# A collection of European sweet cherry phenology data for assessing climate change

Bénédicte Wenden, José Antonio Campoy, Julien Lecourt, Gregorio López Ortega, Michael Blanke, Sanja Radičević, Elisabeth Schüller, Andreas Spornberger, Danilo Christen, Hugo Magein, et al.

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Bénédicte Wenden, José Antonio Campoy, Julien Lecourt, Gregorio López Ortega, Michael Blanke, et al.. A collection of European sweet cherry phenology data for assessing climate change. Scientific Data, 2016, 3, pp.160108. 10.1038/sdata.2016.108. hal-02630975

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# Data Descriptor: A collection of European sweet cherry phenology data for assessing climate change

Bénédicte Wenden<fnref n="1" />, José Antonio Campoy<fnref n="1" />, Julien Lecourt², Gregorio López Ortega³, Michael Blanke⁴, Sanja Radičević⁵, Elisabeth Schüller⁶, Andreas Spornberger⁶, Danilo Christen⁷, Hugo Magein⁸, Daniela Giovannini⁹, Carlos Campillo¹⁰, Svetoslav Malchev¹¹, José Miguel Peris¹², Mekjell Meland¹³, Rolf Stehr¹⁴, Gérard Charlot¹⁵ & José Quero-García<fnref n="1" />

Received: 20 July 2016

Accepted: 18 October 2016

Published: 6 December 2016

Professional and scientific networks built around the production of sweet cherry (Prunus avium L.) led to the collection of phenology data for a wide range of cultivars grown in experimental sites characterized by highly contrasted climatic conditions. We present a dataset of flowering and maturity dates, recorded each year for one tree when available, or the average of several trees for each cultivar, over a period of 37 years (1978–2015). Such a dataset is extremely valuable for characterizing the phenological response to climate change, and the plasticity of the different cultivars’ behaviour under different environmental conditions. In addition, this dataset will support the development of predictive models for sweet cherry phenology exploitable at the continental scale, and will help anticipate breeding strategies in order to maintain and improve sweet cherry production in Europe.

<table><tr><td>Design Type(s)</td><td>observation design • data integration objective</td></tr><tr><td>Measurement Type(s)</td><td>phenology</td></tr><tr><td>Technology Type(s)</td><td>visual observation method</td></tr><tr><td>Factor Type(s)</td><td>selectively maintained organism</td></tr><tr><td>Sample Characteristic(s)</td><td>Prunus avium • French Republic • Germany • Serbia • Kingdom of Spain • Switzerland • United Kingdom • Italy • Belgium • Bulgaria • Kingdom of Norway • Austria</td></tr></table>

<footnote n="1">¹UMR 1332 BFP, INRA, Univ. Bordeaux, Villenave d'Ornon 33140, France. ²NIAB EMR, East Malling, ME19 6BJ, UK. ³IMIDA, Murcia Institute of Agri-Food Research and Development, Murcia 30150, Spain. ⁴INRES—Horticultural Science, University of Bonn, 53121 Bonn, Germany. ⁵Fruit Research Institute (FRI), Čačak 32000, Republic of Serbia. ⁶University of Natural Resources and Life Sciences, Vienna, Department of Crop Sciences, Division of Viticulture and Pomology, Vienna 1180, Austria. ⁷Agroscope Changins—Wädenswil Research Station ACW, 1964 Conthey, Switzerland. ⁸Walloon Agricultural Research Center (CRA-W), Gembloux 5030, Belgium. ⁹CREA, Council for Agricultural Research and Economics, Fruit Tree Research Unit of Forlì, Forlì 47121, Italy. ¹⁰Scientific and Technological Research Center of Extremadura (CICYTEX), Guadajira (Badajoz) 06187, Spain. ¹¹Fruit Growing Institute—Plovdiv, Plovdiv 4004, Bulgaria. ¹²IRTA, Experimental Station of Lleida, Lleida 25003, Spain. ¹³Norwegian Institute of Bioeconomy Research—NIBIO Ullensvang, Lofthus N-5781, Norway. ¹⁴Fruit Research Center Jork, Jork D-21635, Germany. ¹⁵Ctifl, 751 chemin de Balandran, Bellegarde 30127, France. Correspondence and requests for materials should be addressed to B.W. (email: benedicte.wenden@bordeaux.inra.fr).</footnote>
## Background & Summary

The impact of climate change on plant phenology has been described in recent decades, highlighting a hastening of flowering phenology in response to increasing winter and spring temperatures¹⁻⁷. Long records of flowering dates have been proven extremely valuable to reconstruct past phenology and to predict phenology under future climatic scenarios. In Japan for example, flowering dates of cherry trees (Prunus jamasakura) have been recorded for centuries and analyses of these records have revealed that cherry flowering is currently occurring earlier than at any time in the previous seven to 12 centuries, due to the impact of warming and urbanization on phenology⁵,⁸,⁹. This earlier flowering trend has been observed for other fruit trees¹⁰⁻¹⁴, which are particularly vulnerable to temperature changes due to their long life span. Peach (Prunus persica), apricot (Prunus armeniaca), almond (Prunus dulcis), plum (Prunus salicina and domestica) and sweet cherry (Prunus avium L.) are amongst the most commercially important Prunus fruit tree species planted in temperate climate zones. In Europe, cherry tree blossom of early maturing cultivars showed an advance up to 4.7 days/°C in Germany¹⁰,¹⁴, and warmer winters have dramatically affected the sweet cherry production in South-Western France, with a 30% yield in 2007. Warmer winters can as well be associated with delayed spring phenology for some species and, occasionally resulting in abnormal flowering phenology and reduced productivity¹⁵⁻¹⁸. Models for chill availability predict an increase in the delaying effect of mild winters as temperature increase becomes more pronounced⁶,¹⁹,²⁰, especially in warmer locations²¹. In the context of substantial changes to environmental conditions induced by climate change, it will be essential that plant cultivars are well adapted to warmer winter and spring temperatures and to more extreme climatic events such as erratic spring frosts and summer heat waves. This is especially true for perennial fruit crops, which require more than a decade before a new cultivar is released.

