A Post-fire Ecological Study of Xanthorrhoea australis Following Prescribed Burning in the Warby Range State Park, North-eastern Victoria, Australia

1998 ◽  
Vol 46 (2) ◽  
pp. 253 ◽  
Author(s):  
N. Peter Curtis
Keyword(s):  
Ecological Study ◽  
Prescribed Burning ◽  
Plant Density ◽  
Ground Cover ◽  
Ground Level ◽  
Adaptive Traits ◽  
High Soil Moisture ◽  
North Eastern ◽  
A Site

Xanthorrhoea australis R.Br. is considered a fire-tolerant species, a statement evidently based on established adaptive traits rather than fire recorded studies. This two-year post-fire study of X. australis in areas that have been subjected to prescribed burning in 1976 and 1991 compares results with a site unburnt for about 100 years. In the sites burnt in 1991, arborescent plants had a mortality of between 10% and 40% (average 21%), with highest mortality in the youngest and oldest plants, and in the site with the lowest plant density. In the site burnt in 1976, plants were still dying. Mortality of plants in the unburnt site was 4%. Flowering in the first post-fire spring varied from 0–100% throughout the size classes, with no flowering observed in plants smaller than 0.5 m. In the unburnt sites and the 1976 burnt sites, where understorey protected seedlings, recruitment was significantly higher (P < 0.001) than in the areas burnt in 1991 that had little ground cover. Plants with severe burn damage to stems at ground level often developed leans (P < 0.001) that were more often opposite to the burnt side (P < 0.001). Leans increased from 2.5˚ to 35˚, and some plants continued to grow, lying horizontally. In all fire sites the horizontal plants had a mortality of 44–92% compared with 29% for those in the unburnt site. In some sites, particularly in areas of high soil moisture, 3–10% of plants developed epicormic shoots after their stems fractured, or their shoot apices died. The study showed that fire has a long-term deleterious effect on large plants of this species. These data should be taken into account by authorities engaged in prescribed burning in forests with significant stands of this species.

scholarly journals Overview of a prescribed burning experiment within a boreal forest in Finland

2013 ◽  
Vol 13 (8) ◽  
pp. 21703-21763 ◽  
Author(s):  
A. Virkkula ◽  
J. Levula ◽  
T. Pohja ◽  
P. P. Aalto ◽  
P. Keronen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Radiative Forcing ◽  
Prescribed Burning ◽  
Geometric Mean ◽  
Sonic Anemometer ◽  
Ground Level ◽  
Organic Layer ◽  
Available Nitrogen ◽  
Mean Diameter

Abstract. A prescribed burning of a boreal forest was conducted on 26 June 2009 in Hyytiälä, Finland, to study aerosol and trace gas emissions from wildfires and the effects of fire on soil properties in a controlled environment. A 0.8 ha forest near the SMEAR II was cut clear; some tree trunks, all tree tops and branches were left on the ground and burned. The amount of burned organic material was ~46.8 t (i.e., ~60 t ha−1). The flaming phase lasted 2 h 15 min, the smoldering phase 3 h. Measurements were conducted on the ground with both fixed and mobile instrumentation, and from a research aircraft. In the middle of the burning area, CO2 concentration peaks were around 2000–3000 ppm above the baseline and peak vertical flow velocities were 6 ± 3 m s−1, as measured a 10-Hz 3-D sonic anemometer placed within the burn area. Peak particle number concentrations were approximately 1–2 × 106 cm−3 in the plume at a distance of 100–200 m from the burn area. The geometric mean diameter of the mode with the highest concentration was at 80 ± 1 nm during the flaming phase and in the middle of the smoldering phase but at the end of the smoldering phase the largest mode was at 122 nm. In the volume size distributions geometric mean diameter of the largest volume mode was at 153 nm during the flaming phase and at 300 nm during the smoldering phase. The lowest single-scattering albedo of the ground-level measurents was 0.7 in the flaming-phase plume and ~0.9 in the smoldering phase. The radiative forcing efficiency was negative above dark surfaces, in other words, the particles cool the atmosphere. Elevated concentrations of several VOCs (including acetonitrile which is a biomass burning marker) were observed in the smoke plume at ground level. The forest floor (i.e., richly organic layer of soil and debris, characteristic of forested land) measurements showed that VOC fluxes were generally low and consisted mainly of monoterpenes, but a clear peak of VOC flux was observed after the burning. After one year, the fluxes were nearly stabilised close to the level before the burning. The clearcutting and burning of slash increased the total long-term CO2 release from the soil, altered the soil's physical, chemical and biological properties such as increased the available nitrogen contents of the soil, which in turn, affected the level of the long-term fluxes of greenhouse gases.

