scholarly journals Intensive moose browsing and small-scale domestic woodcutting impacts on forest successional trajectories in Gros Morne National Park, Canada

2021 ◽  
pp. 1-11
Author(s):  
Shannon White ◽  
Xinbiao Zhu ◽  
Fanrui Meng ◽  
Scott Taylor ◽  
Charles P.-A. Bourque

Moose (Alces alces L.) browsing in Gros Morne National Park has damaged its balsam fir (Abies balsamea (L.) Mill.)dominated forest. A forest estate model was used to evaluate (i) the impacts of moose browsing and woodcutting on forest succession and (ii) strategies of forest restoration through planting and moose population management. The simulation results show that under current heavy browsing pressure growing stock of balsam fir decreases by 38%, but the area of spruce (Picea mariana (Mill.) BSP and P. glauca (Moench) Voss) increases by 32% over a 100-year planning horizon, compared to that under light browsing scenario which is assumed to be similar to the forest outside the Park due to moose population management. Annual allowable cut (AAC) for the Park’s 19 400 ha domestic harvest area is estimated to be around 120 979 m3 in a light browsing scenario, 21% higher than the sustainable harvest level in a heavy browsing scenario. The model forecasts a 97% reforestation of the Park’s 7 194 ha disturbed area by planting in the heavy browsing scenario, leading to an increase in total forest growing stock by 22% and AAC by 12%. Integration of planting with moose population management could be a more efficient way of restoring forest under high browsing pressure in GMNP.

2021 ◽  
Vol 97 (3) ◽  
pp. 315-325
Author(s):  
Shannon White ◽  
Xinbiao Zhu ◽  
Fanrui Meng ◽  
Scott Taylor ◽  
Charles P.-A. Bourque

Moose (Alces alces L.) browsing in Gros Morne National Park has damaged its balsam fir (Abies balsamea (L.) Mill.)-dominated forest. A forest estate model was used to evaluate (i) the impacts of moose browsing and woodcutting on forest succession and (ii) strategies of forest restoration through planting and moose population management. The simulation results show that under current heavy browsing pressure growing stock of balsam fir decreases by 38%, but the area of spruce (Picea mariana (Mill.) BSP and P. glauca (Moench) Voss) increases by 32% over a 100-year planning horizon, compared to that under light browsing scenario which is assumed to be similar to the forest outside the Park due to moose population management. Annual allowable cut (AAC) for the Park’s 19 400 ha domestic harvest area is estimated to be around 120 979 m3 in a light browsing scenario, 21% higher than the sustainable harvest level in a heavy browsing scenario. The model forecasts a 97% reforestation of the Park’s 7 194 ha disturbed area by planting in the heavy browsing scenario, leading to an increase in total forest growing stock by 22% and AAC by 12%. Integration of planting with moose population management could be a more efficient way of restoring forest under high browsing pressure in GMNP.


2010 ◽  
Vol 86 (2) ◽  
pp. 178-192 ◽  
Author(s):  
Xinbiao Zhu ◽  
Charles P.-A. Bourque ◽  
Scott Taylor ◽  
Roger Cox ◽  
Carson Wentzell

Long-term scenario analysis was used to predict the effects of domestic harvesting and moose (Alces alces) browsing on forest growing stock, species composition, and age-class distribution for two groups of managed forest blocks dominated by balsam fir (Abies balsamea [L.] Mill.) in Gros Morne National Park (GMNP), western Newfoundland. Four scenarios were examined. The first scenario assumed no timber harvesting and light moose browsing. Transition rules applied to this scenario came from neighbouring industrial forests, where moose populations are regulated by hunting. The other test scenarios use GMNP-specific transition rules to address increased moose browsing in the park, where hunting has been prohibitedsince the park’s inception in 1973. One of the three tested scenarios was also given a “no timber harvest treatment” so that the effects of moose browsing on park forests may be quantified by comparison with the first scenario. The two remaining test scenarios were designed to address compound effects of timber harvesting and moose browsing within the park, each representingan alternative management sce- nario currently being implemented in GMNP. For both harvest scenarios, the overall achievable wood volume was found to be at least five orders of magnitude lower than growing stock, thus providing sufficient volume for the ongoing domestic wood- cutting program (1973-2060) in the park. The proposed levels of woodcutting were predicted to have little impact on forest growing stock and old-growth forest after 160 years of management, but not on maintaining white birch (Betula papyrifera Marsh.), which is already in low numbers. In contrast, moose browsing, although it was predicted to have little effect on age-class distribution, was estimated to cause a 12% to 32% reduction in growing stock over a 160-year planning horizon, depending on the scenario. This was characterized by a 47% to 50% reduction in growing stock of balsam fir and a 50% to 87% reduction in white birch, and a commensurate expansion in low-density black spruce (Picea mariana [Mill.] BSP) and grassland cover. Key words: balsam fir, black spruce, domestic harvest, grassland, scenario analysis, white birch


