Water Relations of Mountain Ash (Eucalyptus regnans F. Muell.) Forests

1977 ◽  
Vol 4 (5) ◽  
pp. 753 ◽  
Author(s):  
DJ Connor ◽  
NJ Legge ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Vertical Gradient ◽  
Stomatal Resistance ◽  
Water Yield ◽  
Eucalyptus Regnans ◽  
Mature Forest ◽  
Mountain Ash ◽  
Static Head ◽  
Regrowth Forest ◽  
Made In

Measurements of the vertical gradients of water potential and stomatal resistance were made in adjacent mature and regrowth forests of mountain ash to follow diurnal and seasonal behaviour. The vertical gradient of water potential at dawn in either forest was shown to be consistent with the theoretical static head of -0.1 bar m-1 but the daytime gradients in the regrowth forest were steeper (down to - 0.45 bar m-1) than in the mature forest which did not fall below -0.27 bar m-1. Stomatal resistance measurements could not be related to height but, consistent with the water potential data, the leaves of the mature forest had higher resistance to water loss than did those of the regrowth. The observations are discussed in relation to the problems of water supply to the leaves of tall trees and the possible contribution of stomatal control to the established water yield characteristics of mountain ash forests.

Relating Water Potential Gradients in Mountain Ash (Eucalyptus regnans F. Muell.) To Transpiration Rate

1985 ◽  
Vol 12 (1) ◽  
pp. 89 ◽  
Author(s):  
NJ Legge
Keyword(s):  
Water Potential ◽  
Transpiration Rate ◽  
Vapour Pressure Deficit ◽  
Stem Water Potential ◽  
Sapwood Area ◽  
Eucalyptus Regnans ◽  
Tree Transpiration ◽  
Mountain Ash ◽  
Simple Tree

Osmotic tensiometers recording in situ stem water potential, Ψst, were implanted at two heights in the trunks of mountain ash (Eucalyptus regnans) in mature and 1939 regrowth forests. Measurements over one summer showed that Ψst gradients, obtained from the mean Ψst values at each height, reached over 50 kPa/m, with the diurnal maxima generally occurring between 1500 and 1600 h. When Ψst gradients were averaged over 24 h it was found that, unless temperatures were extremely high or the foliage was wet, the average diurnal gradient was linearly related to the average vapour pressure deficit. From this relationship the average diurnal gradient during two earlier summers was estimated to be 23 kPa/m. The forest transpiration rate during this time was estimated to be 4.1 mm/day and when these data, together with sapwood area data, were put into a simple tree transpiration model, the relative conductivity of the sapwood was found to be approximately 7.9 × 10-12 m2.

Some factors affecting water yield from mountain ash (Eucalyptus regnans) dominated forests in south-east Australia

1993 ◽  
Vol 150 (2-4) ◽  
pp. 345-367 ◽  
Author(s):  
M.D.A. Jayasuriya ◽  
G. Dunn ◽  
R. Benyon ◽  
P.J. O'Shaughnessy
Keyword(s):  
Water Yield ◽  
Eucalyptus Regnans ◽  
Factors Affecting ◽  
Mountain Ash

Does nitrogen limit the growth of native eucalypt forests:some observations for mountain ash (Eucalyptus regnans)

2001 ◽  
Vol 52 (1) ◽  
pp. 111 ◽  
Author(s):  
P. M. Attiwill ◽  
P. M. Attiwill ◽  
B. M. May ◽  
B. M. May
Keyword(s):  
N Availability ◽  
Ecological Research ◽  
Biological Fixation ◽  
Ecological Processes ◽  
Eucalyptus Regnans ◽  
Rate Of Growth ◽  
Wild Fire ◽  
N Supply ◽  
Eastern Australia ◽  
Mountain Ash

It is often stated that the availability of N limits the rate of growth of native forests. We discuss this hypothesis with particular reference to the mountain ash (Eucalyptus regnans) forests of south-eastern Australia. The abundance of 15 N in leaves and soil of mountain ash forest is in accord with data for Northern Hemisphere temperate forests and for tropical forests,and indicates that N availability is relatively high.None of the nutrient elements has limited the rate of growth of mountain ash forest regenerating after major disturbance (clear-felling and intense wild-fire). There is some evidence that P may be limiting to some ecological processes (e.g. the rate of litter decomposition). We conclude that phosphorus is more likely to be limiting than nitrogen in mountain ash forest because nitrogen cycling is conservative and continual inputs of N through biological fixation supplement this conservative N supply, and the stands never become N-deficient. The development of methodologies to determine the rate of N2-fixation in forests should be of high priority in ecological research.

Economics of a nest-box program for the conservation of an endangered species: a reappraisal

2001 ◽  
Vol 31 (11) ◽  
pp. 1992-2003 ◽  
Author(s):  
Daniel A Spring ◽  
Michael Bevers ◽  
John OS Kennedy ◽  
Dan Harley
Keyword(s):  
Net Present Value ◽  
Population Recovery ◽  
Optimal Management ◽  
Present Value ◽  
Eucalyptus Regnans ◽  
Nest Boxes ◽  
Mountain Ash ◽  
Local Abundance ◽  
Leadbeater's Possum

An optimization model is developed to identify timing and placement strategies for the installation of nest boxes and the harvesting of timber to meet joint timber–wildlife objectives. Optimal management regimes are determined on the basis of their impacts on the local abundance of a threatened species and net present value (NPV) and are identified for a range of NPV levels to identify production possibility frontiers for abundance and NPV. We apply the model to a case study focusing on an area of commercially productive mountain ash (Eucalyptus regnans F. Muell.) forest in the Central Highlands region of Victoria, Australia. The species to be conserved is Leadbeater's possum (Gymnobelideus leadbeateri McCoy), which is locally limited by a scarcity of nesting hollows. The modeling is exploratory but indicates that nest boxes may offer a promising population recovery tool if consideration is taken of their placement and areal extent through time.

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