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

2009 ◽  
Vol 39 (9) ◽  
pp. 1785-1785
Author(s):  
Takanobu Yagi
2009 ◽  
Vol 39 (6) ◽  
pp. 1186-1196 ◽  
Author(s):  
Takanobu Yagi

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.


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

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.


2005 ◽  
Vol 22 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Juan Manuel Dupuy ◽  
Robin L. Chazdon

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.


2010 ◽  
pp. 38-40
Author(s):  
O I Grigorjeva ◽  
N V Beljaeva
Keyword(s):  

1994 ◽  
Vol 59 ◽  
Author(s):  
D. Maddelein ◽  
B. Muys ◽  
J. Neirynck ◽  
G. Sioen

The  forest of Halle (560 ha), situated 20 km south of Brussels is covered by a  beech (Fagus sylvatica)  forest, locally mixed with secundary species (Tilia,  Fraxinus, Acer, Quercus,... ). In almost all  stands, herbal vegetation is dominated by bluebell (Hyacinthoides  non-scripta).     The research intended to classify 36 plots of different tree species  composition according to their site quality. Three classification methods  were compared: the first one based on the indicator value of the understorey  vegetation, a second one on the humus morphology and a last one on some  quantitative soil characteristics. According to the plant sociological site  classification, the plots have the same site quality. However, humus forms  differ apparently and significant differences were found in pH value and base  cation saturation of the soil, abundance and biomass of earthworms and  biomass of the ectorganic horizon. Tree species proved to be the main cause  of these differences.     The results illustrate that the herbal vegetation is not always a reliable  indicator of site quality. In the case of a homogeneous vegetation dominated  by one or more indifferent species, classification on humus morphology or  soil analysis are more appropriate. In the forest of Halle, the tree species  is probably the main cause of the observed differences in site quality.


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