Risk Of Frost Damage Research Articles

Hemp-lime – contemporary usage of traditional materials

Hemp-lime is a comparatively unknown building material in Estonia. Scientific interest in this material is increasing remarkably quickly around the world, yet the practical competence regarding its usage is lacking in Estonia as far as the construction industry is concerned.
 Hemp occupies an important place amongst crops that have traditionally been cultivated in Estonia, but its use has not been typically associated with the construction industry. Owing to its strong fibre, hemp has primarily been seen as raw material for the production of textile products, particularly rope, and the inner core of the plant or ‘hemp hurd’, has been cast aside as a by-product. Since the porosity of hemp hurds results in a relatively low thermal conductivity, hemp-lime, the composite material made by mixing hemp with lime, is suitablefor insulating pre-existing building envelopes as well as for installing insulation for new buildings during construction. Lime creates an alkaline environment around the hemp hurds, making it difficult for fungi and pest insects to thrive. Compared to other natural insulation materials, hemp-lime therefore has a rather good balance between durability and cost-effectiveness.
 The essential feature of hemp-lime relevant to construction engineering is that the material is monolithic – any occurrences of sparsity and the resultant risk of thermal bridging in building envelopes is kept to a minimum, since the hemp-lime filling that surrounds the load-bearing structure forms a solid external surface, when properly installed. Owing to its high level of air-tightness, external structures made from hemp-lime can reduce the risk both of excessive cooling and of overheating. In addition to creating a comfortable indoor climate for residents, mitigating any sharp fluctuations also protects the wooden construction elements surrounded by the hemp-lime, which thus also reduces the risk of moisture and frost damage.
 Reducing the annual energy consumption of buildings and ensuring healthy indoor air quality pose significant challenges to the construction industry, since according to the current building code, the energy performance indicator of the buildings being put up from 1st January, 2021, should not exceed the limit established for nearly zero-energy buildings. In short, this calls for a more efficient use of resources, including the production, transport, installation, and recycling of materials. Compared to the majority of contemporary building materials, hemp-lime is relatively eco-friendly, and its energy content is low.
 Keywords: industrial hemp, lime, clay, hemp-lime

Dynamic distribution of thermal effects of an oscillating frost protective fan in a tea field

Wind machines are one of the most effective and prevalent methods of frost protection for crops. However, their physical and physiological effectiveness should be re-examined because climate change from global warming can reduce the cold tolerance of crops, leading to higher risk of frost damage. Here, we experimentally elucidate thermal effects of a wind machine by spatiotemporal analysis of leaf heat balance, with the aid of a new method facilitating continuous and multipoint evaluation of leaf boundary layer conductance ( G A ). G A regulates convective heat exchange between leaves and ambient air. This analysis was performed in a tea field with a frost protective fan (oscillating wind machine), thereby visualising the spatiotemporal distribution of thermal effects from the oscillating fan. Those effects showed a dynamically varying distribution in space and time, as shown in the supplementary animation, under strong influences of both changes in G A and air-to-leaf temperature difference. The change in G A was synchronised with airflow from the oscillating fan onto leaves. However, the change in air-to-leaf temperature difference was complicated, with delay in transient thermal responses of leaves and ambient air. These spatiotemporal characteristics of thermal effects varied substantially with field location, owing to different intervals and durations of airflow from the oscillating fan. Consequently, remarkable non-uniformities in thermal effects appeared across the field, increasing potential risk of frost damage. These results indicate that the effectiveness of the fan still has room for improvement by considering the spatiotemporal characteristics of thermal effects reported herein, toward more reliable frost protection under global warming.

