scholarly journals Threshold responses of juniper tree growth and regeneration to climate warming and drought stress at alpine treeline

Trees ◽  
2021 ◽  
Author(s):  
Xiaoming Lu ◽  
J. Julio Camarero ◽  
Eryuan Liang
Keyword(s):  
Drought Stress ◽  
Climate Warming ◽  
Tree Growth ◽  
Alpine Treeline

scholarly journals Effects of warming and fertilization interacting with intraspecific competition on fine root traits of Picea asperata

2020 ◽  
Author(s):  
Dan-Dan Li ◽  
Hong-Wei Nan ◽  
Chun-Zhang Zhao ◽  
Chun-Ying Yin ◽  
Qing Liu
Keyword(s):  
Root Growth ◽  
Climate Warming ◽  
Tree Growth ◽  
Root Length ◽  
Root Biomass ◽  
Fine Root ◽  
Root Traits ◽  
Root Surface ◽  
Root Branching ◽  
Picea Asperata

Abstract Aims Competition, temperature, and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau. Although many studies have reported their individual effects on tree growth, little is known about how the interactions of competition with fertilization and temperature affect root growth. We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors. Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature (ET) and fertilization. We measured root traits, including the root tip number over the root surface (RTRS), the root branching events over the root surface (RBRS), the specific root length (SRL), the specific root area (SRA), the total fine root length and area (RL and RA), the root tips (RT) and root branching events (RB). These root traits are considered to be indicators of plant resource uptake capacity and root growth. The root biomass and the nutrient concentrations in the roots were also determined. Important Findings The results indicated that ET, fertilization and competition individually enhanced the nitrogen (N) and potassium (K) concentrations in fine roots, but they did not affect fine root biomass or root traits, including RL, RT, RA and RB. However, both temperature and fertilization, as well as their interaction, interacting with competition increased RL, RA, RT, RB, and nutrient uptake. In addition, the SRL, SRA, RTRS and RBRS decreased under fertilization, the interaction between temperature and competition decreased SRL and SRA, while the other parameters were not affected by temperature or competition. These results indicate that Picea asperata maintains a conservative nutrient strategy in response to competition, climate warming, fertilization, and their interactions. Our results improve our understanding of the physiological and ecological adaptability of trees to global change.

scholarly journals Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators

2015 ◽  
Vol 6 (1) ◽  
pp. 245-265 ◽  
Author(s):  
U. Schickhoff ◽  
M. Bobrowski ◽  
J. Böhner ◽  
B. Bürzle ◽  
R. P. Chaudhary ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Tree Growth ◽  
Empirical Studies ◽  
Growth Patterns ◽  
Niche Modelling ◽  
Ongoing Research ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Response Gradient

Abstract. Climate warming is expected to induce treelines to advance to higher elevations. Empirical studies in diverse mountain ranges, however, give evidence of both advancing alpine treelines and rather insignificant responses. The inconsistency of findings suggests distinct differences in the sensitivity of global treelines to recent climate change. It is still unclear where Himalayan treeline ecotones are located along the response gradient from rapid dynamics to apparently complete inertia. This paper reviews the current state of knowledge regarding sensitivity and response of Himalayan treelines to climate warming, based on extensive field observations, published results in the widely scattered literature, and novel data from ongoing research of the present authors. Several sensitivity indicators such as treeline type, treeline form, seed-based regeneration, and growth patterns are evaluated. Since most Himalayan treelines are anthropogenically depressed, observed advances are largely the result of land use change. Near-natural treelines are usually krummholz treelines, which are relatively unresponsive to climate change. Nevertheless, intense recruitment of treeline trees suggests a great potential for future treeline advance. Competitive abilities of seedlings within krummholz thickets and dwarf scrub heaths will be a major source of variation in treeline dynamics. Tree growth–climate relationships show mature treeline trees to be responsive to temperature change, in particular in winter and pre-monsoon seasons. High pre-monsoon temperature trends will most likely drive tree growth performance in the western and central Himalaya. Ecological niche modelling suggests that bioclimatic conditions for a range expansion of treeline trees will be created during coming decades.

scholarly journals The Radial Growth of Picea wilsonii Was More Restricted by Precipitation Due to Climate Warming on Mt. Guandi, China

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1602
Author(s):  
Xiaoxia Huang ◽  
Xiaoneng Sun ◽  
Yuan Jiang ◽  
Feng Xue ◽  
Minghao Cui ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Radial Growth ◽  
Management Strategies ◽  
Ring Width ◽  
Elevational Gradient ◽  
Summer Drought ◽  
Clear Trend ◽  
Biological Variables ◽  
Picea Wilsonii

Transitional climate zones (TCZ) are characterized by instability due to rapid changes in climate and biological variables, and trees growing there are particularly sensitive to climate change. Therefore, knowledge about the shifted relationships of tree growth in response to climate warming will shape regional forest conservation and management strategies. China has experienced rapid warming in recent decades. However, how tree growth in semihumid to semiarid regions, such as the Guandi Mountains, responds to more sophisticated changes in the hydrothermal combination is not yet clear. In this study, we used tree-ring width data from three sites along an elevational gradient in the Guandi Mountains to present the response of Picea wilsonii Mast. radial growth to increasing temperature and elevational differences in the relationship between tree growth and climate. The results indicated that the Guandi Mountains have experienced rapid warming with a clear trend toward aridity. From 1959 to 1995, the radial growth of P. wilsonii was mainly influenced by temperature, while it was controlled by both temperature and precipitation after rapid warming in 1996. From 1959 to 2017, this species showed a generally consistent growth–climate relationship at different elevations in the Guandi Mountains. However, the radial growth of trees at higher elevations had a higher climatic correlation than at lower elevations, and it was more conditioned by higher summer temperatures and precipitation in December of the previous year. These results suggested that P. wilsonii was more susceptible to drought and high temperatures due to a warming climate and that more attention should be devoted to forest management, especially the adverse consequences of summer drought on P. wilsonii.

