Overstory influences on light attenuation patterns and understory plant community diversity and composition in southern boreal forests of Quebec

2006 ◽  
Vol 36 (9) ◽  
pp. 2065-2079 ◽  
Author(s):  
Paula Bartemucci ◽  
Christian Messier ◽  
Charles D Canham
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Boreal Forests ◽  
Forest Floor ◽  
Light Transmission ◽  
Forest Type ◽  
Light Attenuation ◽  
Understory Vegetation ◽  
Light Levels ◽  
Understory Plant

We have characterized overstory light transmission, understory light levels, and plant communities in mixed wood boreal forests of northwestern Quebec with the objective of understanding how overstory light transmission interacts with composition and time since disturbance to influence the diversity and composition of understory vegetation, and, in turn, the further attenuation of light to the forest floor by the understory. Overstory light transmission differed among three forest types (aspen, mixed deciduous–conifer, and old cedar-dominated), with old forests having higher proportions of high light levels than aspen and mixed forests, which were characterized by intermediate light levels. The composition of the understory plant communities in old forests showed the weakest correlation to overstory light transmission, although those forests had the largest range of light transmission. The strongest correlation between characteristics of overstory light transmission and understory communities was found in aspen forests. Species diversity indices were consistently higher in aspen forests but showed weak relationships with overstory light transmission. Light attenuation by the understory vegetation and total height of the understory vegetation were strongly and positively related to overstory light transmission but not forest type. Therefore, light transmission through the overstory influenced the structure and function of understory plants more than their diversity and composition. This is likely due to the strong effect of the upper understory layers, which tend to homogenize light levels at the forest floor regardless of forest type. The understory plant community acts as a filter, thereby reducing light levels at the forest floor to uniformly low levels.

scholarly journals Plant community composition and tree seedling establishment in response to seeding and weeding treatments on different reclamation cover soils

2019 ◽  
Vol 49 (7) ◽  
pp. 836-843 ◽  
Author(s):  
Leah A. deBortoli ◽  
Bradley D. Pinno ◽  
M. Derek MacKenzie ◽  
Edith H.Y. Li
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Relative Abundance ◽  
Forest Floor ◽  
Anthropogenic Activities ◽  
Deciduous Tree ◽  
Native Plant ◽  
Tree Seedling ◽  
Understory Plant ◽  
Understory Plant Communities

The majority of plant diversity in North American boreal forests is comprised of understory plant communities undergoing continuous interspecific competition. Anthropogenic activities, particularly surface mining, have introduced higher severity disturbances that not only remove vegetation, but also modify soil. During reclamation, soils used to cap overburden materials have inhibited native plant growth and increased weed invasion. This study aimed to examine the effectiveness of seeding and weeding treatments for promoting the establishment of native understory plant communities, as well as a common deciduous tree species, on three different reclamation cover soils (forest floor – mineral mix, peat–mineral mix, and transitional). The broadcasting of a native forb seed mix was not successful on any of the cover soils, whereas weeding affected each cover soil differently. With weeding, the forest floor – mineral mix and transitional cover soils experienced a decrease in the relative abundance of introduced forbs and an increase in the relative abundance of graminoids. The increase in graminoid cover on the forest floor – mineral mix was mostly attributed to the expansion of Calamagrostis canadensis (Michx.) P. Beauv. Overall, weeding effectively eliminated introduced plant species, allowing competitive native grasses to establish. However, weeding may have unintentionally hindered the development of a native understory plant community via the over-establishment of grass on reclamation sites.

Analysing species-specific light transmission and related crown characteristics of Pinus sylvestris and Betula pendula using a shoot-level 3D model

2013 ◽  
Vol 43 (10) ◽  
pp. 929-938 ◽  
Author(s):  
Anna Lintunen ◽  
Pekka Kaitaniemi ◽  
Jari Perttunen ◽  
Risto Sievänen
Keyword(s):  
Pinus Sylvestris ◽  
Boreal Forests ◽  
Betula Pendula ◽  
Light Transmission ◽  
Light Attenuation ◽  
Mixed Forest ◽  
Ray Casting ◽  
Area Index ◽  
Crown Characteristics ◽  
Species Specific

This is a first attempt to analyse species-specific light attenuation in mixed boreal forests created by shoot-level 3D tree models. The models are configurations of real individual Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.) trees grown in mixed-forest stands. We study species-specific differences in radiation transmission by using the ray-casting method. Light transmission was found to be higher in dense birch-dominated stands compared with dense pine-dominated stands because of the higher total foliage area and the higher location of foliage in the pine canopy. Transmission of light per leaf area index (LAI) was nevertheless higher in the pine canopy compared with the birch canopy because of foliage clumping. Especially in clumped canopy, species-specific shoot-level light simulations enable a more realistic estimation of light transmission compared with simpler calculations based on LAI and Beer–Lambert’s law. The observed differences in light-transmission characteristics of the studied species may influence the development of target crowns in the neighbourhood. Light attenuation caused by the dense foliage zone in the upper pine canopy could be avoided in dense stands by mixing species with different vertical foliage distributions.

scholarly journals Diversity of Understory Communities in Boreal Forests: Influences of Forest Type, Latitude, and Spatial Scale