Large phenological datasets are key for the development of phenological models (e.g., refs 22–25), which are valuable tools to support breeding strategies. Although recent studies have shown the value of a wide range of data²⁶,²⁷, most analyses for fruit tree crops are based on phenological data for a very limited number of experimental sites, and rarely include more than two cultivars within a species (e.g., refs 28,29).

Sweet cherry trees are particularly interesting for phenology studies, their long orchard life providing the potential for long-term datasets. Reference cultivars have been planted and observed for decades for phenology and productivity traits in trials dedicated to new hybrids characterization. For example, at the Fruit Experimental Station (Toulenne, INRA Bordeaux, France), phenological data have been recorded for ‘Burlat’ cultivar for 35 years. Consequently, large phenological datasets are available for reference cultivars in many European orchards involved in breeding programmes. Despite this, long historical datasets of fruit tree phenology are rarely analysed together or made available to the scientific community. A few analyses on sweet cherry phenology in Europe were published using the phenological observations of fruit trees by the German Weather Service (DWD)¹⁰,¹², from non-publicly available datasets³⁰,³¹ or from the PEP725 data¹⁴. In addition, published studies often focus on specific location¹⁰,¹²,³⁰⁻³³.

In this study, we describe a unique dataset of sweet cherry flowering and maturity records for 25 sites in Europe (Fig. 1) with highly contrasted climates. Past studies showed that phenology data spanning

<figure><img src="image_2.png" /></figure>

**Figure 1.** Experimental orchards location. Flowering and maturity dates were recorded in 25 sites from 11 European countries, indicated by the red circles. Size of the circle is proportional to the number of cultivars recorded in each site.
<table><thead><tr><th>Country</th><th>Institute</th><th>Location</th><th>Altitude (m)</th><th>Lat</th><th>Long</th><th>Nb of cultivars</th><th>Years of observation</th><th>1980</th><th>1985</th><th>1990</th><th>1995</th><th>2000</th><th>2005</th><th>2010</th></tr></thead><tbody><tr><td>Germany</td><td>Bonn University</td><td>Bonn</td><td>180</td><td>50.62</td><td>6.98</td><td>1</td><td>1978 - 2015</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>United Kingdom</td><td>EMR</td><td>East Malling</td><td>38</td><td>51.28</td><td>0.45</td><td>4</td><td>1978 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Switzerland</td><td>Agroscope</td><td>Conthey</td><td>504</td><td>46.22</td><td>7.33</td><td>1</td><td>1979 - 2007</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>INRA</td><td>Toulenne</td><td>8</td><td>44.58</td><td>-0.28</td><td>191</td><td>1981 - 2015</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Austria</td><td>BOKU</td><td>Vienna</td><td>162</td><td>48.29</td><td>16.43</td><td>8</td><td>1982 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>CTIFL</td><td>Balandran</td><td>52</td><td>43.76</td><td>4.46</td><td>170</td><td>1982 - 2015</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Sefra</td><td>Etoile</td><td>134</td><td>44.82</td><td>4.89</td><td>154</td><td>1985 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Belgium</td><td>CRA-W</td><td>Gembloux</td><td>170</td><td>50.55</td><td>4.66</td><td>1</td><td>1989 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Italy</td><td>CREA-FRF</td><td>Forli</td><td>34</td><td>44.22</td><td>12.02</td><td>3</td><td>1991 - 2015</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Serbia</td><td>FRI</td><td>Čačak</td><td>260</td><td>43.88</td><td>20.35</td><td>16</td><td>1992 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Germany</td><td>OVA</td><td>Jork</td><td>-1</td><td>53.51</td><td>9.74</td><td>79</td><td>1993 - 2011</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>La Tapy</td><td>Carpentras</td><td>84</td><td>44.09</td><td>5.05</td><td>57</td><td>1994 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Norway</td><td>NIBIO</td><td>Ullensvang</td><td>27</td><td>60.32</td><td>6.66</td><td>10</td><td>1995 - 1998</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Spain</td><td>IRTA</td><td>Corbins</td><td>233</td><td>41.70</td><td>0.69</td><td>16</td><td>1996 - 2006</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Serfel</td><td>St Gilles</td><td>38</td><td>43.69</td><td>4.43</td><td>37</td><td>2004 - 2013</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Verexal</td><td>Obernai</td><td>179</td><td>48.47</td><td>7.51</td><td>21</td><td>2006 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Spain</td><td>IMIDA</td><td>Cieza</td><td>244</td><td>38.29</td><td>-1.5</td><td>3</td><td>2006 - 2010</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Bulgaria</td><td>Fruitgrowing Institute</td><td>Plovdiv</td><td>130</td><td>42.11</td><td>24.7</td><td>8</td><td>2006 - 2011</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Sefra</td><td>Bozas</td><td>536</td><td>45.06</td><td>4.65</td><td>24</td><td>2007 - 2011</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>La Morinière</td><td>St Epain</td><td>95</td><td>47.16</td><td>0.60</td><td>25</td><td>2007 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Sefra</td><td>St Laurent d'Agny</td><td>388</td><td>45.63</td><td>4.68</td><td>37</td><td>2007 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Cefel</td><td>Montauban</td><td>90</td><td>44.04</td><td>1.31</td><td>29</td><td>2004 - 2012</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>France</td><td>Centrex</td><td>Torreilles</td><td>10</td><td>42.76</td><td>2.98</td><td>20</td><td>2008 - 2014</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Spain</td><td>CAEM</td><td>El Torno</td><td>463</td><td>40.14</td><td>-5.95</td><td>2</td><td>1994, 2010 - 2013</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Spain</td><td>IMIDA</td><td>Jumilla</td><td>395</td><td>38.04</td><td>-1.98</td><td>36</td><td>2010 - 2015</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>

