Short-term effects of surface fire on the biomass and nutrient standing crop of Populustremuloides in southern Ontario

1977 ◽  
Vol 7 (4) ◽  
pp. 666-679 ◽  
Author(s):  
T. D. W. James ◽  
D. W. Smith

The standing crop of biomass and nutrients (N, P, K, Ca, and Mg) were estimated for Populus tremuloides trunk, lateral branch twig, and foliage in a 30-year-old open stand in West Luther Township, Wellington County, Ontario. Separate estimates were made for trees in areas subjected to light surface burning (about 160 °C at the surface) and in unburned areas. Allometric relations between a variety of tree measures showed that the best estimates of standing crop were derived from simple log regressions with trunk dbh as the independent variable.The range of 7.0 to 8.9 t/ha of total aerial aspen biomass was considerably lower than other reported values and reflected both the low stand density and poor site conditions. Accumulation of tree biomass was unchanged by light surface burning. Evidently, the environmental changes were too slight to cause postfire changes in the established overstory.Distribution of nutrients within the tree components was similar to that reported elsewhere; Ca and N were the two most abundant, while P, K, and Mg accumulations were much lower. The relative importance of various tree components as nutrient accumulation sites followed the order leaves > twigs > lateral branches > trunk. The leaves were the site of the accumulation of functionally important N, P, K, and Mg whereas the trunk was the prominent site for structurally important calcium. The total accumulation of all nutrients (103.5 kg/ha) was strikingly low in comparison with amounts reported for other deciduous forests. Accumulation of nutrients in the trunk, lateral branches, and twigs was not appreciably altered by fire. Major proportions of nutrients in these components would have accumulated before burning.Amounts of nutrients contained in leaf biomass were significantly changed after burning. Concentrations in leaves from burned areas were 24–42% higher than control levels, whereas the preburn levels were similar. These substantial postburn increases in leaf nutrient levels, related to a flush of soil nutrients from ash, would have an important effect on those wildlife species utilizing the aspen as a food source.

1970 ◽  
Vol 48 (8) ◽  
pp. 1459-1469 ◽  
Author(s):  
E. B. Peterson ◽  
Y. H. Chan ◽  
J. B. Cragg

A 1967 aboveground harvest of 49 ramets of aspen (Populus tremuloides Michx.), aged from 66 to 89 years, at an altitude of 1430 m in Alberta revealed a leaf area index of 1.8 (one side of foliage) and a clone standing crop of 77.11 metric tons/hectare (oven-dry weight) with an energy equivalent of 3630 × 108 gram calories/hectare. This standing crop estimate fell within the range of 58 to 290 metric tons/hectare reported elsewhere for aspen. The amount of aspen foliage and branch wood, as a percentage of total aboveground standing crop, increased from the bottom to the top of a slope gradient within the 0.02-hectare sample plot, indicating that topographic position exerted a phenotypic expression on production structure within the clone. Topographic position did not have a significant influence on the applicability of the two most reliable independent variables ((i) diameter at breast height squared × tree height, (ii) diameter of trunk at crown base) for prediction of the total aboveground weight and component weights of aspen ramets. The allometric relations reported here are not necessarily applicable to other clones of the species but the allometric methods have potential application to other studies of the International Biological Programme.


