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122 results for “temperate trees”

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dryad36/100

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

The growth trajectories of trees are not fully understood due to their long lifespan. 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.

opencc-zeroMar 2024View details →

dryad36/100

Data from: Positive effects of tree species diversity on productivity switch to negative after severe drought mortality in a temperate forest experiment

Synthesis of a large body of evidence from field experiments suggests more diverse plant communities are both more productive as well as more resistant to the effects of climatic extremes like drought. However, this view is strongly based on data from grasslands due to limited empirical evidence from tree diversity experiments. Here we report on the relationship between tree diversity and productivity over ten years in a field experiment established in 2005 that was then affected by the 2018 megadrought in central Europe. Across a number of years, tree species diversity and productivity were significantly positively related, however, the slope switched to negative in the year of the drought. Net diversity effects increased through time, with complementarity making greater continuations to the net diversity effect than selection effects. Complementarity was clearly positive (95 % credible interval) in three and five species mixtures before the drought (2012-2016) but was found to decrease in the year of the drought. Selection effects were clearly positive in 2016, and remained positive in 2018, the drought year in two, three, and five species mixtures. Survival of the Norway spruce (Picea abies) plummeted during drought and a negative relationship between species diversity and spruce survival was found. Our findings suggest that tree diversity per se may not buffer communities against the impacts of extreme drought and that tree species composition and the drought tolerance of tree species (i.e., species identity) will be important determinants of community productivity as the prevalence of drought increases.

opencc-zeroMar 2024View details →

dryad36/100

Stem decomposition of temperate tree species is determined by stem traits and fungal community composition during early stem decay

Dead trees are vital structural elements in forests playing key roles in the carbon and nutrient cycle. Stem traits and fungal community composition are both important drivers of stem decay, and thereby affect ecosystem functioning, but their relative importance for stem decomposition over time remains unclear. To address this issue, we used a common garden decomposition experiment in a Dutch larch forest hosting fresh logs from 13 common temperate tree species. In total 25 fresh wood and bark traits were measured as indicators of wood accessibility for decomposers, nutritional quality, and chemical or physical defense mechanisms. After one and four years of decay, we assessed the richness and composition of wood-inhabiting fungi using amplicon sequencing and determined the proportional wood density loss. Average proportional wood density loss for the first year was 18.5%, with further decomposition occurring at a rate of 4.3% yr-1 for the subsequent three years across tree species. Proportional wood density loss varied widely across tree species in the first year (8.7-24.8% yr-1) and subsequent years (0-11.3% yr-1). The variation was directly driven by initial wood traits during the first decay year, then later directly driven by bark traits and fungal community composition. Moreover, bark traits affected the composition of wood-inhabiting fungi and thereby indirectly affected decomposition rates. Specifically, traits promoting resource acquisition of the living tree, such as wide conduits that increase accessibility and high nutrient concentration, increased initial wood decomposition rates. Fungal community composition, but not fungal richness explained differences in wood decomposition after four years of exposure in the field, where fungal communities dominated by brown-rot and white-rot Basidiomycetes were linked to higher wood decomposition rate. Synthesis. Understanding what drives deadwood decomposition through time is important to understand the dynamics of carbon stocks. Here, using a tailor-made experimental design in a temperate forest setting, we have shown that stem trait variation is key to understanding the roles of these drivers; Initially, wood traits explained decomposition rates while subsequently, bark traits and fungal decomposer composition drove decomposition rates. These findings inform forest management with a view to selecting tree species to promote carbon storage.

opencc-zeroDec 2023View details →

dryad36/100

Tree canopy accession strategy changes along the latitudinal gradient of temperate Northeast Asia

