The effects of climate change on the phenology of selected Estonian plant, bird and fish populations

This paper summarises the trends of 943 phenological time-series of plants, fishes and birds gathered from 1948 to 1999 in Estonia. More than 80% of the studied phenological phases have advanced during springtime, whereas changes are smaller during summer and autumn. Significant values of plant and bird phases have advanced 5–20 days, and fish phases have advanced 10–30 days in the spring period. Estonia’s average air temperature has become significantly warmer in spring, while at the same time a slight decrease in air temperature has been detected in autumn. The growing season has become significantly longer in the maritime climate area of Western Estonia. The investigated phenological and climate trends are related primarily to changes in the North Atlantic Oscillation Index (NAOI) during the winter months. Although the impact of the winter NAOI on the phases decreases towards summer, the trends of the investigated phases remain high. The trends of phenophases at the end of spring and the beginning of summer may be caused by the temperature inertia of the changing winter, changes in the radiation balance or the direct consequences of human impacts such as land use, heat islands or air pollution.     

The phenological calendar of Estonia and its correlation with mean air temperature

A phenological calendar with 24 phenological phases was compiled for three meteorological stations in Estonia for the period 1948–1996. We analysed the length of the vegetation period, the order of the phenological phases, and the variability and possible changes for two incremental climate change scenarios (±2°C), and compared the results with examples of extreme years. The statistically significant linear trends show that the spring and summer-time phenological phases occurred earlier and the autumn phases moved later during the study period. The study of extreme (minimum and maximum) years shows that 70% of the earliest dates of the 24 phases studied have occurred during the last 15 years with an absolute maximum in 1990 with 8 extreme phases. The phenological spring has shortened (slope –0.23), the summer period has lengthened (slope 0.04), and the autumn has lengthened too. The length of the growing season, determined by the vegetation of rye, has shortened (slope –0.09), which could be the result of changing agricultural technology. The correlation between the starting dates of the phenological phases with the air temperature of the previous 2–3 months is relatively high (0.6–0.8). Studying the +2°C and –2°C scenarios and values for the extreme years shows that, in the case of short variations of air temperature, the phenological development remains within the limits of natural variation. Received: 29 November 1999 / Revised: 15 May 2000 / Accepted: 16 May 2000     

Effects of aging on thermoregulatory responses and hormonal changes in humans during the four seasons in Japan

Physiological functions are impaired in various organs in aged people, as manifest by, e.g., renal and cardiac dysfunction and muscle atrophy. The elderly are also at increased risk of both hypothermia and hyperthermia in extreme temperatures. The majority of those over 65 years old have elevated serum osmolality. Our hypothesis is that the elderly have suppressed osmolality control in different seasons compared to the young. Eight healthy young men and six healthy older men participated in this study. The experiments were performed during spring, summer, autumn and winter in Japan, with average atmospheric temperatures of 15–20°C in spring, 25–30°C in summer, 15–23°C in autumn and 5–10°C in winter. Each subject immersed his lower legs in warm water at 40°C for 30 min. Core (tympanic) temperature and sweat rate at chest were recorded continuously. Blood was taken pre-immersion to measure the concentrations of antidiuretic hormone, serum osmolality, plasma renin activity, angiotensin II, aldosterone, leptin, thyroid stimulating hormone, fT₃ and fT₄. The results suggested that the elderly have suppressed osmolality control compared to the young; osmolality was especially elevated in winter compared to the summer in elderly subjects. Therefore, particularly in the elderly, balancing fluid by drinking water should be encouraged to maintain euhydration status in winter.     

Comprehensive methodological analysis of long‐term changes in phenological extremes in Germany

