Estimating coarse root biomass of balsam fir

2007 ◽  
Vol 37 (6) ◽  
pp. 991-998 ◽  
Author(s):  
M.B. Lavigne ◽  
M.J. Krasowski

Root systems of 31 balsam fir ( Abies balsamea (L.) Mill.) trees were excavated at five sites in central New Brunswick. Sites ranged from 10 to >80 years in stand age; most had been thinned at least once, and densities ranged from 750 to 44 000 trees·ha–1. The relationship between diameter at breast height and coarse root biomass in the present investigation was similar to one reported for balsam fir in northern New Brunswick but differed from two other published biomass equations. Coarse root biomass per hectare ranged from 3 to 30 Mg·ha–1 among studied sites. Coarse root biomass in the smaller root diameter classes was similar at all sites, but biomass in diameter classes >50 mm increased with stand age. Precommercial thinning added 3 Mg coarse root biomass·ha–1 to the detrital pool. The ratio of coarse root biomass to stem biomass averaged 0.36 (±0.02 SE). These results show that there is more belowground biomass in balsam fir ecosystems than would be expected from the generic ratio of belowground to aboveground biomass often applied to coniferous ecosystems, pointing to a need for using ratios that are more specific.

2005 ◽  
Vol 35 (8) ◽  
pp. 1844-1853 ◽  
Author(s):  
A Achim ◽  
J -C Ruel ◽  
B A Gardiner

A tree-pulling experiment was carried out in stands of balsam fir (Abies balsamea (L.) Mill.) to evaluate the effects of early thinning on windthrow resistance. Forty trees from four stands were pulled over. Two stands had received a precommercial thinning 9 and 14 years previously, respectively, and the two others were unthinned controls. There were no significant inter-stand differences in the relationship between the critical turning moments required to overturn or snap the trees and their stem mass. The results were input into a model calculating critical wind speeds using the approach developed for the ForestGALES model. Simulations were run for four different stand densities. The mensurational characteristics for each run were taken from the results of a spacing trial established in balsam fir stands at Green River, New Brunswick. For stem breakage, the model predicted a gradual increase in critical wind speeds with wider spacing. The increase was smaller for tree overturning. The pattern of differences remained very similar after a simulated commercial thinning removing 30% of the basal area. Reductions in critical wind speeds were on the order of 4 m·s–1 in all cases. Simple indices were developed that could estimate the relative results given by the model.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Serdar Akburak ◽  
Ender Makineci

Abstract Background Thinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes. Method Two replicated control and thinning plots (50 m × 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0–2 mm (fine roots), 2–5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed. Results Except coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g∙m− 2) and thinned plots (1060 g∙m− 2) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period. Conclusion The results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics.


2004 ◽  
Vol 82 (4) ◽  
pp. 671-676 ◽  
Author(s):  
François Potvin ◽  
Barry Boots

Determining at what scale to operate and how much cover is needed are important questions for winter habitat management of white-tailed deer, Odocoileus virginianus (Zimmermann, 1780), through logging. We used binary cover maps (reclassified forest vegetation maps) and windows of different sizes (0.2 km × 0.2 km, 0.5 km × 0.5 km, 1 km × 1 km, 2 km × 2 km, and 3 km × 3 km) to describe the relationship between deer density from an aerial survey and the proportion of balsam fir, Abies balsamea (L.) P. Mill., forest (BF) cover in a 270-km2 block on Anticosti Island, Quebec. Maximum white-tailed deer densities reached were quite similar (31–34 deer/km2) irrespective of window size, except for the 3 km × 3 km window for which maximum density remained half lower. Density increased with the amount of BF cover and then reached a plateau above 60% or 70% (two smaller windows) or decreased above 50% or 60% (1 km × 1 km and 2 km × 2 km windows). Results confirm goals previously used for habitat management of deeryards. This new method allows greater flexibility in research applications for describing density–cover relationships because both scale and proportion of cover can be analysed simultaneously.


2010 ◽  
Vol 142 (5) ◽  
pp. 466-472
Author(s):  
Bertrand Guillet ◽  
Andrew Morrison ◽  
Drew Carleton ◽  
Don Ostaff ◽  
Dan Quiring

AbstractWe collected midcrown branches of balsam fir, Abies balsamea (L.) Mill. (Pinaceae), at six different sites located in five different plant-hardiness zones, along a north–south transect in New Brunswick, Canada, to evaluate the effect of plant-hardiness zone, crown class (overstory versus understory), and shoot length during the previous 10 years on the annual incidence of gouting by the balsam woolly adelgid, Adelges piceae (Ratzeburg) (Homoptera: Adelgidae). Site, crown class, and their interaction, along with the square of shoot length, explained 78% of the variation in gouting. Variations in gouting attributed to plant-hardiness zone were probably primarily due to variation in mean January temperature: at each site, the mean January temperature was positively and closely related to the mean level of gouting. The level of gouting was consistently higher on trees in the understory than on those in the overstory. Shoot length was parabolically related to the proportion of shoots with gout. The parabolic relationship between shoot size and the level of gouting is similar to that previously reported for galling adelgids, and suggests that gouting by A. piceae may be greatest on trees with an intermediate growth rate.


1989 ◽  
Vol 67 (12) ◽  
pp. 3513-3516 ◽  
Author(s):  
John A. Johnson ◽  
Norman J. Whitney

Endophytic fungi were isolated from the interiors of surface-sterilized needles of balsam fir (Abies balsamea) and red spruce (Picea rubens) in New Brunswick, Canada. Four different fungi were isolated frequently. One species, designated X-W, was isolated exlusively from the petiole segment of red spruce needles. There was no difference in the variety of species isolated from fir needles from two sites, but a difference in frequency of species did exist. Micrographs of the interior of balsam fir needles showed hyphae occupying intercellular spaces and adhering to the outer walls of parenchyma cells. No penetration of cells by either fungus was observed.


