Aspen Seedlings Research Articles

Genetic variation in postfire aspen seedlings in yellowstone national park

A rare episode of regeneration of aspen (Populus tremuloides Michx.) by seeds occurred in Yellowstone National Park (YNP), Wyoming, USA, following extensive fires that occurred in 1988. In 1997, we sampled 410 aspen seedlings from 23 local populations distributed widely across YNP to determine how genetic diversity varies with elevation, substrate, plant competition, ungulate browsing, and geographical location. We employed 132 randomly amplified polymorphic DNA (RAPD) markers based on six primers to show genetic relationships within and among the postfire aspen seedling populations. Measures of genetic variation, including estimates of percentage polymorphic loci, expected heterozygosity, and Nei's FST, indicated that most of the variation occurred within rather than among local populations. There was no indication of geographical differentiation among sampled populations based on hierarchal estimates of Nei's FST, neighbour-joining, or correlations between genetic distance and geographical distance. Even genetically distant populations shared nearly 90% of the same markers. Within plots, the amount of genetic variation decreased slightly in response to increased percentage vegetative cover, mean seedling basal diameter, and mean seedling height. Geological substrate, density of lodgepole pine (Pinus contorta var. latifolia Dougl.) seedlings, browsing intensity, and elevation were not significantly related to levels of genetic variation within the seedling plots. These data suggest that genetic variation and geographical structure among seedling populations may occur over time as the transition from seedling-dominated stands to clone-dominated stands occurs.

Responses of Boreal Plants to High Salinity Oil Sands Tailings Water

AbstractIn the extraction of bitumen from oil sands ore, large volumes of railings water (CT water) containing elevated levels of Na, sulfate, bicarbonate and chloride are produced. High salinity process waters will probably affect terrestrial reclamation options. The present study tested the impact of tailings waters on boreal forest species including aspen (Populus tremuloides Michx.), buffalo berry [Sheperdia canadensis (L.) Nutt], northwest hybrid poplar (Populus deltoides × Populus balsamifera), dogwood (Cornus stolonifera Michx.), jack pine (Pinus banksiana Lamb.), and white spruce [Picea glauca (Moench) Voss]. Seedlings were grown in solution culture containing mineral nutrients and different dilutions of CT water, with and without supplemental salts (Na2SO4 and NaCl). After 4 wk of treatment, dogwood, hybrid poplar, and buffalo berry showed relatively high resistance to saline CT waters. Conifer seedlings developed leaf necrosis in all treatments, while aspen seedlings rapidly lost their foliage and produced new leaves. In comparison to the controls, elevated Na levels were measured in plant tissue of all species grown in CT water. However, some differences between species were observed, with jack pine seedlings showing much higher Na content than aspen, dogwood, or hybrid poplar. In hybrid poplar, the accumulation of Na was accompanied by a significant reduction in K, Mg, Ca, and P. Buffalo berry, aspen, jack pine, and white spruce showed elevated levels of S after growth in the sulfate‐enriched CT waters. High tissue Na content did not induce leaf injury in dogwood, hybrid poplar and buffalo berry, suggesting possible Na resistance.

Induction of nitrate uptake and nitrate reductase activity in trembling aspen and lodgepole pine

