A synthesis of radial growth patterns preceding tree mortality

Tree mortality is a key process in forest dynamics. Despite decades of effort to understand this process, many uncertainties remain. South American broadleaf species are particularly under-represented in global studies on mortality and forest dynamics. We sampled monospecific broadleaf Nothofagus pumilio forests in northern Patagonia to predict tree mortality based on stem growth. Live or dead conditions in N. pumilio trees can be predicted with high accuracy using growth rate as an explanatory variable in logistic models. In Paso Córdova (CO), Argentina, where the models were calibrated, the probability of death was a strong negative function of radial growth, particularly during the six years prior to death. In addition, negative growth trends during 30 to 45 years prior to death increased the accuracy of the models. The CO site was affected by an extreme drought during the summer 1978–1979, triggering negative trends in radial growth of many trees. Individuals showing below-average and persistent negative trends in radial growth are more likely to die than those showing high growth rates and positive growth trends in recent decades, indicating the key role of droughts in inducing mortality. The models calibrated at the CO site showed high verification skill by accurately predicting tree mortality at two independent sites 76 and 141 km away. Models based on relative growth rates showed the highest and most balanced accuracy for both live and dead individuals. Thus, the death of individuals across different N. pumilio sites was largely determined by the growth rate relative to the total size of the individuals. Our findings highlight episodic severe drought as a triggering mechanism for growth decline and eventual death for N. pumilio, similar to results found previously for several other species around the globe. In the coming decades, many forests globally will be exposed to more frequent and/or severe episodes of reduced warm-season soil moisture. Tree-ring studies such as this one can aid prediction of future changes in forest productivity, mortality, and composition.

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Disentangling Mechanisms of Drought-Induced Dieback in Pinus nigra Arn. from Growth and Wood Isotope Patterns

Forests ◽

10.3390/f11121339 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1339

Author(s):

Ester González de Andrés ◽

Jesús Julio Camarero

Keyword(s):

Water Use ◽

Radial Growth ◽

Tree Mortality ◽

Pinus Nigra ◽

Growth Patterns ◽

Natural Forests ◽

Northern Spain ◽

Hydraulic Failure ◽

Intrinsic Water Use Efficiency ◽

Growth Decline

The increased frequency and intensity of warming-induced droughts have triggered dieback episodes affecting many forest types and tree species worldwide. Tree plantations are not exempt as they can be more vulnerable to drought than natural forests because of their lower structural and genetic diversity. Therefore, disentangling the physiological mechanisms leading to growth decline and tree mortality can provide tools to adapt forest management to climate change. In this study, we investigated a Pinus nigra Arn. plantation situated in northern Spain, in which some trees showed canopy dieback and radial-growth decline. We analyzed how radial growth and its responses to drought events differed between non-declining (ND) and declining (D) trees showing low and high canopy defoliation, respectively, in combination with carbon (δ13C) and oxygen (δ18O) isotope ratios in tree rings. The radial growth of P. nigra was constrained by water availability during the growing season and the previous autumn. The radial growth of D trees showed higher sensitivity to drought than ND trees. This fact is in accordance with the lower drought resilience and negative growth trends observed in D trees. Both tree classes differed in their growth from 2012 onwards, with D trees showing a reduced growth compared to ND trees. The positive δ13C-δ18O relationship together with the uncoupling between growth and intrinsic water-use efficiency suggest that D trees have less tight stomatal regulation than ND trees, which could involve a high risk of xylem embolism in the former class. Our results suggest that different water use strategies between coexisting ND and D trees were behind the differences in growth patterns and point to hydraulic failure as a possible mechanism triggering dieback and growth decline.