Author(s):  
Monica Turner ◽  
Rebecca Reed ◽  
William Romme ◽  
Gerald Tuskan

An unexpected consequence of the 1988 Yellowstone fires was the widespread establishment of seedlings of quaking aspen (Populus tremuloides) in the burned forests, including areas outside the previous range of aspen (Kay 1993; Romme et al. 1997). Although aspen is the most widely distributed tree species in North America (Powells 1965), it is relatively uncommon and localized in distribution within Yellowstone National Park (Despain 1991). Most aspen stands in Yellowstone are found in the lower elevation landscapes in the northern portion of the park, and the species was absent - prior to 1988 -- across most of the high plateaus that dominate the southern and central park area. Aspen in the Rocky Mountain region reproduces primarily by means of vegetative root sprouting. Although viable seeds are regularly produced, establishment of seedlings in the wild is apparently a rare event due to the limited tolerance of aspen seedlings for desiccation or competition (e.g., Pearson 1914; McDonough 1985). In the immediate aftermath of the 1988 Yellowstone fires, there was a brief "window of opportunity" for aspen seedling establishment, as a result of abundant aspen seed production, moist weather conditions in spring and summer, and bare mineral soil and reduced plant competition within extensive burned areas (Jelinski and Cheliak 1992; Romme et al. 1997). We initiated this 3-year study in 1996 to address four questions about the aspen seedlings now growing in burned areas across the Yellowstone Plateau: (1) What are the broad-scale patterns of distribution and abundance of aspen seedlings across the subalpine plateaus of Yellowstone National Park? (2) What is the morphology and population structure -- e.g., proportions of genets (genetic individuals that developed from a single seed) and ramets (vegetative root sprouts produced by a genet) of various ages - in aspen seedling populations? (3) What are the mechanisms leading to eventual persistence or extirpation of seedling populations along an elevational gradient, particularly with respect to ungulate browsing and plant competition? (4) What is the genetic diversity and relatedness of the seedling populations along gradients of elevation and substrate?


2001 ◽  
Vol 31 (12) ◽  
pp. 2089-2097 ◽  
Author(s):  
Thomas T Veblen ◽  
Dominik Kulakowski ◽  
Karen S Eisenhart ◽  
William L Baker

As windstorm intensity increases above some threshold, disturbance spread and damage patterns are expected to be less strongly shaped by preblowdown forest composition and structure than by the pattern of the storm itself. We examined this generalization by analyzing differences in wind damage among tree species and stands following a severe blowdown in 1997 affecting over 10 000 ha of subalpine forest in the Routt Divide area of northern Colorado, U.S.A. Individual tree traits such as species, height, and status as standing dead or alive strongly influenced the amount and type (uprooting vs. snapping) of wind damage. Populus tremuloides Michx. exhibited much less uprooting and overall damage than the conifers. Among the canopy trees of the conifer species, Pinus contorta Dougl. ex. Loud and Abies lasiocarpa (Hook.) Nutt. sustained the lowest and highest rates of snapping, respectively. Standing dead conifers were more likely to be snapped than uprooted, and taller trees were more likely to be damaged than shorter trees. Stand-level characteristics such as stand density, amount of dead basal area, and species composition were predictive of the amount of wind damage for areas of moderate- but not high-severity blowdown. Even in such an extreme windstorm as the Routt blowdown, which had estimated wind speeds of 200–250 km/h, individual tree attributes and stand-level characteristics significantly influenced the severity and type of wind damage.


2004 ◽  
Vol 34 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Jill F Johnstone ◽  
F S Chapin III ◽  
J Foote ◽  
S Kemmett ◽  
K Price ◽  
...  

This paper presents data on early postfire tree regeneration. The data were obtained from repeated observations of recently burned forest stands along the Yukon – British Columbia border and in interior Alaska. Postfire measurements of tree density were made periodically for 20–30 years, providing direct observations of early establishment patterns in boreal forest. Recruitment rates of the dominant tree species in both study areas were highest in the first 5 years after fire, and additional net establishment was not observed after 10 years. The postfire population of spruce (Picea mariana (Mill.) BSP and Picea glauca (Moench) Voss s.l.) remained constant after the first decade in the two study areas. Populations of aspen (Populus tremuloides Michx.) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) both declined after 10 years in mixed-species stands along the Yukon – British Columbia border. Mortality rates of aspen and pine were positively correlated with their initial densities, indicating that thinning occurred as a density-dependent process. At all sites, measurements of stand density and composition made early were highly correlated with those made late in the monitoring period, indicating that patterns of stand structure initiated within a few years after fire are maintained through subsequent decades of stand development.


