Competition Within Stands of Picea sitchensis and Pinus contorta

Cannell, M. G. R.; Rothery, P.; Ford, E. David

doi:10.1093/oxfordjournals.aob.a086699

Cited by 172 publications

(124 citation statements)

References 13 publications

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“…In particular, the fact that our model 480 predictions overestimated the species abundance evenness of the communities indicates that some level of asymmetry cannot be ignored to fully understand the dynamics of these 482 herbaceous communities. This result is in accord with previous knowledge on plant competitive asymmetry (Begon, 1984, Cannell et al, 1984. It further provides clues on how 484 to proceed to improve the model in the future.…”

Section: Discussion 460supporting

confidence: 88%

Predicting stochastic community dynamics in grasslands under the assumption of competitive symmetry

Lohier

Jabot

Weigelt

et al. 2016

Journal of Theoretical Biology

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Community dynamics is influenced by multiple ecological processes such as environmental spatiotemporal variation, competition between individuals and demographic stochasticity. Quantifying the respective influence of these various processes and making predictions on community dynamics require the use of a dynamical framework encompassing these various components. We here demonstrate how to adapt the framework of stochastic community dynamics to the peculiarities of herbaceous communities, by using a short temporal resolution adapted to the time scale of competition between herbaceous plants, and by taking into account the seasonal drops in plant aerial biomass following winter, harvesting or consumption by herbivores. We develop a hybrid inference method for this novel modelling framework that both uses numerical simulations and likelihood computations. Applying this methodology to empirical data from the Jena biodiversity experiment, we find that environmental stochasticity has a larger effect on community dynamics than demographic stochasticity, and that both effects are generally smaller than observation errors at the plot scale. We further evidence that plant intrinsic growth rates and carrying capacities are moderately predictable from plant vegetative height, specific leaf area and leaf dry matter content. We do not find any trade-off between demographical components, since species with larger intrinsic growth rates tend to also have lower demographic and environmental variances. Finally, we find that our model is able to make relatively good predictions of multi-specific community dynamics based on the assumption of competitive symmetry. Quantifying the respective influence of these various processes and making predictions on community dynamics require the use of a dynamical framework encompassing these various 30components. We here demonstrate how to adapt the framework of stochastic community dynamics to the peculiarities of herbaceous communities, by using a short temporal resolution 32 adapted to the time scale of competition between herbaceous plants, and by taking into account the seasonal drops in plant aerial biomass following winter, harvesting or 34 consumption by herbivores. We develop a hybrid inference method for this novel modelling framework that both uses numerical simulations and likelihood computations. Applying this 36 methodology to empirical data from the Jena biodiversity experiment, we find that environmental stochasticity has a larger effect on community dynamics than demographic 38 stochasticity, and that both effects are generally smaller than observation errors. We further evidence that plant intrinsic growth rates and carrying capacities are moderately predictable 40 from plant vegetative height, specific leaf area and leaf dry matter content. We do not find any trade-off between demographical components, since species with larger intrinsic growth 42 rates tend to also have lower demographic and environmental variances. Finally, we find that our model is able to make ...

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Section: Discussion 460supporting

confidence: 88%

Predicting stochastic community dynamics in grasslands under the assumption of competitive symmetry

Lohier

Jabot

Weigelt

et al. 2016

Journal of Theoretical Biology

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“…stands, respectively: absence of severe competition when the distribution of RGR with tree size is negative, initiation of competition-induced mortality when the distribution of RGR with tree size is flat, and intense competition when RGR increases with tree size. Similar patterns were also obtained by Schmitt et al [55] for Impatiens capensis and by Cannell et al [7] for Sitka spruce (Picea sitchensis (Bong.) Carr.)…”

Section: Growth Analysessupporting

confidence: 84%

Performance of young jack pine trees originating from two different branch angle traits under different intensities of competition

Larocque¹

2000

Ann. For. Sci.

