Phenology and stem-growth periodicity of tree species in Amazonian floodplain forests

To study the impact of the annual long-term flooding (flood-pulse) on seasonal tree development in Amazonian floodplains, the phenology and growth in stem diameter of various tree species with different leaf-change patterns were observed over a period of 2 y. The trees of the functional ecotypes, evergreen, brevi-deciduous, deciduous and stem-succulent showed a periodic behaviour mainly triggered by the flood-pulse. Trees have high increment during the terrestrial phase. Flooding causes a shedding of some or all leaves leading to a cambial dormancy of about 2 mo and the formation of an annual ring. Studies carried out in tropical dry forests verify a strong relationship between the phenological development and the water status of the trees, strongly affected by seasonal drought. The comparison of the phenology and the diameter growth of the corresponding ecotypes in floodplain forest and a semi-deciduous forest in Venezuela shows a displacement of at least 2 mo in the periodicity, except for stem-succulent tree species. For stem-succulent trees it remains unclear which factors influence phenology and stem diameter growth.

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Change in hydraulic properties and leaf traits in a tall rainforest tree species subjected to long-term throughfall exclusion in the perhumid tropics

Biogeosciences ◽

10.5194/bg-8-2179-2011 ◽

2011 ◽

Vol 8 (8) ◽

pp. 2179-2194 ◽

Cited By ~ 25

Author(s):

B. Schuldt ◽

C. Leuschner ◽

V. Horna ◽

G. Moser ◽

M. Köhler ◽

...

Keyword(s):

Tree Species ◽

Large Scale ◽

Stem Diameter ◽

Soil Drought ◽

Diameter Growth ◽

The Sun ◽

Exclusion Experiment ◽

Throughfall Exclusion ◽

Stem Diameter Growth

Abstract. A large-scale replicated throughfall exclusion experiment was conducted in a pre-montane perhumid rainforest in Sulawesi (Indonesia) exposing the trees for two years to pronounced soil desiccation. The lack of regularly occurring dry periods and shallow rooting patterns distinguish this experiment from similar experiments conducted in the Amazonian rainforest. We tested the hypotheses that a tree's sun canopy is more affected by soil drought than its shade crown, making tall trees particularly vulnerable even under a perhumid climate, and that extended drought periods stimulate an acclimation in the hydraulic system of the sun canopy. In the abundant and tall tree species Castanopsis acuminatissima (Fagaceae), we compared 31 morphological, anatomical, hydraulic and chemical variables of leaves, branches and the stem together with stem diameter growth between drought and control plots. There was no evidence of canopy dieback. However, the drought treatment led to a 30 % reduction in sapwood-specific hydraulic conductivity of sun canopy branches, possibly caused by the formation of smaller vessels and/or vessel filling by tyloses. Drought caused an increase in leaf size, but a decrease in leaf number, and a reduction in foliar calcium content. The δ13C and δ18O signatures of sun canopy leaves gave no indication of a permanent down-regulation of stomatal conductance during the drought, indicating that pre-senescent leaf shedding may have improved the water status of the remaining leaves. Annual stem diameter growth decreased during the drought, while the density of wood in the recently produced xylem increased in both the stem and sun canopy branches (marginally significant). The sun canopy showed a more pronounced drought response than the shade crown indicating that tall trees with a large sun canopy are more vulnerable to drought stress. We conclude that the extended drought prompted a number of medium- to long-term responses in the leaves, branches and the trunk, which may have reduced drought susceptibility. However, unlike a natural drought, our drought simulation experiment was carried out under conditions of high humidity, which may have dampened drought induced damages.

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Long-term effects of stump removal and tree species composition on the diversity and structure of soil fungal communities

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa061 ◽

2020 ◽

Vol 96 (5) ◽

Author(s):

Dixi Modi ◽

Suzanne Simard ◽

Jean Bérubé ◽

Les Lavkulich ◽

Richard Hamelin ◽

...

Keyword(s):

Species Composition ◽

Fungal Community ◽

Tree Species ◽

Management Practice ◽

Tree Regeneration ◽

Root Disease ◽

Fungal Communities ◽

Tree Species Composition ◽

The Impact

ABSTRACT Stump removal is a common forest management practice used to reduce the mortality of trees affected by the fungal pathogen-mediated root disease, Armillaria root rot, but the impact of stumping on soil fungal community structure is not well understood. This study analyzed the long-term impact of stumping and tree species composition on the abundance, diversity and taxonomic composition of soil fungal communities using internal transcribed spacer (ITS) marker-based DNA metabarcoding in a 48-year-old trial at Skimikin, British Columbia. A total of 108 samples were collected from FH (fermented and humus layers), and soil mineral horizons (A and B) from stumped and unstumped plots of six tree species treatments (pure stands and admixtures of Douglas-fir, western red-cedar and paper birch). Fungal α-diversity in the A horizon significantly increased with stumping regardless of tree species composition, while β-diversity was significantly affected by stumping in all the horizons. We also observed that the relative abundance of the saprotrophic fungal community declined while that of the ectomycorrhizal fungal community increased with stumping. In conclusion, increase in ectomycorrhizal fungal associations, which are positively associated with tree productivity, suggests that stumping can be considered a good management practice for mitigating root disease and promoting tree regeneration.