Beginning of flowering (■) – Full flowering (■) – End of flowering (■) – Maturity (■)

<caption>**Figure 2.** Description of data source, time-span, number of observed cultivars, and location within Europe.</caption>

20 or 30 years were valuable for climate change related analyses$^{7,34}$. Thus the dataset presented here, with an overall 37 year-period (1978–2015, Fig. 2) will be valuable for phenology and climate change studies. This dataset covers a wide range of European latitudes and longitudes and is unique in its collection of cultivars (between 1 and 191 cultivars per site), each cultivar being represented by clones of the same original tree in each country, which supports robust analyses of plasticity and response to climatic conditions.

Since data were collected from various experimental stations, the dataset is not homogeneous regarding the number of cultivars (Figs 1 and 2, Table 1) or the record length (Fig. 2). Past research have shown the value of using heterogeneous records combined from different sites and cultivars for the evaluation of climate change response and phenology modelling approaches (e.g., refs 21,35–38). In particular, phenology models have been successfully tested and optimized using data sourced from different sites$^{27,38}$. Therefore, we want to highlight the value of this dataset, combining data from various geographical sites and contrasted cultivars, for potential multi-environment analyses yet to be implemented. 13 out of 25 sites meet the criteria of more than 15 recorded years that was shown to be useful for climate change analysis$^{7}$ (Fig. 3; Table 1). Single site analyses can thus be applied to track phenological climate shifts in a given environment. Subsequently, phenology models can be further evaluated by pooling data across geographically and climatically varied sites, leading to a better
<table><caption>**Table 1.** Overall description of the data records.</caption><thead><tr><th rowspan="2">Site</th><th rowspan="2">Number of observed cultivars</th><th colspan="5">Number of data points</th></tr><tr><th>Beginning of flowering</th><th>Full flowering</th><th>End of flowering</th><th>Maturity</th><th>Total</th></tr></thead><tbody><tr><td>Balandran</td><td>170</td><td>2530</td><td>2714</td><td>2192</td><td>2555</td><td>9991</td></tr><tr><td>Bonn</td><td>1</td><td>30</td><td>6</td><td></td><td></td><td>36</td></tr><tr><td>Bozas</td><td>24</td><td>72</td><td>100</td><td>87</td><td>32</td><td>291</td></tr><tr><td>Čačak</td><td>16</td><td>338</td><td>336</td><td>286</td><td>49</td><td>1009</td></tr><tr><td>Carpentras</td><td>57</td><td></td><td>552</td><td>8</td><td>282</td><td>842</td></tr><tr><td>Cieza</td><td>3</td><td>15</td><td>15</td><td>15</td><td></td><td>45</td></tr><tr><td>Conthey</td><td>1</td><td></td><td>29</td><td></td><td></td><td>29</td></tr><tr><td>Corbins</td><td>16</td><td>157</td><td>156</td><td>147</td><td>10</td><td>470</td></tr><tr><td>East Malling</td><td>4</td><td>167</td><td>167</td><td>167</td><td></td><td>501</td></tr><tr><td>El Torno</td><td>2</td><td>10</td><td>10</td><td>9</td><td>10</td><td>39</td></tr><tr><td>Etoile</td><td>154</td><td>1675</td><td>1686</td><td>1409</td><td>1229</td><td>5999</td></tr><tr><td>Forli</td><td>3</td><td>38</td><td>38</td><td>31</td><td>7</td><td>114</td></tr><tr><td>Gembloux</td><td>1</td><td>27</td><td>27</td><td>27</td><td>22</td><td>103</td></tr><tr><td>Jork</td><td>79</td><td>685</td><td>685</td><td>682</td><td></td><td>2052</td></tr><tr><td>Jumilla</td><td>36</td><td>234</td><td>234</td><td>205</td><td>234</td><td>907</td></tr><tr><td>Montauban</td><td>29</td><td>9</td><td>79</td><td></td><td></td><td>88</td></tr><tr><td>Obernai</td><td>21</td><td></td><td>154</td><td></td><td>95</td><td>249</td></tr><tr><td>Plovdiv</td><td>8</td><td>45</td><td>45</td><td>23</td><td>14</td><td>127</td></tr><tr><td>St Epain</td><td>25</td><td></td><td>221</td><td></td><td>216</td><td>437</td></tr><tr><td>St Gilles</td><td>37</td><td>325</td><td>401</td><td>2</td><td>255</td><td>983</td></tr><tr><td>St Laurent d'Agny</td><td>37</td><td>67</td><td>236</td><td>53</td><td>9</td><td>365</td></tr><tr><td>Torreilles</td><td>20</td><td>128</td><td>128</td><td>85</td><td>121</td><td>462</td></tr><tr><td>Toulenne</td><td>191</td><td>4218</td><td>3518</td><td>3603</td><td>3476</td><td>14815</td></tr><tr><td>Ullensvang</td><td>10</td><td>231</td><td>29</td><td>23</td><td></td><td>283</td></tr><tr><td>Vienna</td><td>8</td><td>153</td><td>147</td><td>146</td><td>42</td><td>488</td></tr></tbody></table>