2015 ◽  
Vol 45 (6) ◽  
pp. 659-666 ◽  
Author(s):  
Edward A. Wilson ◽  
David A. MacLean

Forest management regimes increasingly focus on the emulation of natural disturbance events, e.g., fire or insect outbreaks, to help increase ecosystem sustainability. We determined the residual stand response to a variable retention harvest inspired by spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks in New Brunswick, Canada. Our objectives were to analyze the differences between surviving residual trees and those that succumbed to windthrow and to quantify growth release. The treatment was based on harvesting the estimated spruce budworm outbreak mortality, i.e., 90% of mature balsam fir (Abies balsamea (L.) Mill., 60% of mature spruce (Picea spp.), and no hardwoods. Windthrow increased with the proportion of trees harvested and averaged 52% over 7–9 years in these stands with high balsam fir – spruce content. One-third of 42 harvested plots sustained >30% windthrow, whereas 73% of 11 similar unharvested plots had <10% windthrow. Balsam fir had higher windthrow than spruce at 53% and 41%, respectively. Windthrown balsam fir trees had significantly larger diameters at breast height (DBH, 1.3 m), larger heights, and smaller crown ratios than surviving residual trees. Substantial growth release occurred, with DBH increment of residual trees 48%–64% greater than trees in unharvested plots. Balsam fir and intolerant hardwoods exhibited the largest growth response. We suggest that future spruce budworm inspired harvests in stands with high balsam fir – spruce content use two or three entries about 5 years apart to reduce windthrow.


2015 ◽  
Vol 45 (3) ◽  
pp. 314-324 ◽  
Author(s):  
Guillaume B. Sainte-Marie ◽  
Daniel D. Kneeshaw ◽  
David A. MacLean ◽  
Chris R. Hennigar

Silvicultural treatments recommended to reduce damage by spruce budworm (SBW; Choristoneura fumiferana Clemens) include reducing balsam fir (Abies balsamea (L.) Mill.) abundance and age and increasing spruce (Picea spp.) and hardwood content. To evaluate the effect of these measures on forest timber supply, we assessed stand characteristics, disturbance history, and timber supply for an intensively managed eastern Quebec forest from 1985 to 2004, encompassing a major SBW outbreak. During this time, mean stand age declined from 55 to 51 years, and proportions of areas in balsam fir stands declined (42% to 27%), spruce–fir stabilized (12% to 11%), and mixedwoods increased (32% to 52%). We estimated forest vulnerability using softwood volume reductions following simulated outbreak scenarios of different severity (low, moderate, and high) and different effects of hardwood content in reducing spruce–fir defoliation. Volume reductions for outbreaks simulated to begin in either 1985 or 2004 were similar, ranging from 15%–46% (no hardwood effect in reducing defoliation) to 13%–39% (given a maximum hardwood content effect) for light and severe outbreaks, respectively. Considering the net detrimental effect of increased hardwood content on softwood timber supply, we question the dividends of promoting hardwoods and recommend increasing the combined use of plantations and weeding treatments to increase spruce content.


2008 ◽  
Vol 38 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Rock Ouimet ◽  
Claude Camiré ◽  
Marcel Brazeau ◽  
Jean-David Moore

Estimates of belowground biomass and mineralomass are fundamental to understanding carbon and element cycling in forest ecosystems. At two sites, we measured coarse root (diameter ≥2 mm) biomass by diameter class and their mineralomass for sugar maple ( Acer saccharum Marsh.), black spruce ( Picea mariana (Mill.) BSP), and jack pine ( Pinus banksiana Lamb.) trees to relate them to stem diameter at breast height (DBH). All regressions describing coarse root biomass and nutrient content as a function of stem DBH were highly significant (r2 ≥ 0.89, P < 0.001). Root mineral element (N, P, K, Ca, Mg, and S) concentrations varied with tree species and root diameter class. Sugar maple roots had higher N, P, and S concentrations than the other two tree species. Black spruce had higher root Ca concentrations. Element concentrations increased consistently with the reduction of root diameter for the three studied species. We also found that the horizontal root extent of sugar maple was related to tree DBH. In conjunction with other studies, the relationship suggests that this tree species could tolerate a 10%–20% root loss but not losses ≥28%–34%; otherwise, sugar maple health and vigour would be compromised in the short term.


2000 ◽  
Vol 76 (2) ◽  
pp. 329-337 ◽  
Author(s):  
J.-C. Ruel ◽  
S. Meunier ◽  
C. P. Quine ◽  
J. Suarez

Balsam fir (Abies balsamea (L.) Mill.) forests are inherently vulnerable to windthrow, especially when silvicultural treatments are applied. During recent years, it has become possible to model windthrow risk based on a good understanding of windthrow mechanics. In the present paper, the British ForestGales model has been adapted for balsam fir with data from a winching study in Quebec, Canada. This model calculates the threshold wind speed required to break or overturn the average tree in a stand and then calculates the probability of exceeding the threshold value. Modifications of the equations predicting crown characteristics and overturning resistance were introduced. The effects of age, site quality, wind exposure, thinning and the creation of new edges were assessed. The estimated critical wind speed for overturning and breakage decreases with age but the probability of damage remains low on sheltered sites. The creation of a new edge leads to an increased probability of damage, especially on exposed, highly productive sites. Thinning alone also increases the probability of damage and the magnitude of the increase varies with age and thinning intensity. On highly productive sheltered sites, the effect of thinning becomes especially important when thinning exceeds 35% of the number of stems or when stand age is greater than 70 years for a 35% thinning intensity. Thinning of new edges was also found to further increase the risk of windthrow on the most sheltered, high quality sites.


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