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Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽

10.3390/f12081015 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1015

Author(s):

Xuan Wu ◽

Liang Jiao ◽

Dashi Du ◽

Changliang Qi ◽

Ruhong Xue

Keyword(s):

Climate Change ◽

Tree Growth ◽

Central Region ◽

Radial Growth ◽

Growing Season ◽

Qilian Mountains ◽

Growth Patterns ◽

Total Precipitation ◽

Picea Crassifolia ◽

The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

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Timeline of Leaf and Cambial Phenology in Relation to Development of Initial Conduits in Xylem and Phloem in Three Coexisting Sub-Mediterranean Deciduous Tree Species

Forests ◽

10.3390/f11101104 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1104

Author(s):

Jožica Gričar ◽

Andreja Vedenik ◽

Gregor Skoberne ◽

Polona Hafner ◽

Peter Prislan

Keyword(s):

Tree Species ◽

Leaf Development ◽

Radial Growth ◽

Secondary Growth ◽

Growth Patterns ◽

Deciduous Tree ◽

Cambial Cell ◽

Cell Production ◽

Sieve Tubes ◽

Earlywood Vessels

It is unclear how the anticipated climate change will affect the timing of phenology of different tree organs/tissues and thus the whole-tree functioning. We examined the timing of leaf phenology and secondary growth in three coexisting deciduous tree species (Quercus pubescens Willd., Fraxinus ornus L. and Ostrya carpinifolia Scop) from a sub-Mediterranean region in 2019. In addition, we investigated the relationship between leaf and cambial phenology and the onset of the potential functioning of initial conduits, as determined by the completed differentiation process (vessels) or final size (sieve tubes). For this purpose, leaf development was monitored and the microcores of cambium and the youngest phloem and xylem increments were repeatedly collected at 7–10-day intervals during the growing season. The results revealed differences in the timing of leaf development and seasonal radial growth patterns in spring among the studied tree species, depending on wood porosity. We found that cambial cell production started in all cases in the first half of March. However, in ring-porous Q. pubescens and F. ornus, radial growth in the stem occurred more than a month before buds were swollen, whereas in diffuse-porous O. carpinifolia, these two events were detected at almost the same time. The end of cambial cell production occurred earliest in F. ornus (mid-July) and two weeks later also in the other two species. The widest initial earlywood vessels and early phloem sieve tubes were found in Q. pubescens, the narrowest initial earlywood vessels in O. carpinifolia and the narrowest early phloem sieve tubes in F. ornus. This indicates differences in the efficiency of conducting systems among the studied species. This novel approach of studying phloem phenology and anatomy in relation to leaf and xylem development contributes to a better understanding of how different tree species adapt their structure of secondary vascular tissues in response to environmental change.

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Tectonic influences on tree growth in northern Patagonia, Argentina: the roles of substrate stability and climatic variation

Canadian Journal of Forest Research ◽

10.1139/x95-182 ◽

1995 ◽

Vol 25 (10) ◽

pp. 1684-1696 ◽

Cited By ~ 44

Author(s):

Thomas Kitzberger ◽

Thomas T. Veblen ◽

Ricardo Villalba

Keyword(s):

Tree Ring ◽

Tree Growth ◽

Tree Mortality ◽

Synergistic Effects ◽

Climatic Variation ◽

Growth Patterns ◽

Great Earthquake ◽

Northern Patagonia ◽

South Central ◽

Substrate Stability

In northern Patagonia, Argentina, we examined the influences of climatic variation and inter-site variation in substrate stability on the dendroecological effects of earthquakes. In association with the great earthquake in 1960 centered off the coast of nearby Valdivia, Chile, extensive tree mortality occurred in northern Patagonia in Nothofagusdombeyi–Austrocedruschilensis stands on unstable debris fans. To examine the effects of the 1960 and earlier earthquakes on tree growth, we developed tree-ring chronologies from samples of the surviving A. chilensis on unstable debris fan sites and at adjacent nonfan sites of more stable substrates. For controlling the effects of regional climatic variation, we also produced a tree-ring chronology from this species in a more distant and undisturbed stand. Strong variations in tree-growth patterns on fan sites were associated with the historically documented major seismic events of south central Chile that occurred in 1737, 1751, 1837, and 1960. Tree-ring chronologies from nonfan sites (i.e., sites of greater substrate stability) showed much less response to these earthquakes. On the fan sites, strong growth suppressions were associated with the former three earthquakes, whereas strong releases followed the 1960 earthquake. The difference in response is explained by the occurrence of the 1960 earthquake during a period of drought, which in combination with the violent shaking of the ground, resulted in extensive tree mortality followed by growth releases of the survivors. However, severe droughts in the absence of earthquakes also can produce tree mortality and subsequent release of the survivors. Consequently, the synergistic effects of climatic variation and earthquake events must be carefully considered in developing records of both climatic variation and earthquakes.

