Competition and tree crowns: A neighborhood analysis of three boreal tree species

Thorpe, H. C.; Astrup, Rasmus; Trowbridge, Amy M.; Coates, K. David

doi:10.1016/j.foreco.2010.01.035

Cited by 149 publications

(123 citation statements)

References 39 publications

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“…The potential importance of the competitive trees' species-identity is well recognized for tree growth, and has been demonstrated in several studies (e.g. Sumida et al 2002;Canham et al 2004;Uriarte et al 2004;Boivin et al 2010; Thorpe et al 2010). A plastic response in tree growth and architecture may be dependent on the neighbouring species, because species-specific differences exist e.g.…”

Section: Between-tree Interactionsmentioning

confidence: 98%

Crown architecture and its role in species interactions in mixed boreal forests

Lintunen¹

2013

Diss. For.

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The species specific growth patterns make plastic crown architecture respond in different manner to different environments modifying their influence to neighbours. The main aims of this thesis were to separate the effect of neighbour species identity from the abundance, size and proximity of the neighbours in between-tree competition and to link crown architecture with hydraulic architecture by identifying the associated within-tree variation of crown traits.The empirical part of the work was based on digitising three-dimensional (3D) crown architecture and measuring xylem anatomy. Digitising allowed the development of crown architecture models for Betula pendula (Roth.) and Pinus sylvestris (L.). The models were further applied to simulate light transmission in mixed stands.Crown architecture of the studied species responded to increased competition intensity primarily by reducing branch number and size. Proportional biomass distribution to foliage and main branches over the stem increased in young B. pendula with increasing competition intensity, whereas Pinus sylvestris used the opposite strategy. In addition to competition intensity, crown architecture of the studied species showed plastic responses to the species identity of neighbouring trees. Lower overall growth but added height growth indicating stronger competition was found in mixtures of B. pendula and Pinus sylvestris when a tree was surrounded by interspecific neighbours compared to trees surrounded by intraspecific neighbours. Both species-specific effects on resource gradients and nonresource signals remain plausible explanations for this result: B. pendula transmitted more light than Pinus sylvestris at simulated dense stands.Hydraulic architecture was shown to be interlinked with crown architecture as the conduit diameter varied as a function of tree compartment, branching hierarchy, leaf area and distance from the apex.The results suggest that the use of detailed tree structure models and species-specific competition analysis is useful in predicting and understanding growth in mixed boreal stands.

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Section: Between-tree Interactionsmentioning

confidence: 98%

Crown architecture and its role in species interactions in mixed boreal forests

Lintunen¹

2013

Diss. For.

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“…Boivin et al (2010) relataram aumento do poder preditivo do modelo de crescimento quando incluído no cálculo da competição o sombreamento da árvore-objetivo causado pela árvore vizinha competidora. Esta melhora pode estar associada ao fato que o resultado da interação (competição) determina o tamanho da copa de cada árvore individual, o que reflete na interceptação de luz, capacidade fotossintética, crescimento e até mesmo sobrevivência (Thorpe et al 2010).…”

Section: Análise Dos íNdices De Competiçãounclassified

Competição assimétrica e o incremento diamétrico de árvores individuais de Cedrela odorata L. na Amazônia ocidental

Cunha

Finger

2013

Acta Amaz.

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RESUMOUm modelo de crescimento dependente e independente da distância foi ajustado para avaliar como variáveis de competição explicam a variação do crescimento periódico em diâmetro de 132 árvores de cedro (Cedrela odorata). Utilizando a abordagem de crescimento potencial relativo (PRI), estimou-se o incremento relativo em diâmetro (IRd) a partir do produto do crescimento máximo em diâmetro (incremento potencial) e da função modificada (porção do crescimento reduzido). A significância do modelo do crescimento reduzido ajustado demonstrou influência da competição assimétrica sobre o crescimento em diâmetro, explicando 71% do total da variação e também revelou que a resposta à competição não foi constante, mas variou entre as diferentes classes de tamanho dos indivíduos arbóreos. PalavRaS-chavE: incremento periódico em diâmetro; índices de morfometria; índices de competição. Asymmetric competition and the diameter increment of Cedrela odorata L. trees in western Amazonia.aBSTRacT A dependent and independent growth distance model was fitted to evaluate how competition variables may account for the variation of periodic diameter increment of 132 Cedrela odorata trees. Using a Potential Relative Increment (PRI), the relative diameter increment (IRd) was estimated from the multiplication of maximum diameter growth (potential increment) by modified function (portion of the reduced growth due to competition by light and growth space). The significance of the reduced fitted model demonstrated the influence of asymmetric competition variables on diameter growth, explaining 71% of the total variation as well as indicated that competition responses were not constant, but it varied among the different size classes of trees.

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“…Finally, the crown radius and crown depth models (Eqs. (2) and (3)) are relatively simple and do not account for the influence of neighborhood characteristics (e.g., density) on crown dimension (Thorpe et al, 2010).…”

Section: Model Evaluationmentioning

confidence: 99%

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

Beaudet

Harvey

Messier

et al. 2011

Forest Ecology and Management

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a b s t r a c tIn the context of partial harvesting, adequately managing post-harvest light conditions are essential to obtain a desired composition of tree species regeneration. The objective of this study was to determine how varying the intensity and spatial pattern of harvest would affect understory light conditions in boreal mixedwood stands of northwestern Quebec using the spatially explicit SORTIE-ND light model. The model was evaluated based on comparisons of observed and predicted light levels in both mapped and un-mapped plots. In mapped plots, reasonably accurate predictions of the overall variation in light levels were obtained, but predictions tended to lack spatial precision. In un-mapped plots, SORTIE-ND accurately predicted stand-level mean GLI (Gap Light Index) under a range of harvest intensities. The model was then used to simulate nine silvicultural treatments based on combinations of three intensities of overstory removal (30%, 45% and 60% of basal area) and three harvest patterns (uniform, narrow strips, large gaps). Simulations showed that increasing overstory removal had less impact on light conditions with uniform harvests, and a more marked effect with more aggregated harvest patterns. Whatever the harvest intensity, uniform cuts almost never created high light conditions (GLI > 50%). Gap cuts, on the other hand, resulted in up to 40% of microsites receiving GLI > 50%. Our results suggest that either a 30% strip or gap cut or a 45-60% uniform partial harvest could be used to accelerate the transition from an aspen dominated composition to a mixedwood stand because both types of cut generate the greatest proportion of moderately low light levels (e.g., 15-40% GLI). These light levels tend to favour an accelerated growth response among shade-tolerant conifers, while preventing excessive recruitment of shade-intolerant species. A better understanding of how spatial patterns of harvest interact with tree removal intensity to affect understory light conditions can provide opportunities for designing silvicultural prescriptions that are tailored to species' traits and better suited to meet a variety of management objectives.

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Competition and tree crowns: A neighborhood analysis of three boreal tree species

Cited by 149 publications

References 39 publications

Crown architecture and its role in species interactions in mixed boreal forests

Crown architecture and its role in species interactions in mixed boreal forests

Competição assimétrica e o incremento diamétrico de árvores individuais de Cedrela odorata L. na Amazônia ocidental

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

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