Effects of the frequency, timing, and intensity of simulated browsing on growth and mortality of tree seedlings

1994 ◽  
Vol 24 (4) ◽  
pp. 817-825 ◽  
Author(s):  
Charles D. Canham ◽  
Jay B McAninch ◽  
David M. Wood
Keyword(s):  
New York ◽  
Tree Species ◽  
Experimental Tests ◽  
Light Level ◽  
Early Summer ◽  
Tree Seedlings ◽  
Negative Effects ◽  
Growth And Survival ◽  
Wide Range ◽  
Simulated Browsing

Field exclosure studies have shown that mammalian browsers such as white-tailed deer (Odocoileusvirginianus) can have pervasive effects on forest dynamics in eastern North America. Direct experimental tests of the effects of browsing on growth and survival of a wide range of tree species, however, have yielded conflicting results. This study was designed to assess the effects of variation in the frequency, seasonal timing, and intensity of browsing (simulated by mechanical clipping) on the growth and mortality of three of the major tree species of the Hudson Valley, New York. The clipping treatments were applied to seedlings grown under two different light regimes (full sun and 8% of full sun) to examine seedling responses under different levels of shade-induced carbon stress. Our results demonstrate that even 2 successive years of heavy winter clipping (75% of new shoot growth removed) has little immediate effect on growth or survival of any of the three species. It is possible that winter browsing only has significant negative effects when seedlings are browsed repeatedly over long periods of time. However, comparable levels of summer browsing for only 2 years significantly reduced both growth and survival of all three species. While most natural browsing occurs in the dormant season, our results suggest that it is the less frequent browsing during late spring and early summer that has the greatest immediate effect on tree seedlings. Shading reduced growth and increased mortality in all three species; however, there was only a limited interaction between light level and the simulated browsing treatments. The effects of browsing on survival were similar in all three species; however, the effects of browsing on cumulative height and annual growth varied enough among the species to suggest that browsing could cause significant variation among these species in their rate of invasion in old fields and rights of way, and their rate of regeneration following logging or disturbance of forests.

Strong competitive effects of African savanna C4 grasses on tree seedlings do not support rooting differentiation

2018 ◽  
Vol 34 (1) ◽  
pp. 65-73
Author(s):  
Benjamin L. Ketter ◽  
Ricardo M. Holdo
Keyword(s):  
Tree Species ◽  
Interspecific Variation ◽  
Rooting Depth ◽  
Tree Seedlings ◽  
Negative Effects ◽  
Competitive Response ◽  
African Savanna ◽  
University Of Missouri ◽  
Competitive Effects ◽  
Irrigation Depth

Abstract:Rooting differentiation between established trees and grasses has been well documented in savannas, but it remains unclear to what extent tree-grass rooting differences affect competition between newly established seedlings and grasses. To examine this question, a greenhouse experiment was conducted at the University of Missouri, USA. Twenty 3-mo-old seedlings each of two African savanna tree species (Acacia nigrescens and Colophospermum mopane) were grown for 8 mo with two crossed factors: grass competition and irrigation depth. Strong negative effects of grass competition on final seedling biomass and leaf photosynthetic and stomatal conductance occurred in both tree species, but no effects of irrigation depth were detected. There was a clear tree species by grass competition interaction, suggesting interspecific variation in competitive response. The results emphasize the importance of below-ground competition with grasses for physiological and morphological responses of tree seedlings, while minimizing the importance of tree-grass rooting depth differences as a factor in modulating the competitive response of trees to grasses at the seedling stage.