<figure><img src="image_3.png" /><figcaption>**Figure 3.** Information on the number of observed cultivars and the overall record length for each site.</figcaption></figure>

Some site names were omitted for ease the comprehension. The numbers between brackets indicate the number of cultivars with more than 15 years of observation. The dash line indicate the 15 years limit for the record length, criteria mentioned in (Fu *et al.* 7) as sufficient to perform climate change response analysis.
<table><thead><tr><th>BBCH code</th><th>Description</th><th></th></tr></thead><tbody><tr><td>60</td><td>First flowers open</td><td></td></tr><tr><td>61</td><td>Beginning of flowering: about 10% of flowers open</td><td></td></tr><tr><td>65</td><td>Full flowering: at least 50% of flowers open, first petals falling</td><td></td></tr><tr><td>67</td><td>Flowers fading: majority of petals fallen</td><td></td></tr><tr><td>69</td><td>End of flowering: all petals fallen</td><td></td></tr><tr><td>87</td><td>Fruit ripe for picking</td><td></td></tr><tr><td>89</td><td>Fruit ripe for consumption: fruit have typical taste and firmness</td><td></td></tr></tbody></table>

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /></figure>

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /><figcaption>**Figure 4.** BBCH descriptors (Meier<sup>40</sup>) corresponding to the flowering and maturity stages observed in the dataset. Pictures @INRA.</figcaption></figure>

knowledge of climate-phenology relations. Extreme European climate, e.g., South of Spain, can be used to investigate climate analogues for projected climatic scenarios<sup>39</sup>. In addition, for eight sites, two or more cultivars were observed for at least 15 years (Fig. 3). Between cultivar differences can be assessed at a single site and across sites with common cultivars. These analyses can reveal whether some cultivars are more susceptible to evolution in climatic conditions. The dataset offers the possibility to study different flowering phase data, namely beginning, full and end of flowering, together with maturity dates for some cultivars (Table 1), and to perform sequential phenology phase assessments.

Overall, despite the fact that they are heterogeneous, data from the different sites can be combined in integrated analysis to study their responses to environment. Such dataset is extremely valuable for characterizing the phenology response to climate change and the plasticity of the different cultivar behaviour under various environmental conditions. In addition, these records can support the development of predictive models exploitable at the continental scale that can be used by growers and breeders, and to anticipate breeding strategies in order to maintain and improve sweet cherry production in Europe.