Increase in the risk of exposure of forest and fruit trees to spring frosts at higher elevations in Switzerland over the last four decades

Winters and early springs are predicted to become warmer in temperate climates under continued global warming, which in turn is expected to promote earlier plant development. By contrast, there is no consensus about the changes in the occurrence and severity of late spring frosts. If the frequency and severity of late spring frosts remain unchanged in the future or change less than spring phenology of plants does, vulnerable plant organs (dehardened buds, young leaves, flowers or young fruits) may be more exposed to frost damage. Here we analyzed long-term temperature data from the period 1975–2016 in 50 locations in Switzerland and used different phenological models calibrated with long-term series of the flowering and leaf-out timing of two fruit trees (apple and cherry) and two forest trees (Norway spruce and European beech) to test whether the risk of frost damage has increased during this period. Overall, despite the substantial increase in temperature during the study period, the risk of frost damage was not reduced because spring phenology has advanced at a faster rate than the date of the last spring frost. In contrast, we found that the risk of frost exposure and subsequent potential damage has increased for all four species at the vast majority of stations located at elevations higher than 800m while remaining unchanged at lower elevations. The different trends between lower and higher elevations are due to the date of the last spring frost moving less at higher altitudes than at lower altitudes, combined with stronger phenological shifts at higher elevations. This latter trend likely results from a stronger warming during late compared to earlier spring and from the increasing role of other limiting factors at lower elevations (chilling and photoperiod). Our results suggest that frost risk needs to be considered carefully when promoting the introduction of new varieties of fruit trees or exotic forest tree species adapted to warmer and drier climates or when considering new plantations at higher elevations.

Slow community responses but rapid species responses 14 years after alpine turf transplantation among snow cover zones, south–central New Zealand

Alpine ecosystems are particularly vulnerable to the impact of global climate change. Depth and duration of seasonal snow cover are major drivers of variation in alpine plant community composition, so a reduction in snow cover as a result of climate change would expose plants that are currently protected by snow in winter and spring to greater extremes of temperature and increased risk of frost damage. We reciprocally transplanted 64 intact 60 cm × 60 cm × 10 cm (minimum depth) turves of alpine vegetation among four topographic zones on the Rock and Pillar Range, south-central South Island, New Zealand to investigate how shifts along a snow cover gradient affected plant growth, survival and community composition. The four zones: late-melting snowbed and early-melting snowbed in depressions, moderately exposed leeward upper slopes dominated by herbfield, and extremely exposed summit plateau dominated by cushionfield, differed in winter and spring snow cover. As expected, the highest species losses occurred in turves transplanted to very different zones e.g. late snowbed to summit plateau and vice versa. However many snowbed species still survived on the summit plateau seven years following transplantation. The degree to which turves had been colonised after seven years was significantly related to transplant zone rather than turf origin or original species richness; turves transplanted to the most species-rich zones were affected most by colonisation. Measurements of leaf production over three years in three focal Celmisia species (Asteraceae), characteristic of the herbfield on leeward slopes, and early and late snowbeds, showed that the late snowbed specialist suffered significantly reduced growth when transplanted to more exposed sites, but its survival was more affected by invertebrate herbivory rather than the direct effects of exposure. The cosmopolitan focal lichen species Thamnolia vermicularis, monitored over 14 years, rapidly colonised turves transplanted to cushionfield on the exposed summit plateau, where this and other lichens are abundant, but equally rapidly declined in turves transplanted to snowbeds. These findings add to a growing body of evidence that biotic interactions and species-specific traits will be critical drivers of alpine vegetation change under future climate scenarios.

Xylogenesis in stems and roots after thinning in the boreal forest of Quebec, Canada.

The reduction of competition through thinning increases radial growth in the stem and roots of many conifer species. However, not much is known about the effect of thinning on the dynamics of wood formation and intra-annual development of the growth ring, especially in the roots, which are an essential part of the tree for stability and resource acquisition. The aim of this study was to evaluate the effect of an experimental thinning on the dynamics and phenology of xylogenesis in the stem and roots of black spruce and balsam fir. Experimental and control trees were selected in two mature even-aged stands, one black spruce (Picea mariana (Mill.) BSP) and one balsam fir (Abies balsamea (L.) Mill.). Wood microcores were collected weekly in the stem and roots from May to October for a period of 4 years. The onset and ending of each cell differentiation phase were computed, as well as growth rate and total cell production. Results show that thinning increased the cell production rate of stem and roots of black spruce and balsam fir. This higher daily growth rate caused an increase in the total number of cells produced by the cambium. The intensity of the treatment was sufficient to significantly increase light availability for residual trees, but insufficient to modify soil temperature and water content to a point at which a significant change in the timing or duration of xylogenesis would be induced. Thus, thinning increased cell production rate and total number of cells produced in both stem and roots, but did not result in a change in the phenology of wood formation that could lead to increased risks of frost damage in the spring or autumn.