Trade-offs between growth and survival of non-pioneer light-demanding tree seedlings in tropical forest of Hainan Island, China

2011 ◽  
Vol 27 (6) ◽  
pp. 611-620 ◽  
Author(s):  
Wenjie Yang ◽  
Fude Liu ◽  
Lingyan Zhou ◽  
Shiting Zhang ◽  
Shuqing An
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Tree Species ◽  
Seed Mass ◽  
High Light ◽  
Tree Seedlings ◽  
Low Light ◽  
Relative Growth ◽  
Growth And Survival ◽  
Light Levels

Abstract:We performed a pot experiment in which 540 seedlings of nine non-pioneer light-demanding tree species were grown for 12 months in shade houses at three light levels, 46% daylight, 13% daylight and 2% daylight, to examine the mechanisms contributing to the coexistence of seedlings of non-pioneer light-demanding tree species in secondary successional tropical rain forest in Hainan, China. Growth and survival of tree seedlings were compared at different light levels, and the morphological and physiological correlates of high-light seedling growth and low-light survival across species were determined. For all species, mortality was very low in the 46% daylight and 13% daylight treatment but increased significantly in the 2% daylight treatment. Seedling survival in 2% daylight treatment was positively related to seed mass. Trade-off between high-light growth and low-light survival was more evident in the relationship with 2% daylight treatment as compared with 13% daylight treatment. Relative growth rate in the 2% daylight treatment was not significantly related to relative growth rate in the 13% daylight or 46% daylight treatment; although a slight negative correlation was apparent. Interspecific variation in RGRm was only closely correlated with net assimilation rate (NAR). The results provide some support for the niche-partitioning hypothesis.

Biscogniauxia (Hypoxylon) Canker or Dieback in Trees

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Claudia Paez ◽  
Jason A. Smith
Keyword(s):  
Water Stress ◽  
Tree Species ◽  
Soil Compaction ◽  
Urban Areas ◽  
Root Disease ◽  
Poor Health ◽  
Green Spaces ◽  
Opportunistic Pathogens ◽  
Wide Range ◽  
Quercus Spp

Biscogniauxia canker or dieback (formerly called Hypoxylon canker or dieback) is a common contributor to poor health and decay in a wide range of tree species (Balbalian & Henn 2014). This disease is caused by several species of fungi in the genus Biscogniauxia (formerly Hypoxylon). B. atropunctata or B. mediterranea are usually the species found on Quercus spp. and other hosts in Florida, affecting trees growing in many different habitats, such as forests, parks, green spaces and urban areas (McBride & Appel, 2009).  Typically, species of Biscogniauxia are opportunistic pathogens that do not affect healthy and vigorous trees; some species are more virulent than others. However, once they infect trees under stress (water stress, root disease, soil compaction, construction damage etc.) they can quickly colonize the host. Once a tree is infected and fruiting structures of the fungus are evident, the tree is not likely to survive especially if the infection is in the tree's trunk (Anderson et al., 1995).

Brief history and ways of further development of the department of hydraulic engineering and hydraulics FSBI «VNIIGiM named after A.N. Kostyakov»

2020 ◽  
pp. 18-23
Author(s):  
Alexey Shcherbakov ◽  
Valentin Zhezmer
Keyword(s):  
Land Reclamation ◽  
Water Source ◽  
Water Sources ◽  
Hydraulic Engineering ◽  
Negative Effects ◽  
Extensive Experience ◽  
Safety Level ◽  
Theoretical Substantiation ◽  
Wide Range ◽  
Construction Operation

Department of hydraulic engineering and hydraulics FGBNU «VNIIGiM them. A.N. Kostyakova «has a long history. For many years, the department’s staff has been such scientists and water engineers with extensive experience as M.A. Volynov, V.S. Verbitsky, S.S. Medvedev, N.V. Lebedev, B.C. Panfilov, T.G. Voynich-Syanozhentsky, V.A. Golubkova, G.V. Lyapin and others. The department solved a wide range of tasks, the main areas of research were the following: – theoretical and applied hydrodynamics and hydraulics, with reference to the open channel flows that affect the state and level of safety of the hydraulic structures; – integrated use and protection of water bodies – water sources and water sources of water resources used in land reclamation; – development of measures and technical solutions for the protection of objects from the negative effects of water; – theoretical substantiation of works to improve the safety level of the GTS (declaration); – development and implementation of digitalization methods for solving design, construction, operation and control of landreclamation facilities. Currently, promising areas of research is the development of a decision-making algorithm in the designation of measures to rationalize the provision of resources to water amelioration. The algorithm is developed on the basis of a detailed study, systematization and processing of data both on safety and on the efficiency of systems and structures, ensuring the delivery of irrigation water of the required quality and in sufficient quantity from a water source to the field.