This study reports on alterations in the magnitude and frequency of extremes in reproductive phenology using long‐term records (1951–2008) for plant species widely distributed across Germany. For each of fourteen indicator phases studied, time series of annual onset dates at up to 119 stations, providing 50–58 years of observation, were standardized by their station mean and standard deviation. Four alternative statistical models were applied and compared to derive probabilities of extreme early or late onset times for the phases: (1) Gaussian models were used to describe decadal probabilities of standardized anomalies, defined by data either falling below the 5th or exceeding the 95th percentile. (2) Semi‐parametric quantile regression was employed for flexible and robust modelling of trends in different quantiles of onset dates. (3) Generalized extreme value distributions (GEV) were fitted to annual detrended minima and maxima of standardized anomalies, and (4) Generalized Pareto distributions (GPD) were fitted to extremes defined as peaks over threshold. Probabilities of extreme early phenological events inferred from Gaussian models, increased on average from 3 to 12%, whereas probabilities of extreme late phenological events decreased from 6 to 2% over the study period. Based on quantile regressions, summer and autumn phases revealed a more pronounced advancing pattern than spring phases. Estimated return levels by GEV were similar for the GPD methods, indicating that extreme early phenological events of magnitudes 2.5, 2.8, and 3.6 on the detrended standardized anomaly scale would occur every 20 years for spring, summer and autumn phases, respectively. This corresponds to absolute onset advances of up to 2 months depending on the season and species. This study demonstrates how extreme phenological events can be accurately modelled even in cases of inherently small numbers of observations, and underlines the need for additional evaluation related to their impacts on ecosystem functioning.     

近30年北京自然历的主要物候期、物候季节变化及归因

根据中国物候观测网资料并结合气象观测数据, 重新编制了北京颐和园地区1981-2010年的自然历。通过与原自然历比较, 揭示了北京物候季节变化特征, 分析了1963年以来物候季节变化的可能原因。研究发现: 与原自然历相比, 1981-2010年北京的春、夏季开始时间分别提前了2天和5天, 秋、冬季开始时间分别推迟了1天和4天; 夏、秋季长度分别延长了6天和3天, 春、冬季长度则分别缩短了3天和6天; 各个物候期的平均日期、最早日期、最晚日期在春、夏季以提前为主, 在秋、冬季以推迟为主; 且春、秋、冬季节内部分物候期次序也出现了不同程度的变化。春、夏、冬季开始日期前的气温变化和秋季开始日期前的日照时数变化可能是北京颐和园地区物候季节变化的主要原因; 不同物种、不同物候期对气温变化的响应程度不同, 导致了物候季节内各种物候现象出现的先后顺序发生变化。     

Effect of season on peripheral resistance to localised cold stress

This study was carried out to determine the effect that seasonal changes have on the effect of localised cold stress on peripheral temperatures using the foot immersion method with a cold water bath. The subjects were six males and four females. The data were obtained in April, July, October and January. Skin temperature of the right index finger, the forehead, the arm, the cheek, the second toe and the instep were measured before, during and after the immersion of the feet in water at 15°C for 10 mins, as well as oxygen consumption before immersion of the feet.The average finger temperature was highest during foot immersion in the summer, next highest in the winter, then spring, and the lowest during foot immersion in the autumn. The finger temperatures during the pre-immersion period in the autumn tended to be lower than in other seasons. The finger temperatures during the pre-immersion period affected the temperature change of the finger during the immersion period. The rate of increase of the toe temperature and the foot temperature during post-immersion in the summer and the spring were greater than those in the autumn and winter. Oxygen consumption during the pre-immersion period in the autumn was significantly lower than in the other seasons (p<0.001 or 0.010). Cooling the feet caused no significant changes in the temperatures the cheek, forehead or forearm. The cheek temperature in the summer and autumn was cooler than corresponding temperatures taken in the winter and spring.     

Estivation and hibernation of Pieris brassicae (L.) in southern Spain: synchronization of two complex behavioral patterns

 The large white butterfly, Pieris brassicae, has an unusually complex life-history in its southernmost range in Western Europe. This complexity results (1) from two developmental rests, a short-day induced hibernation and a long-day induced estivation response, and (2) from the exceptionally early appearance of the first adult generation in January/February and a subsequent winter diapause in some of their progeny. It was found that in spring and autumn, different generations are faced with critical photophases which induce hibernation or estivation, with the consequence that in five out of six generations per year, only some develop directly whereas the others enter a dormancy phase. To assess the implications of this high number of optional responses on the generation succession, the development time was studied at various photoperiods and temperatures. The results showed that a threshold response determines the duration of estivation. With unchanged summer conditions (daylengths ≥15 h) estivation lasts on average 18–19 weeks, while with autumn conditions (daylengths ≤14 h) it lasts only 7 weeks. A change of photophases from ≥15 h to ≤14 h terminates estivation within about 3–5 weeks, slightly depending on the pupal exposure time in summer conditions. The duration of estivation is not affected by temperature or by the photophases experienced by the caterpillars. The winter diapause lasts 18–19 weeks on average with winter conditions (12°C/10.30 h light), but only 8–10 weeks with late spring conditions (21°C/15 h light). These results were used to assess the effects on the population phenology, with the finding that despite the different developmental pathways, a desynchronization of the generation succession is largely prevented. Estivation, hibernation, and direct development at different seasons are well adjusted to a common phenological pattern of a continuously reproducing population. This pattern of activity covers a cryptic dormant subpopulation, and could not have been deduced by field observations. Received: October 3, 2001 / Accepted: October 3, 2002     