ISRN Forestry ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
John-Pascal Berrill ◽  
Christa M. Dagley

Awareness of geographic patterns and stand variables that influence tree growth will help forest managers plan appropriate management and monitoring strategies. We quantified influences of stand location, species composition, stand density, and tree size on aspen tree growth and vigor around the Lake Tahoe Basin in the Sierra Nevada Mountains of California and Nevada, USA. Radial growth data were taken from increment cores. Aspen trees on the south and west sides of the lake grew 20–25% faster than aspen in north and east side stands. Diameter growth at 2,400 m elevation was 58% of growth at 1,900 m near lake level. Aspen grew faster with less competition from neighbor trees. At any level of competition, aspen growth was slower beside conifer neighbors and correlated with crown ratio (CR: length of live crown relative to total tree height, a proxy for tree vigor). Analysis of independent CR data for 707 aspen trees in nine additional stands indicated that aspen had smaller crowns in the presence of greater competition, and that composition of neighbor trees also affected CR: aspen trees had shorter crowns in the presence of conifer at higher stand densities. Taken collectively, our analyses point towards a cascading decline in aspen growth and vigor incited by succession of aspen stands to conifers. Our findings suggest that conifer removal and stand density control in aspen-conifer stands at Lake Tahoe will enhance aspen growth and vigor.


1991 ◽  
Vol 21 (3) ◽  
pp. 300-305 ◽  
Author(s):  
N. J. Smith

Salal (Gaultheriashallon Pursh) leaf biomass, leaf area index, specific leaf area, and leaf morphology were examined in 13 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands from 37 destructively measured 1-m2 quadrats. In response to light and stand overstory density, salal shoots produced either mainly sun leaves or mainly shade leaves. Sun leaves were associated with sunflecks in open-grown or variably stocked stands. Shade leaves were associated with diffuse light under denser stands. Sun-leaf quadrats had mean specific leaf areas less than 90 cm2/g; shade-leaf quadrats had mean specific leaf areas greater than 90 cm2/g. Sun leaves were narrower, with average leaf widths less than 5 cm. Quadrat salal leaf biomass and leaf area index peaked at Curtis' metric relative density 5.9, which corresponded to an availability of 15% of global photosynthetically active radiation. Sun-leaf quadrats occurred below relative density 5; shade-leaf quadrats occurred above relative density 4. A mixture of sun- and shade-leaf quadrats occurred between about relative density 4 and 5, depending on the uniformity of stocking.


2002 ◽  
Vol 32 (9) ◽  
pp. 1525-1541 ◽  
Author(s):  
Katherine P O'Neill ◽  
Eric S Kasischke ◽  
Daniel D Richter

Boreal forests contain large amounts of stored soil carbon and are susceptible to periodic disturbance by wildfire. This study evaluates the relationship between post-fire changes in soil temperature, moisture, and CO2 exchange in paired burned and control stands of three Alaskan forest systems: Picea mariana (Mill.) BSP, Picea glauca (Moench) Voss, and Populus tremuloides Michx. In these systems, the environmental factor that most directly controlled rates of carbon exchange varied depending upon burn status and soil drainage. In mature unburned stands, CO2 flux was highly correlated with seasonal patterns of soil temperature. Following fire, these soils became significantly warmer, and carbon exchange became more sensitive to fluctuations in surface moisture conditions. The effect of fire on soil climate was most pronounced in the P. mariana stands, which experienced a mean seasonal temperature increase of 5–8°C in the upper 1 m of the soil profile, a 200% increase in the rate of active layer thaw, and a reduction in mean surface moisture potential. Evidence from soil CO2 profiles suggests that these environmental changes may have resulted in enhanced decomposition of carbon previously immobilized by permafrost, potentially transforming a landscape that was once a net sink for carbon into a carbon source.


