Harvesting impacts on soil and understory vegetation: the influence of season of harvest and within-site disturbance patterns on clear-cut aspen stands in Minnesota

2004 ◽  
Vol 34 (10) ◽  
pp. 2159-2168 ◽  
Author(s):  
Alaina L Berger ◽  
Klaus J Puettmann ◽  
George E Host
Keyword(s):  
Species Composition ◽  
Soil Disturbance ◽  
Understory Vegetation ◽  
Vegetation Composition ◽  
Forest Patches ◽  
Clear Cut ◽  
Variable Species ◽  
Understory Plant ◽  
Understory Plant Communities ◽  
Remnant Forest

We investigated impacts of harvesting on soil disturbance and vegetation in the aspen cover type of northern Minnesota, United States. The soil disturbance (resistance to penetration) and understory vegetation were characterized for 19 sites on five 60-m2 plots placed along a disturbance gradient: landings (high harvesting traffic), skid trails (intermediate harvesting traffic), and areas off skid trails (low to no harvesting traffic). Penetration levels were quite variable, but they still indicated that within-site responses to disturbance patterns created by clear-cut harvesting were not uniform. In general, soil disturbance and understory species composition within landings were similar to those with skid trails. The soil disturbance and vegetation composition of these two levels differed from those of the low-disturbance plots (off skid trails), indicating that removing trees alone did not affect vegetation composition as much as creating an established skid trail, regardless of harvest timing. However, sites with more variable species composition (winter-harvested sites) and lower disturbance levels were less altered than sites with likely lower initial diversity (summer-harvested sites). The results suggest that it is important for recovery of understory plant communities to not only limit the amount and level of disturbances but also consider the spatial layout of harvesting, thus maintaining a spatially connected network of remnant forest patches large enough to contain interior forest species.

Forest harvesting impacts on soil properties and vegetation communities in the Northwest Territories

2002 ◽  
Vol 32 (4) ◽  
pp. 713-724 ◽  
Author(s):  
Michael D Bock ◽  
Ken CJ Van Rees
Keyword(s):  
Species Composition ◽  
Soil Properties ◽  
Forest Harvesting ◽  
Understory Vegetation ◽  
Vegetation Community ◽  
Clear Cut ◽  
Mixedwood Forests ◽  
Crown Cover ◽  
Composition And Structure ◽  
Harvesting Systems

Management of boreal mixedwood forests in Canada has traditionally relied almost exclusively on the clear-cut silvicultural system. In recent years, greater utilization of the hardwood component of boreal mixedwoods and increased societal concerns over maintenance of the integrity and sustainability of these ecosystems has provided impetus for forest managers to consider alternative silvicultural practices in boreal mixedwood forests. Little is currently known, however, concerning the response of soils and vegetation to forest harvesting systems in the mixedwood forests of the Liard River valley, Northwest Territories (NWT). Therefore, the objective of this study was to quantify the effects of patch clear-cut, strip clear-cut, and clear-cut harvesting systems on soil properties and understory vegetation composition and structure. Treatment sites with 3 or 4 years of recovery since harvesting and adjacent uncut forest sites were sampled using transect methodology. Soil samples were collected and understory vegetation community species composition and percent crown cover were assessed in 1-m2 quadrats. Compared with the range of conditions present in the uncut forest, increases in mineral soil bulk density (2%), exchangeable calcium (7%), LFH horizon thickness (13%), pH (0.2 units), and total organic carbon (5%) and decreases in LFH horizon total nitrogen (6%) and exchangeable potassium (22%) were observed following harvesting. Harvesting resulted in the reduction in crown cover of feathermoss species and increased abundance of shrub and herb species and minimal changes to species composition. Multivariate analysis of the data indicated that the method of harvesting did not result in significant differences in species composition and structure of the understory vegetation community. Overall, winter harvesting of these boreal mixedwood sites did not have a major impact on the majority of soil properties evaluated or on the species composition of the understory vegetation community.

scholarly journals Conserving a geographically isolated Charaxes butterfly in response to habitat fragmentation and invasive alien plants

Koedoe ◽  
2015 ◽  
Vol 57 (1) ◽  
Author(s):  
Casparus J. Crous ◽  
James S. Pryke ◽  
Michael J. Samways
Keyword(s):  
South Africa ◽  
Tree Species ◽  
Geographical Area ◽  
Alien Plants ◽  
Western Cape ◽  
Forest Patches ◽  
Agricultural Matrix ◽  
Conservation Implications ◽  
Invasive Tree Species ◽  
Remnant Forest