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Radial growth patterns of dominant trees in two old-growth forests in eastern Fennoscandia

Journal of Forest Research ◽

10.1007/s10310-011-0259-4 ◽

2011 ◽

Vol 16 (3) ◽

pp. 228-236 ◽

Cited By ~ 6

Author(s):

Laura Niukkanen ◽

Timo Kuuluvainen

Keyword(s):

Radial Growth ◽

Growth Patterns ◽

Old Growth ◽

Old Growth Forests

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Dendrochronology of a fir wave

Canadian Journal of Forest Research ◽

10.1139/x84-011 ◽

1984 ◽

Vol 14 (1) ◽

pp. 51-56 ◽

Cited By ~ 23

Author(s):

Peter J. Marchand

Keyword(s):

High Frequency ◽

Carbon Balance ◽

Radial Growth ◽

Photosynthetic Efficiency ◽

Production Efficiency ◽

Tree Mortality ◽

Wood Production ◽

Mechanical Loss ◽

Overstory Trees ◽

Wave Edge

Standard analyses in dendrochronology were combined with estimates of wood production efficiency to clarify patterns of tree mortality in wave-regenerated fir forests (Abiesbalsamea (L.) Mill.). Results revealed important differences in radial growth and wood production per unit foliage area between dieback stands of young (37 years) and old (74 years) wave sites, indicating that wave mortality is not related to age nor restricted to trees of low vigor. Overstory trees in both young and old dieback areas are characterized by a high frequency of missing or partial rings in late years without significant change in wood production efficiency, suggesting that the primary cause for a decline at the wave edge is a mechanical loss of foliage rather than a decrease in photosynthetic efficiency. This is supported by a highly significant reduction (P = 0.005) in projected leaf area for dieback-zone trees. Tree-ring characteristics reported here are symptomatic of a carbon balance problem which may lead to tree death through a number of secondary causes.

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Tree mortality and radial growth losses caused by the western spruce budworm in a Douglas-fir stand in British Columbia

Canadian Journal of Forest Research ◽

10.1139/x82-117 ◽

1982 ◽

Vol 12 (4) ◽

pp. 780-787 ◽

Cited By ~ 71

Author(s):

R. I. Alfaro ◽

G. A. Van Sickle ◽

A. J. Thomson ◽

E. Wegwitz

Keyword(s):

Radial Growth ◽

Tree Mortality ◽

Small Diameter ◽

Basal Area ◽

Spruce Budworm ◽

Douglas Fir ◽

Radial Increment ◽

Western Spruce Budworm ◽

Number Of Stems ◽

The Relationship

The effects of defoliation by western spruce budworm (Choristoneuraoccidentalis (Freeman)), on Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) radial growth at breast height and tree mortality are given. Four hundred and twenty trees were marked in an 81-year-old stand, and their defoliation levels were recorded annually from 1970 to 1980 in an outbreak that lasted from 1970 to 1974, inclusive. Forty-one trees were felled and dissected in 1977, 3 years after recovery began. The number of stems per hectare was reduced by 39.3% and basal area by 11.6% through mortality, most occurring among the small diameter, suppressed, and intermediate trees. Relationships were established between mortality and defoliation. Radial increments were examined, and the presence of four outbreaks during the life of the stand was detected. The combined effect of these infestations amounted to a loss of about 12% of the estimated potential diameter had not the insects been active. The most recent outbreak (1970–1974) caused a total of 10 years of subnormal growth, including 5 years due to defoliation and 5 years of recovery. The relationship between radial increment losses and defoliation intensity and duration is studied and quantified.