## Methods

Sweet cherry phenological data were collated from French and European networks. Established in 1952, CTIFL is a non-profit organization involved in the French fruit and vegetable industry. It developed a private database dedicated to information on cultivars planted in experimental orchards. Flowering and maturity dates for up to 191 reference cultivars grown in French experimental stations were extracted from the database. At the European scale, in the context of the COST Action 1104 (2012–2016; https://www.bordeaux.inra.fr/cherry/), which aimed at creating a dynamic network of scientists and other professionals conducting research to improve sweet or sour cherry production in Europe, we established a working group (WG) for phenology studies. Flowering and maturity dates together with the protocol details for the observations were collected. Although a standardisation of the recorded stages is on-going within the group, past observation standards for the different flowering stages are not homogeneous and
<table><caption>**Table 2.** Stages recorded in the experimental sites, when available, associated with the corresponding BBCH stage.</caption><thead><tr><th>Country</th><th>Location</th><th colspan="2">Beginning of flowering</th><th colspan="2">Full flowering</th><th>End of flowering</th><th colspan="2">Maturity</th></tr></thead><tbody><tr><td>Belgium</td><td>Gembloux</td><td>10% open flowers</td><td>BBCH 61</td><td>50% open flowers</td><td>BBCH 65</td><td>petal fall</td><td>BBCH 67</td><td>ripe fruits, harvest</td><td>BBCH 89</td></tr><tr><td>Bulgaria</td><td>Plovdiv</td><td>5% open flowers</td><td>BBCH 61</td><td>25-75% open flowers</td><td>BBCH 65</td><td>Petal falls for 75% of flowers</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>France</td><td>All experimental sites</td><td>10% open flowers</td><td>BBCH 61</td><td>80% open flowers</td><td>BBCH 65</td><td>10-20% petal fall</td><td>BBCH 67</td><td>30% ripe fruits (color, taste)</td><td>BBCH 89</td></tr><tr><td>Germany</td><td>Bonn</td><td>5-10% open flowers</td><td>BBCH 61</td><td>50-75% open flowers to beginning of petal fall</td><td>BBCH 65</td><td></td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Germany</td><td>Jork</td><td>1% open flowers</td><td>BBCH 60</td><td>80% open flowers</td><td>BBCH 65</td><td>Petal falls for 90% of flowers</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Italy</td><td>Forlì</td><td>5-10% open flowers</td><td>BBCH 61</td><td>80% open flowers</td><td>BBCH 65</td><td>No more pollen is shed by the open flowers</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Norway</td><td>Ullensvang</td><td>1% open flowers</td><td>BBCH 60</td><td></td><td>BBCH 65</td><td></td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Serbia</td><td>Čačak</td><td>10-20% open flowers</td><td>BBCH 61</td><td>90-100% open flowers</td><td>BBCH 65</td><td>90% petal fall</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Spain</td><td>Cieza</td><td>5-10% open flowers</td><td>BBCH 61</td><td>50-75% open flowers to beginning of petal fall</td><td>BBCH 65</td><td>75% open flower to the most petals have fallen</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Spain</td><td>Jumilla</td><td>5-10% open flowers</td><td>BBCH 61</td><td>50-75% open flowers to beginning of petal fall</td><td>BBCH 65</td><td>75% open flower to the most petals have fallen</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Spain</td><td>Lleida</td><td>1% open flowers</td><td>BBCH 60</td><td>80% open flowers</td><td>BBCH 65</td><td>100% open flowers</td><td>BBCH 67</td><td></td><td></td></tr><tr><td>Switzerland</td><td>Changins</td><td></td><td></td><td>80% open flowers</td><td>BBCH 65</td><td></td><td></td><td></td><td></td></tr><tr><td>United Kingdom</td><td>East Malling</td><td>1% open flowers</td><td>BBCH 60</td><td>50% open flowers</td><td>BBCH 65</td><td>90% petal fall</td><td>BBCH 67</td><td></td><td></td></tr></tbody></table>

<table><caption>**Table 3.** Metadata.</caption><thead><tr><th>Header</th><th>Description</th></tr></thead><tbody><tr><td>Country</td><td></td></tr><tr><td>Institute</td><td>Research or experimental institute attached to the experimental station</td></tr><tr><td>Station</td><td>Name of station</td></tr><tr><td>Latitude</td><td>Latitude in decimal degrees</td></tr><tr><td>Longitude</td><td>Longitude in decimal degrees</td></tr><tr><td>Altitude</td><td>Altitude in meters</td></tr><tr><td>Plantation</td><td>Year of plantation of the tree</td></tr><tr><td>Year</td><td>Year of observation</td></tr><tr><td>Cultivar</td><td>Registered name of the cultivar</td></tr><tr><td>Clone</td><td>Number of clone</td></tr><tr><td>Rootstock</td><td>Name of the rootstock</td></tr><tr><td>Beginning of flowering (date)</td><td>Date observed for the BBCH stage corresponding to beginning of flowering</td></tr><tr><td>Full flowering (date)</td><td>Date observed for the BBCH stage corresponding to full flowering</td></tr><tr><td>End of flowering (date)</td><td>Date observed for the BBCH stage corresponding to end of flowering</td></tr><tr><td>Beginning of maturity (date)</td><td>Date observed for the BBCH stage corresponding to maturity</td></tr><tr><td>Beginning of flowering</td><td>Number of days in year [1-365/366] for the BBCH stage corresponding to beginning of flowering</td></tr><tr><td>Full flowering</td><td>Number of days in year [1-365/366] for the BBCH stage corresponding to full flowering</td></tr><tr><td>End of flowering</td><td>Number of days in year [1-365/366] for the BBCH stage corresponding to end of flowering</td></tr><tr><td>Beginning of maturity</td><td>Number of days in year [1-365/366] for the BBCH stage corresponding to maturity</td></tr><tr><td>Flowering duration</td><td>Number of days between beginning and end of flowering</td></tr></tbody></table>
<table><caption>**Table 4. Consistency of data between sites.** Spearman correlation and average date for beginning of flowering (BBCH 61) were calculated for cultivars grown in the different sites.</caption><thead><tr><th>Compared sites</th><th></th><th>Distance (km)</th><th>Cultivar</th><th>Number of common years</th><th>Spearman correlation</th><th>Average date for beginning of flowering</th></tr></thead><tbody><tr><td>Balandran</td><td>Etoile</td><td>123</td><td>Burlat</td><td>22</td><td>0.93</td><td>89</td></tr><tr><td>Balandran</td><td>Etoile</td><td>123</td><td>Ferdouce</td><td>15</td><td>0.67</td><td>82</td></tr><tr><td>Balandran</td><td>Etoile</td><td>123</td><td>Summit</td><td>26</td><td>0.84</td><td>93</td></tr><tr><td>Balandran</td><td>Etoile</td><td>123</td><td>Sweetheart Sumtare</td><td>21</td><td>0.87</td><td>85</td></tr><tr><td>Gembloux</td><td>Bonn</td><td>164</td><td>Burlat</td><td>20</td><td>0.85</td><td>104</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Arcina Fercer</td><td>18</td><td>0.95</td><td>87</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Burlat</td><td>24</td><td>0.88</td><td>87</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Coralise Gardel</td><td>15</td><td>0.57</td><td>81</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Duroni 3</td><td>15</td><td>0.77</td><td>94</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Earlise Rivedel</td><td>19</td><td>0.76</td><td>81</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Ferdouce</td><td>17</td><td>0.88</td><td>80</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Ferobri</td><td>18</td><td>0.84</td><td>85</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Fertard</td><td>16</td><td>0.68</td><td>92</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Folfer</td><td>16</td><td>0.93</td><td>81</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Hedelfingen</td><td>21</td><td>0.88</td><td>90</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Kordia</td><td>17</td><td>0.72</td><td>88</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Lapins</td><td>20</td><td>0.78</td><td>84</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Napoleon</td><td>18</td><td>0.90</td><td>87</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Rainier</td><td>27</td><td>0.88</td><td>85</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Regina</td><td>17</td><td>0.79</td><td>92</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Stark Hardy Giant</td><td>24</td><td>0.90</td><td>85</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Summit</td><td>29</td><td>0.84</td><td>93</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Sweetheart Sumtare</td><td>19</td><td>0.87</td><td>85</td></tr><tr><td>Balandran</td><td>Toulenne</td><td>390</td><td>Van</td><td>17</td><td>0.90</td><td>83</td></tr><tr><td>Toulenne</td><td>Etoile</td><td>411</td><td>Burlat</td><td>28</td><td>0.93</td><td>89</td></tr><tr><td>Toulenne</td><td>Etoile</td><td>411</td><td>Duroni 3</td><td>16</td><td>0.87</td><td>96</td></tr><tr><td>Toulenne</td><td>Etoile</td><td>411</td><td>Summit</td><td>26</td><td>0.91</td><td>93</td></tr><tr><td>Toulenne</td><td>Etoile</td><td>411</td><td>Sweetheart Sumtare</td><td>15</td><td>0.86</td><td>85</td></tr></tbody></table>

