Acer saccharum response to concurrent disturbances: the importance of stem layering as an adaptive trait

2010 ◽  
Vol 40 (8) ◽  
pp. 1627-1635 ◽  
Author(s):  
Stacie A. Holmes ◽  
Christopher R. Webster
Keyword(s):  
Entire Range ◽  
Acer Saccharum ◽  
Height Growth ◽  
Canopy Gaps ◽  
Regeneration Dynamics ◽  
Adaptive Trait ◽  
The Face ◽  
Important Trait ◽  
Gap Creation ◽  
Interacting Disturbances

For shade-tolerant saplings persisting under heavy forest shade, the probability of release by disturbance is directly related to longevity. We examined the effects of two concurrent disturbances, overstory removal and herbivory, on the regeneration dynamics and release response of Acer saccharum Marsh. within 20 artificial canopy gaps ranging in size from 50 to 450 m2. To examine the influence of herbivory, we constructed arrays of deer exclosures within each canopy gap. Five years after gap creation, A. saccharum dominated the taller sapling classes across the entire range of gap sizes examined, and evidence of stem layering in this species was common across all treatments (52%), especially in taller saplings. The presence of stem layering was significantly associated with greater postdisturbance height growth (P < 0.001), regardless of gap area or herbivory. The increase in height of layered A. saccharum on control plots was in spite of the fact that 70% of these saplings were browsed at least once following gap creation; compared with 46% of nonlayered individuals. Consequently, our results suggest that stem layering likely fosters resilience in the face of complex or interacting disturbances and may be an important trait for forecasting gap capture and succession.

The time course of diameter increment responses to selection harvests in Acer saccharum

2004 ◽  
Vol 34 (7) ◽  
pp. 1525-1533 ◽  
Author(s):  
Trevor A Jones ◽  
Sean C Thomas
Keyword(s):  
Acer Saccharum ◽  
Time Course ◽  
Sustainable Forest Management ◽  
Basal Area ◽  
Tree Size ◽  
Growth Enhancement ◽  
Growth Responses ◽  
Diameter Increment ◽  
The North ◽  
Gap Creation

We used dendroecological techniques to analyze the temporal pattern in diameter growth following selection harvests in stands dominated by Acer saccharum Marsh. in central Ontario and examined differences in growth responses related to tree size, damage, and orientation relative to canopy gaps. While dendroecological studies have commonly assumed that trees show immediate growth responses to gap creation (i.e., within 1–2 years), we found that the growth enhancement in A. saccharum was gradual and did not reach a peak until 3–5 years following gap creation. Trees of intermediate size showed the largest proportional growth increases after gap creation, with the largest responses observed in trees on the north side of gaps. Trees with visible damage to the crown or bole had significantly lower preharvest basal area increments than trees with little or no damage, but showed greater proportional growth responses to gap creation. Both the long observed time delay in tree growth response to canopy opening and the variability in response relative to tree size and damage have important implications for attempts to reconstruct disturbance history using dendroecological methods and to sustainable forest management under selection system silviculture.

scholarly journals All the Dark Triad and Some of the Big Five Traits are Visible in the Face

2020 ◽  
Author(s):  
Sinan Alper ◽  
Fatih Bayrak ◽  
Onurcan Yilmaz
Keyword(s):  
Personality Traits ◽  
Big Five ◽  
Dark Triad ◽  
Partial Support ◽  
Adaptive Trait ◽  
Aggregate Analysis ◽  
Big Five Traits ◽  
The Us ◽  
The Face ◽  
Source Of Information

Some of the recent studies suggested that people can make accurate inferences about the level of the Big Five and the Dark Triad personality traits in strangers by only looking at their faces. However, later findings provided only partial support and the evidence is mixed regarding which traits can be accurately inferred from faces. In the current research, to provide further evidence on whether the Big Five and the Dark Triad traits are visible in the face, we report three studies, two of which were preregistered, conducted on both WEIRD (the US American) and non-WEIRD (Turkish) samples (N = 880). The participants in both US American and Turkish samples were successful in predicting all Dark Triad personality traits by looking at a stranger’s face. However, there were mixed results regarding the Big Five traits. An aggregate analysis of the combined dataset demonstrated that extraversion (only female), agreeableness, and conscientiousness were accurately inferred by the participants in addition to the Dark Triad traits. Overall, the results suggest that inferring personality from faces without any concrete source of information would be an evolutionarily adaptive trait.

