False Spring Research Articles

Innovation’s false spring: U.S. export controls and Chinese patent quality

This paper evaluates the effect of U.S. export restrictions, enacted in 2018, on China’s patent production. An analysis of patent-level datasets indicates a significant surge in Chinese patent filings in sanctioned technological domains. This quantitative growth, however, is accompanied by a decrease in patent quality, evidenced by reduced citation counts and market worth. Specifically, state-owned enterprises (SOEs) have witnessed a substantial rise in patent filings post-2018, while private firms exhibit a more modest increase. Despite the surge in patent quantity, the overall quality of patents—particularly those originating from SOEs—has deteriorated significantly. This study contributes to the body of research concerning the economic consequences of the U.S.-China trade dispute and offers original insights into the implications of trade sanctions on innovation quality.

Weighing the risks and benefits of flowering early in the spring for the woody perennial Prunus pumila.

There are advantages to flowering early in the spring, including greater pollinator fidelity and longer fruit maturation time. But plant phenology has advanced in recent years, making many plants vulnerable to freezing damage from late frosts. To determine the costs and benefits of flowering early in the growing season, we exposed Prunus pumila plants to two freezing treatments and a delayed flowering treatment in subsequent years. Data were collected on ovary swelling, fruit production, and pollinator visitation on hand- and open-pollinated plants in all treatments. We also measured tissue damage after freeze events. Our results suggest that flowering time and temperature affect reproductive success, with fewer fruits produced after hard freezes. The same was not true for light freezes, which had minimal impact on reproduction. Freezing damage to plants after a hard freeze did affect the number of dipteran pollinators but not the overall pollinator visitation rate. Despite the clear impact of freezing temperatures on plant reproduction, flowering early provided an advantage in that reproductive output decreased with delayed flowering. Our findings suggest that Prunus pumila will retain the ability to attract pollinators and produce viable seeds if exposed to false spring conditions that involve a light freeze, but hard freezes may reduce yield by an order of magnitude. Although the advantages to flowering early may outweigh the risk of freezing damage under current conditions, it is possible that flower viability may be constrained under continued climate warming.

False spring events in the eastern part of the Baltic Sea region

False spring events in the eastern part of the Baltic Sea region

Floral freezing tolerance is tied to flowering time in North American woody plant species.

As winter and spring temperatures continue to increase, the timing of flowering and leaf out is advancing in many seasonally cold regions. This advancement could put plants that flower early in the spring at risk of decreased reproduction in years when there are late freeze events. Unfortunately, relatively little is known about floral freezing tolerance in forest communities. In this study, we examined the impact of freezing temperatures on the flowers of woody plants in a region where there is rapid winter warming in North America. We subjected the flowers of twenty-five woody species to a hard (-5ºC) and a light freeze (0ºC). We assessed tissue damage using electrolyte leakage. In a subset of species, we also examined the impact of a hard freeze on pollen tube growth. To determine if the vulnerability of flowers to freezing damage relates to flowering time and to examine the responsiveness of flowering time to spring temperature, we recorded the date of first flower for our study species for three years. Across species, we found that floral freezing tolerance was strongly tied to flowering time with the highest freezing tolerance occurring in plants that bloomed earlier in the year. We hypothesize that these early blooming species are unlikely to be impacted by a false spring. Instead, the most vulnerable species to a false spring should be those that bloom later in the season. The flowering time in these species is also more sensitive to temperature, putting them at a great risk of experiencing a false spring. Ultimately, floral damage in one year will not have a large impact on species fitness, but if false springs become more frequent, there could be long-term impacts on reproduction of vulnerable species.

False springs in the Netherlands: climate change impact assessment with the false spring damage indicator model

Strong night frosts in spring have the potential to cause severe damage to fruit trees, causing up to €3.3 billion of damage in Europe in 2017. If temperatures drop below − 2.2 °C after the growing season starts, this phenomenon is referred to as a false spring. For the Netherlands, the risk of false spring damage increased during the past 70 years, due to the decreasing time between the last strong night frost and the flower budburst. This raises the question of whether this trend will continue under future influences of climate change. To analyse the development of false spring damage risks, we developed the False Spring Damage Indicator (FSDI) model. Applying this model to the Dutch KNMI’14 climate change scenarios for 2050 and 2085 showed a decrease in false spring damage risk. The historical risk for 60% bud damage was reduced to around 40% for the moderate scenario in 2050 and to less than 15% for the severe scenario in 2050 and all scenarios in 2080. False spring damage varied spatially throughout the Netherlands. Currently, more severe damage can be expected in the east, while coastal regions in the north and west are less prone to false spring damage. In the future, this is expected to become more uniform over the Netherlands, as the risk in the east is predicted to decrease strongly, becoming similar to the low damage risk in the coastal regions.

