Disturbance history affects dead wood abundance in Newfoundland boreal forests

2006 ◽  
Vol 36 (12) ◽  
pp. 3194-3208 ◽  
Author(s):  
Martin T Moroni

Dead wood (dead standing tree (snag), woody debris (WD), buried wood, and stump) abundance was estimated in Newfoundland balsam fir (Abies balsamea (L.) Mill.) and black spruce (Picea mariana (Mill.) BSP) forests regrown following natural and anthropogenic disturbances. Although harvesting left few snags standing, natural disturbances generated many snags. Most were still standing 2 years after natural disturbance, but almost all had fallen after 33–34 years. Snag abundance then increased in stands aged 86–109 years. Natural disturbances generated little WD 0–2 years following disturbance. Harvesting, however, immediately generated large amounts of WD. Thirty-two to forty-one years following disturbance, most harvesting slash had decomposed, but naturally disturbed sites had large amounts of WD from collapsed snags. Harvested sites contained less WD 32–72 years following disturbance than naturally disturbed sites. Amounts of WD in black spruce regrown following harvesting and fire converged 63–72 years following disturbance, despite significant initial differences in WD quantities, diameter distribution, and decay classes. Abundance of WD increased from sites regrown 32–72 years following disturbance to older sites. Precommercial thinning had a minor impact on dead wood stocks. Stumps contained minor biomass. Buried wood and WD biomass were equivalent at some sites.

2005 ◽  
Vol 22 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Neal P.P. Simon ◽  
Francis E. Schwab

Abstract To assess the differences between forest management and natural disturbance, we retrospectively compared crown cover of woody plant species between burned and clearcut sites after 5, 14, and 27 years of succession. All 16 sites had been dominated by black spruce (Picea mariana) before disturbance. We found no difference in species richness between disturbance types, but richness was lowest on 5-year-old sites for both disturbances. Burned and clearcut sites differed in the cover of woody plant species, differences increasing slightly with time since disturbance. Both balsam fir (Abies balsamea) and black spruce were more abundant on 14- and 27-year-old clearcut plots than burned plots. Black spruce cover was always greater than fir, but the spruce:fir ratio on clearcut plots was lower than on burned plots. Our data suggest that fire and clearcut logging affect postdisturbance succession differently. Contrary to other studies, logging resulted in more commercially valuable black spruce than fire, and broad-leaved woody plants were not in greater abundance on logged sites. However, the persistence of fir through logging suggests that the resulting forest would be of lower commercial value than a pure black spruce forest. North. J. Appl. For. 22(1):35–41.


2010 ◽  
Vol 86 (4) ◽  
pp. 498-510 ◽  
Author(s):  
Jérôme Cimon-Morin ◽  
Jean-Claude Ruel ◽  
Marcel Darveau ◽  
Jean-Martin Lussier ◽  
Philippe Meek ◽  
...  

It is increasingly accepted that silviculture must now try to maintain complex stands. In this context, selection cutting has been suggested as an option for irregular boreal stands. However, selection cutting in virgin stands could prove difficult to apply at a reasonable cost. In an attempt to reduce harvesting costs, two selection cutting patterns were implemented, avoiding tree marking. The efficacy of this approach was evaluated by comparing the results of plots harvested without tree marking to those with tree marking. To proceed in the absence of tree marking, silvicultural types were defined as well as a rule for the selection of stems to harvest; the final choice of stems to fell was therefore left to the operator upon harvesting. The effects of the different silvicultural and tree marking treatments were examined in relation to their ability to maintain the main structural and functional attributes of irregular boreal stands. A follow-up was conducted with regards to structure, composition, residual stand basal area, abundance of woody debris and mortality. The absence of marking did not affect the performance of selection cutting treatments in terms of basal area, quadratic mean diameter and Shannon index. Tree vigour was not modified by harvesting, both with and without tree marking. Stand composition was not influenced by the absence of marking. Snag abundance was reduced to similar levels regardless of marking. Tree marking did not influence the abundance of downed woody debris. As a consequence, it seems possible to apply a simplified approach of selection cutting, without compromising the success of the treatment in these stands.Key words: black spruce, Picea mariana, balsam fir, Abies balsamea, irregular stand, selection cutting, ecosystem management, forest attributes


