Predicting the date of leaf emergence for sugar maple across its native range

Abstract

A combined winter chilling and spring warming model is presented for predicting the date for the onset of foliation of sugar maple (Acer saccharum Marsh.) trees. The model is calibrated using both local data obtained in two sugar maple stands during two consecutive years with contrasting foliation dates and data obtained from the literature and chosen to span the full range of sugar maple distribution. Despite the disparity of the data used, more than 84% of the variation for the observed foliation date is explained by the model. Forty-one days separate the earliest and the latest foliation dates, and on average, the predicted date is within an interval of ±1.5 days of the observed date. Unusual events like exceptionally cool or warm springs are also well represented by the model. The counts for chilling days and degree-days are both started on December 1, but choosing any other date between November 1 and April 1 would yield nearly as good a fit to the foliation data. Temperature thresholds for chilling days and degree-days are both set at 10°C. Although this temperature gives the best fit to the foliation data, any temperature down to about 3°C would give good results as long as both threshold temperatures are the same.Résumé : Un modèle combinant le temps d'exposition au froid et la somme de degrés-jours est proposé pour prédire la date d'initiation de la feuillaison de l'érable à sucre (Acer saccharum Marsh.). Le modèle est calibré à l'aide de données recueillies dans deux érablières pendant deux années contrastées quant à la date de feuillaison, ainsi qu'à l'aide de données colligées dans la littérature et choisies pour couvrir l'ensemble du domaine de distribution de l'érable à sucre. Malgré la disparité des observations, plus de 84 % de la variabilité de la date de feuillaison est expliquée par le modèle. Quarante et un jours séparent la date de feuillaison la plus hâtive de la plus tardive et la date observée se situe en moyenne dans un intervalle de 1,5 jours autour de la date prédite. Des évènements exceptionnels comme des printemps particulièrement chauds ou froids sont bien pris en compte. Le comptage du nombre de jours d'exposition au froid et la sommation des degrés-jours sont débutés le 1 er décembre, mais le choix d'une autre date entre le 1 er novembre et le 1 er avril fournit approximativement la même qualité d'ajustement aux observations. Les seuils de température utilisés pour le nombre de jours d'exposition au froid et la somme des degrés-jours sont fixés identiquement à 10°C. Bien que ces seuils fournissent le meilleur ajustement, le choix d'un seuil inférieur, jusqu'à 3°C, permet une performance approximativement équivalente, pour autant que les deux seuils de température aient la même valeur.

Seedling responses to decreased snow depend on canopy composition and small‐mammal herbivore presence

“…To understand how our snow-removal treatment altered soil temperature, we modelled the effect of snow removal on cumulative growing-degree days (GDD), using a growing threshold of 10°C (Raulier and Bernier 2000), and the frequency of freeze-thaw events using MANOVA. For each snow removal session (mid-February, early March, mid-March), we modeled the mean snow depth in each plot after removal as a function of snow removal treatment and shoveling session, using a linear mixed model with a random intercept term for site.…”

Impact of tree leaf phenology on growth rates and reproduction in the spring flowering species Trillium erectum (Liliaceae)

“…On a broader scale, Acer saccharum leaf development also followed a latitudinal gradient (Leith, 1974). These differences could be under genetic control (Kriebel, 1957), although Raulier and Bernier (2000) recently proposed that a combination of chilling days and warming days could explain the date of leaf emergence in sugar maple populations. However, as leaf emergence occurs at cooler temperatures in northern sugar maple populations, other factors than degree-days alone control leaf emergence in this species.…”

“…In sugar maple, genetic differences between populations only explain a small fraction of the variation in the date of leaf emergence (Kriebel and Wang, 1962). Recently, Raulier and Bernier (2000) developed a model, based on the number of chilling days and degree-days during winter and early spring, to predict the date of leaf emergence in sugar maple. This model predicts that leaf emergence occurs earlier with respect to snow melting in more northern sites due to the higher number of chilling days and the fact that fewer degree-days are required before leaf emergence.…”

Phenology of a northern hardwood forest canopy

“…In this regard, we anticipate that a more widespread use of the phenology index will prove useful both for the interpretation of remote sensing indices, such as NDVI, and for improved modeling of forest-atmosphere CO 2 exchange. Raulier & Bernier (2000) found that they could account for 84% of the variation in the date of leaf emergence across the native range of sugar maple using a simple model based on heating and chilling degree-days. However, this model was not validated against a fully independent data set.…”

“…However, increased late-winter chilling can reduce the thermal sum required for the induction of spring development (Cannell & Smith, 1983), which argues for a more complex model than one based simply on heating degree-days. Raulier & Bernier (2000) thus used a model that combined accumulated heating degree-days with winter chilling requirements to predict leaf emergence in sugar maple. This model worked well across the entire native range of the species.…”