The role of plant functional traits in shrub distribution around alpine frost hollows

Introduction/Aims Functional traits aid understanding of species distribution and community composition along environmental gradients. However, studies that detail trait measurements along fine-scale environmental gradients are lacking for many vulnerable ecosystems. In this paper, we quantify how plant traits might explain the composition of shrubs in one such vulnerable system – frost hollows. Location Bogong High Plains, Victoria, Australia. Methods We measured species composition and a suite of traits (shrub height, stem specific density, leaf area and SLA, xylem vessel area and density, and leaf bud traits) for shrub species in three, 10 m × 10 m quadrats located across transition from hilltops down into frost hollows. We used ordinal regression to model vegetation transitions by relating the changes in shrub species occurrence along frost hollow gradients to each trait, and across multiple traits. We also assessed intraspecific trait variations along gradients. Results Several traits explained the position of species along a gradient of cold air accumulation (slopes leading into frost hollows). The most important traits were maximum shrub height, leaf area and xylem traits, which were clearly related to species location on the slopes in single trait models. More complex relationships were revealed with multi-trait models, which indicated that shorter species, those with smaller leaves and larger buds for their leaf size, and those with lower vessel density were more likely to be found toward the bottom of the slope. Within species, taller individuals and those with denser stems were also more common up-slope. Conclusion Our results suggest a shift in ecological strategies in frost hollows: the advantages of being taller and having large leaves may be diminished in these stressful environments. Shrubs that are shorter and have smaller leaves may also be better at avoiding the risk of frost damage. Our study shows how the fine-scale turnover of shrub species composition around frost hollows relates to plant functional traits, and captures the allocation trade-offs between coping with environmental stress and being competitive within these plant communities.

기상자료를 이용한 우리나라 한중콘크리트 적용기간과 초기동해 위험일 산정

본 연구는 기상자료를 토대로 우리나라 각 지역별 한중 콘크리트 적용기간을 KCI 및 AIJ 규정에 의한 방법으로 각각 산정하고 초기동해 위험일을 각 지역 및 온도 단계별로 제안하고자 하였다. 한중 콘크리트 적용기간의 경우 최근 5년간의 기상자료를 토대로 조사한 결과와 종전의 연구결과를 비교하였다. 연구결과에 따르면 국내 91개 지역의 한중 콘크리트 적용기간은 평균 98일로 조사되었고, 고위도 지역일수록, 산악 및 내륙지역일수록 적용기간은 증가되는 것으로 나타났으며, 종전 연구 대비 본 연구의 적용기간이 1~2일 정도 감소되는 것으로 나타났다. 지구온난화, 도시화 등의 영향으로 판단된다. 초기동해 위험일의 경우 <TEX>$-5^{\circ}C$</TEX>, <TEX>$-2^{\circ}C$</TEX> 및 <TEX>$0^{\circ}C$</TEX> 단계별로 시작일 및 종료일을 제시하였으며, 이를 토대로 <TEX>$0^{\circ}C$</TEX> 이하 출현일 수, 출현일 및 평균 추위도를 제시하였다. 본 연구 범위에서 제시된 초기동해 위험일은 KCI에 의한 한중콘크리트 적용기간보다 길게 나타난 지역이 다수 존재하여 한중콘크리트 적용기간 이외에도 초기동해 위험이 있음을 확인할 수 있었다. In this paper, the periods of cold weather concrete and early frost damage depending on each region in South Korea were studied using the climate data from Korea meteorological administration. The specifications of Korea Concrete Institute(KCI) and Architectural Institute of Japan(AIJ) were applied to provide the periods of cold weather concrete. The periods of early frost damage risk(EFD) were calculated by Hasegawa's suggestion depending on 91 cities in Korea. Climate data for 5 years (2008~2012) were used to obtain both of the periods. Existing data from 1971 to 2000 were also used to compare differences in the periods between past and present study. The periods of cold weather concrete by KCI were calculated about 98 days on average. As the latitude goes up and close to mountain areas, the periods tend to be increased. The periods by present study was shown to be reduced compared to that of previous study by 1~2days. The period of EFD was provided with the level of daily lowest temperature from <TEX>$-5^{\circ}C$</TEX>, <TEX>$-2^{\circ}C$</TEX> and <TEX>$0^{\circ}C$</TEX>. The beginning day of the period of EFD was earlier than the period of cold weather concrete and the finishing day of the period of EFD was later than the period of cold weather concrete.