Фенология начала нерестовых миграций бесхвостых амфибий (Anura, Amphibia) в долинах рек Саратовского Правобережья

The intra-century dynamics of the spawning migrations start of the three most numerous species of anuran amphibians (Pelobates vespertinus, Bombina bombina and Pelophylax ridibundus) was analyzed. Local populations of the above anurans in the valley of the middle course of the Medveditsa River (Don Basin, Saratov region) were the object of the study. From 1892 to 2023 the phenological norm of this phase of the annual cycle shifted to earlier dates by an average of 7 days for each species in a climate warming. By 2023, the henological norm of the spawning migration start of P. vespertinus, B. bombina and P. ridibundus was April 14, April 21, and April 22, respectively. In addition, the change rate of this phenological parameter in the model species was similar as well, about 8 days/100 years. The absolute value of the phenological norm change, as well as the rate of its transformation, is comparable among the three species of anuran amphibians, despite any differences in their thermobiological characteristics. The early snow clearence in the Northern Lower Volga region may be one of the reasons for shifting the start dates of amphibian spawning migrations to earlier dates. The continued phenological changes in the spring phase of the annual cycle require continued monitoring of this process. This will allow forming scientifically based forecasts of local population dynamics in the future. Possible consequences of this transformation of the spring phenology of anuran amphibians are increased probability of metamorph survival in low water availability in the floodplain, and spawning migration development in the false spring scenario and susceptibility to return cold weather. This is discussed in relation to the changes identified.

False springs and spring phenology: Propagating effects of downscaling technique and training data

AbstractProjected changes to spring phenological indicators (such as first leaf and first bloom) are of importance to assessing the impacts of climate change on ecosystems and species. The risk of false springs (when a killing freeze occurs after plants of interest bloom), which can cause ecological and economic damage, is also projected to change across much of the United States. Given the coarse nature of global climate models, downscaled climate projections have commonly been used to assess local changes in spring phenological indices. Few studies that examine the influence of the sources of uncertainty sources in the downscaling approach on projections of phenological changes. This study examines the influence of sources of uncertainty on projections of spring phenological indicators and false spring risk using the South Central United States. The downscaled climate projections were created using three statistical downscaling techniques applied with three gridded observation datasets as training data and three global climate models. This study finds that projections of spring phenological indicators and false spring risk are primarily sensitive to the choice of global climate models. However, this study also finds that the formulation of the downscaling approach can cause errors representing the daily low‐temperature distribution, which can cause errors in false spring risk by failing to capture the timing between the last spring freeze and the first bloom. One should carefully consider the downscaling approach used when using downscaled climate projections to assess changes to spring phenology and false spring risk.

Dynamically Downscaled Projections of Phenological Changes across the Contiguous United States

Abstract Phenological indicators (PI) are used to study changes to animal and plant behavior in response to seasonal cycles, and they can be useful to quantify the potential impacts of climate change on ecosystems. Here, multiple global climate models and emission scenarios are used to drive dynamically downscaled simulations using the WRF Model over the contiguous United States (CONUS). The wintertime dormancy of plants [chilling units (CU)], timing of spring onset [extended spring indices (SI)], and frequency of proceeding false springs are calculated from regional climate simulations covering historical (1995–2005) and future periods (2025–2100). Southern parts of the CONUS show projected CU decreases (inhibiting some plants from flowering or fruiting), while the northern CONUS experiences an increase (possibly causing plants to break dormancy too early, becoming vulnerable to disease or freezing). Spring advancement (earlier SI dates) is projected, with decadal trends ranging from approximately 1–4 days per decade over the CONUS, comparable to or exceeding those found in observational studies. Projected changes in risk of false spring (hard freezes following spring onset) vary across members of the ensemble and regions of the CONUS, but generally western parts of the CONUS are projected to experience increased risk of false springs. These projected changes to PI connote significant effects on cycles of plants, animals, and ecosystems, highlighting the importance of examining temperature changes during transitional seasons. Significance Statement This study examines how phenological indicators, which track the life cycles of plants and animals, could change from 2025 to 2100 as simulated in a regional climate model over the contiguous United States. Chilling units quantify the presence of cooler weather that can benefit plants prior to their growing season. They are projected to decrease in the southern United States, possibly inhibiting agricultural production. Spring onset is projected to occur earlier in the year, advancing by 1–4 days on average over each future decade. Risk of false springs (damaging hard freezes after spring onset) increases in the western United States. Our findings highlight the need to understand effects of climate change during transitional seasons, which can impact agriculture and ecosystems.