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The Price Impact of Lending Relationships

German Economic Review ◽

10.1111/geer.12057 ◽

2015 ◽

Vol 16 (3) ◽

pp. 367-389 ◽

Cited By ~ 10

Author(s):

Ingrid Stein

Keyword(s):

Strong Relationship ◽

Price Impact ◽

Bank Debt ◽

Relationship Strength ◽

Borrowing Costs ◽

Lending Relationships ◽

Relationship Length ◽

The Impact ◽

Over Time

Abstract This study analyzes the impact of bank relationships on a firm’s borrowing costs. We find that a firm’s borrowing costs decrease with relationship strength, proxied by the share of bank debt provided by the lender. Borrowing costs, however, rise with relationship length. While the increase over time is weak on average, bank-dependent borrowers face a substantial premium after several relationship years. Switching the lender initially leads to only a small price discount on average. However, the discount is considerable for borrowers that switch and had a strong relationship with their previous lender. Our results suggest that close lending relationships lead to benefits for the firm, but may also imply hold-up costs in the long term.

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MORBIDITY BY TUBERCULOSIS IN THE JIU VALLEY: RELATION WITH DIAGNOSTIC PRACTICE AND THE IMPACT ON THERAPEUTIC RESULTS

Medicine and Pharmacy Reports ◽

10.15386/cjmed-649 ◽

2017 ◽

Vol 90 (1) ◽

pp. 49-53

Author(s):

Nicolae Petre ◽

Daniela Homorodean ◽

Carmen Monica Pop

Keyword(s):

Quality Of Life ◽

Life Style ◽

Strong Relationship ◽

Epidemiological Data ◽

Health State ◽

Tuberculous Disease ◽

Poor Area ◽

The Impact

Background and aim. In the last two and a half decades the dynamics of tuberculosis has been modelled by social and economic conditions, with consequences on the life style, and effects on the onset and evolution of the disease. The Jiu Valley is an area with social problems: mining, mines closing down and ceasing activity, poverty. We looked for a relationship between changes of life style in the Jiu Valley and the dynamics of tuberculosis.Methods. We studied 528 patients who asked for medical services in different hospitals in the Jiu Valley between 2010-2013. We structurally characterized this group, we identified the characteristics of life style, and we assessed the health state, in particular the relation with tuberculosis.Results. We found out that the quality of life was influenced by the health state, especially by tuberculous disease. Quality of life was influenced by the life style, professional factors and their long term consequences. The study evidenced a strong relationship between apparently very different factors such as life style, professional factors on one side and those characterizing tuberculosis.Conclusions. We report the first detailed epidemiological data on tuberculosis in an economically poor area, the Jiu Valley.

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The Impact of a Time Gap on the Process of Building a Sustainable Relationship between Employee and Customer Satisfaction

Sustainability ◽

10.3390/su12187446 ◽

2020 ◽

Vol 12 (18) ◽

pp. 7446

Author(s):

Lukasz Skowron ◽

Marcin Gąsior ◽

Monika Sak-Skowron

Keyword(s):

Customer Satisfaction ◽

Customer Service ◽

Strong Relationship ◽

Management Policy ◽

Time Shift ◽

Time Gap ◽

One Year ◽

The Impact ◽

The Relationship

The aim of this paper is to describe the relationships between changes in employee indices (motivation and satisfaction) and customer indices (satisfaction and loyalty) in a single- and multi-term perspective. The article presents the results of primary research conducted in two industries (banking services and shopping centers) during three annual reference periods. The authors used the PLS-SEM method in the analytical process. The results of the research suggest that there is a strong relationship between changes in the areas of employee and customer satisfaction in the studied sectors, with a one-year time shift, which the authors called the “time gap”. In addition, it turned out that the strength of influence of the employee’s motivation level on customers is clearly lower than the strength of influence of the employee satisfaction. The occurrence of a “time gap” between employee and customer processes suggests that any changes introduced in the area of customer service as well as broadly understood human resource management policy need some time to become sustainable—to be noticed by the market and coded in the minds of the recipients of the offer as the new and currently applicable standard. The article makes a successful attempt at a long-term analysis of the relationship between employees and customers, assuming a time delay between both phenomena. As a result of the conducted research, it was possible to operationalize the discussed relationship in terms of strength and direction as well as the time shift.