Characterization of high rate composting of vegetable market waste using Fourier transform-infrared (FT-IR) and thermal studies in three different seasons

Fourier transform-infrared (FT-IR), Thermogravimetry (TG), Differential thermal analyses (DTA) and Differential Thermogravimetric (DTG) studies of a mixture of vegetable waste, saw dust, tree leaves and cow dung for microbial activity (feedstock) and their compost were reported in three different seasons i.e. winter, spring and summer. The correlation between spectral studies and compost composition provide information regarding their stability and maturity during composting. FT-IR spectra were conferred the functional groups and their intensity and TG, DTG and DTA for wt. loss, rate of wt. loss and enthalpy change in compost. Weight loss in feedstock and compost at two different temperatures 250–350 and 350–500°C was found 38.06, 28.15% for inlet and 14.08, 25.67% for outlet zones in summer and 50.59, 29.76% for inlet and 18.08, 25.67% in outlet zones in spring season, higher (5–10%) than winter. The corresponding temperatures in DTA in the samples from inlet to outlet zone were; endotherm (100–200°C), due to dehydration, exotherm (300–320°C), due to peptidic structure loss and exotherm (449–474°C) due to the loss of polynuclear aromatic structures, which were higher by 4°C and 10–20°C and rate of wt. loss was higher by 5–10% in spring and summer season, respectively than winter season composting, reported regardless of the maturation age of the compost. Relative intensity of exotherms (300–320/449–474°C) gave the thermally more stable fractions of organic compound. Our results indicated that the rotary drum composting of organic matters in spring and summer season gave higher molecular complexity and stability than the winter season.     

Climate change fingerprints in recent European plant phenology

A paper published in Global Change Biology in 2006 revealed that phenological responses in 1971–2000 matched the warming pattern in Europe, but a lack of chilling and adaptation in farming may have reversed these findings. Therefore, for 1951–2018 in a corresponding data set, we determined changes as linear trends and analysed their variation by plant traits/groups, across season and time as well as their attribution to warming following IPCC methodology. Although spring and summer phases in wild plants advanced less (maximum advances in 1978–2007), more (~90%) and more significant (~60%) negative trends were present, being stronger in early spring, at higher elevations, but smaller for nonwoody insect‐pollinated species. These trends were strongly attributable to winter and spring warming. Findings for crop spring phases were similar, but were less pronounced. There were clearer and attributable signs for a delayed senescence in response to winter and spring warming. These changes resulted in a longer growing season, but a constant generative period in wild plants and a shortened one in agricultural crops. Phenology determined by farmers’ decisions differed noticeably from the purely climatic driven phases with smaller percentages of advancing (~75%) trends, but farmers’ spring activities were the only group with reinforced advancement, suggesting adaptation. Trends in farmers’ spring and summer activities were very likely/likely associated with the warming pattern. In contrast, the advance in autumn farming phases was significantly associated with below average summer warming. Thus, under ongoing climate change with decreased chilling the advancing phenology in spring and summer is still attributable to warming; even the farmers’ activities in these seasons mirror, to a lesser extent, the warming. Our findings point to adaptation to climate change in agriculture and reveal diverse implications for terrestrial ecosystems; the strong attribution supports the necessary mediation of warming impacts to the general public.     

Phenological responses of plants to climate change in an urban environment

Global climate change is likely to alter the phenological patterns of plants due to the controlling effects of climate on plant ontogeny, especially in an urbanized environment. We studied relationships between various phenophases (i.e., seasonal biological events) and interannual variations of air temperature in three woody plant species (Prunus davidiana, Hibiscus syriacus, and Cercis chinensis) in the Beijing Metropolis, China, based on phenological data for the period 1962–2004 and meteorological data for the period 1951–2004. Analysis of phenology and climate data indicated significant changes in spring and autumn phenophases and temperatures. Changes in phenophases were observed for all the three species, consistent with patterns of rising air temperatures in the Beijing Metropolis. The changing phenology in the three plant species was reflected mainly as advances of the spring phenophases and delays in the autumn phenophases, but with strong variations among species and phenophases in response to different temperature indices. Most phenophases (both spring and autumn phenophases) had significant relationships with temperatures of the preceding months. There existed large inter- and intra-specific variations, however, in the responses of phenology to climate change. It is clear that the urban heat island effect from 1978 onwards is a dominant cause of the observed phenological changes. Differences in phenological responses to climate change may cause uncertain ecological consequences, with implications for ecosystem stability and function in urban environments.     

