Missing growth rings at the trunk base in suppressed balsam fir saplings

2002 ◽  
Vol 32 (10) ◽  
pp. 1776-1783 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Radial Growth ◽  
Adventitious Roots ◽  
Abies Balsamea ◽  
Dry Mass ◽  
Balsam Fir ◽  
Leaf Biomass ◽  
Growth Rings ◽  
Terminal Bud ◽  
Below Ground ◽  
Age Estimates

Numerous researchers have suggested a causal relationship between low leaf biomass in suppressed trees and the lack of radial growth at the base of the trunk. The objective of this study was to verify this relationship with suppressed balsam fir (Abies balsamea (L.) Mill.) saplings found growing in an old-growth fir stand. A total of 29 saplings varying in height from 67 to 183 cm were uprooted. All saplings had adventitious roots. All terminal bud scars (TBS) found between the apex of the terminal leader and the trunk base (first adventitious root) as well as those found below ground were localized, and rings were counted between TBS along the aboveground trunk. Various morphological traits and the ratio of photosynthetic tissue dry mass (P, needles) to non-photosynthetic tissue dry mass (nP, aboveground stem) were used as an indicator of tree vigour. Between 3 and 33 rings counted along the aboveground trunk were missing at the trunk base. The number of missing rings at the base of the trunk was correlated with total height (r = 0.41), height growth (r = –0.51), radial growth (r = –0.44), the P/nP ratio (r = –0.73), and the proportion of live crown (r = –0.62). Moreover, from 2 to 35 additional rings, missing at the trunk base, were found in the belowground section of trunk and these missing rings were associated with the adventitious roots phenomenon. In conclusion, suppressed firs had missing rings at the base of the trunk. When all of the missing rings were added to the number of rings counted at the base of the trunk, age estimates provided a different temporal pattern of recruitment compared with that obtained by solely counting rings at the base of the trunk. Stem analysis on the entire trunk is the best aging method for suppressed balsam fir saplings.

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

2000 ◽  
Vol 30 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Adventitious Roots ◽  
Age Determination ◽  
Abies Balsamea ◽  
Annual Growth ◽  
Balsam Fir ◽  
Growth Rings ◽  
Annual Growth Rings ◽  
Terminal Bud ◽  
Closed Forest ◽  
Reverse Taper

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.

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

2002 ◽  
Vol 32 (7) ◽  
pp. 1296-1300 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin
Keyword(s):  
Boreal Forests ◽  
Adventitious Roots ◽  
Age Determination ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Careful Examination ◽  
Growth Rings ◽  
Reverse Taper ◽  
Closed Canopy

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, <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.

Changes in root morphology after precommercial thinning in balsam fir stands

2003 ◽  
Vol 33 (12) ◽  
pp. 2452-2459 ◽  
Author(s):  
Jean-Claude Ruel ◽  
Catherine Larouche ◽  
Alexis Achim
Keyword(s):  
Radial Growth ◽  
Abies Balsamea ◽  
Stand Density ◽  
Balsam Fir ◽  
Cross Sectional ◽  
Beam Shape ◽  
Precommercial Thinning ◽  
Beneficial Effects ◽  
Density Control ◽  
Over Time

Precommercial thinning is often used to control stand density in naturally regenerated balsam fir (Abies balsamea (L.) Mill.) stands. Early stand density control could have beneficial effects on longer term stand stability through a modification of stem shape and root development. To assess the effect of precommercial thinning, two thinned and two unthinned stands were selected. Root sections were collected at 25 cm from the centre of the stem for all major roots (diameter greater than 2 cm). A disk was also cut at breast height level. From these disks, response in radial growth was determined. Detailed root measurements were taken on the sample disks to assess treatment effect on the following variables: asymmetry in root cross-sectional area (CSA) distribution, individual root shape, as well as changes in root shape over time. A quick and pronounced response in root growth occurred. This response was greater than that observed in the trunk. No asymmetry in root CSA distribution was observed at the stand level. Trees allocated more to radial growth above the biological centre of the root both in treated and control stands, but this trend was increased by thinning. Roots also tended to develop T-beam shapes over time, both in control and thinned stands. Most roots initially did not possess an I-beam shape and did not develop one during the course of the study. According to our results, trees respond quickly to the new growing conditions created by thinning by increasing biomass allocation to parts of the roots where mechanical stresses are greater.

scholarly journals EFFECTS OF DEFOLIATION BY SPRUCE BUDWORM (CHORISTONEURA FUMIFERANA CLEM.) ON RADIAL GROWTH AT BREAST HEIGHT OF BALSAM FIR (ABIES BALSAMEA (L.) MILL.) AND WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS.)

1958 ◽  
Vol 34 (1) ◽  
pp. 39-47 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Picea Glauca ◽  
Radial Growth ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
First Year ◽  
Growth Ratio ◽  
Breast Height

The relationship between spruce budworm defoliation and radial growth at breast height for balsam fir and white spruce trees of merchantable size was studied in various stands in northwestern Ontario. Defoliation was recorded yearly for these stands from the beginning of the infestation, and radial growth measurements were obtained from increment cores. The first year of radial growth suppression was calculated by comparing the growth of the affected species with that of jack pine and red pine trees by means of a growth-ratio technique. Apparent suppression in balsam fir and white spruce varied between stands, and, generally, occurred at the earliest in the second year and at the latest in the fourth year of severe defoliation. A wide ring at the base of the tree coinciding with the first year of suppression as reported by Craighead was non-existent.

