Balsam Fir Seedlings Research Articles

Age and size structure of gap-dynamic, old-growth boreal forest stands in Newfoundland

The age and size structure of trees in old Abies-Picea-Betula forests on Newfoundland’s Great Northern Peninsula were examined. It was hypothesized that the size and age structure of both the tree and regeneration “strata” of these stands display the complex structural heterogeneity characteristic of classic, self-regenerating, uneven-aged old-growth stands, and that the development and dynamics of such structures occur over long periods of time. With all tree species combined, dbh (diameter at breast height) and height distributions exhibited a strong reverse-J character, with well-defined, semi-logarithmic rotated sigmoid height and size frequencies. Seedling height and basal diameter frequency distributions were reverse-J in character. Live tree ages for all species, except white birch (Betula papyrifera Marsh), ranged from 25 to 269 years, and were characterized by all-age frequency distributions. Tree age and size were poorly correlated. On average, balsam fir (Abies balsamea (L.) Mill.) required 62 years to reach breast height (1.3 m), with black spruce (Picea mariana (Mill.) B.S.P.) and white spruce (Picea glauca (Moench) Voss) requiring 40 and 48 years, respectively. Total age of dead standing trees ranged from 45 to 232 years. Reverse-J age frequencies characterized the seedling bank, with balsam fir seedlings present in nearly all age classes up to 110, 120 and 85 years in three sample stands. Seedling size (height and basal diameter)-age relationships were characteristic of decades-long suppression. The combination of tree and seedling bank size and age structure provide strong evidence of quasi-equilibrium, small-scale, gap dynamic old-growth boreal forest stands.

Long-term decline in white-tailed deer browse supply: can lichens and litterfall act as alternative food sources that preclude density-dependent feedbacks

Selective browsing by cervids has persistent impacts on forest ecosystems. On Anticosti Island, Quebec, Canada, introduced white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) have caused massive changes to the native boreal forest. Despite the apparent stability of the deer population over recent decades, we suspected that they were not at equilibrium with their browse supply and that further degradation of the habitat had occurred. A comparison of two browse surveys conducted 25 years apart showed a strong decline in browse availability. Although balsam fir (Abies balsamea (L.) P. Mill.) remained the most available browse species, it declined or disappeared from most stands (n = 13). Preferred deciduous species that were still available 25 years ago have almost disappeared. The continuous decline of the browse supply confirmed our hypothesis. This situation may be exacerbated by a subsidy from the winter litterfall, a significant and stable alternative food source. The abundance of litterfall from mature trees is independent of browsing over a long time period, which introduces a temporal uncoupling between the impact of deer browsing on balsam fir seedlings and the negative feedback from recruitment failure of mature balsam fir on the deer population. This means that the system is susceptible to being forced into an alternative regime.

Impact of old foliage removal, simulating defoliation by the balsam fir sawfly, on balsam fir tree growth and photosynthesis of current-year shoots

To investigate the effect of defoliation by the balsam fir sawfly ( Neodiprion abietis) on current-year growth and photosynthesis, all 1-year-old and older foliage were removed by manual clipping before the start of the growing season from balsam fir seedlings cultivated at two levels of fertilization. Measurements carried out late in the same growing season showed that both defoliation and withholding fertilizer reduced current-year foliar dry weight, shoot length, needle size, and stem xylem radial width, as well as total foliar dry weight, and root dry weight. Defoliation increased the projected area to weight ratio, nitrogen concentration, net photosynthetic rate per unit of dry weight, and ratio of photosynthesis to internal CO 2 concentration in current-year needles. In contrast, withholding fertilizer did not alter the projected area to weight ratio and decreased the nitrogen concentration, net photosynthetic rate per unit of dry weight, and ratio of photosynthesis to internal CO 2 concentration. Both defoliation and withholding fertilizer also decreased the number of current-year needles produced in the growing season following treatment. The results indicate that (1) the reduction in total photosynthesizing biomass caused by removing old foliage is much greater than the biomass of old foliage removed due to decreased production of current-year foliage, and (2) old foliage removal stimulates net photosynthesis in current-year shoots, probably by improving foliar nitrogen relations. Removing old foliage reduced the total photosynthesizing biomass more, and stimulated net photosynthesis of remaining foliage less, than the removal of current-year foliage measured in earlier studies, which helps explain why tree recovery is slower following defoliation by the balsam fir sawfly than after spruce budworm ( Choristoneura fumiferana) attack.

