Tree Growth Trajectories Research Articles

Exacerbated Tree Growth Decline of an Old Platycladus orientalis Forest after Rapid Warming at the Northern Edge of the Taihang Mountain of China

Old trees are irreplaceable conservation resources with numerous ecological and socio-cultural values. While many forests have experienced significant declines under recent climate warming, the risk of growth declines in old trees remains unknown. Here, we tackle this problem by dendrochronological studies of 30 old trees in a Platycladus orientalis forest at the northern boundary of the Taihang Mountain of China. We examined annual growth trajectories of trees at individual level and discovered four severe growth decline events over the last 150 years, including the periods of 1894–1899, 1913–1919, 1964–1967 and 2004–2018. The most recent growth decline event lasted for 15-year and involced 50% to 75% of the old trees. This decline was unprecedented in both its extent and duration. Furthermore, the growth–climate relationship of these old trees has changed since 1990. Before 1990, tree growth was significantly correlated with minimum winter; after 1990, tree growth became significantly correlated with the self-calibrating Palmer Drought Index. These results suggest that warming-induced droughts after 1990 could be the primary driver of the recent growth decline. If climate warming continues and drought stresses intensify, the old trees may face an increased risk of growth decline and even mortality.

Grow or die: A 49‐year growth history of a Japanese warm‐temperate tree species

AbstractThe growth trajectories of trees are not fully understood due to their long life span. We characterized the population dynamics of the canopy tree Castanopsis cuspidata (Thunb.) Schottky in a Japanese warm‐temperate forest over 49 years (1966–2015). Our study was initiated approximately 50 years after our study site was clear‐cut. The forest had a closed canopy for the first 23 years of the study. Strong typhoons in 1991 and 1993 seriously damaged the forest, and since then the forest has been recovering from these disturbances. The diameter distribution of this species was bell‐shaped in 1966, suggesting that the trees emerged simultaneously after the clear‐cut in the 1910s, and the recruitment of trees has remained unchanged since then. The lack of recruitment of C. cuspidata before the typhoon disturbance supports this conclusion. Assuming that the C. cuspidata trees in 1966 were cohorts that were established soon after the clear‐cut, the size differences reflect differences in growth rate, with small trees corresponding to slow growers and large trees corresponding to fast growers. Before the typhoon, slow growers had low survival, and the mortality rate of fast growers was low. Many fast growers were uprooted or snapped by strong winds by the typhoons. However, their mortality rate did not differ from that of slow growers because many slow growers were killed by large fallen trees. The growth of some slow‐growing survivors increased after the typhoon, which allowed them to rapidly reach the canopy. Therefore, the typhoon altered the distribution of canopy trees among slow and fast growers. Survivors experienced faster growth than trees that died during the census period, suggesting that growth rate provides a robust indicator of future survival. Before the typhoon, the survival of fast growers was higher than that of slow growers. This suggests that fast growers disproportionally contribute to reproduction compared with slow growers. However, no recruited tree was observed in this subperiod, suggesting that fast growers made no contribution to reproduction. Fast growers might not play a more significant demographic role than slow growers in this species.

Impacts of recurrent dry and wet years alter long‐term tree growth trajectories

Abstract Climate extremes, such as abnormally dry and wet conditions, generate abrupt shifts in tree growth, a situation which is expected to increase under predicted climate conditions. Thus, it is crucial to understand factors determining short‐ and long‐term tree performance in response to higher frequency and intensity of climate extremes. We evaluated how three successive droughts and wet years influenced short‐ and long‐term growth of six dominant Iberian tree species. Within species variation in growth response to repeated dry and wet years was evaluated as a function of individual traits related to resource and water use (diameter at breast height [DBH], wood density [WD] and specific leaf area [SLA]) and tree‐to‐tree competition across climatically contrasted populations. Furthermore, we assessed how short‐term accumulated impacts of the repeated dry and wet years influenced long‐term growth performance. All species showed strong short‐term growth decreases and enhancements due to repeated dry and wet years. However, patterns of accumulated growth decreases (AcGD) and enhancements (AcGE) across climatically contrasting populations were species‐specific. Furthermore, individual trait data were weakly associated with either AcGD or AcGE and the few relevant associations were found for conifers. Intraspecific variations in tree growth responses to repeated climates extremes were large, and not explained by intraspecific variability in SLA and WD. Accumulated impacts of repeated dry and wet years were related to long‐term growth trends, showing how the recurrence of climate extremes can determine growth trajectories. The relationships of AcGD and AcGE with long‐term growth trends were more common in conifers species. Synthesis. Repeated climate extremes do not only cause short‐term growth reductions and enhancements but also determine long‐term tree growth trajectories. This result shows how repeated droughts can lead to growth decline. Conifers were more susceptible to the accumulated effects of extreme weather events indicating that in the future, more intense and frequent climate extremes will alter growth performance in forests dominated by these species.