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

2000 ◽  
Vol 30 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Adventitious Roots ◽  
Age Determination ◽  
Abies Balsamea ◽  
Balsam Fir

Insect defoliators as major disturbance factors in the high-altitude balsam fir forest of Mount Mégantic, southern Quebec

1998 ◽  
Vol 28 (12) ◽  
pp. 1832-1842 ◽  
Author(s):  
Louise Filion ◽  
Serge Payette ◽  
Ann Delwaide ◽  
Najat Bhiry
Keyword(s):  
North America ◽  
High Altitude ◽  
Tree Ring ◽  
Radial Growth ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Cumulative Impact ◽  
Tree Ring Data ◽  
Paper Birch

Tree-ring data from a mature balsam fir forest, located at the top of Mount Mégantic (elevation 1100 m), southern Quebec, suggest that insect defoliators were major disturbance factors in the development of high-altitude balsam fir forests. A comparison between the radial growth trend of balsam fir (Abies balsamea (L.) Mill.), a host species of the spruce budworm (Choristoneura fumiferana Clem.), and paper birch (Betula papyrifera Marsh), a nonhost species, showed that several growth depressions in the balsam fir chronology corrresponded to documented spruce budworm outbreaks in southern Quebec in the 1910s, 1950s, 1970s, and possibly in the 1870s. Tree mortality was extensive during the last infestation because of the relatively old age (>60 years) of many balsam fir and, possibly, to the cumulative impact of defoliation. The tree-ring series from paper birch showed several drops in radial growth after the 1930s, possibly related to the large-scale birch dieback that occurred in eastern North America. Macrofossil data (insect remains) from one sample of the uppermost organic soil layers (F horizon) confirm the presence of the spruce budworm at the study site. The ecological role of insect defoliators is discussed in the context of the high-altitude balsam fir forests in northeastern North America where abiotic disturbances are considered the primary controlling factors in stand dynamics.

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

2003 ◽  
Vol 33 (4) ◽  
pp. 597-603 ◽  
Author(s):  
Sylvain Parent ◽  
Marie-Josée Simard ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Adventitious Roots ◽  
Seedling Recruitment ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Disturbance Regime ◽  
Hylocomium Splendens ◽  
Substrate Type ◽  
Age Classes ◽  
Estimation Errors ◽  
Seedling Bank

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.

Regeneration development under shelterwoods in a lowland red spruce – balsam fir stand

2008 ◽  
Vol 38 (1) ◽  
pp. 31-39 ◽  
Author(s):  
David Pothier ◽  
Marcel Prévost
Keyword(s):  
Light Availability ◽  
Abies Balsamea ◽  
Tree Regeneration ◽  
Red Spruce ◽  
Balsam Fir ◽  
Leaf Biomass ◽  
Attractive Alternative ◽  
Clear Cutting ◽  
Cutting Intensity ◽  
Final Harvest

The shelterwood system can be used to establish regeneration and to improve the growing conditions of seedlings and, thereby, increase their probability of survival after final harvest. To determine the cutting intensity that best promotes the development of red spruce ( Picea rubens Sarg.) regeneration, an experiment, including four repetitions of five treatments (control; low, moderate, and heavy partial cuttings; and clear-cutting), was established in a lowland stand in Quebec, Canada, dominated by red spruce and balsam fir ( Abies balsamea (L.) Mill.). Regeneration development responses to treatments varied according to cutting intensity, species, and position relative to the skidding trails in the residual stands. Ten years after treatment, red spruce seedlings were well established but were smaller than those of balsam fir and deciduous species. Red spruce seedling height was generally greater in partial-cut skidding trails, as was light availability. However, in clearcuts, the size of red spruce seedlings established in skidding trails seemed to be negatively affected by the considerable quantity of woody debris strewn over them. Among the partial-cut treatments, tree regeneration leaf biomass was the highest where 60% of the initial basal area was removed. Thus, this treatment is an attractive alternative to clear-cutting in such lowland stands where watering-up is anticipated after final harvest.

Balsam fir (Abies balsamea) establishment dynamics during a spruce budworm (Choristoneura fumiferana) outbreak: an evaluation of the impact of aging techniques

2001 ◽  
Vol 31 (3) ◽  
pp. 373-376 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Conventional Method ◽  
Seedling Recruitment ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Adult Mortality ◽  
Balsam Fir ◽  
Tree Age ◽  
Terminal Bud ◽  
The Impact

The effects of recurrent spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks on balsam fir (Abies balsamea (L.) Mill.) mortality have been extensively studied in Canada. Most studies report substantial seedling recruitment of balsam fir during outbreaks when reproductive trees are dying. According to previous research, this contradiction could be due to inaccuracies in the conventional aging method. Counting the maximum number of growth rings found at the tree base would significantly underestimate tree age. Counting terminal bud scars found on the entire trunk, including buried stem, would give a more accurate tree age. In this study, we compare recruitment dynamics obtained for aging seedlings in two balsam fir populations (about 500 km apart) using (i) the conventional method and (ii) bud scar counts. For both populations, the conventional method shows substantial recruitment during adult mortality, while the second aging technique reveals reduced recruitment during the epidemic phase of the spruce budworm outbreak.

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