The growth of past, present, and future forests was, is and will be affected by climate variability. This multifaceted relationship has been assessed in several regional studies, but spatially resolved, large-scale analyses are largely missing so far. Here we estimate recent changes in growth of 5800 beech trees (Fagus sylvatica L.) from 324 sites, representing the full geographic and climatic range of species. Future growth trends were predicted considering state-of-the-art climate scenarios. The validated models indicate growth declines across large region of the distribution in recent decades, and project severe future growth declines ranging from -20% to more than -50% by 2090, depending on the region and climate change scenario (i.e. CMIP6 SSP1-2.6 and SSP5-8.5). Forecasted forest productivity losses are most striking towards the southern distribution limit of Fagus sylvatica, in regions where persisting atmospheric high-pressure systems are expected to increase drought severity. The projected 21st century growth changes across Europe indicate serious ecological and economic consequences that require immediate forest adaptation.
- MeSH
- buk (rod) * MeSH
- klimatické změny MeSH
- lesy MeSH
- období sucha MeSH
- stromy MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Climatic constraints on tree growth mediate an important link between terrestrial and atmospheric carbon pools. Tree rings provide valuable information on climate-driven growth patterns, but existing data tend to be biased toward older trees on climatically extreme sites. Understanding climate change responses of biogeographic regions requires data that integrate spatial variability in growing conditions and forest structure. We analyzed both temporal (c. 1901-2010) and spatial variation in radial growth patterns in 9,876 trees from fragments of primary Picea abies forests spanning the latitudinal and altitudinal extent of the Carpathian arc. Growth was positively correlated with summer temperatures and spring moisture availability throughout the entire region. However, important seasonal variation in climate responses occurred along geospatial gradients. At northern sites, winter precipitation and October temperatures of the year preceding ring formation were positively correlated with ring width. In contrast, trees at the southern extent of the Carpathians responded negatively to warm and dry conditions in autumn of the year preceding ring formation. An assessment of regional synchronization in radial growth variability showed temporal fluctuations throughout the 20th century linked to the onset of moisture limitation in southern landscapes. Since the beginning of the study period, differences between high and low elevations in the temperature sensitivity of tree growth generally declined, while moisture sensitivity increased at lower elevations. Growth trend analyses demonstrated changes in absolute tree growth rates linked to climatic change, with basal area increments in northern landscapes and lower altitudes responding positively to recent warming. Tree growth has predominantly increased with rising temperatures in the Carpathians, accompanied by early indicators that portions of the mountain range are transitioning from temperature to moisture limitation. Continued warming will alleviate large-scale temperature constraints on tree growth, giving increasing weight to local drivers that are more challenging to predict.
- MeSH
- borovice * MeSH
- klimatické změny MeSH
- lesy MeSH
- smrk * MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Determining the drivers of shifting forest disturbance rates remains a pressing global change issue. Large-scale forest dynamics are commonly assumed to be climate driven, but appropriately scaled disturbance histories are rarely available to assess how disturbance legacies alter subsequent disturbance rates and the climate sensitivity of disturbance. We compiled multiple tree ring-based disturbance histories from primary Picea abies forest fragments distributed throughout five European landscapes spanning the Bohemian Forest and the Carpathian Mountains. The regional chronology includes 11,595 tree cores, with ring dates spanning the years 1750-2000, collected from 560 inventory plots in 37 stands distributed across a 1,000 km geographic gradient, amounting to the largest disturbance chronology yet constructed in Europe. Decadal disturbance rates varied significantly through time and declined after 1920, resulting in widespread increases in canopy tree age. Approximately 75% of current canopy area recruited prior to 1900. Long-term disturbance patterns were compared to an historical drought reconstruction, and further linked to spatial variation in stand structure and contemporary disturbance patterns derived from LANDSAT imagery. Historically, decadal Palmer drought severity index minima corresponded to higher rates of canopy removal. The severity of contemporary disturbances increased with each stand's estimated time since last major disturbance, increased with mean diameter, and declined with increasing within-stand structural variability. Reconstructed spatial patterns suggest that high small-scale structural variability has historically acted to reduce large-scale susceptibility and climate sensitivity of disturbance. Reduced disturbance rates since 1920, a potential legacy of high 19th century disturbance rates, have contributed to a recent region-wide increase in disturbance susceptibility. Increasingly common high-severity disturbances throughout primary Picea forests of Central Europe should be reinterpreted in light of both legacy effects (resulting in increased susceptibility) and climate change (resulting in increased exposure to extreme events).
