Ontogenetic strategy shift in sapling architecture of Fagus crenata in the dense understorey vegetation of canopy gaps created by selective cutting

2009 ◽  
Vol 39 (6) ◽  
pp. 1186-1196 ◽  
Author(s):  
Takanobu Yagi
Keyword(s):  
Light Availability ◽  
Fagus Crenata ◽  
Canopy Gaps ◽  
Shade Avoidance ◽  
Exponential Relationship ◽  
Understorey Vegetation ◽  
Strategy Shift ◽  
Spread Monolayer ◽  
Architectural Development ◽  
Understorey Plants

Ontogenetic architectural variation is a key aspect of the light foraging of saplings under canopy gaps, where the interactions with the surrounding understorey plants are intense and change as saplings grow. Therefore, relationships between the allometry of 58 Fagus saplings (15–184 cm tall) and both the surrounding vegetation and light environment were investigated in the dense understorey of canopy gaps. The light available to the saplings exhibited a positive exponential relationship to their height, and at a given sapling height, it was inversely related to the height of the surrounding understorey. The slenderness of the saplings' stems increased as their height increased, and their crown architecture shifted from horizontally spread monolayer to vertically extended multilayer forms, indicating an ontogenetic strategy shift from shade tolerance to shade avoidance. These changes in sapling architecture were independent of the height of the surrounding understorey and, therefore, light availability, although the length of their current-year shoots (reflecting the rate of architectural development) was inversely related to the surrounding understorey height. Thus, ontogenetic architectural variation in Fagus saplings probably has the character of a developmentally programmed growth trajectory preadjusted to the most likely environments; the surrounding environments mainly affect the rate at which saplings move along this trajectory.

scholarly journals Similar understorey structure in spite of edaphic and floristic dissimilarity in Amazonian forests

2015 ◽  
Vol 45 (4) ◽  
pp. 393-404 ◽  
Author(s):  
Lassi SUOMINEN ◽  
Kalle RUOKOLAINEN ◽  
Timo PITKÄNEN ◽  
Hanna TUOMISTO
Keyword(s):  
Satellite Imagery ◽  
Forest Structure ◽  
Satellite Image ◽  
Light Availability ◽  
Floristic Composition ◽  
Structural Features ◽  
Canopy Openness ◽  
Understorey Plants ◽  
Amazonian Forests ◽  
Geological Formations

Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristic features over a larger area. The floristic compositions of forests on the two formations were clearly different, and this could also be modelled with the satellite imagery. In contrast, the field observations of forest structure gave only a weak indication that forests on the Nauta Formation might be denser than those on the Pebas Formation. The modelling of forest structural features with satellite imagery did not support this result. Our results indicate that the structure of forest understorey varies much less than floristic composition does over the studied edaphic difference.

The effect of treefall gaps on the understorey structure and composition of the tropical dry forest of Nizanda, Oaxaca, Mexico: implications for forest regeneration

2016 ◽  
Vol 32 (2) ◽  
pp. 89-106 ◽  
Author(s):  
Yanus A. Dechnik-Vázquez ◽  
Jorge A. Meave ◽  
Eduardo A. Pérez-García ◽  
José A. Gallardo-Cruz ◽  
Marco Antonio Romero-Romero
Keyword(s):  
Forest Regeneration ◽  
Tropical Dry Forest ◽  
Canopy Gaps ◽  
Dry Forest ◽  
Gap Formation ◽  
Understorey Vegetation ◽  
Phase Dynamics ◽  
Treefall Gaps ◽  
Almost All

Abstract:The role of canopy gaps in tropical dry forest (TDF) dynamics remains unclear. Here, 75 canopy gaps, mostly formed by the fall of Bursera spp. and Pachycereus pecten-aboriginum individuals, are described, and their potential consequences for forest regeneration are analysed in a Mexican TDF. In 50 randomly selected gaps, understorey vegetation was sampled with a paired design (inside and outside gaps) and by distinguishing two plant height categories. In total, 1940 plants were recorded (63% in gaps and 37% in non-gap plots). Community attributes (density, community cover, taxonomic richness and Shannon diversity) were significantly higher for both height categories in gap plots. Conversely, neither an NMDS ordination nor a multinomial classification of 187 species by habitat affinities revealed floristic segregation between gaps and non-gaps; almost all species were classified as habitat generalists, with only a few opportunistic forbs (but no single tree species) being classified as gap specialists. The most important effects of gap formation are significant increases in plant abundance and species richness, but not a different species composition. Against earlier views that gap-phase dynamics is inconsequential for TDF dynamics, these results suggest a more active, albeit modest, role of treefall gaps in TDF, through promoting an abundant establishment.