OCCURRENCE OF THE RISKS FOR DEVELOPMENT OF RESPIRATORY DISEASES IN CHILDREN EXPOSED TO THE CHEMICAL FACTORS OF THE EXPOSURE OF ALUMINA REFINERY- ASSOCIATED BUSINESS ACTIVITY

2019 ◽  
pp. 42-47 ◽  
Author(s):  
M.A. Zemlianova ◽  
I.V. Tikhonova
Keyword(s):  
Respiratory Tract ◽  
Respiratory Diseases ◽  
Inflammatory Diseases ◽  
Allergic Inflammation ◽  
Respiratory Morbidity ◽  
Upper Respiratory Tract ◽  
Negative Effects ◽  
Wide Range ◽  
Chemical Factors ◽  
Chronic Lymphoproliferative Diseases

Alumina refineries are among the leading sources of atmospheric air pollution with a wide range of pollutants hazardous to human respiratory organs. It is relevant to study and evaluate the occurrence of the risks for development of respiratory diseases in children living in the area affected by the emission components of an alumina refinery. We assessed air quality of the area under observation and comparison according to monitoring observations, risk of non-carcinogenic effects from the respiratory organs. The content of chemicals in the blood and urine adequate to risk factors was quantified. The structure of individual groups of respiratory diseases was analyzed. The causal relationships of violations of laboratory parameters with an increased content of chemicals in biological media were evaluated. It was found that an aerogenic exposure of chemical pollutants is formed on the territory with the production of metallurgical alumina. It determines the risk for development of respiratory diseases, exceeding an acceptable level up to 49.9 times. In the exposed children, the content of manganese, chromium, nickel, copper, xylenes, formaldehyde and aluminum, fluoride ion in the urine was increased to 4.2 times in relation to the indices in the comparison group. A high level of additional respiratory morbidity(1.8 times) was revealed. Chronic lymphoproliferative diseases of the nasopharynx and inflammatory diseases of the upper respiratory tract (up to 6.6 times more often), inflammatory diseases with a predominance of the mechanism of allergic inflammation ( up to 2.1 times more often)are more often detected in the framework of the respiratory diseases. Negative effects on the part of the respiratory system in the form of activation of antioxidant processes, the development of an inflammatory reaction, local, general and specific sensitization of the respiratory tract were established. It confirms the occurrence of the risks for the development of respiratory diseases in children in the exposure area of the chemical factors of alumina refinery-associated economic activity.

Charles Olson and American Modernism

2018 ◽  
Author(s):  
Mark Byers
Keyword(s):  
New York ◽  
Political Action ◽  
The Self ◽  
Instrumental Reason ◽  
Charles Olson ◽  
American Modernism ◽  
Avant Garde ◽  
Wide Range ◽  
American Poet ◽  
Mark Rothko

The Practice of the Self situates the work of American poet Charles Olson (1910–70) at the centre of the early postwar American avant-garde. It shows Olson to have been one of the major advocates and theorists of American modernism in the late 1940s and early 1950s; a poet who responded fully and variously to the political, ethical, and aesthetic urgencies driving innovation across contemporary American art. Reading Olson’s work alongside that of contemporaries associated with the New York Schools of painting and music (as well as the exiled Frankfurt School), the book draws on Olson’s published and unpublished writings to establish an original account of early postwar American modernism. The development of Olson’s work is seen to illustrate two primary drivers of formal innovation in the period: the evolution of a new model of political action pivoting around the radical individual and, relatedly, a powerful new critique of instrumental reason and the Enlightenment tradition. Drawing on extensive archival research and featuring readings of a wide range of artists—including, prominently, Barnett Newman, Mark Rothko, David Smith, Wolfgang Paalen, and John Cage—The Practice of the Self offers a new reading of a major American poet and an original account of the emergence of postwar American modernism.