Establishment and dynamics of the balsam fir seedling bank in old forests of northeastern Quebec

This study examines balsam fir (Abies balsamea (L.) Mill.) recruitment in old fir stands. Studying the regeneration of these stands is essential to understand the regeneration dynamic of the species in the absence of stand-destroying disturbances. The objectives were (1) to obtain substrate–seedling associations for different age-classes and according to the presence or absence of adventitious roots; (2) to evaluate the contribution of the seed rain to seedling recruitment; (3) to re-examine age structures using the most appropriate method that minimizes estimation errors due to the presence of adventitious roots. A total of 90 quadrats (1 m2) were established along transects. In each quadrat, subtrates were characterized (type and topography) and their area was estimated. All balsam fir seedlings (<50 cm tall) present in the quadrats were located, harvested whole (root and shoot), and described (age, height, presence of adventitious roots, etc). Fir seedlings were strongly associated with woody mounds covered with thin mats of mixed mosses and Pleurozium shreberi (Bird.) Mitt. but negatively associated with flat topography particularly dominated by Hylocomium splendens (Hedw.) B.S.G. The presence of adventitious root is related to seedling age more than substrate type or topography. The age structure is in agreement with seed production and disturbance regime.

The eradication of balsam fir stands by white-tailed deer on Anticosti Island, Québec: A 150-year process

White-tailed deer (Odocoileus virginianus) were introduced 100 y ago on Anticosti, a 7,943-km2 island located in the Gulf of St. Lawrence, Québec. The forest of the island is typically boreal and, at the time of the introduction, was dominated by balsam fir (Abies balsamea), white spruce (Picea glauca), and black spruce (P. mariana). Since then, the vegetation has been modified as a result of high deer density (16 deer·km-2) and heavy browsing. The most important change is the progressive decline of balsam fir stands, formerly the prevalent forest type. We describe that process at three spatial and time scales. On the largest scale (whole island, 100 y), we examined the age and species composition of stands on recent forest maps as well as the age structure of 2,555 individual balsam fir and white spruce trees. Balsam fir was largely dominant before 1930, but was replaced by white spruce afterwards. We also estimated that fir stands, which now cover 20% of the island, occupied about 40% of the total area initially. On an intermediate scale (1,200 km2, 30 y), we examined the natural regeneration established after an insect outbreak that took place in 1971-1972 and massively killed predominantly balsam fir forests. In that area, white spruce regeneration now largely replaces that of balsam fir. On a finer scale (< 1 km2, 3 y), we monitored 1,800 balsam fir seedlings (2-5 cm high) individually tagged. Seedlings were browsed throughout the snow-free season, and the annual browsing incidence in forest was estimated at 26%. Considering the present age of remnant fir stands, we estimate that most of these will have been eradicated in 40-50 y.

Chronologie de la croissance chez des semis de sapin baumier (Abies balsamea (L.) Mill.) après une coupe à blanc avec protection de la régénération

The method of harvesting with protection of the advanced regeneration consists of a complete removal of the main canopy to release a seedling bank established under the overstory shade. After harvesting, seedlings acclimated to understory conditions could suffer from moisture stress, especially the small, juvenile seedlings (less than six years). The objective of the study is to determine the capacity of understory-acclimated balsam fir seedlings to respond positively and immediately to release. The response to release was studied in two seedling populations belonging to two distinct climatic regions of Quebec, the Western and the Eastern sections of the balsam fir-white birch ecological domain. Results show that the response patterns were similar in both populations. Response to release occurred in two steps. One year after harvesting, basal ring width was on the average five times larger than prior to harvesting (p &gt; 0.001). Height growth only became significantly higher the second year after release (p &lt; 0.001). On average, juveniles showed higher height growth rates (height growth/height) than older seedlings. This rate was negatively correlated to seedling height at harvesting (r = -0,68, p &lt; 0.001). Our study clearly shows that balsam fir seedlings can respond immediately and positively to large openings. The strong response of juvenile seedlings to release indicates that these can contribute significantly to the future stand. The geographic and climatic differences between the two stands under study suggest that these observations apply to a wide range of balsam fir stands. Key words: advance growth, balsam fir, release