Bud endodormancy – a familiar but still unknown key adaptive trait in extratropical woody plants

In autumn, the buds of extratropical trees are in a state of endodormancy, since regardless of the prevailing environmental conditions, growth cannot be activated in these buds because the dormancy is caused by physiological factors in the buds. In natural conditions the growth-arresting physiological factors are removed by prolonged exposure to low chilling temperatures. This phenomenon is a key adaptive trait, for it prevents ‘false spring’, i.e., untimely bud burst during mild spells in autumn and winter, which would lead to cold damage during subsequent cold periods. Traditionally, endodormancy and the chilling requirement have been important in practical horticulture, as cultivars with low and high chilling requirements have been bred for locations in warm and cool climates, respectively. More recently, endodormancy and the chilling requirement have become major research themes in climate change studies where climatic change impacts are assessed by means of process-based tree phenology models. The dormancy phenomenon has been studied thoroughly at the whole-tree level for a hundred years, and several genes and genetic pathways involved have recently been identified in tree species such as hybrid aspen, apple, and pear. There is an urgent need, however, to integrate molecular physiological studies with modelling studies so as to understand the impact of climate change on the regulation of dormancy. To that end, we shall provide an overview of bud endodormancy research.

Past and present risk of spring frosts for fruit trees in the Czech Republic

Recent climate warming is reflected in the advanced onset of spring phenological phases of fruit trees and in so-called false springs. This then manifests as an increased risk of trees being damaged by late frosts in the sensitive growing stage. Based on the homogenised temperature series of 155 climatological stations divided into two altitudinal groups (below 300 m a.s.l. and 301–600 m a.s.l.), a climatological analysis of selected variables in relation to atmospheric circulation over the territory of the Czech Republic during the period 1961–2021 was performed. The number of frost days and the dates of their latest onset exhibited negative linear trends; however, only 16% and 20% were statistically significant. The onset of false spring (at least ten consecutive days with daily maximum ≥ 10 °C) was also characterised by decreasing trends, which significantly deepened after 1980. Spring frost days were particularly attributed to higher frequencies of anticyclonic circulation types such as the central anticyclone and circulation types with northeastern, eastern and southeastern airflow. False spring onset was particularly connected with the central anticyclone and circulation types with western and southwestern airflow. The increasing trends of frost risk days (days between the beginning of the false spring and the date of the latest frost with daily minimum < −1.5 °C) were statistically nonsignificant. Local series of fruit trees from southeastern Moravia proved to have significantly earlier onset of the first blossom and full blossoming phenophases. Although the damage by late frosts has been identified as an important factor contributing to low yields of fruit trees during the period 1996–2021 in the Czech Republic, other factors (e.g. other weather phenomena, diseases, pests, site, taking preventive measures against frost) must also be taken into account.

Cross‐disciplinary insights into the mechanisms of plant cold hardiness: From molecules to ecosystems

Cross‐disciplinary insights into the mechanisms of plant cold hardiness: From molecules to ecosystems

Biomass, carbohydrate, and leakage conductance in buds of six ornamental tree species subjected to a “false spring” in Northeast China

Information is highly scarce about the possible effect of a late spring frost on physiological response of buds in ornamental trees. In this study, spring temperature of Changchun at Northeast China was recorded to identify the characteristics of a false spring by detecting extraordinary warming and sudden freeze in early April of 2017. Buds of six local ornamental tree species were investigated for their dynamics in biomass, non-structural carbohydrates, frost resistance on days of 7, 14, 21, and 28 April 2017. According to a comparison with spring temperature records historically from 2007 to 2016, a false spring was determined. Black pine (Pinus tabuliformis var. mukdensis) had greater bud biomass than apricot (Prunus sibirica L.). Peach (Prunus persica L. var. persica f. rubro-plena Schneid.) reserved greater non-structural carbohydrate content in post-chilling buds than black pine, and apricot and willow (Salix babylonica L.) had greater soluble sugars and starch contents in buds, respectively. Cumulative number of days with temperature below 12°C had a negative relationship with relative conductance in sorbus (Sorbus pohuashanensis [Hance] Hedl.). Chokecherry (Padus virginiana ‘Canada Red’) had greatest bud starch content on 21 April. Overall, a late spring frost imposed interruption on carbohydrate metabolism rather than direct damage on buds of ornamental trees before late April. Advanced warming induced more pronounced negative impact of a false spring than the sudden decline of minimum temperature.