are described in Fig. 4 and Table 2. They correspond to a percentage of open flowers or fallen petals. Since the development of the BBCH scale (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie), this standard has been applied as a coding system for the characterization of the entire developmental cycle of annual and perennials plants<sup>40,41</sup>. Here, where possible, we associated the recorded stages, as defined in each experimental location for observations, with the corresponding BBCH stage (Table 2). In every location, one or two observers were in charge of recording the phenology dates. At the end of the season, records were added to the dataset. We calculated the length of the flowering season, which is the number of days between beginning and end of flowering, where these dates were available.

## Data Records

Flowering and maturity dates from all sites can be found in the dataset file stored in the Dryad Digital Repository (Data Citation 1). The spread sheet consists of a table with the description of all phenological data (Table 3). The experimental sites are described by name, latitude, longitude and altitude. Each row corresponds to the dates (beginning of flowering, full flowering, end of flowering, beginning of maturity) documented each year for one tree when available, or the average of several trees for each cultivar. For registration reasons, one cultivar can be registered and observed under different clone numbers, ranging from 1 to 7 clone accession numbers, so the clone number was indicated when available. The cultivar name was always indicated and when available the rootstock information was provided. Dates recorded were also provided as day of year (starting with 1 for January 1st) and the duration of flowering was calculated (days).

## Technical Validation

All data were checked for consistency and anomalous values were corrected or removed (Supplementary Table 1). Some old cultivars, that can be found in many countries, have names that differ slightly between
<figure><img src="image_11.png" /></figure>

**Figure 5.** Comparison of flowering dates in days (from 1st of January) for 6 cultivars from our dataset and, unless otherwise stated, for BBCH60 stage for the 'Early cultivar' and 'Late cultivar' collected from PEP725 (http://www.pep725.eu) for stations geographically close to our experimental sites. For the Bonn site, PEP725 data were obtained from the station 1360, located in Zülpich (Germany; longitude: 6.67; latitude: 50.68; distance from Bonn: 23 km). Gembloux data were compared to flowering dates from the station 1498, located in Übach-Palenberg (Germany, longitude: 6.12; latitude: 50.92; distance: 110 km). For Jork, PEP725 data were obtained from the station 346, located in Hamburg-Altengamme (Germany; longitude: 10.28; latitude: 53.43; distance: 37 km). Conthey data were compared to full flowering (BBCH stage 65) dates from station 3260 (Müllheim, Germany; longitude: 7.63; latitude: 47.82, distance: 178 km). Spearman's correlation coefficient was calculated for each site between our data and corresponding PEP725 data.

the sites so we arbitrarily chose one common name: 'Badacsony' was selected as the common name for 'Badacsony', 'Badacsoner' and 'Badacsonyi'; 'Francesca' and 'Francescca' were regrouped as 'Francesca'. In total, 51 records were corrected (Supplementary Table 1).

For records of more than 15 years, we checked the consistency of collected data between sites. This cross-checking showed data for a given cultivar were highly correlated, even for sites as far as 400 km from each other (Table 4), confirming that the collected data are consistent. In addition, when possible, we chose to compare our data to similar phenological observational records from the European phenology database PEP725 (http://www.pep725.eu). Data for 'early cultivar' and 'late cultivar' were retrieved from the database and correlated with close-by sites when at least 15 common years of data were available. We identified PEP stations located within a range of 200 km for Bonn, Conthey, Gembloux and
Jork. Strong correlations and minimal differences were found between our data and the flowering dates recorded and validated in PEP725 (Fig. 5). Flowering dates records for six cultivars met the criteria of 15 year-records and the Spearman correlations were all higher than 0.76, regardless of the flowering precocity of the cultivar or the site (Fig. 5).

