Estimating the time since fire of long-unburnt Eucalyptus salubris (Myrtaceae) stands in the Great Western Woodlands

2013 ◽  
Vol 61 (1) ◽  
pp. 11 ◽  
Author(s):  
Carl R. Gosper ◽  
Suzanne M. Prober ◽  
Colin J. Yates ◽  
Georg Wiehl
Keyword(s):  
Plant Height ◽  
Growth Ring ◽  
Plant Size ◽  
Current Approach ◽  
Significant Advance ◽  
Growth Rings ◽  
Trunk Diameter ◽  
Class Distribution ◽  
Age Class ◽  
Time Since Fire

Establishing the time since fire in infrequently burnt, yet fire-prone, communities is a significant challenge. Until this can be resolved for >50-year timeframes, our capacity to understand important ecological processes, such as the periods required for development of habitat features, will remain limited. We characterised the relationship between observable tree growth rings, plant age and plant size in Eucalyptus salubris F.Muell. in the globally significant Great Western Woodlands in south-western Australia. In the context of recent concerns regarding high woodland fire occurrence, we then used this approach to estimate the age of long-unburnt E. salubris stands, and the age-class distribution of Eucalyptus woodlands across the region. Time since fire was strongly predicted by trunk growth rings and plant size predicted growth rings with reasonable accuracy. The best model estimating growth rings contained parameters for trunk diameter, plant height and plot location, although simple models including either trunk diameter or plant height were nearly as good. Using growth ring–size relationships to date long-unburnt stands represents a significant advance over the current approach based on satellite imagery, which substantially truncates post-fire age. However, there was significant uncertainty over the best model form for estimating the time since fire of stands last burnt over 200 years ago. The management implications of predicted age-class distributions were highly dependent on both the choice of what, if any, transformation was applied to growth rings, and the theoretical age-class distribution to which the actual age-class distribution was compared.

Ageing mallee eucalypt vegetation after fire: insights for successional trajectories in semi-arid mallee ecosystems

2010 ◽  
Vol 58 (5) ◽  
pp. 363 ◽  
Author(s):  
Michael F. Clarke ◽  
Sarah C. Avitabile ◽  
Lauren Brown ◽  
Kate E. Callister ◽  
Angie Haslem ◽  
...  
Keyword(s):  
Fire History ◽  
Food Sources ◽  
Validation Data ◽  
Class Distribution ◽  
Age Class ◽  
Ecological Features ◽  
Time Since Fire ◽  
The Status ◽  
Minimum Age ◽  
Semi Arid

A critical requirement in the ecological management of fire is knowledge of the age-class distribution of the vegetation. Such knowledge is important because it underpins the distribution of ecological features important to plants and animals including retreat sites, food sources and foraging microhabitats. However, in many regions, knowledge of the age-class distribution of vegetation is severely constrained by the limited data available on fire history. Much fire-history mapping is restricted to post-1972 fires, following satellite imagery becoming widely available. To investigate fire history in the semi-arid Murray Mallee region in southern Australia, we developed regression models for six species of mallee eucalypt (Eucalyptus oleosa F.Muell. ex. Miq. subsp. oleosa, E. leptophylla F.Muell. ex. Miq., E. dumosa J. Oxley, E. costata subsp. murrayana L. A. S. Johnson & K. D. Hill, E. gracilis F.Muell. and E. socialis F.Muell. ex. Miq.) to quantify the relationship between mean stem diameter and stem age (indicated by fire-year) at sites of known time since fire. We then used these models to predict mean stem age, and thus infer fire-year, for sites where the time since fire was not known. Validation of the models with independent data revealed a highly significant correlation between the actual and predicted time since fire (r = 0.71, P < 0.001, n = 88), confirming the utility of this method for ageing stands of mallee eucalypt vegetation. Validation data suggest the models provide a conservative estimate of the age of a site (i.e. they may under-estimate the minimum age of sites >35 years since fire). Nevertheless, this approach enables examination of post-fire chronosequences in semi-arid mallee ecosystems to be extended from 35 years post-fire to over 100 years. The predicted ages identified for mallee stands imply a need for redefining what is meant by ‘old-growth’ mallee, and challenges current perceptions of an over-abundance of ‘long-unburnt’ mallee vegetation. Given the strong influence of fire on semi-arid mallee vegetation, this approach offers the potential for a better understanding of long-term successional dynamics and the status of biota in an ecosystem that encompasses more than 250 000 km2 of southern Australia.