Aim: Understanding how natural forest disturbances control tree regeneration is key to predict the consequences of globally accelerating forest diebacks on carbon stocks and forest biodiversity. Tropical cyclones (TCs) are important drivers of forest dynamics in Eastern Asia and it is predicted that their importance will increase. However, little is known about TC impact on forest regeneration. Location: Latitudinal gradient from south Korea (33°N) to the Russian Far East (45°N). Time period: Last 300 years. Major taxa studied: Quercus mongolica, Abies nephrolepis and Pinus koraiensis. Methods: We explore the effects of TC activity on canopy accession strategies derived from long-term tree radial growth patterns along a 1500-km latitudinal gradient of decreasing TC activity. We analyzed canopy accession strategies for more than 800 trees of three widely distributed tree species by dividing them into gap trees (GTs) that established immediately after gap formation, and released trees (RTs) that accessed the upper canopy after a period of competitive suppression. Results: We found a substantial decrease in GTs and increase in RTs proportionally along the gradient of decreasing TC activity. P. koraiensis and A. nephrolepis exhibited high variability in the proportions of the individual canopy accession strategies along the latitudinal gradient, while it was more stable for Q. mongolica. We identified the gradient of TC activity as the main driver influencing canopy dynamics and thus changes in life history traits for P. koraiensis and Q. mongolica, while maximal growth rate was the main driver for A. nephrolepis. Main conclusions: Flexibility in growth strategies enabled the studied species to cover extensive areas and indicates that they will be able to cope with shifts in disturbance regimes induced by the poleward migration of TCs and increasing TC intensity. Our results highlight the canopy accession strategy as an ecological indicator of past disturbance activity.

opencc-zeroDec 2021View details →

dryad36/100

High variation in hydraulic efficiency but not xylem safety between roots and branches in four temperate broad-leaved tree species

Xylem hydraulic safety and efficiency are key traits determining tree fitness in a warmer and drier world. While numerous plant hydraulic studies have focused on branches, our understanding of root hydraulic functioning remains limited, although roots control water uptake, influence stomatal regulation and have commonly been considered as the most vulnerable organ along the hydraulic pathway. We investigated 11 traits related to xylem safety and efficiency along the hydraulic pathway in four temperate broad-leaved tree species. Continuous vessel tapering from coarse roots to stems and branches caused considerable reduction in hydraulic efficiency. Wood density was always lowest in roots, but did not decline linearly along the flow path. In contrast, xylem embolism resistance (P50) did not differ significantly between roots and branches, except for one species. The limited variation in xylem safety between organs did not adequately reflect the corresponding reductions in vessel diameter (by ~70%) and hydraulic efficiency (by ~85%). Although we did not observe any trade-off between xylem safety and specific conductivity, vessel diameter, vessel lumen fraction and wood density were related to embolism resistance, both across and partly within organs. We conclude that coarse roots are not highly vulnerable to xylem embolism as commonly believed, indicating that hydraulic failure during soil drying might be restricted to fine roots.

opencc-zeroJan 2022View details →

dryad36/100

Non-structural carbohydrates predict survival in saplings of temperate trees under carbon stress

1. Non-structural carbohydrates (NSCs) mediate plant survival when the plant's carbon (C) balance is negative, suggesting that NSCs could predict plant survival under C stress. To examine this possibility, we exposed saplings of six temperate tree species to diverse levels of C stress created by the combination of two light conditions (full light availability and deep shade) and two defoliation levels (severe defoliation and non-defoliation). We then measured survival, biomass, and total NSCs and soluble sugar (SSs) concentrations in different organs of both dead and live saplings. 2. We estimated mean NSCs and SSs contents and concentrations per sapling and fitted logistic generalized mixed-effects models to determine if NSCs and SSs predict survival. Using inverse prediction modelling, we also determined whether there is a common NSCs and SS threshold across species at the time of sapling's death. 3. Defoliation and shade reduced the mean sapling's NSCs and SSs contents, indicating C stress. Mean sapling NSCs and SSs contents and concentrations predicted survival and the robustness of the models improved with the inclusion of species. At death, saplings of the exotic deciduous tree species Acer pseudoplatanus exhibited significantly lower mean NSCs and SSs contents than saplings of the evergreen conifer species Podocarpus nubigenus and lower stem NSCs and SSs concentrations than the broadleaf evergreen species Drimys winteri. 4. The energetic role that NSCs and SSs play in plants under C stress was evidenced by the capacity of these compounds to predict sapling survival under C stress. No common threshold of NSCs and SSs contents or concentrations for sapling survival amongst species was found, indicating that the level of these compounds may not be good proxies for interspecific comparisons of tolerance to C stress. Presumably, there are species-specific limits for the mobilization and use of NSCs and SSs in metabolism. 5. Our results anticipate that the inclusion of NSCs and SSs in modelling will improve predictions regarding tree responses to ongoing climate change. Nonetheless, a better understanding of the many roles that carbohydrates play in plant survival under C stress is required to scale predictions up to the community level.