## Usage Notes

The sweet cherry phenology dataset was collected with the objective to support climate change and phenological analyses for varied European environments. These data can be associated with other *Prunus avium* flowering data provided by the European phenology database PEP725 (http://www.pep725.eu) to perform a wide evaluation of phenology in early and late cultivars.

## References

1. Chmielewski, F.-M. & Rötzer, T. Response of tree phenology to climate change across Europe. *Agric. For. Meteorol.* **108**, 101–112 (2001).

2. Cook, B. I. et al. Sensitivity of Spring Phenology to Warming Across Temporal and Spatial Climate Gradients in Two Independent Databases. *Ecosystems* **15**, 1283–1294 (2012).

3. Gordo, O. & Sanz, J. J. Phenology and climate change: a long-term study in a Mediterranean locality. *Oecologia* **146**, 484–495 (2005).

4. Menzel, A. et al. European phenological response to climate change matches the warming pattern. *Glob. Chang. Biol.* **12**, 1969–1976 (2006).

5. Primack, R. B., Higuchi, H. & Miller-Rushing, A. J. The impact of climate change on cherry trees and other species in Japan. *Biol. Conserv.* **142**, 1943–1949 (2009).

6. Vitasse, Y. et al. Assessing the effects of climate change on the phenology of European temperate trees. *Agric. For. Meteorol.* **151**, 969–980 (2011).

7. Fu, Y. H. et al. Declining global warming effects on the phenology of spring leaf unfolding. *Nature* **526**, 104–107 (2015).

8. Aono, Y. & Omoto, Y. Variation in the March mean temperature deduced from cherry blossom in Kyoto since the 14th century. *J. Agr. Met.* **48**, 635–638 (1993).

9. Aono, Y. & Kazui, K. Phenological data series of cherry tree flowering in Kyoto, Japan, and its application to reconstruction of springtime temperatures since the 9th century. *Int. J. Biometeorol.* **28**, 905–914 (2008).

10. Chmielewski, F.-M., Müller, A. & Bruns, E. Climate changes and trends in phenology of fruit trees and field crops in Germany, 1961–2000. *Agric. For. Meteorol.* **121**, 69–78 (2004).

11. Dose, V. & Menzel, A. Bayesian analysis of climate change impacts in phenology. *Glob. Chang. Biol.* **10**, 259–272 (2004).

12. Estrella, N., Sparks, T. H. & Menzel, A. Trends and temperature response in the phenology of crops in Germany. *Glob. Chang. Biol.* **13**, 1737–1747 (2007).

13. Legave, J.-M., Guédon, Y., Malagi, G., El Yaacoubi, A. & Bonhomme, M. Differentiated Responses of Apple Tree Floral Phenology to Global Warming in Contrasting Climatic Regions. *Front. Plant Sci.* **6**, 1054 (2015).

14. Jochner, S., Sparks, T. H., Laube, J. & Menzel, A. Can we detect a nonlinear response to temperature in European plant phenology? *Int. J. Biometeorol.* **60**, 1551–1561 (2016).

15. Doi, H., Gordo, O. & Katano, I. Heterogeneous intra-annual climatic changes drive different phenological responses at two trophic levels. *Clim. Res.* **36**, 181–190 (2008).

16. Yu, H., Luedeling, E. & Xu, J. Winter and spring warming result in delayed spring phenology on the Tibetan Plateau. *Proc. Natl Acad Sci.* **107**, 22151–22156 (2010).

17. Sherry, R. A. et al. Divergence of reproductive phenology under climate warming. *Proc. Natl. Acad. Sci. USA* **104**, 198–202 (2007).

18. Cook, B. I., Wolkovich, E. M. & Parmesan, C. Divergent responses to spring and winter warming drive community level flowering trends. *Proc. Natl. Acad. Sci. USA* **109**, 9000–9005 (2012).

19. Luedeling, E. Climate change impacts on winter chill for temperate fruit and nut production: A review. *Sci. Hortic.* **144**, 218–229 (2012).

20. Pope, K. S. et al. Detecting nonlinear response of spring phenology to climate change by Bayesian analysis. *Glob. Chang. Biol.* **19**, 1518–1525 (2013).

21. Guo, L., Dai, J., Wang, M., Xu, J. & Luedeling, E. Responses of spring phenology in temperate zone trees to climate warming: A case study of apricot flowering in China. *Agric. For. Meteorol.* **201**, 1–7 (2015).

22. Chung, U., Mack, L., Yun, J. I. & Kim, S. H. Predicting the timing of cherry blossoms in Washington, DC and Mid-Atlantic States in response to climate change. *PLoS ONE* **6**, e27439 (2011).

23. Ruml, M., Milatovic, D., Vulic, T. & Vukovic, A. Predicting apricot phenology using meteorological data. *Int. J. Biometeorol.* **55**, 723–732 (2011).

24. Legave, J. M. et al. A comprehensive overview of the spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe. *Int. J. Biometeorol.* **57**, 317–331 (2013).