Spatial and temporal variability of the frost‐free season in Central Europe and its circulation background

ABSTRACTThe aim of the study was to investigate the temporal and spatial variability of last spring and first autumn frost events as well as the length of the frost‐free season (FFS) in Central Europe in relation to atmospheric circulation. Studies were conducted for the period 1951–2010 using gridded, daily minimum air temperature data obtained from the E‐OBS dataset at 0.25° spatial resolution. To assess the possible impact of air temperature variability on plants, late spring frost events and severe frost events were also examined with respect to the beginning of the thermal growing season. The role of atmospheric circulation was described using Grosswetterlagen circulation types and NAO index, and finally estimated using empirical orthogonal function analysis (EOF). The results confirm a significant increase in the length of the FFS, up to 10 days per decade in the western parts of Europe. This is mostly a result of earlier occurrence of last spring frost in the west up to 5 days. The occurrence of first autumn frost shows no significant trend in most of the studied regions. The obtained spatial pattern of the trends reflects oceanic (west) and continental (east) climatic conditions of the study area. Detailed analysis of circulation types favouring the occurrence of frost in Central Europe indicates that anti‐cyclonic situations are mainly responsible. EOF analyses for the springtime confirm that the first mode, which accounts for 56% of total variance, is related to an extensive high pressure system over eastern Ukraine and Belarus, which brings an inflow of cold, continental air masses to Central Europe. The results provide a broaden information on the region climatologically important due to its transitional location, which may be relevant for investigating past and future trends in spring freeze risk for perennial crops, as changes in the frequency of these airflow patterns will result in changes in the risk of frost damage.

The impacts of key adverse weather events on the field‐grown vegetable yield variability in the Czech Republic from 1961 to 2014

ABSTRACTThe response of field‐grown vegetables to adverse weather conditions is strongly coupled to the timing of adverse events, the sensitivity of the growth stage of the impacted crop and the management actions that are taken. To estimate the long‐term yield response to changes in temperature and precipitation as well as the short‐term response to key adverse weather events (e.g. heavy precipitation, drought and heat stress) on the yields of vegetable crops, we used several statistical approaches with six daily impact‐indicators, the four monthly drought indices and the climate trends. Our study integrated a newly available historical yield dataset at the district level (the finest spatial resolution) for all highly marketable vegetables (celeriac, late carrots, root parsley, early kohlrabi, summer savoy cabbage, late cauliflower, late cabbage, onions, green peas, tomatoes, salad and pickling cucumbers) and a high‐resolution historical climate dataset (seven daily meteorological variables at a 10 × 10 km resolution) over a 54‐year period in the Czech Republic (CZ). Different indices were used to reflect different dimensions of water and heat stress, which have different impacts on vegetable growth and yield. We find positive long‐term impacts of recent warming on fruiting vegetables (from 4.9 to 12.2% °C−1) but decreases in the yield stability of traditionally grown root vegetables in the warmest areas of the country. Short‐term extreme temperature variabilities (days with heat stress) were found to be the dominant type of adverse event for tomato and cucumber production due to its effect on increased soil water demand, which increased transpiration rates, whereas changes in both the diurnal temperature ranges and minimum temperature (Tmin) were associated with minimal risk of frost damage. Brassicas vegetables are widely irrigated in the CZ, but irrigation does not fully mitigate drought effects; hence, short‐term extreme precipitation variability largely controls crop production in the growing districts. The high frequencies of dry days and days with heavy precipitation within the critical growth stages of brassicas reflect a competition between more dry days and greater precipitation intensity on wet days. The yield variability of bulbs is largely explained by both short‐term extreme precipitation and temperature variability (drought‐heat stress), which reflects the predominantly rain‐fed system of onion cultivation. Both drought and heat stress and changes in Tmin were important in explaining yield losses of root vegetables. Legumes had the lowest risk of multiple stresses during their short growth cycle, but droughts remain the dominant type of adverse event. Years with yield gains were substantially more common than years with yield losses for brassicas, bulbs and legumes vegetables in all of the cultivated regions.