2007 ◽  
Vol 83 (3) ◽  
pp. 326-337 ◽  
Author(s):  
Yves Bergeron ◽  
Pierre Drapeau ◽  
Sylvie Gauthier ◽  
Nicolas Lecomte

Several concepts are at the basis of forest ecosystem management, but a relative consensus exists around the idea of a forest management approach that is based on natural disturbances and forest dynamics. This type of approach aims to reproduce the main attributes of natural landscapes in order to maintain ecosystems within their natural range of variability and avoid creating an environment to which species are not adapted. By comparing attributes associated with natural fire regimes and current forest management, we were able to identify four major differences for the black spruce forest of the Clay Belt. The maintenance of older forests, the spatial extent of cutover areas, the maintenance of residuals within cutovers and disturbance severity on soils are major issues that should be addressed. Silvicultural strategies that mitigate differences between natural and managed forests are briefly discussed. Key words: natural disturbance, landscape patterns, coarse filter, harvest pattern, volume retention, historic variability, even-aged management


2009 ◽  
Vol 89 (3) ◽  
pp. 343-355 ◽  
Author(s):  
M. T. Moroni ◽  
P. Q. Carter ◽  
D. A.J. Ryan

The effect of harvesting and slash piling on soil respiration, temperature and moisture was examined in a balsam fir (Abies balsamea) and a black spruce (Picea marinara) forest located in western Newfoundland, Canada, 2 mo to 2.5 yr following harvesting. Within 4 mo of harvesting, soil temperature, moisture, and soil respiration rates were affected by harvesting and slash piling. Clearcut areas without slash (CC-S) had significantly lower soil respiration rates than uncut forests (F). However, clearcut areas with slash cover (CC+S) had significantly higher soil respiration rates than CC-S. When harvested areas with and without slash were combined, harvesting decreased soil respiration in the black spruce forest but had no effect on soil respiration in the balsam fir forest. Harvesting increased soil temperatures at 10 cm, however CC+S temperatures were cooler than CC-S temperatures. Harvested areas tended to dry faster than F, although soil moisture levels at >3.5 cm were not significantly depleted. However, there was evidence of soil drying at <3.5 cm. Soil temperature (at 10 cm) at the time of measurement was most strongly correlated to rates of soil respiration. Temporal variability and treatment effects (harvesting and slash piling) played a minor role in explaining soil respiration rates when variations in soil respiration were adjusted for 10-cm soil temperature,. Soil moisture levels (3.5-9.5 cm depth), which did not vary widely, also played a minor role in explaining soil respiration rates.Key words: Clearcut, Abies balsamea, Picea marinara, carbon dioxide, greenhouse gas


Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin

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.


2007 ◽  
Vol 85 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Nicole J. Fenton ◽  
Catherine Béland ◽  
Sylvie De Blois ◽  
Yves Bergeron

Boreal forest bryophyte communities are made up of distinct colonies of feathermosses that cover the forest floor. In some black spruce ( Picea mariana (Mill.) BSP) boreal forests, Sphagnum spp. establish colonies on the forest floor 30–40 years after the feathermosses, and ultimately expand to dominate the community. The mechanisms that permit the Sphagnum spp. to establish and expand are unknown. The objectives of this study were to examine the establishment and expansion substrates of Sphagnum spp., and the conditions correlated with colony expansion. Forty colonies, in six stands, of Sphagnum capillifolium (Ehrh.) Hedw. were dissected to determine their substrates, and the environmental conditions in which all colonies present were growing were measured. Coarse woody debris was the dominant establishment and early expansion substrate for Sphagnum capillifolium colonies. With age as the control factor, large colonies showed a significant partial correlation with canopy openness, and there were fewer individuals per cm3 in large colonies than there were in small colonies. These results suggest that Sphagnum establishment in these communities is dependent on the presence of coarse woody debris, and expansion is linked to the stand break-up, which would allow an increase in light intensity, and rainfall to reach the colony. Consequently the community change represented by Sphagnum establishment and expansion is initially governed by a stochastic process and ultimately by habitat availability and species competition.