- MeSH
- klimatické změny * MeSH
- lesy * MeSH
- období sucha MeSH
- smrk * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Evropa MeSH
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1-100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or bark-beetle outbreaks.
- MeSH
- brouci * MeSH
- fyziologický stres MeSH
- období sucha * MeSH
- stromy růst a vývoj MeSH
- uhlík MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- MeSH
- kontinuální vzdělávání lékařů trendy MeSH
- Publikační typ
- úvodníky MeSH
BACKGROUND: Severe canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand. METHODS: Two stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover. RESULTS: Post-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand's height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights. CONCLUSION: These findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural complexity in early-seral forests as well as variable successional pathways and rates. This influence suggests a continuity in spatial ecosystem structure that may well persist through multiple forest generations.
Úvod: Práce řeší převod specializačního vzdělávání lékařů z Institutu postgraduálního vzdělávání ve zdravotnictví (IPVZ) na univerzity, resp. na 7 lékařských fakult (LF) u základních oborů se zaměřením na gynekologii a porodnictví. Metodika: Je definována specializační oborová rada a její úkoly, popsán postup při zařazení do specializačního vzdělávání na LF a výběr vzdělávacího programu. V rámci oboru gynekologie a porodnictví jsou uvedeny kmenové a předatestační kurzy. Podrobně se práce zabývá požadavky na atestační práci a atestační operace. Jsou rozvedeny termíny a místa atestačních zkoušek (AZ), metodika přihlášek, plateb a průběhu AZ. Výsledky: V roce 2012 proběhlo na sedmi LF v ČR ve všech základních oborech celkem 864 atestačních zkoušek, kdy jarní termíny využilo výrazně méně uchazečů (43 %) než podzimní (57 %). Lišily se počty atestačních oborů na jednotlivých LF, stejně jako počty uchazečů v základních oborech. Celkem uspělo 94 % uchazečů. V gynekologii a porodnictví proběhlo v roce 2012 celkem 56 atestačních zkoušek. V jarním termínu 2012 se konalo na pěti LF 24 atestací a v podzimním termínu se konaly AZ pouze na dvou LF – 32 AZ (57 %). Na jaře 2013 se konal předatestační kurz a atestační zkoušky na 1. LF UK Praha. Z 23 přihlášených uspělo 22 lékařů. V podzimním termínu 2013 se AZ budou konat na LF UP v Olomouci, kdy je přihlášeno 39 kolegů na kurz a 41 uchazečů k AZ. Závěr: Převedení organizace AZ základních oborů specializačního vzdělávání lékařů z IPVZ na LF v našem oboru proběhlo úspěšně. SOR gynekologie a porodnictví úzce spolupracuje s naší Katedrou IPVZ a Akreditační komisí MZ ČR. Je zachována kontinuita specializačního vzdělávání a pokračuje proces kultivování vzdělávacího programu.
Objective: The paper addresses transfer of doctor's specialty training from the national Institute of postgraduate medical education (IPVZ) to University Medical Schools (UMS) with the special focus to Obstetrics and Gynecology (OG). Methods: The National Specialty Board (NSB) has been established. NSB tasks include definition of inclusion criteria and process of specialty choice at UMS. In OG specialty there are defined mid-term and final postgraduate training courses and other requirements for final specialty exam (FSE) – in particular trainee´s scientific work and surgery done with the supervision of NTB member. The system of FSE, its content, application, reimbursement and mechanisms are described in details. Results: In the whole country in 2012 there have been done 864 FSE in all basic medical specialties, which took place at seven UMS. Autumn semester terms has been utilized significantly more than spring terms (57% vs. 43%). There have been differences in the numbers of specialties and also numbers of candidates in each specialty among different UMS. In total 94% of applicants succeed in the FSE. In 2012 within OG specialty training there has been held 56 FSE – 24 exams on five UMS in spring term and 32 (57%) exams only on two UMS in autumn term. In the spring 2013 FSE were organized on 1st LF UK in Prague with 23 applicants, from which 22 successfully passed. During autumn 2013 the FSE in OG will be held on LF UP in Olomouc with 44 applicants for final postgraduate training course and 39 candidates for FSE. Conclusion: Within OG specialty the transfer of doctor's specialty training from IPVZ to UMS has been successfully managed. The NSB in OG specialty closely cooperates with past IPVZ and the Accreditation Commission of the Czech Ministry of Health. Thus continuity, quality and continuous enhancement of specialty training program in OG in Czech Republic is assured.