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Long-term changes in tree species composition in the Dinaric mountain forests of Slovenia

The Forestry Chronicle ◽

10.5558/tfc79227-2 ◽

2003 ◽

Vol 79 (2) ◽

pp. 227-232 ◽

Cited By ~ 27

Author(s):

Andrej Boncina ◽

Franc Gaspersic ◽

Jurij Diaci

Keyword(s):

Species Composition ◽

Tree Species ◽

European Beech ◽

Anthropogenic Factors ◽

Silver Fir ◽

Tree Species Composition ◽

Virgin Forest ◽

Forest Remnant ◽

The Impact

This study utilizes data from long-term research sites in managed fir-beech forests (Hrusica, Leskova dolina and Rog) and a virgin forest remnant (Rajhenav), used as a reference site. Data obtained from old forest management plans and forest inventories were analysed. The results of the study support the hypothesis that two main tree speciessilver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.)alternate site dominance. The causes of species dominance alternation include both natural processes and anthropogenic factors, in particular silvicultural practices and the impact of ungulates. More than a hundred years ago, European beech dominated stand volume. The proportion of silver fir increased until 19401970 when a gradual decrease started. All indicators suggest that the proportion of silver fir will decrease further in the coming decades. Key words: tree species composition alternation, diameter distribution, silver fir, European beech, forest history, forest planning, managed forests, virgin forest remnant

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Herbaria as Functional Trait Databases

Biodiversity Information Science and Standards ◽

10.3897/biss.2.25766 ◽

2018 ◽

Vol 2 ◽

pp. e25766 ◽

Cited By ~ 1

Author(s):

Sofie Meeus

Keyword(s):

Tree Species ◽

Functional Trait ◽

Climatic Conditions ◽

Congo Basin ◽

Forest Community ◽

Herbarium Specimens ◽

Water Losses ◽

Climatological Data ◽

The Impact

Although tropical rainforests play an important role in regulating the world’s climate, they are at the same time particularly vulnerable to changes in the climate. Intense and prolonged droughts, for instance, can lead to biomass loss which will further accelerate these changes. Especially for tree species it becomes problematic, due to their long lifespan, to quickly adapt to or evade unfavorable climatic conditions affecting the composition of the forest community as a whole and consequently the ecosystem services that the rainforests provide. A long-term drying trend currently threatens tropical regions worldwide but is especially strong in the central African rainforest, the second-largest rainforest on Earth. The impact of this decrease in precipitation on the vegetation is, however, still largely unknown due to the limited amount of historical eco-climatological data. Fortunately, these kind of data do exist albeit in a poorly accessible (analog) format in herbarium collections. To investigate if trees show changes in morphology and/or physiology invoked by climatic changes in the last century, the COBECORE team (Congo Basin Eco-Climatological Data Recovery and Valorization”) is exploring the usability of herbaria as potential sources of plant leaf functional trait data using established protocols adjusted to dried leaf material. Photosynthesis as well as gas exchange and transpiration are processes regulated by a plant’s leaves, and depend on the specific leaf area (SLA) and the number and size of the stomata. The less area the latter structures occupy on the leaf the less the plant will suffer from water losses which increases the resistance to drought of plants. We explored the recently digitized African Herbarium of the Botanic Garden Meise which contains over 1.2 million African specimens with a very good coverage of the Congo Basin, dating back to 1880. Currently, we obtained average SLA measurements for 833 herbarium specimens from 59 of the most common tree species of central African rainforests. Pictures for stomata counts and size measurements were taken from over one hundred specimens mainly focused on three Prioria species, giant tree species (up to 60 metres) currently suffering from overexploitation. The data generated in this project will be valuable to understand some lower-level vegetation responses such as plant water use needed to model and predict long-term climate change impacts on vegetation.

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Diversity of Tree Species in Gap Regeneration under Tropical Moist Semi-Deciduous Forest: An Example from Bia Tano Forest Reserve

Diversity ◽

10.3390/d12080301 ◽

2020 ◽

Vol 12 (8) ◽

pp. 301 ◽

Cited By ~ 2

Author(s):

Maame Esi Hammond ◽

Radek Pokorný

Keyword(s):

Tree Species ◽

Deciduous Forest ◽

Diversity Indices ◽

Iucn Red List ◽

Forest Reserve ◽

Ecological Benefits ◽

Gap Regeneration ◽

Disturbed Areas ◽

Biological Legacies

In a quest to improve the diversity and conservation of native tree species in tropical African forests, gap regeneration remains all-important nature-promoting silviculture practice and ecosystem-based strategy for attaining these ecological goals. Nine gaps of varying sizes (286–2005 m2) were randomly selected: three each from undisturbed, slightly disturbed and disturbed areas within Bia Tano Forest Reserve of Ghana. Within individual gaps, four transects (North–South–East–West directions) followed by 10 subsampling regions of 1 m2 at 2 m apart were established along each transect. Data showed 63 tree species from 21 families in the study. Although, all estimated diversity indices showed significant biodiversity improvements in all gaps at p < 0.05 level. Yet, there were no significant variations amongst gaps. Additionally, tree species differed between gaps at the undisturbed and the two disturbance-graded areas while no differences were presented between disturbance-graded areas. Balanced conservation between Green Star and Reddish Star species and imbalanced conservation between Least Concern, Near Threatened and Vulnerable species in the International Union for Conservation of Nature (IUCN) Red List were found, showing the reserve’s long-term prospects for economic and ecological benefits of forest management. Thus, there is a need for higher priority for intensive management to regulate various anthropogenic disturbances so as to protect the biological legacies of the reserve.

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