Do dipterocarp seedlings really partition tropical rain forest gaps?

1992 ◽  
Vol 335 (1275) ◽  
pp. 369-378 ◽  
Keyword(s):  
Rain Forest ◽  
Seedling Survival ◽  
Canopy Gaps ◽  
Forest Recovery ◽  
Canopy Openness ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Regeneration Dynamics ◽  
Closed Forest ◽  
Survival And Growth

The theory of gap regeneration dynamics proposes that different species of tree partition canopy gaps because they are preferentially adapted to a particular gap size class. A variety of gap sizes would therefore favour the regeneration of a range of species. The theory has been used to explain the extraordinarily high tree species diversity of tropical rain forests. A test was mounted in lowland evergreen dipterocarp rain forest in the Danum Valley, Sabah, East Malaysia by the creation of ten, artificial canopy gaps ranging in size from 10 m 2 to 1500 m 2 (6 to 30% canopy openness). The responses of established populations of seedlings of three dipterocarp species ( Hopea nervosa , Parashorea malaanonan and Shorea johorensis ) with contrasting silvicultural reputations were monitored for 40 months in these gaps and under closed forest. There were significant differences in survival and growth under closed forest between these three species. However, in gaps, the most important determinant of seedling survival and growth was seedling size at the time of gap creation, regardless of species. An ability to persist for long periods under closed forest and slowly accumulate growth may bestow an enormous size advantage on seedlings when gaps occur. Generalizations on the regeneration dynamics of dipterocarp rain forests need to be modified in the light of this result. Further observations for several years are important to see whether forest recovery eventually converges on predictions from the original paradigm.

scholarly journals Leaf-level acclimation to gap creation in mature Acer saccharum trees

2007 ◽  
Vol 27 (2) ◽  
pp. 281-290 ◽  
Author(s):  
T. A. Jones ◽  
S. C. Thomas
Keyword(s):  
Acer Saccharum ◽  
Leaf Level ◽  
Gap Creation

scholarly journals A comparison of regeneration dynamics following gap creation at two geographically contrasting heathland sites

2000 ◽  
Vol 37 (5) ◽  
pp. 832-844 ◽  
Author(s):  
A.J. Britton ◽  
P.D. Carey ◽  
R.J. Pakeman ◽  
R.H. Marrs
Keyword(s):  
Regeneration Dynamics ◽  
Gap Creation

scholarly journals A Methodology for the Historiography of Ancient Religion

2021 ◽  
pp. 13-32
Author(s):  
Jörg Rüpke
Keyword(s):  
Cultural Production ◽  
Entire Range ◽  
Lived Religion ◽  
Urban Religion ◽  
Social Agents ◽  
Historical Approach ◽  
The Past ◽  
Ancient Religion ◽  
The Face ◽  
Selection Of

Starting from a discussion about the usefulness of a historical approach to ancient religion, I propose basing the historiography of ancient religion on a set of three concepts, replacing three others that have been widely used. First, I contend that we need to shift our focus from questions of identity to questions of agency, not least in the face of earlier traditions of historiography of regions outside the imperial capitals. The application of an agentic perspective entails a further unavoidable consequence. The concept of “religions” must be replaced by that of “lived religion”, even for the past, once again shifting the focus to the local and the entire range of social agents and their cultural production. This agentic and material focus is further supplemented by a spatial one. Thus, I propose moving away from the widespread focus on civic religion in cities to embrace the perspective of urban religion. Lastly, I briefly touch upon the problem of the selection of forms of contemporary historiography of religion.

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