2014 ◽  
Vol 82 (3) ◽  
pp. 553-566 ◽  
Author(s):  
Laura E. Strickland ◽  
Richard G. Baker ◽  
Robert S. Thompson ◽  
Dane M. Miller

AbstractNinety plant macrofossil taxa from the Ziegler Reservoir fossil site near Snowmass Village, Colorado, record environmental changes at high elevation (2705 m asl) in the Rocky Mountains during the Last Interglacial Period. Present-day vegetation is aspen forest (Populus tremuloides) intermixed with species of higher (Picea,Abies) and lower (Artemisia,Quercus) elevations. Stratigraphic units 4–13 contain montane forest taxa found near the site today and several species that today generally live at lower elevations within (Abies concolor,Lycopus americanus) and outside Colorado (Najas flexilis). These data suggest near-modern climatic conditions, with slightly warmer summer and winter temperatures. This montane forest period was succeeded by a shorter treeless interval (Unit 14) representing colder and/or drier conditions. In units 15–16, conifer trees reoccur but deciduous and herb taxa are lacking, suggesting a return to warmer conditions, although cooler than during the earlier forest period. Comparison of these inferred paleoclimatic changes with the site's geochronologic framework indicates that the lower interval of sustained warmth correlates with late MIS 6–early 5b (~138–94 ka), the cold interval with MIS 5b (~94–87 ka), and the uppermost cool assemblages with MIS 5a (~87–77 ka).


2003 ◽  
Vol 12 (4) ◽  
pp. 259 ◽  
Author(s):  
José M. C. Pereira

Problematic aspects of fire in tropical savannas are reviewed, from the standpoint of their impact on the detection and mapping of burned areas using remotely sensed data. Those aspects include: the heterogeneity of savanna—resulting in heterogeneity of fire-induced spectral changes; fine fuels and low fuel loadings—resulting in short persistence of the char residue signal; tropical cloudiness—which makes multitemporal image compositing important; the frequent presence of extensive smoke aerosol layers during the fire season—which may obscure fire signals; and the potential problem of detecting burns in the understory of woody savannas with widely variable tree stand density, canopy cover and leaf area index. Finally, the capabilities and limitations of major satellite remote sensing systems for pan-tropical burned area mapping are addressed, considering the spatial, spectral, temporal and radiometric characteristics of the instruments.


Author(s):  
Monica Turner ◽  
Rebecca Reed ◽  
William Romme ◽  
Gerald Tuskan

An unexpected consequence of the 1988 Yellowstone fires was the widespread establishment of seedlings of quaking aspen (Populus tremuloides) in the burned forests, including areas outside the previous range of aspen (Kay 1993, Romme et al.1997). Although aspen is the most widely distributed tree species in North America (Powells 1965), it is relatively uncommon and localized in distribution within Yellowstone National Park (Despain 1991). Most aspen stands in Yellowstone are found in the lower elevation landscapes in the northern portion of the park, and the species was absent -- prior to 1988 -- across most of the high plateaus that dominate the southern and central park area. Aspen in the Rocky Mountain region reproduces primarily by means of vegetative root sprouting. Although viable seeds are regularly produced, establishment of seedlings in the wild is apparently a rare event due to the limited tolerance of aspen seedlings for desiccation or competition (e.g., Pearson 1914, McDonough 1985). In the immediate aftermath of the 1988 Yellowstone fires there was a brief "window of opportunity" for aspen seedling establishment, as a result of abundant aspen seed production, moist weather conditions in spring and summer, and bare mineral soil and reduced plant competition within extensive burned areas (Jelinski and Cheliak 1992, Romme et al. 1997). We initiated this 3-year study in 1996 to address four questions about the aspen seedlings now growing in burned areas across the Yellowstone Plateau: (1) What are the broad-scale patterns of distribution and abundance of aspen seedlings across the subalpine plateaus of Yellowstone National Park? (2) What is the morphology and population structure -- e.g., proportions of genets (genetic individuals that developed from a single seed) and ramets (vegetative root sprouts produced by a genet) of various ages -- in aspen seedling populations? (3) What are the mechanisms leading to eventual persistence or extirpation of seedling populations along an elevational gradient, particularly with respect to ungulate browsing and plant competition? (4) What is the genetic diversity and relatedness of the seedling populations along gradients of elevation and substrate? We completed our sampling for questions 2 and 4 in 1996 (see our 1996 annual report for details). In 1997 we continued our annual sampling related to questions 1 and 3.


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