Allometric projections of time-related growth trajectories of two coexisting dipterocarp canopy species in India

Background: The Western Ghats of India contain the westernmost dipterocarp forests of Asia. However, only a few dipterocarp tree species actually coexist in the forest canopy among which Vateria indica and Dipterocarpus indicus are the most common. The mechanisms contributing to the coexistence of these phylogenetically closely related species have not been identified.Aims: We investigated the time-related growth trajectories in diameter, height and crown size of these two species in the Uppangala Permanent Sample Plot to determine if trade-offs in their three-dimensional developmental strategies could contribute to their long-term coexistence.Methods: From annual diameter growth data of 692 trees >9.55 cm in diameter at breast height over a 21-year period, we developed time-related diameter growth models for the two species, accounting for local density-dependent competition effects and topography. Combining the diameter growth models with static stem and crown allometries, we projected time-related tree growth trajectories in height and crown size.Results: While both species can reach similar dimensions, V. indica grows much faster, or at least as fast as D. indicus in diameter, height and crown size in all the observed situations. Both species respond similarly to topography, but V. indica appears to be more responsive to local density-dependent competition than D. indicus. Finally, V. indica shows higher mortality and recruitment rates and a greater basal area increase than D. indicus.Conclusions: These results refute our hypothesis that D. indicus coexists with the outperformer V. indica by a growth strategy allowing selected individuals in favourable conditions to reach the canopy more quickly than their competitors. The current coexistence of the two dipterocarp species at Uppangala appears not to be at a static equilibrium; V. indica probably being in a phase of canopy stand colonisation.

A new approach to prediction of the age-age correlation for use in tree breeding

Early selection in tree breeding requires a credible age-age correlation. Modelling height growth in provenance and progeny trials, we can predict age-age correlations suitable for use in operational breeding as described in this article. Tree breeding involves early selection, which is an indirect selection using a genetic correlation. This study describes a procedure of predicting an age-age phenotypic correlation as a surrogate for a genetic correlation. Although the predicted correlations are based on white spruce (Picea glauca) and lodgepole pine (Pinus contorta) data, they can be used in other coniferous species with similar mode of height growths. The aim of the study is to predict a correlation coefficient used to adjust breeding values at a measurement age to breeding values at a rotation age. This correlation is derived from the observed height growth trajectories of trees in progeny and provenance trials. Correlation prediction equations were developed using modelled height growth in provenance and progeny trials of lodgepole pine and white spruce. The time lag between successive tree ages was used as a correlation predictor variable. Correlations differed between spruce and pine but the differences narrowed as trees grew older. For example, a correlation between 20 and 100 years was 0.607 for spruce and 0.470 for pine, whereas that of 30 and 100 was 0.826 for spruce and 0.832 for pine. Based on the age-age correlation, the optimum selection age for a 100-year rotation age is 40–50 years. Parameters of the tree height growth function exhibited significant genetic variance and genotype × environment interaction. After the age of 40 years, age-age correlation for height may be less important for selection and genetic gain prediction than the correlation between height and diameter, which is declining with tree age.

Examining the influences of site conditions and disturbance on rainforest structure through tree ring analyses in two Araucariaceae species

Tree growth is central to the dynamics of forest ecosystems. Patterns in tree diameter growth from tree rings can yield an understanding of the growth trajectories of trees and how they vary with site conditions but detailed studies have been conducted on relatively few species in tropical forests. Furthermore, tree rings provide information on temporal patterns of tree establishment and thus the influences of disturbance and abiotic conditions on forest structure. Here, we confirm the annularity of growth rings in Agathis robusta and Araucaria cunninghamii from North Queensland, Australia. We then examine tree growth trajectories in two contrasting natural forests (Downfall Creek and Gillies Range) and a plantation. Growth in plantation over 70years was high and growth trajectories were similar among trees within each species. In natural forests age and diameter were only weakly correlated for both species. Growth trajectories were similar and homogeneous for both Agathis and Araucaria in the plantation, whereas there was a great deal of variation in tree ages and growth trajectories observed for the two forest sites. These differences are likely related to dynamics driven by climate and soil that modulate boundaries between sclerophyll and rainforest over the long-term. Downfall Creek (a ridge with poor shallow soils) is likely recently invaded (past couple of hundred years) sclerophyll woodland. The alternative hypothesis—that structural and compositional characteristics result from local disturbance resulting from World War II training activities—was not strongly supported by Agathis establishment dates. The study of tree rings in tropical trees is underappreciated and can provide valuable information on the influences on tree growth and disturbance in tropical forests.