opencc-zeroAug 2022View details →

dryad36/100

Data from: The distribution of tree biomass carbon within the pacific coastal temperate rainforest, a disproportionally carbon dense forest

Spatially explicit global estimates of forest carbon storage are typically coarsely scaled. While useful, these estimates do not account for the variability and distribution of carbon at management scales. We asked how climate, topography, and disturbance regimes interact across and within geopolitical boundaries to influence tree biomass carbon, using the perhumid region of the Pacific Coastal Temperate Rainforest, an infrequently disturbed carbon dense landscape, as a test case. We leveraged permanent sample plots in southeast Alaska and coastal British Columbia and used multiple quantile regression forests and generalized linear models to estimate tree biomass carbon stocks and the effects of topography, climate, and disturbance regimes. We estimate tree biomass carbon stocks are either 211 (SD = 163) Mg C ha-1 or 218 (SD = 169) Mg C ha-1. Natural disturbance regimes had no correlation with tree biomass but logging decreased tree biomass carbon and the effect diminished with increasing time since logging. Despite accounting for 0.3% of global forest area, this forest stores between 0.63% - 1.07% of global aboveground forest carbon as aboveground live tree biomass. The disparate impact of logging and natural disturbance regimes on tree biomass carbon suggests a mismatch between current forest management and disturbance history.

opencc-zeroApr 2024View details →

dryad36/100

Stable water isotopes reveal the onset of bud dormancy in temperate trees, whereas water content is a better proxy for dormancy release

Earlier spring growth onset in temperate forests is a visible effect of global warming and affects global water and carbon cycling. Therefore, it is crucial to accurately predict the shift in spring phenology under projected future warming. However, current phenological models lack physiological information and are rarely experimentally validated. Therefore, twig cuttings of five deciduous tree species were sampled at two climatically different sites throughout the winter of 2019/2020. Twig budburst success, thermal time to budburst, bud water content, and short-term 2H-labelled water uptake into buds were quantified to link bud dormancy status with vascular water transport efficacy. We found strong 2H-labelled water uptake into buds during leaf senescence, followed by a sharp decrease that we attributed to the initiation of dormancy. However, we did not find increasing 2H-labelled water uptake into buds with progression of winter, whereas all species showed a linear relationship between bud water content and dormancy status. Our results show that short term 2H-labelled water uptake appears to be a poor tracer of dormancy release, but could be a promising method to track dormancy induction of deciduous trees, whereas bud water content seems to be an inexpensive and more reliable indicator of dormancy release.

opencc-zeroMay 2024View details →

zenodo36/100

Code for data analysis - intra-community variability of leaf-out in temperate tree canopies

The code and data were used for producing the results of "Phenology across scales: an intercontinental analysis of leaf-out dates in temperate deciduous tree communities", by Delpierre et al.

opencc-by-4.0May 2024View details →

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Data from: Disturbance history is a key driver of tree lifespan in temperate primary forests

AIMS We examined differences in lifespan among the dominant tree species (spruce (Picea abies (L.) H. Karst.), fir (Abies alba Mill.), beech (Fagus sylvatica L.), and maple (Acer pseudoplatanus L.)) across primary mountain forests of Europe. We ask how disturbance history, lifetime growth patterns, and environmental factors influence lifespan. LOCATIONS Balkan mountains, Carpathian mountains, Dinaric mountains. METHODS Annual ring widths from 20,600 cores from primary forests were used to estimate tree life spans, growth trends, and disturbance history metrics. Mixed models were used to examine species-specific differences in lifespan (i.e. defined as species-specific 90th percentiles of age distributions), and how metrics of radial growth, disturbance parameters, and selected environmental factors influence lifespan. RESULTS While only a few beech trees surpassed 500 years, individuals of all four species were older than 400 years. There were significant differences in lifespan among the four species (beech > fir > spruce > maple), indicating life history differentiation in lifespan. Trees were less likely to reach old age in areas affected by more severe disturbance events, whereas individuals that experienced periods of slow growth and multiple episodes of suppression and release were more likely to reach old age. Aside from a weak but significant negative effect of vegetation season temperature on fir and maple lifespan, no other environmental factors included in the analysis influenced lifespan. CONCLUSIONS Our results indicate species-specific biological differences in lifespan, which may play a role in facilitating tree species coexistence in mixed temperate forests. Finally, natural disturbances regimes were a key driver of lifespan, which could have implications for forest dynamics if regimes shift under global change.