Distribution ranges and spring phenology explain late frost sensitivity in 170 woody plants from the Northern Hemisphere

AbstractAimCold events determine the distributional range limits of woody species. Despite global warming, the magnitude of late frost events in boreal and temperate regions is not expected to change. Hence, the risk for late spring frost damage of woody species may increase with an earlier onset of the growing season. Here, we investigated biogeographical, phenological and phylogenetic effects on late frost sensitivity.LocationEcological‐Botanical Gardens Bayreuth, Germany (49°55′45″ N, 11°35′10″ E).MethodsWe inspected 170 woody species in the Ecological‐Botanical Gardens from across the entire Northern Hemisphere for frost damage after an extreme late frost event in May 2011 (air temperature −4.3 °C after leaf unfolding of all species). Distribution range characteristics, climatic parameters of place of origin and phenological strategy were linked to sensitivity to the late frost event.ResultsThe northern distribution limit and the range in continentality across the distributional ranges correlated negatively with a taxon's late frost sensitivity (pseudo‐R2 = 0.42, pseudo‐R2 = 0.33, respectively). Sensitivity to the late frost event was well explained by the climatic conditions within species’ native ranges (boosted regression trees; receiver operating characteristic 0.737). Average (1950–2000) May minimum temperature in species’ native ranges was the main explanatory variable of late frost sensitivity (51.7% of explained variance). Phylogenetic relatedness explained additional variance in sensitivity to the late frost event. Sensitivity to the late frost event further correlates well with species phenological strategy. Frost‐tolerant species flushed on average 2 weeks earlier than frost‐sensitive species.Main conclusionsRange characteristics and the prevalent climatic parameters across species native ranges are strongly related to their susceptibility to late spring frost damage. Further, more late frost‐sensitive species unfolded their leaves later than more tolerant species and late frost tolerance is phylogenetically conserved. Thus, late frost sensitivity may challenge natural and human‐assisted migration of woody species under global warming.

Modelling impact of freezing temperatures on reproductive organs of deciduous fruit trees

This study arises from the need for quantitative methods to assess risks of frost damage in agriculture. Classical mathematical functions were used to model damage due to freezing temperatures and a simple method based on experimental data is described to estimate the model parameters. Using survival data of vegetative and flower buds of deciduous fruit trees reported in the specialized literature, three sigmoidal functions were tested: logistic, Gompertz and Richards. The logistic function was chosen as the best model through the analysis of three comparative criteria: Root Mean Square Error (RMSE), statistical significance of parameters and Akaike Information Criterion (AIC). A parameter estimation method was developed based on a solution of a linear equation system of 2×2 fed only by two pairs of data, obtained from the simulated evolution of LT10 and LT90 for buds of apricot, cherry, apple and pear. The evolution of lethal temperatures (LT10 and LT90) fit well to a monomolecular function (r2 between 0.907 and 0.997, mean errors fluctuating between 0.5°C and 1.3°C). The method proved to be a good estimator of survival of buds and flowers, starting from published values of lethal temperatures. However, the model is highly sensitive to errors in the estimation of lethal temperatures during the flowering period. This study shows that it is possible to model crop response to freezing temperature, on the basis of limited data on freezing damage. Considering the simplicity of the method, it may be a useful tool to assess risks of frost damage and to improve models of climate change impacts.