In South Africa, much of the forest biome is vulnerable to human-induced disturbance. The forest-dwelling butterfly Charaxes xiphares occidentalis is naturally confined to a small forest region in the south-western Cape, South Africa. Most of the remaining habitat of this species is within a fragmented agricultural matrix. Furthermore, this geographical area is also heavily invaded by alien plants, especially Acacia mearnsii. We investigated how C. x. occidentalis behaviourally responds to different habitat conditions in the landscape. We were particularly interested in touring, patrolling and settling behaviour as a conservation proxy for preference of a certain habitat configuration in this agricultural matrix. Remnant forest patches in the agricultural matrix showed fewer behavioural incidents than in a reference protected area. Moreover, dense stands of A. mearnsii negatively influenced the incidence and settling pattern of this butterfly across the landscape, with fewer tree settlings associated with more heavily invaded forest patches. This settling pattern was predominantly seen in female butterflies. We also identified specific trees that were settled upon for longer periods by C. x. occidentalis. Distance to a neighbouring patch and patch size influenced behavioural incidences, suggesting that further patch degradation and isolation could be detrimental to this butterfly. Conservation implications: We highlight the importance of clearing invasive tree species from vulnerable forest ecosystems and identify key tree species to consider in habitat conservation and rehabilitation programmes for this butterfly. We also suggest retaining as much intact natural forest as possible. This information should be integrated in local biodiversity management plans.

scholarly journals Disturbing to restore? Effects of mounding on understory communities on seismic lines in treed peatlands

2020 ◽  
Vol 50 (12) ◽  
pp. 1340-1351
Author(s):  
Laureen F.I. Echiverri ◽  
S. Ellen Macdonald ◽  
Scott E. Nielsen
Keyword(s):  
Community Composition ◽  
Plant Communities ◽  
Oil And Gas ◽  
Reference Sites ◽  
Oil And Gas Exploration ◽  
Understory Plant ◽  
Understory Plant Communities ◽  
Understory Communities ◽  
Associated Species ◽  
Seismic Lines

In peatlands, microtopography strongly affects understory plant communities. Disturbance can result in a loss of microtopographic variation, primarily through the loss of hummocks. To address this, mounding treatments can be used to restore microtopography. We examined the effects of mounding on the understory vegetation on seismic lines in wooded fens. Seismic lines are deforested linear corridors (∼3 to 8 m wide) created for oil and gas exploration. Our objectives were to compare the recovery of understory communities on unmounded and mounded seismic lines and determine how recovery varies with microtopographic position. Recovery was evident in the unmounded seismic lines, with higher shrub and total understory cover at the “tops” of the small, natural hummocks than at lower microtopographic positions — much like the trends in adjacent treed fens. In contrast, mounding treatments that artificially created hummocks on seismic lines significantly changed understory communities. Mounded seismic lines had higher forb cover, much lower bryophyte cover, less variation along the microtopographic gradient, and community composition less similar to that of the reference sites than unmounded seismic lines due to higher abundance of marsh-associated species. Our results suggest that mounding narrow seismic lines can be detrimental to the recovery of the understory communities in treed peatlands.

Attributes of forest strips used by snowshoe hare in winter within clear-cut boreal landscapes

2005 ◽  
Vol 35 (10) ◽  
pp. 2521-2527 ◽  
Author(s):  
François Potvin ◽  
Normand Bertrand ◽  
Jean Ferron
Keyword(s):  
Abies Balsamea ◽  
Basal Area ◽  
Balsam Fir ◽  
Snowshoe Hare ◽  
Forest Patches ◽  
Clear Cut ◽  
Important Prey ◽  
South Central ◽  
Snowshoe Hares ◽  
Riparian Strips

The snowshoe hare (Lepus americanus Erxleben) is an important prey for many predators in the boreal forest. In this biome, clear-cut landscapes are generally large and consist of aggregated cutting blocks separated by narrow forest strips (typically 60–100 m wide). To identify attributes of forest strips that are important for snowshoe hares, we measured the use of strips using track counts over two winters in six clear-cut landscapes (23–256 km2) in south-central Quebec. Surveys were conducted in 20 riparian strips (RS), 20 upland strips (US), and 15 control sites (CO) at the periphery of clear-cut landscapes. Overall, 392 signs of hare presence were recorded along 50 km of transects. Snowshoe hares were present in one-third of the strips surveyed and were five times less abundant in US and RS than in CO. The species avoided strip edges. Hares were more common in the wider strips (>100 m), in the strips adjacent to residual forest patches (≥25 ha), or in those having a denser shrub canopy, which is often associated with a greater basal area in balsam fir (Abies balsamea (L.) Mill.). To maintain snowshoe hare at moderate densities in large clear-cut landscapes, we suggest leaving uncut forest strips >100 m wide in areas having a good shrub cover with presence of balsam fir.

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