Distribution of juvenile wood in two stems of Larixlaricina

1986 ◽  
Vol 16 (5) ◽  
pp. 1041-1049 ◽  
Author(s):  
K. C. Yang ◽  
C. A. Benson ◽  
J. K. Wong
Keyword(s):  
Juvenile Wood ◽  
Growth Ring ◽  
Ring Width ◽  
Tree Level ◽  
Growth Rings ◽  
Vertical Variation ◽  
Strong Negative Correlation ◽  
Ring Number ◽  
Tracheid Length ◽  
Growth Ring Width

The distribution and vertical variation of juvenile wood was studied in an 81-year-old dominant tree and an 83-year-old suppressed tree of Larixlaricina (Du Roi) K. Koch. Two criteria, growth ring width and tracheid length, were used to demarcate the boundary of juvenile wood. The width of juvenile wood, expressed in centimetres and the number of growth rings, decreased noticeably from the base to the top of the tree. The volume of juvenile wood decreased in a similar pattern. These decreasing trends had a strong negative correlation with the year of formation of cambial initials at a given tree level. The length of these cambial initials decreased with increasing age of formation of the cambial initials. In the juvenile wood zone, there was a positive linear regression between the growth ring number (age) and the tracheid length. The slopes of these regression lines at various tree levels increased as the age of the year of formation of the cambial initials increased. At a given tree level, the length of tracheids increased from the pith to a more uniform length near the bark. However, the number of years needed to attain a more uniform tracheid length decreased from the base to the top of the tree. These relationships suggest that the formation of juvenile wood is related to the year of formation of the cambial initials. Consequently, the juvenile wood is conical in shape, tapering towards the tree top.

Plant height and height of the main ear in maize (Zea mays L.) at different locations and different plant densities

2002 ◽  
Vol 50 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Z. Gyenes-Hegyi ◽  
I. Pók ◽  
L. Kizmus ◽  
Keyword(s):  
Plant Height ◽  
Plant Density ◽  
Close Correlation ◽  
Plant Size ◽  
Considerable Effect ◽  
Maximum Height ◽  
The Best Approximation ◽  
Significant Difference ◽  
Plant Densities ◽  
Ear Height

The plant height and the height of the main ear were studied over two years in twelve single cross maize hybrids sown at three different plant densities (45, 65 and 85 thousand plants/ha) at five locations in Hungary (Keszthely, Gönc, Gyöngyös, Sopronhorpács, Martonvásár). The results revealed that plant height and the height of the main ear are important variety traits and are in close correlation with each other. It was found that the hybrids grew the tallest when the genetic distance between the parental components was greatest (Mv 4, Mv 5). The height of the main ear was also the greatest in these hybrids, and the degree of heterosis was highest (193% for plant height, 194% for the height of the main ear). The shortest hybrids were those developed between related lines (Mv 7, Mv 11). In this case the heterosis effect was the lowest for both plant height (128%) and the height of the main ear (144%). The ratio of the height of the main ear to the plant height was stable, showing little variation between the hybrids (37–44%). As maize is of tropical origin it grows best in a humid, warm, sunny climate. Among the locations tested, the Keszthely site gave the best approximation to these conditions, and it was here that the maize grew tallest. The dry, warm weather in Gyöngyös stunted the development of the plants, which were the shortest at this location. Plant density had an influence on the plant size. The plants were shortest when sown at a plant density of 45,000 plants/ha, and the main ears were situated the lowest in this case. At all the locations the plant and main ear height rose when the plant density was increased to 65,000 plants/ha. At two sites (Gönc and Sopronhorpács) the plants attained their maximum height at the greatest plant density (85,000 plants/ha). In Keszthely there was no significant difference between these two characters at plant densities of 65 and 85 thousand plants/ha, while in Gyöngyös and Martonvásár the greatest plant density led to a decrease in the plant and main ear height. The year had a considerable effect on the characters tested.

scholarly journals Jahrringe als Indikatoren für extreme Standortsbedingungen im Gebirge: Schnee, Lawinen und Permafrost | Growth rings as indicators of extreme site conditions in the mountains: snow, avalanches and permafrost

