Phenological Observations of Spring Geophytes in Quebec

Vezina, Paul E.; Grandtner, Miroslav M.

doi:10.2307/1934022

Cited by 55 publications

(27 citation statements)

References 4 publications

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“…It also varies depending on the timing of snowmelt in early spring for G. lutea and other spring ephemerals (Vézina and Grandtner 1965;Muller 1978;Hamerlynck and Smith 1994). Prolonged winter due to late snowmelt could shorten the vegetative period for spring ephemerals.…”

Section: Discussionmentioning

confidence: 99%

“…Their epigeous phase is a short vernal period that occurs prior to canopy closure of the forest (Vézina and Grandtner 1965;Caldwell 1969;Kawano et al 1978Kawano et al , 1982Mahall and Bormann 1978;Muller 1978). Dense shade due to forest canopy closure and high temperatures in summer are unfavorable for the growth of spring ephemerals, since they are shade-intolerant (Sparling 1967;Taylor and Pearcy 1976;Kawano et al 1978Kawano et al , 1982 and high temperatures increase the dark-respiration rate (Kawano et al 1978).…”

Section: Introductionmentioning

confidence: 99%

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Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum)

Yoshie

2008

J Plant Res

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Effects of growth temperature and winter duration on leaf longevity were compared between a spring ephemeral, Gagea lutea, and a forest summergreen forb, Maianthemum dilatatum. The plants were grown at day/night temperatures of 25/20 degrees C and 15/10 degrees C after a chilling treatment for variable periods at 2 degrees C. The temperature regime of 25/20 degrees C was much higher than the mean air temperatures for both species in their native habitats. Warm temperature of 25/20 degrees C and/or long chilling treatment shortened leaf longevity in G. lutea, but not in M. dilatatum. The response of G. lutea was consistent with that reported for other spring ephemerals. Air temperature increases as the vegetative season progresses. The decrease in leaf longevity in G. lutea under warm temperature condition ensures leaf senescence in summer, an unfavorable season for its growth. This also implies that early leaf senescence could occur in years with early summers. Warm spring temperatures have been shown to accelerate the leafing-out of forest trees. The decrease in leaf longevity due to warm temperature helps synchronize the period of leaf senescence roughly with the time of the forest canopy leaf-out. Prolonged winter due to late snowmelt has been shown to shorten the vegetative period for spring ephemerals. The decrease in leaf longevity due to long chilling treatment would correspond with this shortened vegetative period.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum)

Yoshie

2008

J Plant Res

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“…The initiation time of elongation was taken as that of the onset of foliation (Gregory 1980). In some cases curves of leaf emergence or shoot elongation are given as a function of time (Vézina and Grandtner 1965;Close et al 1996;Gill et al 1998). In such cases, the date of foliation was determined as for our own data.…”

Section: Phenological Datamentioning

confidence: 99%

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

Raulier¹,

Bernier²

2000

Can. J. For. Res.

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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.

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“…3 suggests tree growth since June 25. (Schomaker 1968) and 0.10-0.12 (Vezina and Grandtner 1965) have been reported. The higher values in the present study indicate a sparser foliage and, hence, less absorption.…”

Section: Global Radiation Transmissionmentioning

confidence: 94%

The transmission of global and photosynthetically active radiation within a dwarf apple orchard

Suckling¹,

Davies²,

Proctor³

1975

Can. J. Bot.

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SUCKLING, P. W., J. A. DAVIES, and J. T. A. PROCTOR. 1975. The transmission of global and photosynthetically active radiation withinadwarfappleorchard. Can. J. Bot. 53: 1428-1441. Measurements of incoming global radiation, K J , beneath a dwarf apple orchard canopy were made with a traversing sensor and a randomly located set of 10 stationary sensors. The location of the latter was changed once during the period of the experiment. On a daily basis, satisfactory agreement between the two sets of measurements was attained only for the second network location.Above-canopy and track measurements were used to calculate diurnal and daily values of canopy transmissivity, absorptivity, and reflectivity. Average values for the whole period were 0.53,0.28, and 0.19. Analogous coefficients were obtained for photosynthetically active radiation (PAR). Extracanopy values of PAR were evaluated from PAR = 0.49 KJ on 'bright' days (days with cloud cover less than 6 / , , ) and PAR = 0.5 KJ for cloudy days. These relationships were obtained by regression from sample measurements of PAR and KJ. Average PAR transmissivity, absorptivity, and reflectivity were evaluated as0.42,0.51, and 0.07. SUCKLING, P. W., J. A. DAVIES et J. T. A. PROCTOR. 1975. The transmission of global and photosynthetically active radiation within adwarfapple orchard. Can. J. Bot. 53: 1428-1441. Les auteurs ont mesurt I'irradiation incidente globale, K J , sous le couvert d'un verger de pommiers nains, I'aide d'une cellule photosensible se d t p l a~a n t a travers le verger et d'une batterie de 10 cellules stationnaires distributes au hasard. La position de ces dernikres a t t i changte une fois au cours de la ptriode d'observations. Sur une base quotidienne, ce n'est que dans cette deuxikme position que les rtsultats obtenus avec les deux types de cellules ttaient suffisamment concordants. Les mesures obtenues au-dessus du couvert et celles obtenues avec le senceur mobile ont kt6 utilistes pour calculer les valeurs diurnes et quotidiennes de la transmittance, de I'absorbance et de la rtflectance du couvert. Des valeurs moyennes de 0.53,0.28 et 0.19 ont CtC obtenues pour toute la ptriode d'observation. Des coefficients analogues ont e t t obtenus pour la radiation active sur la photosynthkse (PAR). Les valeurs de PAR ii I'exttrieur du couvert ont kt6 CvaluCes a PAR = 0.49 KJ pour les jours ensoleillts (moins de 6jours sur 10 Ctaient couverts), et a PAR = 0.5 KJ pour les jours couverts. Ces relations ont Ctt obtenues par rtgression a partir d'tchantillons de mesures de PAR et KJ.. En moyenne, la transmittance, I'absorbance et la rtflectance de PAR etaient de 0.42,0.51 et 0.07.[Traduit par le journal]

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Phenological Observations of Spring Geophytes in Quebec

Cited by 55 publications

References 4 publications

Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum)

Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum)

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

The transmission of global and photosynthetically active radiation within a dwarf apple orchard

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