13NO3– influx into the roots and in vivo nitrate reductase activity (NRA) in the roots and leaves have been measured in trembling aspen (Populus tremuloides Michx.) and lodgepole pine (Pinus contorta Dougl.) seedlings after exposure to either 0·1 or 1·5 mol m–3 NO3– for varying periods up to 20 d. Both NO3– influx and NRA were inducible in these species and, in trembling aspen, peak induction of nitrate influx and NRA were achieved within 12 h, compared to 2–4 d for influx and 4–12 d for NRA in lodgepole pine. In trembling aspen, ≈ 30% of the total 13N absorbed during a 10 min influx period followed by 2 min of desorption was translocated to the shoot. In lodgepole pine, by contrast, translocation of 13N to the shoot was undetectable during the same time period. Root NRA as well as NO3– influx from 0·1 mol m–3 NO3– were substantially higher in trembling aspen than in lodgepole pine at all stages of NO3– exposure, i.e. during the uninduced, the peak induction, and steady‐state stages. In order to examine whether the lower rates of NO3– influx and NRA were related to proportionately fewer young (unsuberized) roots in lodgepole pine, we determined these parameters in young and old (suberized) roots of this species separately. Induction of influx and NRA were initially greater in young roots but at steady‐state there were only minor differences between the young and the old roots. However, even the elevated initial rates in the young roots of lodgepole pine were substantially lower than those of aspen. In pine, influx at 1·5 mol m–3 NO3– was ~ 6‐fold higher than at 0·1 mol m–3 NO3– and appeared to be mostly via a constitutive system. By contrast, in aspen, steady‐state influxes at 0·1 and 1·5 mol m–3 were not significantly different, being similar to the rate attained by pine at only the higher [NO3–]. In aspen, leaf NRA was ~ 2‐fold higher than that of roots. In lodgepole pine NRA of the needles was below the detection limit. These results show that trembling aspen seedlings are better adapted for NO3– acquisition and utilization than lodgepole pine seedlings.

Effect of high salinity tailings waters produced from gypsum treatment of oil sands tailings on plants of the boreal forest

Bitumen extraction methods currently in use in the operating oil sands plants produce large volumes of fluid tailings. Ions leached from the ore and added by process chemicals during the extraction process result in tailings waters containing elevated ionic content relative to the non-process-affected waters of the area, in particular the sodium, sulfate, and chloride ions. It is anticipated that the areas requiring reclamation will be affected by this high salinity of the process waters. The objectives of this study were to test the impact of a tailings alternative (consolidated tailings process, based on gypsum treatment of extraction tailings) on the viability of plant species of the northern boreal forest and to determine the relative salt tolerance and suitability of selected plant species for land reclamation. Seedlings were grown for 4 weeks in a greenhouse in solution culture containing mineral nutrients and various dilutions of consolidated tailings water and with Na 2SO 4 additions (1 g L −1 and 3 g L −1). Of all examined plant species, raspberry and strawberry seedlings were the most susceptible to damage, while the seedlings of white spruce, black spruce and lodgepole pine survived, but showed some effects. In the willow and aspen seedlings, there was a rapid loss of leaves, which were quickly replaced by new, morphologically different leaves. Dogwood and hybrid poplar showed high tolerance to all treatments.

Distribution, Morphology, Survival, and Genetics of Aspen (Populus tremuloides) Seedlings Following the 1988 Yellowstone Fires

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 (Fowells 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 and again in 1998 we continued our annual sampling related to questions 1 and 3.

CONSEQUENCES OF ENRICHED ATMOSPHERIC CO2 AND DEFOLIATION FOR FOLIAR CHEMISTRY AND GYPSY MOTH PERFORMANCE

Elevated concentrations of atmospheric CO2 are likely to interact with other factors affecting plant physiology to alter plant chemical profiles and plant–herbivore interactions. We evaluated the independent and interactive effects of enriched CO2 and artificial defoliation on foliar chemistry of quaking aspen (Populus tremuloides) and sugar maple (Acer saccharum), and the consequences of such changes for short-term performance of the gypsy moth (Lymantria dispar). We grew aspen and maple seedlings in ambient (~360 ppm) and enriched (650 ppm) CO2 environments at the University of Wisconsin Biotron. Seven weeks after budbreak, trees in half of the rooms were subjected to 50% defoliation. Afterwards, foliage was collected for chemical analyses, and feeding trials were conducted with fourth-stadium gypsy moths. Enriched CO2 altered foliar levels of water, nitrogen, carbohydrates, and phenolics, and responses generally differed between the two tree species. Defoliation induced chemical changes only in aspen. We found no significant interactions between CO2 and defoliation for levels of carbon-based defenses (phenolic glycosides and tannins). CO2 treatment altered the performance of larvae fed aspen, but not maple, whereas defoliation had little effect on performance of insects. In general, results from this experimental system do not support the hypothesis that induction of carbon-based chemical defenses, and attendant effects on insects, will be stronger in a CO2-enriched world.