False Spring in the Spawning Migrations of Spadefoot Toads (Pelobates, Anura): Distribution in European Russia and the Phenomenon Scale in 2020

False Spring in the Spawning Migrations of Spadefoot Toads (Pelobates, Anura): Distribution in European Russia and the Phenomenon Scale in 2020

False Spring in the Southeastern European Russia and Anomalies of the Phenology of Spawing Migrations of the Pallas’ Spadefoot Toad &lt;i&gt;Pelobates vespertinus&lt;/i&gt; (Pelobatidae, Amphibia)

In March 2020, an anomalously early start of the spawning migrations of Pelobates vespertinus was established in the Medveditsa River valley. Males of this species, emerging from a state of hibernation, were observed in the shallow waters of the lake Troynoye on March 13, one month ahead of the long-term mean date over the past 30 years and almost two weeks before the earliest recorded date. From 1892 to 1990 the phenological scenario of a false spring was realized six times only, while seven times — over the past 30 years (1991 – 2020). A second feature of the development of spring processes by the type of false spring in 1990 – 2020 is repeated recurrence of return cooling. The emergence of discreteness (discontinuity) of the spawning migration period against the background of early development of spring processes and repeated periods of return cold is a relatively new feature of the phenology of anuran amphibians. The cumulative proportion of P. vespertinus males arriving at their spawning biotopes from the first to the fifth day from the date of the start of spawning migrations of the species increases on mean (median) from 4 to 38% of the total number of mature males. In 2014, an abrupt change in the proportion of males who came to spawning biotopes during the first five days was found: in 2009 – 2013 was less than a quarter of the total number of males (15 – 23%), and in 2014 – 2017 it was half or more (43 – 70%). Consequences of such phenological abnormalities can become an additional factor in reducing the reproductive success of P. vespertinus and degradation of their local populations. In addition, the abnormal development of spring processes requires correction of census technique and analysis of the sex structure of P. vespertinus populations.

False spring in the spawning migrations of Spadefoot toads (Pelobates, Anura): Distribution in the European Russia and the phenomenon scale in 2020

The 2020 spring processes in the European Russia were developing according to the type of false spring. The absence or weak development of snow cover, as well as its early descent in the last decade of February, determined the rapid warming of the soil profile. A certain complex of meteorological factors led to an abnormally early start of spawning migrations of the common spadefoot toad (Pelobates fuscus (Laurenti, 1768)) and Pallas's spadefoot toad (Pelobates vespertinus (Pallas, 1771)) over a vast territory which included the northwestern, western, central and southeastern parts of the species habitat in the region. Analysis of the snow cover dynamics and the temperature course according to the data of the network of meteorological stations made it possible to assess the phenology of these species of anuran amphibians within this region using the method of reconstructing the reproductive period events of the spadefoot toads. The duration of the period between the start dates of false and true spawning migrations was more than 40 days in the west, in the center and in the south-east of the European Russia. The abnormally early formation of the 2020 false spring phenomenon in the spawning migrations of spadefoot toads is currently registered as a precedent which may have a significant impact on the reproduction success of the species of this genus.

The 13th International Oncolytic Virus Conference: Powerful payloads gain clinical momentum

The 13th International Oncolytic virus conference (IOVC#13) was held November 5–7, 2021, during the “false spring” between the Delta and Omicron phases of the coronavirus disease 2019 (COVID-19) pandemic. IOVC#13 was organized as a hybrid meeting with approximately 90 attendees gathering in person surrounded by the red rocks of Sedona, Arizona and more than 240 attending virtually from around the world. We are grateful to the intrepid organizers, including the American Society of Gene and Cell Therapy (ASGCT) team led by David Barrett and Kah Whye Peng, with Stephen Russell as her first assistant (Mayo Clinic/Vyriad), who took on the challenge of putting together a seamless experience for in-person and virtual attendees.

Climate change reshapes the drivers of false spring risk across European trees.

Temperate forests are shaped by late spring freezes after budburst - false springs - which may shift with climate change. Research to date has generated conflicting results, potentially because few studies focus on the multiple underlying drivers of false spring risk. Here, we assessed the effects of mean spring temperature, distance from the coast, elevation and the North Atlantic Oscillation (NAO) using PEP725 leafout data for six tree species across 11648 sites in Europe, to determine which were the strongest predictors of false spring risk and how these predictors shifted with climate change. All predictors influenced false spring risk before recent warming, but their effects have shifted in both magnitude and direction with warming. These shifts have potentially magnified the variation in false spring risk among species with an increase in risk for early-leafout species (i.e. Aesculus hippocastanum, Alnus glutinosa, Betula pendula) compared with a decline or no change in risk among late-leafout species (i.e. Fagus sylvatica, Fraxinus excelsior, Quercus robur). Our results show how climate change has reshaped the drivers of false spring risk, complicating forecasts of future false springs, and potentially reshaping plant community dynamics given uneven shifts in risk across species.

