We developed a ground-based method for estimating leaf area index (LAI) and vertical distribution of leaf area density (LAD) for two Betula ermanii plots, combining an allometric method for tree leaf area with the MacArthur-Horn (MH) method using a portable laser rangefinder, including a correction for changes in leaf inclination angle along the vertical gradient measured with a portable digital protractor from a canopy access tower in each plot. Vertical distribution of projected leaf area density obtained by the MH method (LAD MH ) was transformed to relative distribution for allotting fixed LAI to different heights. Hence, we first developed an allometric method for estimating tree leaf area for LAI determination. Trunk cross-sectional area at branching height (AB) was accurately estimated (r 2 = 0.97) from ground-based measurements of tree dimensions. We used this method to apply pipe model allometry between tree leaf area and AB, and estimated LAI (4.56 and 4.57 m 2 m -2 ). We then examined how leaf inclination angle affected estimation of the vertical distribution of actual LAD. Leaf inclination angle measurements revealed that actual LAD in the upper canopy was 1.5-1.8-times higher than LAD MH , because of steep leaf inclination, while the correction factor was 1.15-1.25 in the lower canopy. Due to the difference among heights, vertical distribution of LAD estimated with correction for vertical change in leaf inclination was more skewed to the upper canopy than that without correction. We also showed that error in LAD distribution can result if horizontal canopy heterogeneity is neglected when applying the MH method.

The present paper shows simulated results of seasonal and inter-annual variations in energy and carbon exchanges and forest dynamics in a sub-boreal deciduous forest using a fully coupled atmospherevegetation interaction model [multilayered integrated numerical model of surface physics-growing plants interaction (MINoSGI)]. With careful adjustment of site-specific eco-physiological parameters, MINoSGI reproduced successfully stand biomass-tree density relationship based on the forest inventory data for 7 years (1999)(2000)(2001)(2002)(2003)(2004)(2005) and seasonal and inter-annual variations in energy and CO 2 fluxes measured by means of eddy covariance technique for 3 years (2003)(2004)(2005) in the sub-boreal forest, northern Japan. In addition, MINoSGI estimated annual evapotranspiration (E vt ) at 328.6 ± 25.8 mm year À1 , net primary production (NPP) at 372.1 ± 31.5 gC m À2 year À1 and net ecosystem exchange (NEE) at À224.2 ± 32.2 gC m À2 year À1 . We found the estimate of annual NEE in our site lies among the estimates at other forest stands with the almost same climatic conditions in northern Japan, although the tree species and stand age of these forests are different from those of our site. Overall, MINoSGI was found useful to present simultaneous simulations of forest dynamics, surface energy, and carbon exchanges of a forest stand in the future from micro-meteorological and ecophysiological points of view.

As air temperature near the ground changes with height, the present study investigates the effect of those changes and their role on the relationship between frost damage and flower bud height of Hemerocallis esculenta Koidzumi during scape elongation in the Sarobetsu Mire, Hokkaido, Japan. Meteorological observations near the ground and flower bud height of H. esculenta were measured from April to August in 2001August in , 2002August in , and 2003. In the present study, the intensity and duration of low temperature were combined as one variable instead of being treated as separate variables, as is usually done in laboratory experiments. In addition, the raised minimum temperature phenomenon was observed for the first time in a mire. The frost damage event occurred during predawn on 15 June 2001, 5 June 2002, and 5 June 2003. The weather during those nights was calm and clear, and the wind was not strong enough to prevent frost damage. The lower height limit of frost damage, observed in 2003, was found to be around 0.10-0.15 m, as buds below this height were protected by their own leaves. The upper height limit of frost damage was 0.34 and 0.43 m for 2001 and 2002, respectively. Frost damage of H. esculenta depended on the air temperature profile, which was affected mainly by vegetation height during scape elongation during calm, clear nights in the Sarobetsu Mire. Other factors that contributed to frost damage were also intensity-duration of low temperatures, which was treated as one variable in the present study, and the raised minimum temperature phenomenon.Key words: air temperature profile, bud height, lethal temperature, raised minimum temperature phenomenon, scape elongation. Résumé: Comme la température de l'air près du sol varie avec la hauteur, nous avons étudié l' effet de ces changements et leurs rôle dans la relation entre les dommages parle gel et la hauteur du bourgeon floral de l'Hemerocallis esculenta Koidzumi, au cours de l'élongation de la hampe florale, dans la tourbière de Sarobetsu située sur l'île d'Hokkaido, Japon. Les paramètres météorologiques près du sol et la hauteur du bourgeon floral de H. esculenta ont été mesurés d'avril à août en 2001 et 2002 et en juin 2003. L'intensité et la durée des basses températures ont été combinées en une seule variable au lieu d'être séparées comme il est d'usage lors d'expériences en laboratoire. De plus, le phénomène d'élévation de la tempèrature minimale a été observé pour la première fois dans une tourbière. Les dommages par le gel sont apparus juste avant l'aurore du 15 juin 2001, le 5 juin 2002 et le 5 juin 2003. La tempéra-ture au cours de ces nuits était calme et clair et le vent n'était pas assez fort pour empêcher le gel. La limite inférieure de dommages par le gel, observée seulement en 2003, se situait à environ 0,10-0,15 m du sol, car les bourgeons floraux se trouvant sous cette hauteur étaient protégés par leurs propres feuilles. La limite supérieure des dommages par le gel se situait à 0,34 et 0,43 m en 2001 et 2002, respectivement.Le do...

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