opencc-zeroJul 2021View details →

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No risk – no fun: Penalty and recovery from spring frost damages in deciduous temperate trees

Phenological shifts in response to changing climatic conditions are a key acclimation process for the persistence of perennial plants in temperate and boreal climates. The optimal time to leaf-out is the result of evolutionary processes determined by the trade-off between minimizing the risk of freezing damages and herbivory pressure while maximizing resource uptake to increase competitiveness against the other plants. We quantified the penalty exerted by frost exposure at the time of leaf emergence on plant development (reduction in leaf area, canopy duration, and growth) over the potential gains without frost (increased biomass and non-structural carbohydrate reserves), depending on when leaf-out occurs. To this purpose, we exposed 960 saplings of four temperate deciduous tree species with contrasting cold hardiness to two frost intensities shortly after leaf emergence, which was artificially induced at four occasions to reflect the whole range of natural leaf-out dates. One year above-ground biomass (AGB) increments following the frost revealed a clear ranking among the species depending on their strategy to cope with damaging frosts. Prunus avium (-41% of AGB-increment compared to control saplings) resprouted from the stem base, Quercus robur (-62%) rapidly produced new leaves from dormant reserve buds, Fagus sylvatica (-98%) showed the highest chlorophyll content in autumn and delayed senescence together with Carpinus betulus (-105%), which overcompensated NSC reserves after the growing season but showed highest mortality (up to 32%). In all species, NSC reserves recovered rapidly their initial stage at the expense of growth. The timing of leaf-out (advanced and delayed artificially) significantly affected the performance and recovery (regreening and growth) of both frozen and non-frozen saplings, with the lowest performance found at the most delayed leaf-out date. We propose that the potential to recover from frost damages is an important component of a tree's performance, particularly at the juvenile stage. The ability to recover may become even more decisive in the future with the predicted increase of false springs in many extra-tropical regions.

opencc-zeroNov 2022View details →

dryad36/100

Symbiotic nitrogen fixation does not stimulate soil phosphatase activity under temperate and tropical trees

Symbiotic nitrogen (N)-fixing plants can enrich ecosystems with N, which can alter the cycling and demand for other nutrients. Researchers have hypothesized that fixed N could be used by plants and soil microbes to produce extracellular phosphatase enzymes, which release P from organic matter. Consistent with this speculation, the presence of N-fixing plants is often associated with high phosphatase activity, either in the soil or on root surfaces, although other studies have not found this association, and the connection between phosphatase and rates of N fixation—the mechanistic part of the argument—is tenuous. Here, we measured soil phosphatase activity under N-fixing trees and non-fixing trees transplanted and grown in tropical and temperate sites in the USA: two sites in Hawaii, and one each in New York and Oregon. This provides a rare example of phosphatase activity measured in a multi-site field experiment with rigorously quantified rates of N fixation. We found no difference in soil phosphatase activity under N-fixing vs. non-fixing trees nor across rates of N fixation, though we note that no sites were P limited and only one was N limited. Our results add to the literature showing no connection between N fixation rates and phosphatase activity.

opencc-zeroFeb 2023View details →

zenodo36/100

Data for "Trait-based response of deadwood and tree-related microhabitats to decline in temperate lowland and montane forests"