Thermoregulatory anatomy of pronghorn (Antilocapra americana)

We have found that pronghorn (Antilocapra americana) use external heat exchange with the environment and internal heat exchange between the carotid artery rete and cavernous venous sinus blood to regulate body temperature. Now we have investigated the relationship between the histological structure of the skin, cephalic veins, and carotid rete–cavernous sinus system and the physiological mechanisms pronghorn use, and whether their thermoregulatory anatomy has adaptive advantages. We harvested tissue samples of skin, three veins (i.e., angularis oculi vein, dorsal nasal vein, and facial vein), and the carotid rete–cavernous sinus system from four pronghorn, two culled in summer and two in winter, and examined each histologically. The three veins had the typical structure of veins with large lumina and thin walls. The carotid rete consisted of small (0.1–0.5 mm) arterioles with a density of ~10/mm², intertwined with veins (~2/mm²), enclosed within the cavernous sinus; a structure ideal for heat exchange. We concluded that the main function of the dorsal nasal and facial veins is to return cold blood to the body to effect whole body cooling. The cavernous sinus is supplied with warm blood by the palatine veins in winter and cold blood by the deep facial veins in summer, an arrangement different to that in other ungulates, such as sheep, in which the angularis oculi vein supplies the cavernous sinus. Pronghorn skin is richly supplied with blood vessels that facilitate convective heat loss in summer. In winter, the number of coarse and fine hairs per square millimeter increases more than in European deer to form a thick pelage that minimizes heat loss. In summer, the pelage is shed because hair follicles involute. Unlike in other ungulates, pronghorn skin has little adipose tissue. The number of apocrine glands increases in winter rather than in summer. We concluded that the glands have a reproductive/social function rather than a thermoregulatory one. In summary, our study shows that the thermoregulatory anatomy is consistent with our physiological data and has adaptive advantages that help explain the survival of pronghorn in an arid habitat characterized by extreme temperature variation and sparse vegetation.     

Causal analysis of the diversity of medusae in East China Sea

Based on the maritime data collected from 23°30′–33°00′ N and 118°30′–128°00′ E of the East China Sea (ECS) in four seasons during 1997–2000, the dynamics of medusae diversity and their causes were analyzed. A total of 103 medusae species were identified, and these species mainly distributed in the southern and northern offshore areas of the ECS. Species diversity index (H′) of medusae was higher in the south than those in the north, higher in summer and winter than in spring and autumn, and higher in offshore than in the nearshore areas. The species number was closely correlated with H′ value, whereas the abundance of species had no significant relationship with the diversity index. The lower H′ value of the nearshore in spring and autumn resulted from the aggregation of Muggiaea atlantica in the south nearshore and Diphyes chamissonis in the north nearshore. In addition, water temperature, followed by salinity, is the main environmental factor influencing the distribution of species diversity. The H′ value was related to the water temperature at the 10 m layer in winter and spring, and it was associated with the surface water temperature in summer and with the 10 m-salinity-layer in autumn. In spring and summer, the isoline distribution of H′ value reflected the direction of the Taiwan Warm Current and the variation of the water masses in the ECS. In winter, the isoline of the H′ value indicated the incursion of Kuroshio current. In conclusion, the H′ isoline is an good indicator for water masses in ECS. __________ Translated from Biodiversity Science, 2006, 14(6): 508–516 [译自:生物多样性]     

Divergent trends in the risk of spring frost damage to trees in Europe with recent warming