scholarly journals The emergent past: past natural and human disturbances of trees can reduce their present resistance to drought stress

2021 ◽  
Author(s):  
Hans Pretzsch
Keyword(s):  
Drought Stress ◽  
Memory Effect ◽  
Tree Ring ◽  
Tree Growth ◽  
Water Retention ◽  
Annual Growth ◽  
Recent Past ◽  
Ecological Memory ◽  
Growth Variation

AbstractForest tree growth is primarily explained, modelled, and predicted depending on current age or size, environmental conditions, and competitive status in the stand. The accumulated size is commonly used as a proxy for a tree's past development. However, recent studies suggest that antecedent conditions may impact present growth by epigenetic, transcriptional, proteomic, or metabolic changes alongside physiological and structural properties. Here, I analysed the ecological memory effect embedded in the xylem as a tree-ring structure. I used 35 mature Norway spruces (Picea abies (L.) H. Karst.) and 36 European beeches (Fagus sylvatica L.) of the Kranzberg Forest water retention experiment KROOF in South Germany to scrutinise how their past development determines the growth of control plots and plots with 5-year water retention. I hypothesised that the current size and growing conditions determine tree growth and drought stress resistance. Metrics quantifying the trees’ recent and past growth, and correlation and linear mixed models with random effects revealed the following ecological memory effects. (1) For both species, the progressive growth course, low inter-annual growth variation in the long term, and low growth deflections in the recent past increased the growth resistance to drought. (2) The correlation between the past growth metrics and current stress reactions revealed that legacy effects could reach back 5–30 years; I found short- and long-term ecological memory. (3) Parameters of model prediction of the basic model with only size as a predictor of tree growth could be improved. The results suggest differences in the internal stem structure and ring pattern cause-specific differences in the trees' functioning and growth. I conclude that a long-term progressive increase and low variation in ring width may improve water conduction and reduce embolism in both species. Annual growth variation and low growth events in the recent past may have primed the morphology and allocation of the Norway spruce to better resist drought. The strong reduction in current growth, drought resistance by irregular growth, and past growth disturbances reveal a memory effect embedded in the tree ring pattern, suggesting further exploration and consideration in tree monitoring, growth modelling, and silvicultural prescriptions.

Species-specific tree growth responses to 9 years of CO2 enrichment at the alpine treeline

2010 ◽  
pp. no-no ◽  
Author(s):  
Melissa A. Dawes ◽  
Stephan Hättenschwiler ◽  
Peter Bebi ◽  
Frank Hagedorn ◽  
Ira Tanya Handa ◽  
...  
Keyword(s):  
Tree Growth ◽  
Co2 Enrichment ◽  
Growth Responses ◽  
Alpine Treeline ◽  
Species Specific

scholarly journals Beneficial effects of climate warming on boreal tree growth may be transitory

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Loïc D’Orangeville ◽  
Daniel Houle ◽  
Louis Duchesne ◽  
Richard P. Phillips ◽  
Yves Bergeron ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Beneficial Effects

Climate warming does not adequately translate to increased radial stem growth of coniferous species along the Alpine treeline ecotone

2020 ◽  
Author(s):  
Walter Oberhuber ◽  
Ursula Bendler ◽  
Vanessa Gamper ◽  
Jacob Geier ◽  
Anna Hölzl ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Growth Response ◽  
Growing Season ◽  
High Elevation ◽  
Stem Growth ◽  
Stone Pine ◽  
Recent Climate ◽  
Swiss Stone Pine ◽  
Competition For Resources

<p>It is well established, that tree growth at high elevations is mainly limited by low temperature during the growing season and climate warming was frequently found to lead to more growth and expansion of trees into alpine tundra. However, dendroclimatological studies revealed contradictory growth response to recent climate warming at the upper elevational limit of tree growth, and transplant experiments unveiled that high elevation tree provenances are not adequately benefiting from higher temperatures when planted at lower elevation. We therefore re-evaluated growth response of trees to recent climate warming by developing tree ring series of co-occurring conifers (Swiss stone pine (<em>Pinus cembra</em>), European larch (<em>Larix decidua</em>), and Norway spruce (<em>Picea abies</em>)) along several altitudinal transects stretching from the subalpine zone to the krummholz-limit (1630–2290 m asl; n=503 trees) in the Central European Alps (CEA). We evaluated whether trends in basal area increment (BAI) are in line with two phases of climate warming which occurred from 1915–1953 and from mid-1970s until 2015. We expected that BAI of all species shows an increasing trend consistent with distinct climate warming during the study period (1915–2015) amounting to >2 °C. Although enhanced tree growth was detected in all species in response to climate warming, results revealed that at subalpine sites (<em>i</em>) intensified climate warming since mid-1970s did not lead to corresponding increase in BAI, and (<em>ii</em>) increase in summer temperature primarily favored growth of Norway spruce, although Swiss stone pine dominates at high altitude in the CEA and therefore was expected to mainly benefit from climate warming. At treeline BAI increase was above the determined age trend in all species, whereas at the krummholz-limit only deciduous larch showed minor growth increase. We explain missing adequate growth response to recent climate warming (<em>i</em>) by strengthened competition for resources (primarily nutrients and light) in increasingly denser stands at subalpine sites leading to changes in carbon allocation among tree organs, and (<em>ii</em>) by frost desiccation injuries of evergreen tree species at the krummholz-limit. Our findings indicate that tree growth response to climate warming at high elevation is possibly nonlinear, and that increasing competition for resources and the influence of climate factors beyond the growing season impair stem growth. </p>

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