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

scholarly journals Responses to Ecopollutants and Pathogenization Risks of Saprotrophic Rhodococcus Species

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 974
Author(s):  
Irina B. Ivshina ◽  
Maria S. Kuyukina ◽  
Anastasiia V. Krivoruchko ◽  
Elena A. Tyumina
Keyword(s):  
Survival Strategies ◽  
Complex Life Cycle ◽  
Anthropogenic Pressure ◽  
Resting Cells ◽  
Organic Substrates ◽  
Negative Effects ◽  
Anthropogenic Pollutants ◽  
Rhodococcus Species ◽  
Wide Range ◽  
Rigid Cell Wall

Under conditions of increasing environmental pollution, true saprophytes are capable of changing their survival strategies and demonstrating certain pathogenicity factors. Actinobacteria of the genus Rhodococcus, typical soil and aquatic biotope inhabitants, are characterized by high ecological plasticity and a wide range of oxidized organic substrates, including hydrocarbons and their derivatives. Their cell adaptations, such as the ability of adhering and colonizing surfaces, a complex life cycle, formation of resting cells and capsule-like structures, diauxotrophy, and a rigid cell wall, developed against the negative effects of anthropogenic pollutants are discussed and the risks of possible pathogenization of free-living saprotrophic Rhodococcus species are proposed. Due to universal adaptation features, Rhodococcus species are among the candidates, if further anthropogenic pressure increases, to move into the group of potentially pathogenic organisms with “unprofessional” parasitism, and to join an expanding list of infectious agents as facultative or occasional parasites.

scholarly journals Wolbachia: endosymbiont of onchocercid nematodes and their vectors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ranju Ravindran Santhakumari Manoj ◽  
Maria Stefania Latrofa ◽  
Sara Epis ◽  
Domenico Otranto
Keyword(s):  
Control Strategies ◽  
Molecular Data ◽  
Scientific Data ◽  
Growth And Survival ◽  
Vector Borne Diseases ◽  
Wide Range ◽  
Veterinary Importance ◽  
Wolbachia Endosymbiont ◽  
Vector Borne ◽  
And Control

Abstract Background Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. Methods This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. Conclusions The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases. Graphic Abstract

scholarly journals Effects of Temperature on Anoplophora chinensis (Coleoptera: Cerambycidae) Adult Survival, Reproduction, and Egg Hatch

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 432 ◽  
Author(s):  
Melody A. Keena ◽  
Paul M. Moore ◽  
Gregg Bradford
Keyword(s):  
Invasive Species ◽  
Tree Species ◽  
Adult Survival ◽  
Optimum Temperature ◽  
Egg Hatch ◽  
Laboratory Conditions ◽  
Wide Range ◽  
Survival And Reproduction ◽  
Summer Temperatures ◽  
Effects Of Temperature

Anoplophora chinensis (Forster) is an invasive species that can damage many tree species in orchard, urban, and forested habitats. Adult survival, reproduction, and egg hatch of A. chinensis from Italy and China are evaluated at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40 °C) under laboratory conditions. The estimated Tmax for longevity was 42 and 33 °C for females and 42 and 39 °C for males from China and Italy, respectively. The estimated Tmax, Tmin, and optimum temperature for fecundity were 35, 9, and 29 °C, respectively. Females laid eggs at 15–30 °C and eggs hatched at 15–35 °C. Days to first oviposition increased exponentially from 13 days at 30 °C to >300 days near 10 °C. The estimated Tmin for egg hatch was 13 °C, the Tmax at 38 °C, and the optimum 29 °C. Percentage hatch was estimated to be highest at 26 °C and have a Tmax of 31 °C and Tmin of 10 °C. These results indicate that summer temperatures over a wide range of latitudes should support beetle survival and reproduction, but at temperatures ≥35 °C, oviposition ceases, and adult survivorship declines. In addition, females may survive into the fall, but lay fewer eggs that may not hatch. These responses of A. chinensis to temperature can be used for developing phenological models to predict the timing of stages for management or eradication efforts.

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