Sampling design and case studies The study was conducted in two French regions, the Loire valley and the French Pyrenees, and one German region, the Bavarian mountains. In the Loire valley, we studied two lowland sites in oak-dominated (both Quercus petraea (Matt.) Liebl. and Quercus robur L.) forests, one in the Orleans State Forest (107-174 m a.s.l.) and one in the Vierzon State Forest (120-190 m a.s.l.). The main secondary species in these forests were hornbeam (Carpinus betulus L.) and Scots pine (Pinus sylvestris L.). In 2020, we selected nine plots to represent a decline gradient in each of these forests. While the Orleans Forest was healthy overall, the Vierzon Forest had undergone several decline events due to successive droughts aggravated by edaphic factors. In the Pyrenees, we studied two sites in montane forests dominated by silver fir (Abies alba Mill.), whose decline is mainly the result of successive droughts occurring since the 1980’s, and with Norway spruce (Picea abies (L.) H. Karst) and European beech (Fagus sylvatica L.) as secondary species. In 2017, we selected 43 plots: (i) 21 plots in the Aure Valley (854-1570 m a.s.l.) and (ii) 22 plots on the Sault Plateau (705-1557 m a.s.l.). The severe summer drought of 2003 had significant effects on tree mortality in oak and fir forests (Cours and others, 2022). Finally, we studied 19 plots of montane forest in the Bavarian Forest National Park, dominated by Norway spruce (Picea abies (L.) H. Karst) with European beech and silver fir as the main secondary species (Bässler and others, 2009). The dieback results from several cycles of windstorms followed by bark beetle (Ips typographus (L.)) outbreaks (Müller and others, 2010), the dominant drivers of forest dynamics in Norway spruce forests in temperate Europe (Zemlerová and others, 2023). This dieback phenomenon was more severe than either of the aforementioned drought-induced declines, and resulted in greater tree mortality (Cours and others, 2021). In the fir and oak forests in France, our plots were set up in managed forests, and the surrounding forest was also predominantly managed. On the other hand, in the German spruce forest, our plots were set up both within the core area of the Bavarian Forest National Park, and in the surrounding zone (BIOKLIM project), with little or no human intervention (Müller and others, 2010). Field measurements Plots were set up with a Bitterlich relascope with an opening angle corresponding to counting factor n° 1 (ratio 1/50), and mean plot area was about 0.3 ha. For each tree within the plot, we recorded its status (i.e. dead, living, snag, log), tree-species and diameter at breast height (DBH; minimum DBH recorded = 17.5 cm for living trees and logs, 7.5 cm for snags, 67.5 cm for very large trees). We took the proportion of dead trees in basal area (i.e. the ratio of the cumulative basal area of standing and lying dead trees to the basal area of all the trees in the plot), hereinafter referred to as “mortality rate”, as a proxy for the level of local stand decline. Note that this “mortality rate” does not reflect true overall mortality rate in managed oak forests, as foresters removed most valuable declining trees. We visually inventoried TreMs on living trees, logs and snags, and included the 47 types described by Larrieu et al. (2018). For each deadwood item (length > 1 m) in the plot, we measured its decay stage (from 1 = hard dead wood fully covered with bark to 4 = soft wood without bark), length, diameter at mid-length for logs and snags < 4 m long, and DBH for dead trees and snags > 4 m. Deadwood was classified in the following categories: ground-lying (logs and uprooted dead trees) vs standing (snags and standing dead trees); small and mid-size (less than 40 cm in diameter) vs large and very large (more than 40 cm in diameter); and fresh (decay class 1 and 2) vs decayed (decay stage 3 and 4). We calculated the total number of items per hectare by allocating a coefficient Nd related to diameter (d) to each item observed in the relascope sampling: (Nd = π 108 [ArcTan(1/50)/(π d)]2). We estimated TreM diversity and the number of deadwood types per plot. We compiled a list of eco-morphological traits for woody elements (i.e., life status (living, dead) and vertical position (downed, standing), decay stage and diameter) and for TreMs detected in the field (TreM nature, association with deadwood (saproxylic, epixylic, mould), type of bearing substrate (i.e., living tree, dead tree or snag, and log), position in the tree (i.e. base, trunk, crown), degree of wetness, life span or ontogenesis).

opencc-by-4.0Apr 2023View details →

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Coordinated drought responses determine the time to hydraulic failure in five temperate tree species differing in their degree of isohydry

This file contains variables of interest at tree level measured, calculated and presented in the study "Coordinated drought responses determine the time to hydraulic failure in five temperate tree species differing in their degree of isohydry".

opencc-by-4.0Jul 2023View details →

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