Field survey on frost damage to roof tiles under climatic conditions

Purpose – Frost damage is well-known as the main cause of roof tile deterioration. The purpose of this paper is to develop an analytical model for predicting the deterioration process under certain climatic conditions. This paper describes the results of a field survey conducted to acquire fundamental information useful to this aim. Design/methodology/approach – A field survey of roof tile damage by freezing was conducted in an old temple precinct in Kyoto, Japan. Using detailed observations and photographic recordings, the damage progress was clarified. To examine the impact of climatic conditions upon the damage characteristics, weather data and roof tile temperatures were measured and logged in the winter season. Findings – The deterioration process was observed under the climatic conditions associated with the measured temperature of the roof tiles. In particular, it was revealed that the orientation has a significant influence on increasing or decreasing the risk of frost damage. For certain distinctive forms of damage, the deterioration mechanisms were estimated from the viewpoint of the moisture flow and temperature distribution in the tile. Originality/value – This study contributes to the elucidation of the mechanism behind frost damage to roof tiles. The findings will guide the construction of a numerical model for frost damage prediction.

Impact of future climates on the durability of typical residential wall assemblies retrofitted to the PassiveHaus for the Eastern Canada region

Attention to the global warming has influenced many aspects of human activities. Worldwide effort toward energy consumption reduction in building sector is one of the areas affected by climate change. Building regulations demand the building construction industry to be more energy efficient. Studies have been carried out on the thermal performance of energy efficient buildings under future climates, while studies on the durability of energy efficient building envelopes over future climates are limited. This study assesses the impact of future climates on the durability of typical Canadian residential wall assemblies retrofitted to the PassiveHaus over the current, 2020, 2050, and 2080 climatic conditions for Montreal. The durability performance is evaluated in terms of the frost damage risk of bricks and the biodegradation risk of plywood sheathing through simulations using WUFI Pro program. The future weather files are generated based on weather data recorded at the Montreal International Airport weather station using General Circulation Model HadCM3 based on the A2 emission scenario by the Intergovernmental Panel on Climate Change. This study concludes that upgrading wall assemblies to the PassiveHaus recommended level would increase the frost damage risk of bricks, however, this risk would decrease under 2080 climatic conditions. While the decay risk of the plywood sheathing would decrease, the mould growth risk defined by RHT criteria would increase over future climates. Under future climates, mould growth risks of the plywood defined by the mould growth index exist only when rain leakage is introduced and would likely decrease for the double-stud assembly.

Cold temperature extremes during spring do not limit the range shift of Mediterranean pines into regions with intermittent frost

Summary Bioclimatic envelope models have predicted latitudinal range shifts of tree species in Europe following climate change. Accordingly, Mediterranean species will be able to migrate northwards if climatic conditions become warmer and dryer. Frost, on the other hand, is an important and recurring factor in temperate and boreal regions causing damage to buds and leaves, and potentially limiting the survival of Mediterranean tree species or populations at higher latitudes. Since species distribution models rely on average climatic parameters, they may underestimate the risk of frost damage from low temperature extremes. We measured the cold hardiness of Pinus sylvestris, Pinus nigra and Pinus halepensis seedlings from a total of 11 European populations growing in a common garden in a cold Central Alpine valley on seven dates between February and July 2013. On each date, needles were artificially frozen at several temperatures and the temperature estimated at which 50% of the needle tissue is damaged (LT50; relative electrolyte leakage). Cold hardiness did not differ between populations of the same species and was not related to the minimum temperatures at the seed origin. In comparison with deciduous trees, Mediterranean P. sylvestris and P. nigra maintained extremely wide safety margins against frost throughout late winter and spring. By contrast, safety margins of P. halepensis were much narrower until March and winter cold hardiness was in the range of regularly recurring low temperature events in Central Europe. According to the measured LT50 values, the migration of a wide range of drought‐tolerant populations of P. sylvestris and P. nigra from the Mediterranean to Central and Western Europe is not limited by intermittent cold temperature extremes in spring. They are notably as well adapted to frost as populations from Central Alpine origin. Differences in dehardening patterns between species demonstrate the importance of analysing cold hardiness repeatedly during potentially sensitive periods in order to predict species range shifts in the context of climatic change.