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Contrasting radial growth and canopy recruitment patterns in Liriodendrontulipifera and Nyssasylvatica: gap-obligate versus gap-facultative tree species

Canadian Journal of Forest Research ◽

10.1139/x94-276 ◽

1994 ◽

Vol 24 (11) ◽

pp. 2141-2149 ◽

Cited By ~ 39

Author(s):

David A. Orwig ◽

Marc D. Abrams

Keyword(s):

Tree Species ◽

Forest Dynamics ◽

Radial Growth ◽

Life Histories ◽

Ring Width ◽

Canopy Gaps ◽

Growth Patterns ◽

Growth Strategies ◽

Shade Tolerant Species ◽

Quercus Forests

Radial growth patterns, canopy recruitment characteristics, and disturbance histories were examined in a shade-tolerant species, Nyssasylvatica Marsh., and a shade-intolerant species, Liriodendrontulipifera L., to determine the influence of canopy gaps in species with contrasting life histories. Tree cores of these co-occurring species were taken from three mixed-Quercus forests in northern Virginia. Most N. sylvatica individuals became established prior to 1850 and experienced multiple release and suppression periods coinciding with logging during the late 1800s and early 1900s. Many L. tulipifera became established during the early 1900s following logging, and only a few individuals experienced prolonged suppression periods. Regardless of site, L. tulipifera grew faster than N. sylvatica (average radial growth >1.70 mm/year for L. tulipifera vs. <0.82 mm/year for N. sylvatica.). Liriodendrontulipifera also exhibited longer periods of mean yearly growth >2 mm (15–37 years for L. tulipifera vs. <5 years for Nsylvatica). Consecutive growth <0.5 mm/year ranged from 43 to 66 years in N. sylvatica vs. 2–11 years in L. tulipifera. Ring width patterns indicate that both species used different strategies following disturbance that enabled them to coexist in these forests. Nyssasylvatica persisted in subcanopy positions for extended periods of time but was capable of responding to release even after 170 years (i.e., gap facultative). In contrast, L. tulipifera appeared to rely on a strategy of rapid height and radial growth for canopy accession following large disturbances (i.e., gap obligate). The results of this study indicate the importance of using dendroecological techniques in the study of forest dynamics and species' growth strategies.

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Improving tree mortality models by accounting for environmental influences

Canadian Journal of Forest Research ◽

10.1139/x07-078 ◽

2007 ◽

Vol 37 (11) ◽

pp. 2106-2114 ◽

Cited By ~ 5

Author(s):

Henrik Hartmann ◽

Christian Messier ◽

Marilou Beaudet

Keyword(s):

Tree Mortality ◽

External Validation ◽

Growth Patterns ◽

External Factors ◽

Model Parameters ◽

Similar Frequency ◽

Growth Series ◽

Recent Growth ◽

Dead Trees ◽

The Impact

Tree-ring chronologies have been widely used in studies of tree mortality where variables of recent growth act as an indicator of tree physiological vigour. Comparing recent radial growth of live and dead trees thus allows estimating probabilities of tree mortality. Sampling of mature dead trees usually provides death-year distributions that may span over years or decades. Recent growth of dead trees (prior to death) is then computed during a number of periods, whereas recent growth (prior to sampling) for live trees is computed for identical periods. Because recent growth of live and dead trees is then computed for different periods, external factors such as disturbance or climate may influence growth rates and, thus, mortality probability estimations. To counteract this problem, we propose the truncating of live-growth series to obtain similar frequency distributions of the “last year of growth” for the populations of live and dead trees. In this paper, we use different growth scenarios from several tree species, from several geographic sources, and from trees with different growth patterns to evaluate the impact of truncating on predictor variables and their selection in logistic regression analysis. Also, we assess the ability of the resulting models to accurately predict the status of trees through internal and external validation. Our results suggest that the truncating of live-growth series helps decrease the influence of external factors on growth comparisons. By doing so, it reinforces the growth–vigour link of the mortality model and enhances the model’s accuracy as well as its general applicability. Hence, if model parameters are to be integrated in simulation models of greater geographical extent, truncating may be used to increase model robustness.

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