Frost events during the active growth period of plants can cause extensive frost damage with tremendous economic losses and dramatic ecological consequences. A common assumption is that climate warming may bring along a reduction in the frequency and severity of frost damage to vegetation. On the other hand, it has been argued that rising temperature in late winter and early spring might trigger the so called “false spring”, that is, early onset of growth that is followed by cold spells, resulting in increased frost damage. By combining daily gridded climate data and 1,489 k in situ phenological observations of 27 tree species from 5,565 phenological observation sites in Europe, we show here that temporal changes in the risk of spring frost damage with recent warming vary largely depending on the species and geographical locations. Species whose phenology was especially sensitive to climate warming tended to have increased risk of frost damage. Geographically, compared with continental areas, maritime and coastal areas in Europe were more exposed to increasing occurrence of frost and these late spring frosts were getting more severe in the maritime and coastal areas. Our results suggest that even though temperatures will be elevated in the future, some phenologically responsive species and many populations of a given species will paradoxically experience more frost damage in the future warming climate. More attention should be paid to the increased frost damage in responsive species and populations in maritime areas when developing strategies to mitigate the potential negative impacts of climate change on ecosystems in the near future.     

Modulation of Rubisco activity in leaves of <Emphasis Type="Italic">Prosopis juliflora</Emphasis> in response to tropical conditions in north India

The success of P. juliflora, an evergreen woody species has been largely attributed to temperature acclimation and stomatal control of photosynthesis under wide range of environmental conditions prevalent in India. We studied the contribution of the enzyme ribulose-1,5 bisphosphate carboxylase/oxygenase (Rubisco) in diurnal and seasonal photosynthesis changes in P. juliflora. The changes observed in photosynthesis under natural conditions could be effected by the growth temperatures, which ranged from 10–30 °C in winter to 30–47 °C in summer. However, the Total Rubisco activity displayed a constant diurnal pattern and showed a maximum at 1200 in all seasons namely spring, summer, monsoon and winter irrespective of the changes in temperature. The Total Rubisco activity from two cohorts of leaves produced in spring and monsoon appeared to be down-regulated differentially at low PPFD during the evening. The in vivo and in vitro measurements of carboxylation efficiency of Rubisco showed wide variation during the day and were correlated with the photosynthesis rate. The light activation of Rubisco showed the acclimation to moderately high temperatures in different seasons except in summer. The exceptionally high temperatures (>45 °C) in summer, though not affecting Total activity, severely inhibited the light activation of Rubisco and also modulated the recovery process for the activation of Rubisco. Our studies suggest that the modulation of Rubisco driven by Rubisco activase and not Rubisco per se was crucial for the diurnal regulation of photosynthesis. NBRI Publication No.: 528     

Predictors of Seasonal Oxygen Levels in Small Florida Lakes: The Importance of Color

This study examines the relationship of profundal oxygen concentrations in 55 shallow Florida lakes to humic color, trophic state, and lake size during different seasons. The data set represented a broad range of color and trophic state. The percent saturation of dissolved oxygen remained relatively constant during the fall (mean 78.4%), winter (mean 81.3%), and spring (mean 82.5%), but declined markedly during summer (mean 65.2%). Chlorophyll a concentrations were highest during the winter (mean 2.52 mg m^–3) and lowest during the fall (mean 1.17 mg m^–3), while color peaked during the fall (mean 30.1 mg Pt l^–1) and was lowest during the summer (mean 12.7 mg Pt l^–1). The relative importance of lake size, chlorophyll a, and color in explaining variation in percent oxygen saturation was examined using multiple regression. Percent oxygen saturation was negatively correlated with color during the winter, spring, and summer, and positively correlated with lake size in the winter and spring. However, percent oxygen saturation showed no relationship with chlorophyll a during any season. These results suggest that colored Florida lakes are naturally oxygen depleted and that profundal oxygen values have little relationship to lake trophic state. This revised version was published online in July 2006 with corrections to the Cover Date.     

Seasonal variations of size-fractionated phytoplankton along the salinity gradient in the York River estuary, Virginia (USA)