Metabolic costs of altered growth trajectories across life transitions in amphibians.

Climate change is causing increases in temperature and in the frequency of extreme weather events. Under this scenario, organisms should maintain or develop strategies to cope with environmental fluctuations, such as the capacity to modify growth trajectories. However, altering growth can have negative consequences for organisms' fitness. Here, we investigated the metabolic alterations induced by compensatory growth during the larval development of the common frog (Rana temporaria), quantifying changes in oxidative stress, corticosterone levels and telomere length. We induced compensatory growth responses by exposing frog embryos to cold conditions (i.e. a 'false spring' scenario), which cause a delay in hatching. Once hatched, we reared larvae at two different photoperiods (24:0, representing the natural photoperiod of larvae, and 18:6) to test also for the interactive effects of light on growth responses. Larvae experiencing delayed hatching showed fast compensatory responses and reached larger size at metamorphosis. Larvae shortened their developmental period in response to delayed hatching. Non-permanent light conditions resulted in relaxed growth compared with larvae reared under permanent light conditions, which grew at their natural photoperiod and closer to their maximal rates. Growth responses altered the redox status and corticosterone levels of larvae. These physiological changes were developmental stage-dependent and mainly affected by photoperiod conditions. At catch-up, larvae reared at 18:6 light:dark cycles showed higher antioxidant activities and glucocorticoid secretion. On the contrary, larvae reared at 24:0 developed at higher rates without altering their oxidative status, likely an adaptation to grow under very restricting seasonal conditions at early life. At metamorphosis, compensatory responses induced higher cellular antioxidant activities probably caused by enhanced metabolism. Telomere length remained unaltered by experimental treatments but apparently tended to elongate across larval ontogeny, which would be a first evidence of telomere lengthening across metamorphosis. Under the forecasted increase in extreme climatic events, adjusting growth and developmental rates to the dynamics of environmental fluctuations may be essential for survival, but it can carry metabolic costs and affect later performance. Understanding the implications of such costs will be essential to properly estimate the impact of climate change on wild animals.

Rethinking false spring risk.

Temperate plants are at risk of being exposed to late spring freezes. These freeze events-often called false springs-are one of the strongest factors determining temperate plants species range limits and can impose high ecological and economic damage. As climate change may alter the prevalence and severity of false springs, our ability to forecast such events has become more critical, and it has led to a growing body of research. Many false spring studies largely simplify the myriad complexities involved in assessing false spring risks and damage. While these studies have helped advance the field and may provide useful estimates at large scales, studies at the individual to community levels must integrate more complexity for accurate predictions of plant damage from late spring freezes. Here, we review current metrics of false spring, and how, when, and where plants are most at risk of freeze damage. We highlight how life stage, functional group, species differences in morphology and phenology, and regional climatic differences contribute to the damage potential of false springs. More studies aimed at understanding relationships among species tolerance and avoidance strategies, climatic regimes, and the environmental cues that underlie spring phenology would improve predictions at all biological levels. An integrated approach to assessing past and future spring freeze damage would provide novel insights into fundamental plant biology and offer more robust predictions as climate change progresses, which are essential for mitigating the adverse ecological and economic effects of false springs.

Need for False Spring Research in the Northern Great Plains, USA

Core Ideas Late spring frosts (false springs) may increase in northern latitudes of the USA. Researchers need to determine how false springs will affect plants and wildlife. Special attention is required in vulnerable areas such as the northern Great Plains. Global climate change is typically characterized by warming average temperatures and more frequent extreme weather events. An understudied component of climate change is the occurrence of false springs, where warm temperatures in early spring prematurely release plants from dormancy, only to be harmed by a late spring frost event. Only limited research has investigated the nature, extent, and impacts of false springs, despite their potential for extreme environmental and economic consequences. More resources should be devoted to false spring research because they are predicted to increase in several regions, especially the northern Great Plains. We review the existing literature on false springs and identify knowledge gaps in both cropland and natural systems. Further, we propose avenues of research, focusing on ecosystems of the northern Great Plains. This research will be crucial in creating strategies that allow land managers to adapt to changing conditions caused by more frequent false springs.