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-The performance of young jack pine (Pinus banksiana Lamb.) trees, originating from seed orchard trees of two different branch angle traits, was examined under different intensities of competition with morphological measures of crown development and growth efficiency measures. Seedlings were planted under a split-plot design at five initial spacings -0.5 m, 0.75 m, 1.0 m, 1.5 m and 2.0 m -, three blocks, two branching characteristics and four replicates. Relative growth rate for diameter at breast height (dbh) increased by nearly twofold from the closest to the largest spacing. Crown width, crown ratio, needle density ratio and leaf weight ratio decreased significantly with decrease in spacing, which indicated that the efficiency of jack pine crowns to occupy their growing space and the proportion of photosynthesizing biomass relative to respiring biomass were negatively affected by competition. Needle nitrogen concentration decreased with decrease in spacing and was significantly related to leaf weight ratio. Variation with tree size in the ratios of dbh increment to needle biomass and to needle nitrogen content indicated that small trees produced stemwood per unit of photosynthetic tissue and per unit of nitrogen more efficiently than large trees in the absence of severe competition and that this trend was gradually reversed as the intensity of competition increased. Branch angle trait did not constitute a significant advantage for crown development and stem growth. Le taux relatif de croissance en diamètre à hauteur de poitrine (dhp) a presque doublé de l'espacement le plus serré à l'espacement le plus large. La largeur de la cime, le rapport cime-hauteur et les rapports de densité et de masse des aiguilles ont diminué de façon significative avec une diminution de l'espacement initial. Ces résultats indiquent que l'efficacité des couronnes du pin gris à occuper leur espace de croissance et la proportion de tissu assurant la photosynthèse par rapport à la proportion de tissu qui respire a été affectée négativement par la compétition. La concentration en azote des aiguilles, qui a diminué avec une réduction de l'espacement, a été reliée de façon significative au rapport de masse des aiguilles. La variation, en fonction de la taille des arbres, des rapports de croissance en diamètre sur la biomasse foliaire et le contenu en azote des aiguilles indique que, en l'absence de compétition sévère, les petits arbres ont produit plus efficacement de la matière ligneuse par unité de tissu photosynthétique et d'azote que les gros arbres et que cette tendance s'est inversée à mesure que l'espacement diminuait. L'angle de branchaison des arbres ne s'est pas révélé présenter un avantage significatif pour le développement des cimes et la croissance des tiges. compétition / mesures d'efficacité de croissance / angle des branches / azoteAnn. For. Sci. 57 (2000) [635][636][637][638][639][640][641][642][643][644][645][646][647][648][649] 635

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“…In one-sided competition, larger trees are at competitive advantage over smaller trees and neighbours do not affect the growth and survival of larger trees (Cannel et al, 1984). One-sided competition has been expressed here by the ratio of the diameter of the subject tree to the quadratic mean diameter of the 810p4 Modeling individual-tree mortality in Pyrenean oak (Quercus pyrenaica Willd.)…”

Section: Selection Of Variablesmentioning

confidence: 99%

“…In two-sided competition, all trees impose some competition on their neighbours, regardless of their size (Cannel et al, 1984), and this can be described by stand variables such as density and basal area. The following stand variables were tested for inclusion in the model: stand density (N, stems/ha), quadratic mean diameter (DG, cm), basal area (BA, m 2 /ha), dominant height (Ho, m), Hart index (HSI) and Reineke index (SDI).…”

Section: Selection Of Variablesmentioning

confidence: 99%

Modeling individual-tree mortality in Pyrenean oak (Quercus pyrenaica Willd.) stands

Adame¹,

Rı́o²,

Cañellas³

2010

Ann. For. Sci.

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Keywords:individual-tree mortality model / logistic regression / mixed model / rebollo oak / Mediteranean oak Abstract • Tree mortality is an important process in forest ecosystem dynamics and is one of the least understood phenomena, because of the complex interactions between different environmental stresses, minimal understanding of whole-plant mortality processes, and a chronic shortage of data.• A multilevel logistic regression model was developed for predicting the probability of mortality in individual trees with the objective of improving long-term planning in Spanish pyrenean oak forests. The data came from one 10-year re-measurement of the permanent plot network belonging to the Spanish National Forest Inventory distributed throughout north-west Spain.• The probability of mortality decreased with increasing individual diameter at breast height and increasing ratio of the height of subject tree to the dominant height of the sample plot. The resulting mortality model was evaluated using an independent data set from a region close to the study area.• The regeneration of pyrenean oak generally takes place through stump and/or root sprouting; so stand dynamics differ from those of others species. The model developed is expected to improve the accuracy of stand forecasts in northwest Spain.

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Competition Within Stands of Picea sitchensis and Pinus contorta

Cited by 172 publications

References 13 publications

Predicting stochastic community dynamics in grasslands under the assumption of competitive symmetry

Predicting stochastic community dynamics in grasslands under the assumption of competitive symmetry

Performance of young jack pine trees originating from two different branch angle traits under different intensities of competition

Modeling individual-tree mortality in Pyrenean oak (Quercus pyrenaica Willd.) stands

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