The Need for a New Approach to Grazing Management - Is Cell Grazing the Answer?

1996 ◽  
Vol 18 (2) ◽  
pp. 327 ◽  
Author(s):  
JM Earl ◽  
CE Jones
Keyword(s):  
Ground Cover ◽  
Dry Weight ◽  
Grazing Pressure ◽  
Individual Plant ◽  
South Wales ◽  
Continuous Grazing ◽  
Adverse Environmental Conditions ◽  
The Stability ◽  
A Site

With any grazing method, the grazing pressure applied to an individual plant is a site, stock density and time dependent variable and the diet selection hierarchy of grazing animals is to the disadvantage of the most palatable and actively growing pasture components. The greater the differences in palatability and abundance among the components of a sward, and the lower the stock density, the greater the variation in the grazing pressure exerted. These effects are heightened when animals are set-stocked under adverse environmental conditions. This paper reports the comparative effects of cell grazing and continuous grazing on pasture composition on three properties on the Northern Tablelands of New South Wales. The basal diameters, relative frequency and contribution to dry weight of the most desirablelpalatable species at each site were found to remain constant or to increase under cell grazing, while declining significantly under continuous stocking. The converse was true for the least palatable components of the pasture, which declined significantly under cell grazing but changed little under continuous grazing. Percentage ground cover was significantly higher after two years of cell grazing than under continuous grazing. These changes in pasture composition may have long-term benefits with respect to erosion control, nutrient cycling, hydrological function and the stability of animal production at the cell grazed sites.

Hydrology of the Ythan Estuary With Reference to Distribution of Major Nutrients and Detritus

1971 ◽  
Vol 51 (1) ◽  
pp. 137-157 ◽  
Author(s):  
J. H. Leach
Keyword(s):  
Ecological Study ◽  
Trophic Levels ◽  
Environmental Data ◽  
North Eastern ◽  
Energy Relationships ◽  
Algal Productivity ◽  
Major Nutrients ◽  
Physical And Chemical ◽  
Shallow Estuaries

INTRODUCTIONA long-term ecological study is being carried out in the Ythan Estuary in north-eastern Scotland. An understanding of the hydrology of the estuary is a prerequisite for future studies into energy relationships in lower trophic levels of the food web. Much of current research into the estuarine environment is concerned with large coastal-plain systems where physical and chemical characteristics are so different from those of shallow estuaries, such as the Ythan, that comparisons of environmental data are untenable. The present investigation reports information collected between October 1966 and September 1968 on major environmental factors and their effect on the distribution of nutrients and detritus in the ecosystem. Results of a concomitant study of algal productivity in a mudflat of the estuary are reported in Leach (1970).

scholarly journals Yields and root technological quality of sugar beet grown in crop rotation and long-term monoculture

2011 ◽  
Vol 48 (No. 10) ◽  
pp. 458-462 ◽  
Author(s):  
B. Rychcik ◽  
K. Zawiślak
Keyword(s):  
Crop Rotation ◽  
Plant Density ◽  
Plant Protection ◽  
Sugar Yield ◽  
Unit Weight ◽  
North Eastern ◽  
Technological Quality ◽  
Field Static ◽  
Saccharose Content

The paper presents the findings of 6-year (1993&ndash;1998) investigations obtained in the field static experiment continued since 1967. This experiment concerned the estimation of the crop yield and its structure, and root technological quality under the conditions of crop rotation and extreme shortening of the rotation, i.e. monoculture. Investigations have proved that under agroclimatic conditions of north-eastern Poland it is possible to obtain 60 t of roots per ha in a&nbsp;naturally correct crop rotation, while in a&nbsp;long-term monoculture &ndash; 33 t, and 36 t and 19 t of top, respectively. The differences in monoculture crops occurred as a&nbsp;result of a&nbsp;plant loss during germination by 5.6%, and a&nbsp;smaller unit weight per root by 41.6%. The applied procedures of plant protection by herbicides and fungicides improved the root and top crop and favored the maintenance of plant density. A&nbsp;lowering of saccharose content in roots from 15.7% in the crop rotation to 15.0% in monoculture was recorded, and of sugar yield in the technological process from 13.0 to 12.3%, respectively. A&nbsp;high white sugar yield was obtained in crop rotation &ndash; 7.89 t per ha, while in monoculture it was only 4.06 t, i.e. 48.5% less.