Distribution, Morphology, Survival, and Genetics of Aspen (Populus tremuloides) Seedlings Following the 1988 Yellowstone Fires

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.

RAPD markers reveal diversity within and among clonal and seedling stands of aspen in Yellowstone National Park, U.S.A.

Fire in 1988 created a situation that allowed a rare aspen seedling recruitment event to occur within Yellowstone National Park. Through the use of (i) 194 randomly amplified polymorphic DNA (RAPD) markers from 14 select primers, (ii) measures of population diversity, and (iii) neighbor-joining analysis it was determined that the postfire aspen seedling population contains greater diversity within each of the four sampled stands than that found within all of the 10 sampled mature aspen stands that pre-existed the fire. Unlike previous studies, a large portion of the molecular variation in both the seedling and mature populations was partitioned among stands. Furthermore, variation was unexpectedly detected among ramets within each mature stand. The mature stands appear to be clonally derived, yet individual ramets within stands varied slightly and incrementally in their RAPD profile. These data suggest that somatic mutations may be occurring and accumulating in clonal aspen stands. A proposed scenario of stand establishment and development involving the accumulation of somatic mutations and elimination of genetically related seedlings arising from a rare founder event provides the theoretical basis for the observed differences among and within seedling and mature stands of aspen in Yellowstone National Park.

Changes in Pteridium aquilinum growth and phototoxicity following treatments with lime, sulphuric acid, wood ash, glyphosate and ammonium nitrate

SummaryThe comparative effects of lime, sulphuric acid, wood ash, glyphosate and ammonium nitrate on Pteridium aquilinum (L.) Kuhn growth and development were evaluated in a Scots pine (Pinus sylvestris L.) clear‐cut stand in south‐east Sweden over a 4‐year period. P. aquilinum growth was effectively controlled following the application of glyphosate, but the other treatments generally had little effect on growth in terms of shoot density and length. Shoot length was positively related to the number of shoots on plots treated with ammonium nitrate but negatively correlated with the number of P. aquilinum shoots found on wood ash‐treated and control plots. In a bioassay aspen (Populus tremula L.) seedling emergence and pH were significantly lower in humus treated with sulphuric acid, glyphosate, ammonium nitrate and in untreated humus as compared with the humus treated with lime and wood ash. The negative effect of humus on emergence of aspen seedlings may be caused by phytotoxic compounds at a lower pH level. Forest regeneration might be performed with shade‐tolerant species such as Norway spruce (Picea abies (L.) Karst.) planted beneath a thin canopy of trees to prevent the rapid increase of P. aquilinum.

Distribution, Morphology, Survival, and Genetics of Aspen (Populus Tremuloides) Seedlings Following the 1988 Yellowstone Fires

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?

Ectomycorrhizae formed in vitro by quaking aspen: including Inocybe lacera and Amanita pantherina

Ectomycorrhizae formed in synthesis tubes by aspen (Populus tremuloides) seedlings and each of seven fungal isolates are described. Isolates of Amanita muscaria v. formosa, A. pantherina, Inocybe lacera, and Paxillus vernalis, from sporocarps collected in aspen stands in southwestern Montana, developed mantles and Hartig nets on aspen roots, as did the broad-hostrange fungi Cenococcum geophilum and Pisolithus tinctorius from the VPI culture collection. Chalciporus piperatus failed to form mycorrhizae, and Piloderma croceum formed a mantle, but no Hartig net. The first syntheses of I. lacera and A. pantherina with aspen are reported.