2015 ◽  
Vol 45 (12) ◽  
pp. 1739-1747 ◽  
Author(s):  
Kenneth Agbesi Anyomi ◽  
Jean-Claude Ruel

Boreal ecosystem functioning is largely controlled by disturbance dynamics. There have been efforts at adapting forest management approaches to emulate natural disturbance effects, as this is expected to maintain ecosystem resilience. In many instances, this involves resorting to partial cutting strategies that are likely to increase windthrow losses. The objective of this study was to determine the effects of alternative silvicultural practices on windthrow damage and how these effects vary with the scale of treatment. The study was conducted in the Quebec North Shore region (Canada), an area dominated by balsam fir (Abies balsamea (L.) Mill.) and accompanied by black spruce (Picea mariana (Mill) B.S.P.). Four different silvicultural treatments (overstory removal, heavy partial cutting, and two patterns of selection cutting) and control areas were implemented in 2004 and 2005. The experiment used a nested approach where treatment at the plot level was independent and yet nested within the block-level treatment. At the block level, treatments were applied over 10–20 ha units, leaving a small portion of the block for a smaller application of each treatment (plot scale, 2500 m2). Inventory was carried out before harvesting and monitoring was done yearly after harvesting, with the aim to better understand the plot- and block-level factors that drive windthrow damage levels and the effects of alternative silvicultural treatments. Results after 6–7 years show that basal area proportion windthrown differs substantially between treatments, as well as between treated sites and control sites. Windthrow levels were higher under heavy cuts relative to selection cuts and also increased with balsam fir proportion. Windthrow proportions were better correlated to block-level treatment than plot-level treatment, showing that the environment surrounding the treated plot can have an important effect on windthrow losses. Overall, the selection cutting system, particularly SC2, retains the most green-tree basal area and thus best meets the management objective of retaining old-growth attributes. A simple empirical model was calibrated that could aid in hazard rating.


2013 ◽  
Vol 89 (03) ◽  
pp. 290-303 ◽  
Author(s):  
Ben Kuttner ◽  
Jay R. Malcolm ◽  
Sandy M. Smith

Multi-cohort forest management (MFM) is a natural disturbance emulation strategy for boreal forests that recommends a diversification of silvicultural techniques to emulate three broad successive phases of post-fire development, termed “cohort classes”. Here, for boreal mixedwood (n = 308) and black spruce (n = 108) stands of northeastern Ontario, we: 1) present a multivariate approach to classify the three cohort classes based on a broad set of stand structural variables related to live-tree diameters, densities, and measures of canopy stratification and 2) investigate variation in stand age, mode of stand origin (including horse- and mechanically logged and natural-origin stands), and deadwood features among the cohort classes. In both forest types, average stem diameter distributions in cohort class 1 were normally distributed, those in class 2 showed broader normal distributions, and those in class 3 showed inverse-J distributions. Mean stand age increased with cohort class, and was positively correlated with cohort class in both forest types. Overall, variation in age and deadwood features as a function of cohort class in both forest types provided strong support for developmental aspects of our cohort classifications. Previously logged stands were primarily associated with lower cohort classes, whereas natural-origin stands were strongly associated with complex cohort class 3 stand structures, especially in mixedwoods. As it is primarily the silvicultural manipulation of stand structure that has been proposed to emulate age-related multi-cohort development, our structural cohort classification approach is particularly relevant to the application of MFM in Ontario.


2009 ◽  
Vol 39 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Ulrike Hagemann ◽  
Martin T. Moroni ◽  
Franz Makeschin

Deadwood (woody debris (WD), standing dead trees (snags), stumps, and buried deadwood) abundance was estimated in Labrador humid high-boreal black spruce (Picea mariana (Mill.) BSP) forests regrown following natural and anthropogenic disturbances. Aboveground deadwood (DW) abundance in Labrador was similar to values observed in other boreal forests experiencing drier or warmer climates. Clear-cut harvest generated large amounts of WD, which had almost completely decomposed 34–36 years following harvesting, with a fitted volume reduction rate of –0.058 year–1. Total WD in all harvested stands was composed of predominantly <10 cm pieces, which should be included in DW inventories of disturbed coniferous boreal forests. Postfire WD likely peaked ∼20 years following disturbance, as a result of the collapse of snags, and was dominated by large amounts of medium-sized logs (10.0–19.9 cm). Buried DW stocks considerably exceeded total aboveground DW stocks in old-growth, middle-aged, and older harvested stands. Old-growth stands contained 179.3 m3·ha–1 of buried DW, a vast amount indicative of long-term accumulation requiring significantly depressed rates of WD decomposition following burial. DW stocks could be significantly underestimated if buried DW is excluded from DW inventories in cool and moist coniferous forests with long fire-return intervals.


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