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.

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.

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 ◽  
Balsam Fir

scholarly journals Vulnerability of Conifer Regeneration to Spruce Budworm Outbreaks in the Eastern Canadian Boreal Forest

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin
Keyword(s):  
Boreal Forests ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Insect Outbreaks ◽  
Spruce Stands ◽  
Canadian Boreal Forest

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.

Growth, biomass allocation, and adventitious roots of balsam fir seedlings growing in closed-canopy stands

Ecoscience ◽  
2006 ◽  
Vol 13 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier ◽  
Marie-Josée Simard
Keyword(s):  
Biomass Allocation ◽  
Adventitious Roots ◽  
Balsam Fir ◽  
Closed Canopy

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.

Daily weather response of balsam fir (Abies balsamea (L.) Mill.) stem radius increment from dendrometer analysis in the boreal forests of Qu�bec (Canada)

Trees ◽  
2003 ◽  
Vol 17 (6) ◽  
pp. 477-484 ◽  
Author(s):  
Annie Deslauriers ◽  
Hubert Morin ◽  
Carlo Urbinati ◽  
Marco Carrer
Keyword(s):  
Boreal Forests ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Daily Weather

Mountain maple and balsam fir early response to partial and clear-cut harvesting under aspen stands of northern Quebec

2004 ◽  
Vol 34 (10) ◽  
pp. 2049-2059 ◽  
Author(s):  
Laurence Bourgeois ◽  
Christian Messier ◽  
Suzanne Brais
Keyword(s):  
Boreal Forests ◽  
Block Design ◽  
Management Strategies ◽  
Abies Balsamea ◽  
Basal Area ◽  
Early Response ◽  
Balsam Fir ◽  
Clear Cut ◽  
Canopy Opening ◽  
Slight Growth

This study is a component of the Sylviculture et aménagement forestier écosystémique project, which examines ecosystem-based forest management strategies in mixedwood boreal forests. Four harvesting treatments, one no-harvest, one clearcut, and two partial cuts (33% and 61% of basal area removed), were applied to even-aged aspen stands according to a complete block design. Mountain maple (Acer spicatum Lamb.) and balsam fir (Abies balsamea (L.) Mill.) early response was examined to understand how they react to and interact with canopy opening. Only in clearcuts was maple's response (increase in growth and density) sustained and significant. Balsam fir suffered from a very slight "growth shock" 1 year after harvesting in both clear-cut and two-thirds partial-cut treatments, but growth and vigour increased with canopy opening during the next 2 years. The first year following harvesting, balsam fir growth was negatively affected by understorey aspen and mountain maple. Our results show that the two-thirds partial harvesting treatment could speed up the conversion of pure aspen stands toward mixedwood.

scholarly journals Litter-fall and decomposition in harvested and un-harvested boreal forests

2012 ◽  
Vol 88 (05) ◽  
pp. 613-621 ◽  
Author(s):  
M.T. Moroni ◽  
X. Zhu
Keyword(s):  
Litter Decomposition ◽  
Picea Mariana ◽  
Boreal Forests ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Forest Harvesting ◽  
Balsam Fir ◽  
Litter Fall ◽  
Feather Moss ◽  
Field Incubation

Litter fall and litter decomposition were examined in harvested and unharvested western Newfoundland balsam fir (Abies balsamea) and black spruce (Picea mariana) forests. Rates of litterfall in mature 70-year-old forests were 2.4 to 3.5 Mg ha−1 year−1, which was reduced to 0.2 to 0.3 Mg ha−1 year−1 following harvesting. In contrast, rates of black spruce needle, balsam fir needle, fine (<2 mm diameter) root, and moss (dominated by feather moss) litter decomposition were not affected by forest harvesting at either site during 24 to 54 months of field incubation in litterbags. Mass loss of balsam fir needle, black spruce needle, and moss (dominated by feather moss) were not significantly different indicating that moss forms a labile litter type in a forested setting.

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