Tree rings reveal extent of exposure to ionizing radiation in Scots pine Pinus sylvestris

Tree growth has been hypothesized to provide a reliable indicator of the state of the external environment. Elevated levels of background ionizing radiation may impair growth trajectories of trees by reducing the annual growth. Such effects of radiation may depend on the individual phenotype and interact with other environmental factors such as temperature and drought. We used standardized growth rates of 105 Scots pine Pinus sylvestris located near Chernobyl, Ukraine, varying in the level of background radiation by almost a factor 700. Mean growth rate was severely depressed and more variable in 1987–1989 and several other subsequent years, following the nuclear accident in April 1986 compared to the situation before 1986. The higher frequency of years with poor growth after 1986 was not caused by elevated temperature, drought or their interactions with background radiation. Elevated temperatures suppressed individual growth rates in particular years. Finally, the negative effects of radioactive contaminants were particularly pronounced in smaller trees. These findings suggest that radiation has suppressed growth rates of pines in Chernobyl, and that radiation interacts with other environmental factors and phenotypic traits of plants to influence their growth trajectories in complex ways.

Attaining the canopy in dry and moist tropical forests: strong differences in tree growth trajectories reflect variation in growing conditions

Availability of light and water differs between tropical moist and dry forests, with typically higher understorey light levels and lower water availability in the latter. Therefore, growth trajectories of juvenile trees—those that have not attained the canopy—are likely governed by temporal fluctuations in light availability in moist forests (suppressions and releases), and by spatial heterogeneity in water availability in dry forests. In this study, we compared juvenile growth trajectories of Cedrela odorata in a dry (Mexico) and a moist forest (Bolivia) using tree rings. We tested the following specific hypotheses: (1) moist forest juveniles show more and longer suppressions, and more and stronger releases; (2) moist forest juveniles exhibit wider variation in canopy accession pattern, i.e. the typical growth trajectory to the canopy; (3) growth variation among dry forest juveniles persists over longer time due to spatial heterogeneity in water availability. As expected, the proportion of suppressed juveniles was higher in moist than in dry forest (72 vs. 17%). Moist forest suppressions also lasted longer (9 vs. 5 years). The proportion of juveniles that experienced releases in moist forest (76%) was higher than in dry forest (41%), and releases in moist forests were much stronger. Trees in the moist forest also had a wider variation in canopy accession patterns compared to the dry forest. Our results also showed that growth variation among juvenile trees persisted over substantially longer periods of time in dry forest (>64 years) compared to moist forest (12 years), most probably because of larger persistent spatial variation in water availability. Our results suggest that periodic increases in light availability are more important for attaining the canopy in moist forests, and that spatial heterogeneity in water availability governs long-term tree growth in dry forests.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-009-1540-5) contains supplementary material, which is available to authorized users.

Successional replacement mediated by frequency and severity of wind and snow disturbances in a Picea‐Abies forest

AbstractQuestion:How do wind and snow disturbances affect the successional replacement of Picea glehnii by Abies sachalinensis in a sub‐alpine coniferous forest?Location:Cool temperate, northern Japan.Methods:Tree demography (growth, mortality and recruitment rates) was determined by repeated measurements of stem diameter and height, and multiple censuses in four Picea‐Abies stands undergoing succession. Above‐ground stand bio‐mass, residence time and tree growth trajectories of the component species were estimated to examine successional changes in structure and dynamics. Individual based simulations were used to examine the effects of disturbances that slowed down succession. Multiple regression analyses were used to determine the relative importance of disturbance frequency and intensity on species composition during succession.Results:Above‐ground biomass was larger in P. glehnii than in A. sachalinensis stands, whereas residence time, a proxy of productivity, was much shorter for A. sachalinensis than for P. glehnii populations. During successional replacement, both species increased in initial growth rate and decreased in size‐dependency of growth in canopy gaps. These plastic growth responses were more prominent in P. glehnii than in A. sachalinensis. Disturbance frequency was the most important predictor of species composition in the simulations, and windstorms were more important than snowfall in terms of disturbance intensity.Conclusions:The frequency of natural disturbances does not have the potential to initiate stand dynamics but it does, however, slow down succession. When disturbance is locally frequent because of the direction and pitch of the topography, early‐successional P. glehnii stands may persist for thousands of years.

Successional replacement mediated by frequency and severity of wind and snow disturbances in a Picea-Abies forest

Abstract Question: How do wind and snow disturbances affect the successional replacement of Picea glehnii by Abies sachalinensis in a sub-alpine coniferous forest? Location: Cool temperate, northern Japan. Methods: Tree demography (growth, mortality and recruitment rates) was determined by repeated measurements of stem diameter and height, and multiple censuses in four Picea-Abies stands undergoing succession. Above-ground stand biomass, residence time and tree growth trajectories of the component species were estimated to examine successional changes in structure and dynamics. Individual based simulations were used to examine the effects of disturbances that slowed down succession. Multiple regression analyses were used to determine the relative importance of disturbance frequency and intensity on species composition during succession. Results: Above-ground biomass was larger in P. glehnii than in A. sachalinensis stands, whereas residence time, a proxy of productivity, was much shorter for A. sachalinen...