scholarly journals Prescribed burning of logging slash in the boreal forest of Finland: emissions and effects on meteorological quantities and soil properties

2014 ◽  
Vol 14 (9) ◽  
pp. 4473-4502 ◽  
Author(s):  
A. Virkkula ◽  
J. Levula ◽  
T. Pohja ◽  
P. P. Aalto ◽  
P. Keronen ◽  
...  
Keyword(s):  
Soil Properties ◽  
Prescribed Burning ◽  
Geometric Mean ◽  
Sonic Anemometer ◽  
Ground Level ◽  
Organic Layer ◽  
Available Nitrogen ◽  
Clear Cutting ◽  
Mean Diameter

Abstract. A prescribed fire experiment was conducted on 26 June 2009 in Hyytiälä, Finland, to study aerosol and trace gas emissions from prescribed fires of slash fuels and the effects of fire on soil properties in a controlled environment. A 0.8 ha forest near the SMEAR II measurement station (Station for Measuring Ecosystem-Atmosphere Relations) was cut clear; some tree trunks, all tree tops and branches were left on the ground and burned. The amount of burned organic material was ~46.8 tons (i.e., ~60 tons ha−1). The flaming phase lasted 2 h 15 min, the smoldering phase 3 h. Measurements were conducted on the ground with both fixed and mobile instrumentation, and in the air from a research aircraft. In the middle of the burning area, CO2 concentration peaked around 2000–3000 ppm above the baseline, and peak vertical flow velocities were ~9 m s−1, as measured with a 10 Hz 3-D sonic anemometer placed within the burn area. In the mobile measurements the peak particle number concentrations were approximately 1–2 × 106 cm−3 in the plume at a distance of 100–200 m from the burn area. On the ground at the SMEAR II station the geometric mean diameter of the mode with the highest concentration was 80 ± 1 nm during the flaming phase and in the middle of the smoldering phase, but, at the end of the smoldering phase, the largest mode was 122 nm. In the volume size distributions, geometric mean diameter of the largest volume mode was 153 nm during the flaming phase and 300 nm during the smoldering phase. The lowest single-scattering albedo of the ground-level measurements was 0.7 in the flaming-phase plume and ~0.9 in the smoldering phase. Elevated concentrations of several volatile organic compounds (VOC) (including acetonitrile, a biomass burning marker) were observed in the smoke plume at ground level. Measurements at the forest floor (i.e., a richly organic layer of soil and debris, characteristic of forested land) showed that VOC fluxes were generally low and consisted mainly of monoterpenes, and VOC flux peaked after the burning. After one year, the fluxes had nearly stabilized close to the level before the burning. The clear-cutting and burning of slash increased the total long-term CO2 release from the soil, and altered the physical, chemical and biological properties of the soil, such as increased the available nitrogen contents of the soil, which in turn, affected the long-term fluxes of greenhouse gases.

scholarly journals Microhabitat Associations for the Threatened Cheat Mountain Salamander in Relation to Early-stage Red Spruce Restoration Areas

2022 ◽  
Author(s):  
Donald J Brown ◽  
Lacy E. Rucker ◽  
Catherine Johnson ◽  
Shane Jones ◽  
Thomas K. Pauley
Keyword(s):  
Soil Moisture ◽  
Air Temperature ◽  
Soil Ph ◽  
Early Stage ◽  
Canopy Cover ◽  
Ground Level ◽  
Red Spruce ◽  
High Soil Moisture ◽  
Central Appalachia

The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal non-detection sites. We found that soil pH was higher and soil moisture was lower at spruce restoration sites compared to the occupied site, and that light intensity, sub-canopy air temperature, and ground-level air temperature were higher in spruce restoration prescriptions with reduced canopy cover. We found that soil moisture was higher at occupied sites compared to proximal non-detection sites, but soil pH was not significantly different. Our study suggests that Cheat Mountain salamanders are associated with low soil pH and high soil moisture, and thus spruce restoration could enhance habitat quality for this species in the long-term.