Analysis of aspen foliage exposed to multiple stresses: ozone, nitrogen deficiency and drought

summaryTwo field experiments were conducted to examine the impact of a foliar stress (ozone, O3), alone or in combination with a resource stress, on carbon gain of aspen (Populus tremuloides Michx.). The first experiment involved nitrogen deficiency, and the second, drought stress.The patterns of change in leaf area, photosynthetic rate and carbon pain with leaf position from root to apex were altered by O3 alone. Net photosynthesis, and carboxylation capacity of older leaves decreased, and of younger leaves increased, in response to O3. Thus younger leaves partially compensated for the decreased photosynthetic capacity of older leaves. Physiological maturity and senescence were accelerated by O3. Whole plant carbon gain declined with O3 due to reductions in both leaf area and photosynthetic rate.Nitrogen deficiency alone decreased carbon gain via reductions in both leaf area and photosynthetic rate across leaf position. The effects of O3 and nitrogen deficiency together on both leaf area and photosynthetic rate were additive, Aspen seedlings compensated to O3 stress regardless of nitrogen level. Plant responses to both of these stresses may have been mediated by ribulose bisphosphate carboxylase/oxygenase (Rubisco) content or activity, and thus indirectly by nitrogen content.In the second experiment, seedlings were subjected to drought during the first six weeks of exposure to O3 and were measured several weeks after termination of the drought treatment. Drought caused aspen seedlings to produce fewer and smaller leaves. After termination of drought, they produced larger new leaves, and net photosynthesis of most leaves was greater than in continuously well‐watered plants. In plants not exposed to O3, enhanced photosynthetic rate partially compensated for the smaller leaf area. O3 generally decreased leaf area and photosynthesis, and hence carbon gain. The effects of prior exposure to drought and O3 together were additive for whole‐plant photosynthetic rate, but less than additive for whole‐plant leaf area.

Antifungal compounds in aspen: effect of water stress

A thin layer chromatography bioassay was used to detect antifungal compounds in tissue culture plantlets and potted seedlings of aspen. Catechol and the phenolic glycosides salicin and salicortin were identified as inhibitory compounds; a fourth compound was observed but was not identified. Inhibitory compound levels were estimated in eight tissue culture clones grown on unamended media and media amended with 0.22 M mannitol to induce water stress. Aspen tissue culture plantlets grown under water stress conditions had significantly lower levels of catechol, salicortin, and salicin. Significant clonal variation in levels of catechol, salicin, and the unidentified compound was also observed. Catechol, salicortin, and salicin were inhibitory to Hypoxylon mammatum when tested at levels similar to those employed in the thin layer chromatography bioassay. These results suggest that a reduction in the levels of inhibitory compounds in water-stressed aspen may be a factor in the water stress induced susceptibility of aspen to H. mammatum. Key words: Populus tremuloides, Hypoxylon mammatum, water stress, tissue culture.

Survival and Growth of Planted Black Spruce, Alder, Aspen and Willow After Fire on Black Spruce/Feather Moss Sites in Interior Alaska

Seedlings of black spruce, aspen, green alder, and grayleaf willow planted on black spruce/feather moss sites in the boreal forest in interior Alaska survived and grew relatively well over a 6-year period after prescribed burning. Survival of black spruce was significantly greater than that of the broad-leaved species, but height growth was significantly less. Development of feltleaf willow and balsam poplar from unrooted cuttings was poor. Severity of burn appeared to have an important effect on height growth of all species but not on seedling survival. Key words: Planting, Picea, Alnus, Populus, Salix, microsite.

Cultivation and weed control for aspen seedling establishment in the southern Rocky Mountains

Containerized aspen (Populustremuloides Michx.) seedlings were planted at high-elevation sites in southern (May 1982) and northern (July 1983) New Mexico. Each plantation compared fall cultivation (20 cm depth), prior to planting the following spring or summer, with cultivation at the time of planting. Subtreatments of the tests included applications of the postemergent herbicide dalapon and the preemergents linuron, trifluralin, or simazine applied 2 to 3 weeks before planting. First season survival exceeded 75% for the best treatment at each site. Cultivation, in general, effectively reduced weed cover and improved seedling success. Fall cultivation, in particular, improved seedling survival and growth only at the relatively dry southern site. Except for spring-cultivated plots in the south, some herbicide applications improved weed control and seedling performance over cultivation alone. The combination of fall cultivation plus trifluralin is considered the best site preparatory treatment tested.

Effects of carbon dioxide enrichment and nitrogen supply on growth of boreal tree seedlings.

