A5042102007- Tree-ring climate responses
- Plant Water Relations and Carbon Dynamics
- Geology and Paleoclimatology Research
- Climate variability and models
- Archaeology and ancient environmental studies
- Forest ecology and management
- Peatlands and Wetlands Ecology
- Fire effects on ecosystems
- Forest Ecology and Biodiversity Studies
- Cryospheric studies and observations
- Climate change and permafrost
- Hydrology and Watershed Management Studies
- Horticultural and Viticultural Research
- Meteorological Phenomena and Simulations
- Plant responses to elevated CO2
- Lichen and fungal ecology
- Cultural Heritage Materials Analysis
- Atmospheric and Environmental Gas Dynamics
- Ecology and Vegetation Dynamics Studies
- Arctic and Antarctic ice dynamics
- Botany and Plant Ecology Studies
- Pacific and Southeast Asian Studies
- Hydrology and Drought Analysis
- Forest Management and Policy
- Amphibian and Reptile Biology
Natural Resources Institute Finland
2019-2023
Swansea University
2013-2022
Australian National University
2017
Abstract The increasing carbon dioxide (CO 2 ) concentration in the atmosphere combination with climatic changes throughout last century are likely to have had a profound effect on physiology of trees: altering and water fluxes passing through stomatal pores. However, magnitude spatial patterns such natural forests remain highly uncertain. Here, stable isotope ratios from network 35 tree‐ring sites located across Europe investigated determine intrinsic water‐use efficiency ( iWUE ), ratio...
Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure 14C content in 484 individual tree rings formed periods 770-780 and 990-1000 CE. Distinct excursions starting boreal summer 774 spring 993 ensure precise 44 records from five continents. We also identify a meridional...
Combining nine tree growth proxies from four sites, the west coast of Norway to Kola Peninsula NW Russia, provides a well replicated (> 100 annual measurements per year) mean index over last 1200 years that represents much northern pine timberline forests Fennoscandia. The simple series, z-scored their common period, correlates strongly with June August temperature averaged this region ( r = 0.81), allowing reconstructions summer based on regression and variance scaling. correlate...
Tree-ring stable carbon isotope ratios (d 13 C) in environments of low moisture stress are likely to be controlled primarily by photosynthetic rate. Therefore, sunshine, rather than temperature, represents the more direct controlling factor. Temperature reconstructions based on tree-ring d C results thus rest assumption that temperature and sunshine strongly coupled. This is tested using a series from pine trees NW Norway, where there long (>100 yr) records both summer cloud cover. It...
[1] Cloud cover is one of the most important factors controlling radiation balance Earth. The response cloud to increasing global temperatures represents largest uncertainty in model estimates future climate because temperature not well-constrained. Here we present first regional reconstruction summer sunshine over past millennium, based on stable carbon isotope ratios pine treerings from Fennoscandia. Comparison with evolution reveals Little Ice Age (LIA) have been sunny, cloudy conditions...
Abstract Investigating the many internal feedbacks within climate system is a vital component of effort to quantify full effects future anthropogenic change. The stomatal apertures plants tend close and decrease in number under elevated CO 2 concentrations, increasing water‐use efficiency (WUE) reducing canopy evapotranspiration. Experimental modelling studies reveal huge variations these changes such that warming associated with reduced evapotranspiration (known as physiological forcing)...
[1] Measurements of tree ring width and relative density have contributed significantly to many the large-scale reconstructions past climatic change, but extract climate signal it is first necessary remove any nonclimatic age-related trends. This detrending can limit lower-frequency information that may be extracted from archive (the “segment length curse”). paper uses a data set widths, maximum latewood stable carbon oxygen isotopes 28 annually resolved series known-age Pinus sylvestris L....
ABSTRACT Ring‐width dendrochronology, based on matching patterns of ring width variability, works best when trees are growing under significant environmental (climatic) stress. In the UK, and elsewhere in temperate mid‐latitudes, generally experience low stress, so dating is more difficult often fails. Oxygen isotopes tree rings passively record changes isotopic ratios summer precipitation, they carry a strong common signal, which offers potential for cross‐dating. A master chronology...
Stable carbon isotope (δ(13)C) series were developed from analysis of sequential radial wood increments AD 1850 to 2009 for four mature primary rainforest trees the Danum and Imbak areas Sabah, Malaysia. The aseasonal equatorial climate meant that conventional dendrochronology was not possible as tree species investigated do exhibit clear annual rings or dateable growth bands. Chronology established using radiocarbon dating model age-growth relationships date isotopic which intrinsic...
Climate reconstructions produced using regression, with a proxy as the independent variable, are inevitably biased towards mean, exhibit reduced variance and underestimate extremes. Scaling mean to fit those of target climate data produces more realistic range reconstructed values but cost, in terms inflated error, is seldom assessed. We provide simple metric that allows loss skill because scaling be quantified. It can calculated retrospectively for published studies, some which little or no...
ABSTRACT Oxygen isotope ratios from oak tree rings are used to extend the May–August precipitation totals of England and Wales series back 1201 ce. The agreement between instrumental reconstructed values is unusually strong, with more than half variance explained standard verification tests passed. stability this relationship confirmed using split‐period calibration verification. This allows reconstruction be variance‐scaled full length 1766. Direct comparison historical reports very wet dry...
Temporal variability of tree-ring cellulose δ2H (δ2Hring-cel) can be a unique tool for understanding tree physiology and climate. However, we do not fully understand the drivers temporal in δ2Hring-cel. Investigating seasonal δ2Hring-cel boreal forests is particularly challenging. Previous studies on intra-annual δ18Ohave shown that isotope result from combined but opposing effects source water leaf assimilates, dynamic likely relevant as well. To...
Intra-annual variations of oxygen isotope composition (δ18O) in tree rings offer insights into ecophysiology and how trees respond to climate. In this study, we focused on the interplay between δ¹⁸O from source-water, leaf-water photosynthates understand seasonal trends are integrated rings. We conducted a analysis Pinus sylvestris Finland. Our findings reveal significant reduction variability δ18O needle-water This dampening effect is due...
Abstract In regions with seasonal temperate climatic regimes, tree growth is rarely controlled by any single environmental factor. As a consequence, the development of robust palaeoclimate reconstructions has proved challenging. Tree‐ring stable carbon isotope ratios (δ 13 C), however, are primarily photosynthetic rate, not net growth. Therefore, at sites where controls on tree‐ring strongly expressed, (isotopic) signal may still potentially be preserved. This hypothesis was tested using...
Stable carbon isotope ratios from early-wood (EW) and late-wood (LW) are used to test competing models of storage allocation, providing a cost-effective alternative measuring dating non-structural carbohydrates in mature temperate broad-leaf forest trees growing under natural conditions. Annual samples EW LW seven oaks (Quercus robur L.) Scotland, covering AD 1924–2012, were pooled, treated isolate alpha-cellulose pyrolysed measure the ratios. Late-wood values strongly correlated with summer...