2004 ◽  
Vol 155 (6) ◽  
pp. 208-212 ◽  
Author(s):  
Peter Bebi ◽  
Alejandro Casteller ◽  
Andrea Corinna Mayer ◽  
Veronika Stöckli
Keyword(s):  
Natural Hazards ◽  
Growth Ring ◽  
Management Strategies ◽  
Extreme Conditions ◽  
Site Conditions ◽  
Snow Avalanches ◽  
Growth Rings ◽  
Survival And Growth ◽  
Ring Analysis

Snow, avalanches, and permafrost are extreme site conditions for plants. Reactions and adaptations to such extreme conditions can be reconstructed with growth ring analysis and linked with corresponding climate and disturbance data. On the basis of five case studies in and around the long-term research site Stillberg, near Davos, we discuss both the potential and the limits of dendroecology to understand the effect of such extreme site conditions. Despite some uncertainties in reliably assigning plant reactions, growth ring analysis is a valuable addition to better understand the effects of extreme site conditions on the survival and growth of plants. This can lead to improved management strategies associated with natural hazards, especially in the case of avalanches.

scholarly journals Morphologic Characteristics Variability in Prunus spinosa L. Shrubs Identified in Southern Area of Oltenia, Romania

2018 ◽  
Vol 10 (3) ◽  
pp. 447-451 ◽  
Author(s):  
Sina N. COSMULESCU ◽  
Florentina GAVRILA CALUSARU
Keyword(s):  
Plant Height ◽  
Tree Species ◽  
Morphological Characteristics ◽  
Fruit Tree ◽  
High Variability ◽  
Stem Height ◽  
Breeding Programs ◽  
Trunk Diameter ◽  
Prunus Spinosa ◽  
Morphologic Characteristics

This paper aims to analyse the variability of morphological characteristics of Prunus spinosa L. shrubs, identified and studied in the spontaneous flora in southern Oltenia, Romania (localities Calopar and Gura Văii). The observations made on trunk diameter, stem height, spinosity degree, ability to form basal shoots, have outlined the high variability, which is useful in breeding programs. Variability coefficient ranged between 26.02% and 30.87% for the stem diameter, between 23.48% and 32.32% for the plant height, between 30.93% and 37.81% for canopy diameter. Based on the obtained results, the C31, GV26, GV28, GV29, GV30, GV31, GV33, GV34, GV37 and GV8, GV9, GV27, GV35, C5, C24, C25, C26 and C29 genotypes are recommended for fixing the eroded lands, owing to their very strong, strong and medium ability to form basal shoots; while C10, C12, C23, C27, C28, C30, GV6, GV10, GV24, GV25, GV32 and GV36 genotypes are recommended to be studied as rootstocks in fruit tree species, having in view the low or missing vigor and ability to form basal shoots.

Timber production versus old-growth preservation with endogenous prices and forest age-classes

2004 ◽  
Vol 34 (6) ◽  
pp. 1296-1310 ◽  
Author(s):  
Olli Tahvonen
Keyword(s):  
Environmental Values ◽  
Timber Harvesting ◽  
Timber Production ◽  
Forest Age ◽  
Forest Land ◽  
Age Classes ◽  
Old Growth ◽  
Class Distribution ◽  
Age Class ◽  
Long Run

This study combines timber production and environmental values, applying a dynamic forest-level economic model with any number of forest age-classes. The model includes endogenous timber price or nonlinear harvesting costs and various possibilities to specify the dependence of environmental values (related e.g. to species persistence) on the forest age-class structure. The nonlinearities in the net benefits from timber production have the consequence that fluctuations in optimal timber harvesting may totally vanish or at least become smaller than in forest scheduling models without ad hoc even flow constraints. If environmental values are specified to depend on the fraction of forest land preserved as old growth, the optimal long run allocation between timber production and old growth is represented by an equilibrium continuum. Thus the optimal long run allocation depends on the initial age-class distribution. The continuum and the dependence of initial age-class distribution vanish when the rate of discount approaches zero. If the environmental values of age-classes increase smoothly with age, the long run equilibrium may simultaneously include multiple rotation periods. The model determines the optimality of producing timber and environmental values separately at different parts of the forest or at the same piece of forest land. Numerical computation suggests that the optimal solution always converges toward some optimal long run stationary age-class distribution.