The dynamics of phytoplankton size structure were investigatedin the freshwater, transitional and estuarine zones of the YorkRiver over an annual cycle. The contribution of large cells(microplankton, >20 µm) to total concentrations ofchlorophyll a increased downstream during winter, whereas thatof small cells (nanoplankton, 3–20 µm; picoplankton,<3 µm) increased downstream during summer. In the freshwaterregion, the contribution of micro phytoplankton to total concentrationsof chlorophyll a was significant during warm seasons (springand summer) but not during colder seasons (winter), whereasthe contribution of small-sized cells (especially picoplankton)increased during cold seasons. Temperature, light and high flushingrate appear to control phytoplankton community structure inthe freshwater region. In the transitional region, nano-sizedcells dominated the phytoplankton population throughout allseasons except during the spring bloom (April) when the chlorophylla concentration of micro phytoplankton increased. Size structurein the transitional region is most likely regulated by lightavailability. In the mesohaline region, nano- and pico-sizedcells dominated the phytoplankton population during the summerbloom, whereas micro-sized cells dominated during the winterbloom. Factors controlling phytoplankton community size structurein the mesohaline zone may be riverine nitrogen input, temperatureand/or advective transport from up-river. Based on these results,the spatial and seasonal variations in size structure of phytoplanktonobserved on the estuarine scale may be determined both by thedifferent preferences for nutrients and by different light requirementsof micro-, nano- and picoplankton. The results suggest thatanalyses of phytoplankton size structure are necessary to betterunderstand controls on phytoplankton dynamics and to bettermanage water quality in river-dominated, estuarine systems.     

Seasonal variation of photosynthesis and photosynthetic efficiency in <Emphasis Type="Italic">Phalaenopsis</Emphasis>

Nowadays, a quest for efficient greenhouse heating strategies, and their related effects on the plant’s performance, exists. In this study, the effects of a combination of warm days and cool nights in autumn and spring on the photosynthetic activity and efficiency of Phalaenopsis were evaluated; the latter, being poorly characterised in plants with crassulacean acid metabolism (CAM) and, to our knowledge, not reported before in Phalaenopsis. 24-h CO₂ flux measurements and chlorophyll (Chl) fluorescence analyses were performed in both seasons on Phalaenopsis ‘Hercules’ exposed to relatively constant temperature regimes, 25.5/24.0°C (autumn) and 30/27°C (spring) respectively, and distinctive warm day/cool night temperature regimes, 27/20°C (autumn) and 36/24°C (spring), respectively. Cumulated leaf net CO₂ uptake of the distinctive warm day/cool night temperature regimes declined with 10–16% as compared to the more constant temperature regimes, while the efficiency of carbon fixation revealed no substantial differences in both seasons. Nevertheless, a distinctive warm day/cool night temperature regime seemed to induce photorespiration. Although photorespiration is expected not to occur in CAM, the suppression of the leaf net CO₂ exchange during Phase II and Phase IV as well as the slightly lower efficiency of carbon fixation for the distinctive warm day/cool night temperature regimes confirms the involvement of photorespiration in CAM. A seasonal effect was reflected in the leaf net CO₂ exchange rate with considerably higher rates in spring. In addition, sufficiently high levels of photosynthetically active radiation (PAR) in spring led to an efficiency of carbon fixation of 1.06–1.27% which is about twice as high than in autumn. As a result, only in the case where a net energy reduction between the temperature regimes compensates for the reduction in net CO₂ uptake, warm day/cool night temperature regimes may be recommended as a practical sustainable alternative.     

Simulating phenological shifts in French temperate forests under two climatic change scenarios and four driving global circulation models

After modeling the large-scale climate response patterns of leaf unfolding, leaf coloring and growing season length of evergreen and deciduous French temperate trees, we predicted the effects of eight future climate scenarios on phenological events. We used the ground observations from 103 temperate forests (10 species and 3,708 trees) from the French Renecofor Network and for the period 1997–2006. We applied RandomForest algorithms to predict phenological events from climatic and ecological variables. With the resulting models, we drew maps of phenological events throughout France under present climate and under two climatic change scenarios (A2, B2) and four global circulation models (HadCM3, CGCM2, CSIRO2 and PCM). We compared current observations and predicted values for the periods 2041–2070 and 2071–2100. On average, spring development of oaks precedes that of beech, which precedes that of conifers. Annual cycles in budburst and leaf coloring are highly correlated with January, March–April and October–November weather conditions through temperature, global solar radiation or potential evapotranspiration depending on species. At the end of the twenty-first century, each model predicts earlier budburst (mean: 7 days) and later leaf coloring (mean: 13 days) leading to an average increase in the growing season of about 20 days (for oaks and beech stands). The A2-HadCM3 hypothesis leads to an increase of up to 30 days in many areas. As a consequence of higher predicted warming during autumn than during winter or spring, shifts in leaf coloring dates appear greater than trends in leaf unfolding. At a regional scale, highly differing climatic response patterns were observed.