Enhanced growth and ethylene increases spiral grain formation in Picea abies and Abies balsamea trees

Spiral grain angle in Norway spruce (Picea abies) trees and balsam fir (Abies balsamea) seedlings was investigated in relation to growth rate, endogenous and applied ethylene. Trees from stands of Norway spruce, which were irrigated and fertilised in order to enhance growth, and trees having different growth rates in non-treated stands were studied. Stem growth rate at the stand level (m3 ha–1 year–1) was measured annually, or by means of microscopy on stem sections as the number and size of tracheids produced. Enhanced growth increased ethylene evolution and maintained a high level of left-handed spiral grain angle in comparison to slower-growing trees. An increased number of earlywood tracheids in fast growing trees was correlated to a more left-handed spiral grain angle. Ethrel, applied to stems of balsam fir seedlings, increased the internal ethylene levels in parallel with increased left-handed spiral grain angle. The results indicate that ethylene regulates the extent of spiral grain angle.

Reply - Effects of adventitious roots on age determination in balsam fir regeneration

In many Canadian boreal forests, balsam fir (Abies balsamea (L.) Mill.) seedlings established under closed canopy generally develop adventitious roots. Adventitious roots induce the formation of a reverse taper, i.e., a reduction of the diameter and of the number of growth rings towards the true collar (hypocotyl region). Consequently, ring count at any level of the trunk underestimates the true age of firs, and we recommend a reassessment of balsam fir dynamics inferred from studies based on ages estimated by ring count. Recently, Kneeshaw and Claveau (D.D. Kneeshaw and Y. Claveau. 2001. Can. J. For. Res. 31: 1292-1295) presented data from a subsample of fir seedlings to demonstrate that ring count is an accurate aging technique for most fir regeneration. A careful examination of the methodology, data, and samples presented suggests that true collars were not precisely located. We also present data collected on seedlings sampled in the same study area as Kneeshaw and Claveau. Most of the seedlings (57 of 60 seedlings, &lt;50 cm in height) had adventitious roots, and ring count was not an appropriate aging method. According to our study, Kneeshaw and Claveau either did not locate the true collar or presented atypical balsam fir seedlings.

Effect of nitrogen and light on nutrient concentrations and associated physiological responses in birch and fir seedlings

We grew seedlings of two co-occurring high elevation tree species in controlled light and nitrogen (N) environments to examine the effect on foliar N and P concentrations and the resulting correlation with photosynthesis and growth. Foliar N concentrations in both heart-leaf paper birch (Betula cordifolia) and balsam fir (Abies balsamea) seedlings were greater in low light treatments than in high light treatments. P concentrations, however, were lower in birch and fir foliage grown in low light than in high light. N-availability had no effect on foliar N in birch but tended to increase N concentration in fir needles at all but 100% ambient light. N-availability had no effect on P concentration in fir seedlings, but high N decreased foliar P in birch. There was a positive relationship between foliar N-concentration (mg g−1) and mass-based maximum photosynthetic rate (Asat) in birch seedlings and a corresponding growth response to increased N-availability (suggesting N-limitation). Fir photosynthesis exhibited a positive correlation up to 22 mg g−1 – N and a negative correlation above that point, suggesting that high N concentrations may be detrimental to photosynthesis in the fir seedlings. There was no significant effect of N-treatment on growth.