Effects of vegetation cover on seedling and sapling dynamics in secondary tropical wet forests in Costa Rica

2005 ◽  
Vol 22 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Juan Manuel Dupuy ◽  
Robin L. Chazdon
Keyword(s):  
Costa Rica ◽  
Tree Species ◽  
Vegetation Cover ◽  
Secondary Forest ◽  
Canopy Gaps ◽  
Canopy Gap ◽  
Control Treatment ◽  
Secondary Forests ◽  
Tree Seedling ◽  
Understorey Vegetation

We examined effects of experimental manipulations of vegetation cover on recruitment, mortality and density of seedlings (20–100 cm tall) and saplings (≥100 cm tall) of woody growth forms over a 2.5-y period. We created four treatments in each of three 15–20-y-old tropical forest stands in Costa Rica: a large canopy gap (270–350 m2), a small canopy gap (50–100 m2), understorey vegetation removal, and an unmanipulated control treatment. Creation of canopy gaps, especially large ones, increased first-year recruitment and density, as well as overall mortality of seedlings. Saplings experienced lower mortality and more prolonged gap-enhanced recruitment and density than seedlings. Removal of understorey vegetation had little or no effect on tree seedling and sapling dynamics. Recruitment and density of lianas responded only to large gaps, whereas understorey species responded to both gap treatments and to spatial heterogeneity within gaps. Tree species exhibited diverse regeneration requirements, whereas liana and understorey species were more specialized to the high and low ends of the light availability gradient, respectively. Canopy gaps provide a critical mechanism for regeneration of lianas, and canopy tree species that dominate during the early stages of secondary forest succession. The choice of management system for these secondary forests can determine the direction and rate of succession.

scholarly journals Identifying Species and Monitoring Understorey from UAS-Derived Data: A Literature Review and Future Directions

Drones ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 9 ◽  
Author(s):  
Lorna Hernandez-Santin ◽  
Mitchel L. Rudge ◽  
Renee E. Bartolo ◽  
Peter D. Erskine
Keyword(s):  
Remote Sensing ◽  
Spatial Resolution ◽  
Temporal Frequency ◽  
Species Discrimination ◽  
Unmanned Aerial Systems ◽  
Understorey Vegetation ◽  
Species Specific ◽  
Understorey Plants ◽  
Aerial Systems ◽  
Derived Data

Understorey vegetation plays an important role in many ecosystems, yet identifying and monitoring understorey vegetation through remote sensing has proved a challenge for researchers and land managers because understorey plants tend to be small, spatially and spectrally similar, and are often blocked by the overstorey. The emergence of Unmanned Aerial Systems (UAS) is revolutionising how vegetation is measured, and may allow us to measure understorey species where traditional remote sensing previously could not. The goal of this paper was to review current literature and assess the current capability of UAS to identify and monitor understorey vegetation. From the literature, we focused on the technical attributes that limit the ability to monitor understorey vegetation—specifically (1) spatial resolution, (2) spectral sensitivity, (3) spatial extent, and (4) temporal frequency at which a sensor acquires data. We found that UAS have provided improved levels of spatial resolution, with authors reporting successful classifications of understorey vegetation at resolutions of between 3 mm and 200 mm. Species discrimination can be achieved by targeting flights to correspond with phenological events to allow the detection of species-specific differences. We provide recommendations as to how UAS attributes can be tailored to help identify and monitor understorey species.

scholarly journals Domestication reduces phenotypic plasticity in chaya (Cnidoscolus aconitifolius (Mill.) I.M. Johnst)

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Miguel A. Munguía-Rosas
Keyword(s):  
Phenotypic Plasticity ◽  
Artificial Selection ◽  
Stem Elongation ◽  
Light Availability ◽  
Wild Plants ◽  
Cultivated Plants ◽  
Phenotypic Traits ◽  
Shade Avoidance ◽  
Leaf Production ◽  
Cnidoscolus Aconitifolius

Background: Natural selection optimizes phenotypic plasticity in plants found in environmentally variable habitats. However, it is unclear how artificial selection has affected the phenotypic plasticity of crops. Reduced plasticity in crop yield is often considered a desirable feature in cultivated plants; however, limited phenotypic plasticity in this and other traits may also affect the ability of crops to cope with environmental variation. Study species: Wild and domesticated chaya (Cnidoscolus aconitifolius (Mill.) I.M. Johnst). Question: How domestication has affected the phenotypic plasticity of vegetative traits in response to the light environment? Methods: Leaf area, leaf perimeter, leaf specific area, leaf production, trichome density, stem elongation, growth in stem diameter and slenderness were measured in clones of wild and domesticated plants. These clones were allocated to two contrasting light treatments: fully exposed to sun vs. placement beneath a shade cloth. The phenotypic traits and reaction norms were compared between the genotypes of wild and domesticated plants. Results: Lower plasticity in leaf production and slenderness was observed in the domesticated compared to the wild plants. Leaf production and slenderness are associated with the shade avoidance syndrome, which was evident in wild plants but not manifested in domesticated plants. Reduced plasticity in leaf production also suggests yield stability. Conclusion: Artificial selection reduces phenotypic plasticity in the yield of chaya and in its response to variation in light availability.