1964 ◽  
Vol 40 (4) ◽  
pp. 474-481 ◽  
Author(s):  
P. E. Vezina

The concept of stand density in relation to thinning is examined and its development over the years is discussed. Present difficulties of objectively measuring stand density are recognized and probable future trends towards the development of better formulae to express stand density are outlined. Researchers should continue to collect information on interrelationships among stand variables. Certain merits accrue from description of stand density in terms of variables, such as crown closure, that can be measured with some precision from aerial photographs. Conversely, valid estimates of crown closure which are often difficult to obtain by means of devices from the ground, could be predicted from stand density. Three stand variables, used as expressions of stand density, were tested in crown closure simple regressions in even-aged, unmanaged stands of balsam fir (Abies balsamea (L.) Mill.) and jack pine (Pinus banksiana Lamb.). These are: total number of trees, number of trees 4 inches and up, and basal area per acre. The strongest relationship found was the one where crown closure is compared with basal area; it was stronger for jack pine than for balsam fir. This was explained by differences in tolerance among the two species. The significance of these relationships for the stand development, and the feasibility of using height-and diameter-based indices as measures of growing stock in studies of yield are discussed.


2008 ◽  
Vol 38 (6) ◽  
pp. 1621-1633 ◽  
Author(s):  
Mathieu Bouchard ◽  
David Pothier ◽  
Sylvie Gauthier

We evaluated geographic variations in mean fire return intervals and postfire forest succession within a 66 497 km2 land area located in the eastern Quebec boreal forest. Fire return intervals were calculated using a time since last fire map for 1800–2000, and forest dynamics were studied by superimposing 3204 forest inventory plots onto the fire map. Mean fire return interval proved significantly shorter in the western part of the study area, at 270 years, compared with the eastern part, where it was probably more than 500 years. The two main tree species in the study area were balsam fir ( Abies balsamea (L.) P. Mill.) and black spruce ( Picea mariana (Mill.) BSP). Balsam fir abundance increased progressively as a function of time since fire, whereas black spruce abundance increased during the first 90 years after fire and then declined. Balsam fir was significantly more abundant in the southeastern portion of the study area, which we attribute to the combined limitations imposed by temperature along the north–south axis and by fire along the east–west axis. Large forest patches (i.e., ≥200 km2) dominated by early successional tree species, within a matrix of irregular black spruce – balsam fir mixtures, are an important feature of preindustrial forest landscapes in this region.


1985 ◽  
Vol 61 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Harold O. Batzer ◽  
Michael P. Popp

Plots in 24 spruce-fir stands in northeastern Minnesota studied throughout the period 1957 to 1962 at the time of a spruce budworm outbreak were remeasured in 1979. Composition of the overstory changed from an average of 79% of the basal area in host species before to 31% after the budworm outbreak. Twelve percent of the stands showed growth in nonhost species that more than offset the loss in balsam fir and white spruce. The understory was minimally stocked with balsam fir in two-thirds of the stands. Only 4% of the regeneration was spruce. Even so, some well-established white spruce seedlings were found in two-thirds of the stands. Red maple was the most abundant hardwood invader. Raspberry, hazel and mountain maple were the principal shrub species limiting balsam fir reproduction Shrubs were most abundant in stands where balsam fir mortality had exceeded 80%. Half of the stands had seedlings that originated both before and after the outbreak; 45% had seedlings that originated only after the outbreak; and 5% had seedlings that originated only before the outbreak. Stands having moderate mixture of nonhost species in the over-story prior to the budworm outbreak had the most balsam fir regeneration. This resulted from seed produced by surviving balsam fir trees after the outbreak. Key words: Choristoneura fumiferana, Abies balsamea, Balsam fir, spruce-fir shrubs