25. Kalväns, A., Bitäne, M. & Kalväne, G. Forecasting plant phenology: evaluating the phenological models for Betula pendula and Padus racemosa spring phases, Latvia. *Int. J. Biometeorol.* **59**, 165–179 (2015).

26. Legave, J. M. et al. A comprehensive overview of the spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe. *Int. J. Biometeorol.* **57**, 333–335 (2013).

27. Andreini, L. et al. Understanding dormancy release in apricot flower buds (Prunus armeniaca L.) using several process-based phenological models. *Agric. For. Meteorol.* **184**, 210–219 (2014).

28. Luedeling, E., Zhang, M., McGranahan, G. & Leslie, C. Validation of winter chill models using historic records of walnut phenology. *Agric. For. Meteorol.* **149**, 1854–1864 (2009).

29. Matzneller, P., Blümel, K. & Chmielewski, F.-M. Models for the beginning of sour cherry blossom. *Int. J. Biometeorol.* **58**, 703–715 (2014).

30. de Vries, P. Phenological stages in sweet cherry with regard to pre-selection. *Euphytica* **16**, 177–182 (1967).

31. Luedeling, E., Kunz, A. & Blanke, M. M. Identification of chilling and heat requirements of cherry trees-a statistical approach. *Int. J. Biometeorol.* **57**, 679–689 (2013).

32. Gratacós, E. & Cortés, A. Phenology and production of sweet cherry cultivars in a low chilling area of central Chile. *Acta. Hortic.* **795**, 239–244 (2008).

33. Alburquerque, N., García-Montiel, F., Carrillo, A. & Burgos, L. Chilling and heat requirements of sweet cherry cultivars and the relationship between altitude and the probability of satisfying the chill requirements. *Environ. Exp. Bot.* **64**, 162–170 (2008).

34. Sparks, T. H. & Menzel, A. Observed changes in seasons: An overview. *Int. J. Climatol.* **22**, 1715–1725 (2002).

35. Webb, L. B. et al. Earlier wine-grape ripening driven by climatic warming and drying and management practices. *Nat. Clim. Chang* **2**, 259–264 (2012).
36. Fu, Y. H., Campioli, M., Van Oijen, M., Deckmyn, G. & Janssens, I. a. Bayesian comparison of six different temperature-based budburst models for four temperate tree species. *Ecol. Modell* **230**, 92–100 (2012).

37. Pope, K. S., Dose, V., Da Silva, D., Brown, P. H. & DeJong, T. M. Nut crop yield records show that budbreak-based chilling requirements may not reflect yield decline chill thresholds. *Int. J. Biometeorol.* **59**, 707–715 (2014).

38. Darbyshire, R., Pope, K. & Goodwin, I. An evaluation of the chill overlap model to predict flowering time in apple tree. *Sci. Hortic* **198**, 142–149 (2016).

39. Webb, L. B., Watterson, I., Bhend, J., Whetton, P. H. & Barlow, E. W. R. Global climate analogues for winegrowing regions in future periods: Projections of temperature and precipitation. *Aust. J. Grape Wine Res.* **19**, 331–341 (2013).

40. Meier, U. *Growth stages of mono-and dicotyledonous plants BBCH Monograph. Federal Biological Research Centre for Agriculture and Forestry* (2001).

41. Fadón, E., Herrero, M. & Rodrigo, J. Flower development in sweet cherry framed in the BBCH scale. *Sci. Hortic.* **192**, 141–147 (2015).

## Data Citation

1. Wenden, B. et al. Dryad Digital Repository http://dx.doi.org/10.5061/dryad.1d28m (2016).

## Acknowledgements

The authors would like to thank the EU COST FA1104 action for enabling interaction and data sharing between sweet cherry collaborators. We warmly thank Dr Rebecca Darbyshire for her remarks and suggestions on the manuscript. The authors are grateful to the organisations that contributed to the French data (Koala database, administrated by Ctifl): Ctifl (Balandran), Sefra (Bozas, Etoile, Saint Laurent d'Agny), Serfel (Saint Gilles), Centrex (Torreilles), Cefel (Montauban), Verexal (Obernai), La Morinière (Saint Epain), La Tapy (Carpentras), Fruit Experimental Unit (INRA Bordeaux, Toulenne). Data from the Republic of Serbia were obtained within the scope of the Research Project TR-31064, supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia. We thank INRA, Aquitaine Region and CEP Innovation (AQUIPRU project 2014-1R20102-2971) for financing postdoctoral fellowship to JAC. The authors would like to thank NIAB EMR technical team who collected the data for decades, and more recently Mike Davies, Clare Hobson, Carlos Angulo Costa and Helen Longbottom.

## Author Contributions

B.W. collected, checked the data, performed the technical validation and wrote the paper. J.A.C. and J.L. contributed to the technical validation and corrected the paper. J.L., G.L.O., M.B., S.R., E.S., A.S., D.C., H.M., D.G., C.C., S.M., J.M.P., M.M., R.S. and G.C. provided data. J.Q.G. organized the phenology network and provided data.

## Additional Information

Supplementary Information accompanies this paper at http://www.nature.com/sdata

**Competing financial interests:** The authors declare no competing financial interests.

**How to cite this article:** Wenden, B. et al. A collection of European sweet cherry phenology data for assessing climate change. *Sci. Data* 3:160108 doi: 10.1038/sdata.2016.108 (2016).

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<figure><img src="image_12.png" /></figure>

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