Effect of seed predation, shade and soil organic matter on the early establishment of eastern white pine and balsam fir seedlings

Eastern white pine (Pinus strobus L.) does not regenerate well in the absence of fire, or without mechanical exposure of mineral soil, while balsam fir (Abies balsamea L. Mill.) is a common understory species on sites occupied by white pine. We conducted two experiments to explain the difference in regenerative success of these two species. First, the effect of shade and soil organic matter on the emergence of white pine and balsam fir were compared using soil monoliths from a regenerating white pine stand. Balsam fir germination was significantly lower than white pine germination at different shade levels and at different levels of soil organic matter. Second, seed predation was compared between balsam fir and white pine in a non-regenerating white pine stand. Predation of white pine seeds was 10 times greater than balsam fir predation even when seeds of white pine and balsam fir were left as a mixture on the forest floor. We speculate that seed predation is a critical factor in white pine succession and that seed predators favour balsam fir succession by selecting white pine seeds. Key words: seed predation, fire ecology, Pinus strobus, Abies balsamea, Peromyscus maniculatus, succession

Effects of adventitious roots on age determination in Balsam fir (Abies balsamea) regeneration

The age structure of balsam fir (Abies balsamea (L.) Mill.) regeneration is frequently used to investigate boreal forest dynamics of North America. Tree ages are usually estimated by counting annual growth rings at the shoot-root interface located above or close to the root system. Inaccurately locating the shoot-root interface could lead to imprecise age determination. In this study, balsam fir seedlings (&lt;2 m height) were harvested in whole from closed forest stands located in the province of Quebec, Canada. Seedling age was determined by (i) counting the number of annual growth rings at the presumed shoot-root interface, and (ii) counting all terminal bud scars from the apex to the base of the hypocotyl (true collar). For all seedlings with adventitious roots, the number of terminal bud scars on the entire trunk was higher than the number of growth rings at the shoot-root interface. The formation of adventitious roots on the belowground trunk was accompanied by a reverse taper phenomenon, i.e., the number of annual growth rings decreased from the presumed shoot-root interface to the true collar. Counting annual growth rings at any level on the trunk of balsam fir seedlings that form adventitious root systems would not be reliable, underestimation's exceeding 20 years are possible and the resulting age structures could lead to erroneous interpretations of regeneration dynamics.

Effects of adventitious roots on age determination in Balsam fir (&lt;i&gt;Abies balsamea&lt;/i&gt;) regeneration

The age structure of balsam fir (Abies balsamea (L.) Mill.) regeneration is frequently used to investigate boreal forest dynamics of North America. Tree ages are usually estimated by counting annual growth rings at the shoot-root interface located above or close to the root system. Inaccurately locating the shoot-root interface could lead to imprecise age determination. In this study, balsam fir seedlings (<2 m height) were harvested in whole from closed forest stands located in the province of Quebec, Canada. Seedling age was determined by (i) counting the number of annual growth rings at the presumed shoot-root interface, and (ii) counting all terminal bud scars from the apex to the base of the hypocotyl (true collar). For all seedlings with adventitious roots, the number of terminal bud scars on the entire trunk was higher than the number of growth rings at the shoot-root interface. The formation of adventitious roots on the belowground trunk was accompanied by a reverse taper phenomenon, i.e., the number of annual growth rings decreased from the presumed shoot-root interface to the true collar. Counting annual growth rings at any level on the trunk of balsam fir seedlings that form adventitious root systems would not be reliable, underestimation's exceeding 20 years are possible and the resulting age structures could lead to erroneous interpretations of regeneration dynamics.

Uptake and Translocation Studies in Balsam Fir Seedlings with 54Mn and 65Zn Radioisotopes Applied to Soil Surfaces

AbstractPathways of heavy metal deposits in balsam fir [Abies balsamea (L) Mill.] seedlings were investigated by simultaneously applying 54Mn and 65Zn radioisotopes on soil surfaces. Downward movement of 54Mn and 65Zn in soils was documented to the 14 to 16 cm depth 70 d after application. One‐year‐old needles and 3‐yr‐old twigs concentrated more radioisotopes than older needles and younger twigs, respectively, with the sample specific activity (kBq kg−1) of 54Mn 5 to 10 times higher than that of 65Zn. The activity in seedlings on the 70th d of the experiment was 5.2% of the total remaining activity for 54Mn (6290 kBq) and 2.6 % for 65Zn (6031 kBq). The distribution of 54Mn in the seedling was 31% in roots, 31% in twigs, 26% in stems, and 12% in needles, while roots retained 86% of 65Zn. No appreciable migration of elements from internal tissues to epicuticular wax layers was found when shoots were washed in chloroform. The maximum leaching ratio was below 0.5 and 1.0% for 54Mn and 65Zn, respectively, when shoots were washed in simulated acid rain for 5 min.