The effects of two levels of atmospheric carbon dioxide (350 microl l(-1), 750 microl l(-1)) and three levels of nitrogen (15.5 mM, 1.55 mM, 0.155 mM N) on biomass accumulation and partitioning were examined in aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) seedlings grown in controlled environment rooms for 100 days after germination. Nitrogen supply had pronounced effects on biomass accumulation, height, and leaf area of both species. Root weight ratio (RWR) of white spruce was significantly increased at the lowest level of nitrogen, whereas RWR of aspen did not change much with increasing levels of nitrogen. Carbon dioxide enrichment significantly increased (1) the leaf and total biomass of spruce seedlings grown in the high-N regime, (2) the RWR of seedlings in the medium-N regime, and (3) the root biomass of seedlings in the low-N regime after 100 days. Carbon dioxide enrichment of aspen temporarily increased biomass and height in all three nitrogen regimes. Root, stem, and leaf mass, height, and leaf area of aspen were increased only at the 30-day harvest in the high-N treatment and at 50 and 60 days in the low-N treatment. Height, stem biomass, and leaf biomass of aspen seedlings were significantly increased by CO(2) enrichment after 40 days in the medium-N treatment. These effects did not persist, possibly because of the onset of mineral nutrient supply limitations with increasing plant size.

Growth and physiological responses of aspen and jack pine to intermittent SO2 fumigation episodes

Five-week-old aspen seedlings and 8-week-old jack pine seedlings were exposed to a 3-h SO2 fumigation episode (peak = 0.78 μL L−1; mean = 0.30 μL L−1) 0, 2, or 5 times per week. Intermittent fumigation of both species for up to 8 weeks had no consistent, significant effect on aboveground biomass or on net assimilation rate and leaf resistance. A significant decrease (as much as 47%) in biomass of fumigated jack pine seedlings was found after 6 weeks of SO2 exposure, but after 7 weeks the decrease was not significant. In contrast, a significant increase in biomass of fumigated aspen seedlings was found, but only at 6 weeks, and apparently related to increased leaf retention. Fumigation caused transient decreases in net assimilation rate of both species. The maximum decrease in net assimilation rate measured just after an SO2 episode was 13% for aspen and 35% for jack pine, with a mean decrease for both of 12%. During SO2 fumigation, aspen net assimilation rate decreased as much as 38% and leaf resistance increased up to 47%. Both aspen and pine seedlings recovered from these transient SO2 effects, and there was no evidence for increased sensitivity to fumigation with time. After exposure to a single SO2 episode in the laboratory, field-collected branches of mature aspen showed a 30% decrease in net assimilation rate and a 50% increase in leaf resistance, from initial values similar to those of the greenhouse seedlings.

Synthesized ectomycorrhizae of aspen: fungal genus level of structural characterization

The ability of Populus tremuloides Michx. to form ectomycorrhizae with identified species of fungi was investigated using a pouch technique. Twenty-nine out of 54 fungus species formed ectomycorrhizae on aspen seedlings. Aspen seems to display little specificity for ectomycorrhizal fungi. Only epidermal Hartig nets were observed in the synthesized ectomycorrhizae and periepidermal ones were frequently encountered. Structural and morphological characteristics of ectomycorrhizae are presented by genus of mycorrhizal fungi. This grouping of characters by genus seems possible independently of the host plant. The classification of ectomycorrhizae is viewed in a new way in which structural types would be taxonomically related to the genus of the fungal symbiont.

OBSERVATIONS ON THE ORIGIN AND EARLY DEVELOPMENT OF A PLANT COMMUNITY FOLLOWING A FOREST FIRE

The origin of the species on a burned-over area in southwestern Nova Scotia was determined by means of covered plots, and the early stages of succession were followed closely for two years. All of the herbaceous and shrub species which appeared on the area during the first two years were survivors of the fire. Bracken fern showed unquestionable dominance the first year, but its position was severely contested by other herbaceous species and the heath plants during the second year. Seedlings of grey birch and large-toothed aspen appeared the second year and were restricted to patches of bare mineral soil. Sucker growth of red oak, red maple and grey birch was rapid, but it was pruned heavily by deer feeding.