Long-term Performance of Asian Pear Trees in Maryland

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 548b-548
Author(s):  
C.S. Walsh ◽  
A.J. Barton ◽  
M. Newell ◽  
G.R. Welsh
Keyword(s):  
Ground Cover ◽  
Organic Production ◽  
Alternative Crop ◽  
Asian Pear ◽  
Marketable Fruit ◽  
Long Term Performance ◽  
Organic Fruit ◽  
Term Performance ◽  
Direct Market

Three Asian pear plantings were set during the past decade. Plantings included an initial cultivar planting on OH × F rootstock, the SE Zonal planting, and a rootstock by cultivar factorial. Fireblight susceptibility and survival were assessed in the first two plantings following a summer hailstorm. Trees were compared to Magness, a blight-tolerant buttery pear. Shin Li, Daisu Li, Shinsui, and Olympic were more resistant than Magness, while Chojuro and Niitaka were nearly as tolerant. Eleven other cultivars showed greater field-susceptibility. The most-susceptible cultivars were Ya Li and Ts'e Li. The third planting, which was managed “organically,” was set at a different University farm. Trees there were precocious and productive. A high percentage of marketable fruit was picked from that planting over a 4-year period. Fireblight damage in this planting was low, despite its “organic” production. Limited damage was attributed to early bloom date, ground cover management, and a lack of insect vectors to transmit the bacteria. Hosui, Seuri and Ts'e Li produced large-sized fruit. Shinko, 20th Century, Ya Li and Shinseiki fruit were too small to be marketable without heavy hand-thinning. Asian pears are an interesting alternative crop which are suited to direct-market enterprises or to specialty growers interested in producing organic fruit in the mid-Atlantic region.

Problems of the modern society and ethnic separatism in North-Eastern India (NER)

2019 ◽  
Vol 11 (4) ◽  
pp. 315-328
Author(s):  
Sergey Aleksandrovich Mikhailov
Keyword(s):  
Modern Society ◽  
New Delhi ◽  
Eastern India ◽  
Key Factors ◽  
Indian Government ◽  
Systematic Analysis ◽  
Resource Search ◽  
North Eastern ◽  
North Eastern India

This article deals with the issue of North-Eastern India, its current social and economic problems in the context of long-term demonstrations of the ethnic separatism. The main aim of the research implies systematic analysis and identification of key factors and reasons perpetuating separatism in NER as well as resource search which determines Indian strategy in solving this problem. The first part of the article is devoted to separatism peculiarities in the region which remains withdrawn and underexplored in many respects. Apart from this, the author provides a quite detailed analysis of negative mentality of the certain part of NER population which justifiably reproaches New Delhi for “discrimination” and inability to solve many problems of the region. Then the author paid the detailed attention to these problems of NER modern society (ethnic, demographic, economic, transport, social etc.) as well as measures undertaken by the Indian government for its settlement.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

Time-Dependent Changes in Excitability After One-Trial Conditioning of Hermissenda

1997 ◽  
Vol 78 (6) ◽  
pp. 3460-3464 ◽  
Author(s):  
Terry Crow ◽  
Vilma Siddiqi
Keyword(s):  
Time Dependent ◽  
Control Group ◽  
Type B ◽  
Control Groups ◽  
Phototactic Behavior ◽  
Parallel Processes ◽  
Short And Long Term ◽  
A Site ◽  
Different Levels

Crow, Terry and Vilma Siddiqi. Time-dependent changes in excitability after one-trial conditioning of Hermissenda. J. Neurophysiol. 78: 3460–3464, 1997. The visual system of Hermissenda has been studied extensively as a site of cellular plasticity produced by classical conditioning. A one-trial conditioning procedure consisting of light paired with the application of serotonin (5-HT) to the exposed, but otherwise intact, nervous system produces suppression of phototactic behavior tested 24 h after conditioning. Short- and long-term enhancement (STE and LTE) of excitability in identified type B photoreceptors is a cellular correlate of one-trial conditioning. LTE can be expressed in the absence of STE suggesting that STE and LTE may be parallel processes. To examine the development of enhancement, we studied its time-dependent alterations after one-trial conditioning. Intracellular recordings from identified type B photoreceptors of independent groups collected at different times after conditioning revealed that enhanced excitability follows a biphasic pattern in its development. The analysis of spikes elicited by 2 and 30 s extrinsic current pulses at different levels of depolarization showed that enhancement reached a peak 3 h after conditioning. From its peak, excitability decreased toward baseline control levels 5–6 h after conditioning followed by an increase to a stable plateau at 16 to 24 h postconditioning. Excitability changes measured in cells from unpaired control groups showed maximal changes 1 h posttreatment that rapidly decremented within 2 h. The conditioned stimulus (CS) elicited significantly more spikes 24 h postconditioning for the conditioned group as compared with the unpaired control group. The analysis of the time-dependent development of enhancement may reveal the processes underlying different stages of memory for this associative experience.

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