Response of wildlife to forest herbicide applications in northern coniferous ecosystems

Reviewed studies of the effects of forest herbicide applications on wildlife often lacked replication, pretreatment information, and (or) were conducted for only one or two growing seasons after treatment. Because of these problems, as well as the use of dissimilar sampling techniques, study conclusions have sometimes been contradictory. A review of eight studies of the effects of herbicide treatments on northern songbird populations in regenerating clearcuts indicates that total songbird populations are seldom reduced during the growing season after treatment. Densities of species that use early successional brushy, deciduous cover are sometimes reduced, while densities of species which commonly use more open areas, sometimes increase. A review of 14 studies of the effects of herbicide treatments on small mammals indicates that like songbirds, small mammal responses are species specific. Some species are unaffected, while some select and others avoid herbicide-treated areas. Only studies that use kill or removal trapping to study small mammal responses show density reductions associated with herbicide treatment. It seems that some small mammal species may be reluctant to venture into disturbed areas, although residents in those areas are apparently not affected by the disturbance. Fourteen relevant studies examined the effects of conifer release treatments on moose and deer foods and habitat use. Conifer release treatments reduce the availability of moose browse for as long as four growing seasons after treatment. The degree of reduction during the growing season after treatment varies with the herbicide and rate used. Deer use of treated areas remains unchanged or increases during the first growing season after treatment. Eight years after treating a naturally regenerated spruce–fir stand browse was three to seven times more abundant on treated than on control plots (depending on the chemical and rate used). Forage quality (nitrogen, ash, and moisture) of crop trees increased one growing season after the soil-active herbicide simazine was applied to control competition around outplanted 3-year-old balsam fir seedlings.

Impact of Deer Browsing on Regeneration of Balsam Fir in Canaan Valley, West Virginia

Abstract I determined composition and regeneration of balsam fir stands during June 1991 at four sites in Canaan Valley, West Virginia. White-tailed deer had heavily browsed balsam fir, and regeneration did not appear adequate to replace the stands. There was an apparent correlation between relative deer abundance, as measured by numbers of pellet groups, and balsam fir regeneration. The site with the most deer had the fewest balsam fir seedlings (5/ac), and the site with the fewest deer had the most balsam fir seedlings (1040/ac). Balsam fir will probably be replaced by red spruce, one of the few tree species not commonly browsed by deer. North. J. Appl. For. 9(3):89-90.

Infection of red spruce, black spruce, and balsam fir seedlings with tomato mosaic virus

Red spruce (Picearubens Sarg.), black spruce (Piceamariana (Mill.) B.S.P.), and balsam fir (Abiesbalsamea (L.) Mill.) seedlings were root inoculated with tomato mosaic virus, potted, and maintained in a cold frame. The virus was detected by enzyme-linked immunosorbent assay in root extracts of several inoculated seedlings of each species 6–12 months postinoculation, and in root extracts of approximately 35–40% of both inoculated and noninoculated seedlings of each species 12–18 months postinoculation. Virus spread apparently occurred from the roots of infected to noninfected seedlings within the cold frame. The presence of virus in root extracts was confirmed by immunoelectron microscopy. The virus was not detected in the needles of any seedling at any time by either enzyme-linked immunosorbent assay or immunoelectron microscopy. A transitory needle chlorosis was observed in approximately 14% of the inoculated black spruce and 30% of the inoculated red spruce seedlings, but tomato mosaic virus was not detected in all plants with symptoms.