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1003
Author(s):  
Yu-Song Jin ◽  
Yu-Kun Hu ◽  
Jing Wang ◽  
Dan-Dan Liu ◽  
Ying-Hua Lin ◽  
...  
Keyword(s):  
Beta Diversity ◽  
Boreal Forests ◽  
Forest Type ◽  
Critical Role ◽  
Understory Vegetation ◽  
Coniferous Forests ◽  
Lower Latitude ◽  
Forest Types ◽  
Vegetation Diversity ◽  
Alpha And Beta Diversity

Understory vegetation hosts high biodiversity and plays a critical role in the ecosystem processes of boreal forests. However, the drivers of understory plant diversity in this high-latitude ecosystem remain uncertain. To investigate the influences of forest type and latitude on understory beta diversity at different scales, we quantified the species composition of Vaccinium uliginosum Linnaeus communities under broadleaf and coniferous forests at two latitudes at the quadrat (2 × 2 m) and plot (10 × 10 m) scales in the Greater Xing’an Mountains, NE China. At the quadrat scale, species alpha diversity of V. uliginosum communities was higher in broadleaf forests than that in coniferous forests at both latitudes. The differences in species beta diversity (the Sørensen’s dissimilarity) in two forest types depended on the latitude: beta diversity in broadleaf forests was higher than that in coniferous forests at the higher latitude, while beta diversity in coniferous forests was higher at the lower latitude. At the plot scale, alpha and beta diversity of V. uliginosum communities decreased from broadleaf forests to coniferous forests at the higher latitude, and they did not show significant differences between forest types at the lower latitude. These results indicate the interactive effects of forest type and latitude on beta diversity of understory vegetation. Moreover, the influences of forest type and latitude on species alpha and beta diversity were different across the two spatial scales, suggesting that the assembly mechanisms underlying species diversity may be different at different scales. Understanding the maintenance of understory vegetation diversity will benefit the conservation and management of boreal forests.

Response of boreal plant communities to variations in previous fire-free interval

2006 ◽  
Vol 15 (4) ◽  
pp. 497 ◽  
Author(s):  
Jill F. Johnstone
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Populus Tremuloides ◽  
Boreal Forests ◽  
Fire History ◽  
Yukon Territory ◽  
Deciduous Species ◽  
Community Patterns ◽  
Free Interval ◽  
Species Cover

The present study used overlapping burn scars from natural wildfires to examine the effects of changes in the fire-free interval on early successional plant communities in boreal forests of central Yukon Territory, Canada. Data on plant community composition and residual organic material were collected in the first decade of post-fire regeneration in two study areas with recent fire overlap. Sites with a shorter fire-free interval had reduced loads of deadwood and shallower organic layers after the most recent fire. Multivariate analysis of species cover indicated that sites in and out of the burn overlap zones also supported distinct plant communities. Differences in the plant communities were associated with a greater abundance of woody deciduous species, such as Populus tremuloides, Salix spp., and Shepherdia canadensis, at sites that had recently re-burned. Sites that burned after a longer interval had higher moss cover and greater abundance of Picea mariana, Calamagrostis canadensis, and Ribes glandulosum in one study area, and Epilobium angustifolium in the second area. Ordinations of species cover indicated that plant community patterns were most strongly associated with gradients related to fire history and topography. In general, shorter fire-free intervals reduced pools of residual plant material and favored dominance of resprouting, woody deciduous species.

Understory plant community resilience to partial harvesting in riparian buffers of central Canadian boreal forests

2013 ◽  
Vol 289 ◽  
pp. 209-218 ◽  
Author(s):  
Azim U. Mallik ◽  
David P. Kreutzweiser ◽  
Cristina M. Spalvieri ◽  
Robert W. Mackereth
Keyword(s):  
Plant Community ◽  
Boreal Forests ◽  
Community Resilience ◽  
Riparian Buffers ◽  
Partial Harvesting ◽  
Understory Plant

Effects of fire severity on early development of understory vegetation

2005 ◽  
Vol 35 (2) ◽  
pp. 254-262 ◽  
Author(s):  
G. Geoff Wang ◽  
Kevin J Kemball
Keyword(s):  
Plant Community ◽  
Diversity Index ◽  
Fire Severity ◽  
Species Abundance ◽  
Understory Vegetation ◽  
Entire Study ◽  
Dominant Component ◽  
Regeneration Response ◽  
Understory Plant ◽  
Early Regeneration

Four boreal mixedwood stands burned by the 1999 Black River wildfire in southeastern Manitoba were sampled to examine the effects of fire severity on early regeneration dynamics of understory vegetation. In each stand, three fire severity classes (scorched, lightly burned, and severely burned) were identified based on the degree of forest floor consumption, and six plots per severity class were randomly selected. Variation in fire severity significantly affected the initial regeneration of the understory plant community. Regeneration response after fire was largely controlled by interactions between fire severity and species' regeneration strategy. Establishment of invaders, seed bankers, and sprouters was best on severely burned, lightly burned, and scorched plots, respectively. Species richness and Shannon's diversity index was reduced by severe fire only in the first postfire year. However, the effects of fire severity on species abundance and composition persisted through the entire study period (1999–2002). Rapid changes in the understory plant community were only observed during the initial 3 postfire years, regardless of fire severity. At the end of the study, herbaceous plants were the most dominant component, with woody plants being a codominant component on scorched plots, and nonvascular plants being a codominant component on severely burned plots.

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