Hygro Thermal Simulation to Predict the Risk of Frost Damage in Masonry; Effects of Climate Change

According to the Royal Netherlands Meteorological Institute (KNMI) climate change will result in an increase of air temperature and rainfall intensities for the Netherlands in winter in future. In this paper we investigate the effect of the risk of frost damage to masonry. The risk of frost damage to an external building envelope might become less due to the increase in air temperature. However, the risk of frost damage might rise as a construction may be wet for a longer time due to the increase in rainfall intensities. Research has been done on the following topics: (1) which material is sensitive to frost, (2) the conditions under which the material damage occurs, (3) the outside climate conditions (frost damage winters) and (4) the possibility to predicted frost damage with a multi-physical model. Simulations with a hygro thermal model of external building envelopes with the frost- sensitive material calcium silicate brick were able to reproduce so-called frost damage winters in the Netherlands. Using this model to predict future frost behavior indicate a significant reduction of the risk of frost damage in future.

Modeling climate change impact on potato crop phenology, and risk of frost damage and heat stress in northern Europe

Potato (Solanum tuberosum) is one of the main food crops in northern Europe, considered to be the fourth most important crop on a global scale after rice, wheat and maize. Climate change leading to longer growing seasons may call for adjustments in timing of planting and harvesting, and in this modeling study we assess potential effects of a warmer climate on potato crop phenology and temperature stress. A phenological potato model was parameterized with three planting dates to assess management impact on the timing of emergence and maturation of both early and late potato. Estimates on phenological development and occurrence of temperature stress were analyzed by comparing two developmental thresholds (0°C and +2°C) and three temperature response functions. The potato model was driven by observed gridded climate data and two sets of bias corrected climate model data, representing RCP4.5 and RCP8.5 for the period 1991–2100.The future simulations indicated that a warmer climate and earlier planting may move the timing of harvest up to 1 month earlier, however, potato emergence early in the year will be associated with an increased risk of frost damage in most parts of northern Europe. The areas of west Europe most prone to frost damage today may experience a risk of frost damage in response to climate change. The simulation of early potato development was sensitive to the setting of the developmental threshold, while late potato development was sensitive to the optimum temperature setting. While a linear temperature response function is essentially sufficient for current climate conditions in northern Europe, optimum and upper thresholds should be considered in climate change impact assessments. The potato model runs with temperature data corrected according to quantile-mapping indicated in general a slightly higher risk of temperature stress than the corresponding runs with temperature data corrected by linear scaling.

Habitat‐specific responses of shoot growth and distribution of alpine dwarf‐pine (Pinus pumila) to climate variation

AbstractAlpine dwarf‐pine (Pinus pumila) in dominant in the alpine regions of Japan, and often forms the krummholz zone of stunted alpine forest. The distribution of P. pumila is strongly related to the distribution of snow, and shoot growth is also sensitive to weather conditions. Changes in temperature and snowmelt regimes may well affect the distribution patterns of the krummholz zone. P. pumila usually occupies the habitat between the fellfield and snowbed communities, and responses to climate change may differ depending on whether plants are close to the fellfield or the snowbed. We compared the distribution and shoot growth patterns of P. pumila close to both surrounding ecosystems in the Taisetsu Mountains, northern Japan. P. pumila has expanded its distribution area by 14 % toward both edges over the last 32 years. Annual shoot growth was positively affected by summer temperature and sunshine duration, but negatively related to spring temperature toward the fellfield side. Shoot growth was greater at the southeastern edge of patches, where snowdrifts were formed. The results indicated that shoot growth and distribution area increased in warm summers. However, warm springs might have a negative influence on shoot growth, probably because the earlier reduction in cold‐resistance enhances the risk of frost damage in spring close to the fellfield side. This study suggests the importance of understanding the site‐specific responses of shrubs to predict the impacts of climate change on alpine ecosystems.

