1729 trees/ha the mixed stand appeared to be just as productive as the pure stands. The increase in productivity by the mixture at high densities seems to have resulted from the partial stratification observed and most likely also from better use of the site resources. Because of this, less interspecific competition was probably experienced in the mixed stand than intraspecific competition in the pure stands. This study shows the important role density plays in the productivity of mixed stands and thus in comparing mixed and pure stands.

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