Relative volatilization of three insecticides from deposits on fir foliage following spray application under laboratory conditions

Abstract Volatilization of three forestry insecticides, aminocarb, fenitrothion and mexacarbate, from balsam fir seedlings was investigated after spray application of these chemicals as aqueous emulsions in a laboratory chamber at a dosage rate of 210 g (active ingredient)/ha. Highest airborne residues were found in the spray chamber at 0.25 h after mexacarbate application (21.7 μg/L) and lowest after aminocarb (6.3 μg/L). The treated seedlings were transferred to air‐tight chambers for investigation of volatilization over a 12 h post‐spray period. Mexacarbate was the most volatile, while aminocarb was the least. From the initial amounts of deposits on the seedlings, about 30% of mexacarbate, 15% of fenitrothion and 9% of aminocarb were lost within 12 h by volatilization. Residue levels that remained in the seedlings at 12 h post‐spray were ca. 70% of the initial values for aminocarb and fenitrothion, but were only ca. 9% for mexacarbate. Calculations on the mass‐balance indicated that 60% of the deposite...

Moose browsing and allelopathic effects of Kalmiaangustifolia on balsam fir regeneration in central Newfoundland

We collected forest floor organic matter at two sites where exclosures had been established 12 years previously. The exclosures allowed examination of the effects of moose (Alcesalces) herbivory on the growth of balsam fir (Abiesbalsamea). The areas supported an understory with Kalmiaangustifolia, which has been shown to affect seedling growth of black spruce (Piceamariana). Balsam fir seedlings grown in the laboratory in soil from outside the exclosures showed a significant reduction in fresh weight of the primary root compared with plants grown in washed sand. Treatment soils also showed a previously known growth inhibition effect on roots of black spruce. Exclusion of moose browsing resulted in a higher density of balsam fir inside the exclosures, while Kalmia, which was not browsed, was more dense outside the exclosures. We postulate that moose browsing reduces the extent to which balsam fir shades Kalmia, and can result in a higher density of the latter species, with consequent inhibitory effects on regenerating coniferous species.

Response of red spruce and balsam fir seedlings to aluminum toxicity in nutrient solutions

Red spruce (Picearubens Sarg.) and balsam fir (Abiesbalsamea (L.) Mill.) were grown in nutrient solutions containing 0, 25, 50, 100, and 200 mg/L aluminum (Al) at pH 3.8. Seedlings died only when placed directly in solutions containing Al without first being conditioned to growth in a hydroponic system. In preconditioned seedlings, no evidence of Al injury was noted in the tops of seedlings at any level of Al, except for small reductions in shoot growth. Aluminum toxicity symptoms in roots, however, were well developed, though spruce showed less tolerance than fir. Inhibition of root growth in both species was first evident at 50 mg/L Al, root lengths decreasing with increasing concentrations of Al. Spruce seedlings at Al concentrations of 100 mg/L and higher were characterized by thickened, stunted, dark brown roots. Root deterioration was caused by Al-induced destruction of epidermal and cortical cells. Although root elongation was severely restricted in spruce and fir, root dry weight was not significantly reduced. Aluminum decreased seedling uptake of most mineral elements; manganese, magnesium, and zinc were affected most and boron and phosphorus least.

Comparison of the pine wood nematode, Bursaphelenchus xylophilus from pine and balsam fir1

AbstractThe pine wood nematode, Bursaphelenchus xylophilus was found on balsam fir in Minnesota and Wisconsin but was apparently not the primary cause of tree mortality. Unlike B. xylophilus from pine, adult females from balsam fir bad mucronate tails similar to those of B. mucronatus. However, B. xylophilus from balsam fir mated with B. xylophilus from pine and not with B. mucronatus. The balsam fir isolate of B. xylophilus was pathogenic on greenhouse grown balsam fir seedlings and did not kill Scots or red pine seedlings. The converse was true for a pine isolate of B. xylophilus from Minnesota which killed pine and not balsam fir seedlings. Pine and balsam fir isolates of B. xylophilus reproduced equally well on cultures of Botrytis cinera, but the balsam fir isolate reproduced minimally on cultures of Ceratocystis ips.