Past growth variations in <i>Picea sitchensis</i> with differing crown densities

Innes, John L.; Neumann, H. O.

doi:10.1080/02827589109382677

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…This strategy has arisen from the desire to sample the oldest trees in a stand, which are often incorrectly assumed to be the largest. However, tree-ring patterns and the sizes of trees are strongly affected by forest management and natural disturbances [45]. The effects of restricting sampling to the largest trees have never been adequately documented, although recent studies have shown that different sampling strategies achieve different results [46].…”

Section: Tree-ring Growthmentioning

confidence: 99%

Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

2021

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Purpose of Review Society is concerned about the long-term condition of the forests. Although a clear definition of forest health is still missing, to evaluate forest health, monitoring efforts in the past 40 years have concentrated on the assessment of tree vitality, trying to estimate tree photosynthesis rates and productivity. Used in monitoring forest decline in Central Europe since the 1980s, crown foliage transparency has been commonly believed to be the best indicator of tree condition in relation to air pollution, although annual variations appear more closely related to water stress. Although crown transparency is not a good indicator of tree photosynthesis rates, defoliation is still one of the most used indicators of tree vitality. Tree rings have been often used as indicators of past productivity. However, long-term tree growth trends are difficult to interpret because of sampling bias, and ring width patterns do not provide any information about tree physiological processes. Recent Findings In the past two decades, tree-ring stable isotopes have been used not only to reconstruct the impact of past climatic events, such as drought, but also in the study of forest decline induced by air pollution episodes, and other natural disturbances and environmental stress, such as pest outbreaks and wildfires. They have proven to be useful tools for understanding physiological processes and tree response to such stress factors. Summary Tree-ring stable isotopes integrate crown transpiration rates and photosynthesis rates and may enhance our understanding of tree vitality. They are promising indicators of tree vitality. We call for the use of tree-ring stable isotopes in future monitoring programmes.

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Section: Tree-ring Growthmentioning

confidence: 99%

Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

2021

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“…Long-term stability of trees' health and growth ranking is found in other studies. The ranking of trees with regard to their level of defoliation or yellowing is found to correspond to stable differences in growth for several years or even up to a century (Röhle, 1987;Bert, 1993), but occasionally, the ranking with regard to growth and size may change considerably (Cherubini et al, 1998), as a result of severe stress such as drought (Innes and Neumann, 1991;Landmann, 1993). These studies demonstrated that the allocation of the trees to present levels of health scores occurred in certain years of severe stress.…”

Section: Discussionmentioning

confidence: 99%

Crown condition of Norway spruce: within-stand relationships and competition

Solberg¹

1999

Forestry

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This study describes how crown density changes were distributed within monitoring plots, in order to determine whether the reduced crown density observed could be explained as a worsening of a limited number of unhealthy or small and slightly suppressed trees. Crown density, yellowing, coning and stem diameter data were available from 447 selected plots comprising 22 560 single trees all having a complete 1990-97 series of crown condition data. The 8-year record of crown density for each tree was recalculated to two median values, for 1990-93 and 1994-97, in order to reduce the influence from short-term variations including random errors. The scores for yellowing and number of cones were averaged over the years 1990-93. These variables, and diameter, were recalculated to rank indices within each plot. Relationships between variables were described by graphs and examined by correlation analyses of the indices. The trees tended to retain their internal ranking. Generally, when crown density for a plot has changed, most of the trees were affected. The most defoliated trees in each plot had the least negative changes, but apart from that the trees were equally affected regardless of their yellowing, number of cones, and their size. The results demonstrate that any effects from competition between the trees were sufficiently removed in the assessments even in densely stocked stands.

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“…), Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] and several pine species (Innes and Neumann, 1991;Söderberg, 1993;Solberg, 1999;Solberg and Tveite, 2000;Linares and Camarero, 2012;Ferretti et al, 2021); secondly, the ICP Forests provide a long-term consistent framework for annual surveys on tree health by assessing tree defoliation and damage symptoms on ca. 110,000 individual trees located at ca.…”

Section: Introductionmentioning

confidence: 99%

Stem Radial Growth Is Negatively Related to Tree Defoliation and Damage in Conifers, Northern Italy

Ferretti

Ghosh

Gottardini

2021

Front. For. Glob. Change

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Although several manipulative experiments provided evidence for a negative effect of defoliation on tree growth, results from observational studies were less univocal. This may be due to the ability of observed defoliation to reflect the health status of individual trees, to the influence of site condition and to the amplitude of time window used for growth assessment. Here, we investigated the relationship between two tree health indicators (crown defoliation, damage symptoms) and annual (measured by tree-ring width on 69 Norway spruce trees) and periodical (5-year and 10-year diameter increments, 346 trees from five coniferous species) tree growth. Data originated from 14 (seven for tree rings) ICP Forests Level I plots in Trentino, northern Italy. Diameter, defoliation and damage were measured between 1997 and 2011 as part of the annual crown condition survey, while cores for tree-rings were collected on a sub-sample of trees in 2012. We carried out regression modeling combined with model selection in one-step (periodical data) and two-step (annual data) approaches, using moving averages for the annual data with varying time window widths. Our results indicated an overall negative correlation between defoliation and annual or periodical stem diameter growth. The relationship between defoliation and growth changes in relation to the time window considered, and becomes stronger when data are aggregated over longer time windows (>3 years), when also the occurrence of damage symptoms plays a significant role. The effect of the amplitude of the time windows for data aggregation is probably due to the mechanisms behind the defoliation-growth relationship, which may change according to the causal factors involved. In particular, when larger time windows are considered, short-term fluctuations are likely to be smoothed out, and more general patterns may emerge. We concluded that radial growth is significantly negatively related to defoliation, and this supports the use of defoliation as a rapid indicator for forest health and vitality.

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Past growth variations in Picea sitchensis with differing crown densities

Cited by 7 publications

References 4 publications

Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

Crown condition of Norway spruce: within-stand relationships and competition

Stem Radial Growth Is Negatively Related to Tree Defoliation and Damage in Conifers, Northern Italy

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