Chaparral growth-ring analysis as an indicator of stand biomass development

2016 ◽  
Vol 25 (10) ◽  
pp. 1086 ◽  
Author(s):  
Kellie A. Uyeda ◽  
Douglas A. Stow ◽  
John F. O'Leary ◽  
Christina Tague ◽  
Philip J. Riggan
Keyword(s):  
Growth Ring ◽  
Basal Area ◽  
Biomass Accumulation ◽  
Field Measurements ◽  
Solar Irradiation ◽  
Annual Precipitation ◽  
Total Biomass ◽  
Growth Rings ◽  
Close Relationship ◽  
Long Time

Chaparral wildfires typically create even-aged stands of vegetation that grow quickly in the first 2 decades following a fire. Patterns of this growth are important for understanding ecosystem productivity and re-establishment success, but are logistically challenging to measure over long time periods. We tested the utility of a novel method of using shrub growth rings to estimate stand-level biomass accumulation at an annual time scale in southern California chaparral. We examined how temporal variation in precipitation and spatial variation in solar irradiation influence that accumulation. Using field measurements and a relationship between stem basal area and aboveground biomass, we estimated current biomass levels in an 11-year-old chaparral stand, and used growth-ring diameters to estimate growth in each year from age 4 to 11 years. We found that annual growth as measured by shrub growth rings tracked closely with patterns of annual precipitation, but not with time since fire. Solar irradiation was not found to be a significant covariate with total biomass by plot, possibly due to sampling area limitations. The close relationship of annual biomass accumulation with annual precipitation indicates that shrub growth-ring measurements can provide a useful metric of stand-level recovery.

Hydraulic Conductivity in Trunk Xylem of Elm, Ulmus Americana

IAWA Journal ◽  
1985 ◽  
Vol 6 (4) ◽  
pp. 303-307 ◽  
Author(s):  
George S. Ellmore ◽  
Frank W. Ewers
Keyword(s):  
Fluid Flow ◽  
Hydraulic Conductivity ◽  
Fluid Transport ◽  
Growth Ring ◽  
Theoretical Calculations ◽  
Transport Pathway ◽  
Growth Rings ◽  
Ulmus Americana ◽  
Xylem Transport ◽  
Flow Through

The notion that most xylem transport in stems of ring-porous trees occurs in the outermost growth ring requires experimental support. Significance of this ring is challenged by workers who find tracer dyes appearing in 4 to 8 growth rings rather than in only the outermost increment. We test the hypothesis that the outermost growth ring is of overriding significance in fluid transport through stems of Ulmus, a ring-porous tree. Fluid flow through the outermost ring was quantified by removing that ring, calculating gravity flow rates (hydraulic conductivity at 10.13 kPa m-1 ), and by tracing the transport pathway through control and experimental stem segments. From measurements corroborating theoretical calculations based on Poiseuille's law, over 90% of fluid flow through the stem occurs through the outermost ring. Remaining rings combine to account for less than 10% of xylem transport. As a result of dependence upon transport in the most superficial xylem, ring-porous trees such as elm, oak, ash, and chestnut are particularly susceptible to xylem pathogens entering from the bark.

An assessment of the relationship between tree-ring counts and basal girth of high-altitude populations of Eucalyptus pauciflora (Myrtaceae)

2009 ◽  
Vol 57 (7) ◽  
pp. 583 ◽  
Author(s):  
Libby Rumpff ◽  
Seraphina C. Cutler ◽  
Ian Thomas ◽  
John W. Morgan
Keyword(s):  
High Altitude ◽  
National Park ◽  
Linear Growth ◽  
Growth Ring ◽  
Tree Line ◽  
Growth Rings ◽  
Regression Methods ◽  
Ski Resorts ◽  
Non Linear ◽  
The Relationship

We investigated the relationship between the number of growth rings (a surrogate for approximate age of stems) and basal girth for Eucalyptus pauciflora (Maiden & Blakely) L.A.S.Johnson & Blaxell. Using basal-girth measurements and growth-ring counts obtained from trees felled on ski slopes at three Victorian alpine ski resorts, as well as seedlings destructively sampled from near the tree line on four summits, we modelled the relationship between growth rings and basal girth by using simple linear and non-linear regression methods. We compared our data to growth-ring–basal-girth data collected from low- and high-altitude E. pauciflora woodland stands in Kosciuszko National Park. The relationship between the number of tree rings and basal girth at Victorian sites was non-linear (growth rings = 3.62 × girth0.63, R2 = 0.96). In general, the Victorian and Kosciuszko datasets were in broad agreement, although caution is required when attempting to estimate the age of trees with >115-cm girth. We suggest that the model we have developed can be combined with dendrological techniques to estimate the age of older trees accurately.

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