2019 ◽  
Vol 92 (5) ◽  
pp. 659-669 ◽  
Author(s):  
Hugues Power ◽  
Patricia Raymond ◽  
Marcel Prévost ◽  
Vincent Roy ◽  
Frank Berninger

AbstractHarvesting practices in temperate mixedwoods of eastern North America have a history of diameter-limit cuts, which have often resulted in degraded residual stands. In this study, we examined the factors influencing stand basal area (BA) and tree diameter growth in previously high-graded mixedwood forests, to understand which stands are more likely to recover from high-grading. Over 15 years, we monitored tree growth, recruitment and stem quality of 532 sample plots that were located in high-graded stands of Quebec’s mixedwood forest. We found that diameter growth rates were positively correlated with precipitation-related variables for balsam fir (Abies balsamea) and for yellow birch (Betulla alleghaniensis) but opposing trends for temperature-related variables were found. Conversely to balsam fir, yellow birch growth was positively correlated to temperature variables. Our results also show that BA growth was greater for plots with a larger acceptable growing stock (AGS: trees with potential sawlog production) and that the increase in AGS was greater for plots with larger amount of conifer BA. These result highlights the importance to maintain a proportion of conifer trees in these mixed stands. Moreover, the significant effect of asymmetric competition in our study underscores the relevance of considering the spatial distribution when choosing crop trees.


1964 ◽  
Vol 40 (3) ◽  
pp. 362-371 ◽  
Author(s):  
P. E. Vezina

A thinning regime was derived through use of a model developed to grow balsam fir (Abies balsamea (L.) Mill.) trees at any desired size between the limits set by normal and open stand densities. Interpolations were made between the normal number of trees in fully-stocked even-aged balsam fir stands and the number at which crowns of fully open-grown individual balsam fir just close at square spacing. The increase in the number of trees in a fully-stocked balsam fir stand of a given average d.b.h. being little influenced by site was used to establish the basis for the thinning regime. The simple regime prescribes a pre-commercial and two commercial thinnings, and a regeneration cutting when the stand reaches about 7 inches in d.b.h. From comparisons of the amount of growing stock of the hypothetical thinned stands with that of unmanaged fully-stocked stands, it would seem that a managed stand of balsam fir might carry a basal area per acre of 49, 58, and 75 per cent of the unmanaged stands at average d.b.h.'s of 3, 5 and 7 inches respectively.


1956 ◽  
Vol 88 (12) ◽  
pp. 691-697 ◽  
Author(s):  
A. F. Hedlin

The balsam-fir seed chalcid, Megastigmus specularis Walley, destroys a high percentage of seeds of balsam fir, Abies balsamea (L.) Mill. The insect was first recorded in Canada in 1928 from New Brunswick and in 1932 was described by Walley (1932). It has been taken in the United States as far west as Minnesota (Peck, 1951). In 1953 the insect was reared from seeds of balsam fir taken at the Forest Nursery Station, Indian Head, Saskatchewan. Further investigations in 1954 showed the insect to be abundant at Indian Head, and also in natural stands of balsam fir in Riding Mountain National Park, Manitoba.


2019 ◽  
pp. 68-72
Author(s):  
E. A. Volkova

A monograph “Vegetation and biotopes of the “Narochansky” National Park was published in Minsk, Belarus in 2017, edited by A. V. Pugachevsky (Grummo et al., 2017). It includes the Map of terrestrial vegetation (S. 1 : 60 000) and the Map of biotopes (S. 1 : 60 000). Some small-scale maps such as the Map of changes in forest cover of the “Narochansky” National Park for the period 1985–2016, the Map of forest loss in the “Narochansky” National Park for the period 1985–2016 and a series of inventory and analytical maps on the basin of the Naroch Lake are given. This monograph can be considered as a small regional Atlas with detailed explanatory texts to the maps. It presents the experience on vegetation mapping accumulated in the Laboratory of Geobotany and Vegetation mapping of the Institute of Experimental Botany of the National Academy of Sciences of Belarus. Despite some critical comments, mainly concerning the biotope map, this publication of Belarusian geobotanists deserves an approval. They received the full answers to the questions posed: “What do we protect?” and “What is a current state of the vegetation of the National Park and the main trends of its dynamics? Cartographic design is made at a high level; the maps have both scientific and practical importance in the planning of environmental and economic activities.


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