Characteristics of temporal variations in ecosystem CO₂ exchange in a temperate deciduous needle-leaf forest in the foothills of a high mountain

Abstract

We report the four-year (2006)(2007)(2008)(2009)) measurements of the net ecosystem CO 2 exchange flux (NEE) over a deciduous needle-leaf plantation forest in the foothills of Japan's highest mountain, Mt. Fuji. We focus on the characteristics of temporal variations in NEE and their relationships to environmental factors and phenology in a forest stand. We evaluate year-to-year variations in the seasonal patterns of flux components and investigate factors controlling the NEE. During the growing season, light availability is likely to affect the photosynthetic uptake of CO 2 at the site. We found significant differences in the length of the growing season for the four years; these are due mainly to variations in the timing of the progress of the autumnal coloring of leaves. The timing for the start of the autumnal coloring of leaves is highly dependent on when the daily lowest air temperature drops below 10℃. Secondly, we investigate the characteristics of short-term and long-term variations in the structure of CO 2 storage in the forest stand using a newly developed profiling system. We demonstrate the characteristics of temporal variations in the vertical distribution of CO 2 .

Methane uptake in a temperate forest soil using continuous closed-chamber measurements

“…The mean canopy height is approximately 25 m. The soil is classified as coarse volcanic ash with 0.43 ± 0.11 g cm −3 of soil bulk density (Urakawa et al, 2015). Further details about the study site are provided in our previous publications (Ueyama et al, 2012a(Ueyama et al, , 2013Mochizuki et al, 2014;Takahashi et al, 2015).…”

Identification of secondary fatty alcohols in atmospheric aerosols in temperate forests

“…The vegetation type is Larix kaempferi plantation, which was planted uniformly 55 years ago over 150 ha. Tree height is approximately 20-25 m. LAI was estimated to be 2.8 m 2 m −2 based on the leaf mass abundance in 2006 (Takahashi et al, 2015). After tree thinning at the site in 2014, the leaf mass abundance in 2015 and 2016 decreased to 80 % and 96 % of that in 2006, respectively.…”

“…The FHK site is located on a slope in the northern foothills of Mt. Fuji, and the dominant wind direction is characterized by two modes throughout a year: from the north (valley wind) in daytime and from the south (mountain wind) in nighttime (Takahashi et al, 2015).…”

“…Because the main function of plant waxes is to reduce water loss through evaporation, waxes originating from this source tend to have longer chain lengths. The most prominent chain lengths are C 26 to C 30 (Tulloch, 1976). Once emitted into the atmosphere, FAs in atmospheric aerosols can act as tracers of primary biological aerosol particles (PBAPs) (Simoneit et al, 2004).…”

Identification of secondary fatty alcohols in atmospheric aerosols in temperate forests

“…4a). The difference in the appearance of the peaks is attributable to the difference in the growing season at the two sites: the growth of forest vegetation generally starts about one month earlier at FHK (35ºN) than at TMK (42ºN) (Nakaji et al, 2011;Takahashi et al, 2015), which is also evident from the seasonal changes in the net ecosystem production (Saigusa et al, 2008). The primary emissions of these organic compounds clearly depend on the activity of the forest vegetation, and 40 more specifically, plant leaf phenology at these forest sites.…”