scholarly journals Analyzing Spatial Distribution Patterns of European Beech (Fagus sylvatica L.) Regeneration in Dependence of Canopy Openings

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 637 ◽  
Author(s):  
Melissa Stiers ◽  
Katharina Willim ◽  
Dominik Seidel ◽  
Christian Ammer ◽  
Myroslav Kabal ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Fagus Sylvatica ◽  
Natural Regeneration ◽  
Light Availability ◽  
European Beech ◽  
Canopy Gaps ◽  
Canopy Gap ◽  
Direct Radiation ◽  
Northern Edge ◽  
Fagus Sylvatica L

The use of natural regeneration techniques is one of the key elements of modern (close-to-nature) forestry. In natural forests, changes in canopy cover, such as the emergence and successive re-closure of canopy gaps are particularly important, as they influence the light availability on the forest floor. Creating canopy gaps of different size is a promising silvicultural tool allowing the regulation of the light availability in managed forests in order to control regeneration composition and development. In this study, we used terrestrial laser scanning data to investigate the relationship between canopy-gap dimensions and emerging natural regeneration along a gradient of management in forests dominated by European beech (Fagus sylvatica, L.). We analyzed the spatial distribution and height of regeneration patches in dependence of gap characteristics. Mean regeneration height decreases progressively from the gap polygon over a transition zone towards the area under the canopy, while the tallest regeneration plants were placed in positions midway between center and gap edge, and not directly in the gap center as we initially assumed. The centers of regeneration patches were not displaced when compared to the associated canopy gap centers, as has been reported in other studies conducted on the northern hemisphere for various tree species. The observed patterns did not depend on management strategies, indicating that regeneration responded equally to naturally created gaps and gaps that were caused by logging. We conclude that establishment and development of shade-tolerant European beech regeneration in forest stands is driven by gap openings, but not necessarily direct radiation. If at all, pronounced direct radiation mainly occurs at the northern edge of large gaps. Neither regeneration patch center, nor regeneration tree height pointed in that direction. Our study suggests that in the investigated beech-dominated forests the effect of increased light availability at the northern edge of a gap is overruled by other factors increasing towards the gap edge, such as increased belowground competition of the overstory trees.

scholarly journals Structure of the herb stratum under different light regimes in the Submontane Atlantic Rain Forest

2009 ◽  
Vol 69 (2) ◽  
pp. 289-296 ◽  
Author(s):  
RAF. Lima ◽  
S. Gandolfi
Keyword(s):  
Rain Forest ◽  
Light Availability ◽  
Canopy Structure ◽  
Canopy Gaps ◽  
Atlantic Rain Forest ◽  
Strong Correlations ◽  
Light Regimes ◽  
Hemispherical Photographs ◽  
Closed Canopy ◽  
The Difference

This study aimed to characterize the structure of the herb stratum in relation to light availability in the Submontane Atlantic Rain Forest at the Carlos Botelho State Park, SP, Brazil. Fortyone 10 x10 m plots were established under the closed canopy (18 plots), small and medium canopy gaps (11) and large canopy gaps dominated by Guadua tagoara (Ness) Kunth (12). Inside each plot, the line intercept method was applied to assess soil coverage as an estimate of density of herb stratum vegetation. Hemispherical photographs were taken at the centre of the plots to evaluate the annual light regime. Overall, Calathea communis Wanderley and S. Vieira had the greater mean coverage, followed by woody seedlings, ground ferns and other herbs (mainly, Araceae, Acanthaceae, Amaranthaceae and Cyperaceae). There were strong correlations among several groups of the herb stratum, such as the negative correlations between woody seedlings with the coverage of C. communis and with rocks. The analysis of the hemispherical photographs confirmed the difference among environments that led to significant differences in the soil coverage of the herb stratum vegetation but woody seedlings. For instance, C. communis showed great coverage in large gaps while ferns were more abundant in small and medium gaps and in the understorey. Other herbs, in turn, demonstrated bigger soil coverage in small and medium gaps. Although this study represents a rough assessment of the structure and composition of the herb stratum, the results found here illustrated the evident relation between herb species density and the environmental variation promoted by changes on canopy structure and topography.

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