AGROCLIMATIC RISK ASSESSMENT BY SPRING FROST DAMAGE OF OVIDIOPOLSKYI AND LANKA GRAPE VARIETIES

Purpose. The aim is to assess the degree of risk of damage to the grapes of different varieties of spring frost using the developed model, the conditional probability of frost. Methodology. The initial information was compiled observations in the Odessa region in the thermal regime in the spring and autumn periods in five agrometeorological stations (Odessa, Bolhrad, Ishmael, Serb and Sarata) in wine-growing zone. Calculations were made for table varieties and wine grapes – Ovidiopolskii and Lanka. To determine the risk of frost damage to grapes used the method of conditional probabilities. Finding. Termination date of spring frosts observed much earlier onset dates vegetative phases of grapes, in some circumstances, freezing in the active layer can be up to very dangerous levels. Results. In the course of this work it was found that over the past decade, the timing of phenological phases grapes shifted to a later time. Such changes are observed both for dining and for wine grapes with varying degrees of ripening period. For the entire period of time periods offensive phase «Start Sap» and «bud» has shifted almost a decade. Nevertheless, despite the fact that according to the temperature in the meteorological hut (at 2 m) the risk of damage to grapes in the spring varies from 8 to 15% in the layer of air 50 cm from the soil surface can be observed risks of damage from 40 to 95 %.

Frost hardiness of tree species is independent of phenology and macroclimatic niche.

The differences in timing in bud burst between species have been interpreted as an adaptation to late frost events in spring. Thus, it has been suggested that the degree of frost susceptibility of leaves is species-specific and depends on the species' phenology and geographic distribution range. To test for relationships between frost tolerance and phenology as well as between frost tolerance and distribution range across Central European tree species, we studied the frost hardiness of closed buds before bud burst and of freshly opened buds at the time of bud burst. We hypothesized that species with early bud burst and species distributed in eastern and northern areas were more frost tolerant than species with late bud burst and species distributed in western and southern areas. Frost hardiness was estimated by exposing twigs to 11 frost temperatures between -4 °C and -80 °C and by assessing tissue damage by the electrolyte leakage method. In contrast to our hypotheses, neither frost hardiness of closed buds nor frost hardiness of freshly opened buds were related to any variable describing species' macroclimatic niche. Furthermore, frost hardiness of freshly opened buds did not differ among species. Thus, the investigated species with early bud burst take higher risks of frost damage than the species with late bud bursts. These findings indicate that frost hardiness might not play the key role in limiting the geographic distribution ranges previously anticipated.

Frost resistance in alpine woody plants.

This report provides a brief review of key findings related to frost resistance in alpine woody plant species, summarizes data on their frost resistance, highlights the importance of freeze avoidance mechanisms, and indicates areas of future research. Freezing temperatures are possible throughout the whole growing period in the alpine life zone. Frost severity, comprised of both intensity and duration, becomes greater with increasing elevation and, there is also a greater probability, that small statured woody plants, may be insulated by snow cover. Several frost survival mechanisms have evolved in woody alpine plants in response to these environmental conditions. Examples of tolerance to extracellular freezing and freeze dehydration, life cycles that allow species to escape frost, and freeze avoidance mechanisms can all be found. Despite their specific adaption to the alpine environment, frost damage can occur in spring, while all alpine woody plants have a low risk of frost damage in winter. Experimental evidence indicates that premature deacclimation in Pinus cembra in the spring, and a limited ability of many species of alpine woody shrubs to rapidly reacclimate when they lose snow cover, resulting in reduced levels of frost resistance in the spring, may be particularly critical under the projected changes in climate. In this review, frost resistance and specific frost survival mechanisms of different organs (leaves, stems, vegetative and reproductive over-wintering buds, flowers, and fruits) and tissues are compared. The seasonal dynamics of frost resistance of leaves of trees, as opposed to woody shrubs, is also discussed. The ability of some tissues and organs to avoid freezing by supercooling, as visualized by high resolution infrared thermography, are also provided. Collectively, the report provides a review of the complex and diverse ways that woody plants survive in the frost dominated environment of the alpine life zone.