Deforestation Effects on the Micrometeorology in a Cool-temperate Forest in Northernmost Japan

Fukuzawa

Liang

et al. 2009

Global Change Biology

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To evaluate the effects on CO2 exchange of clearcutting a mixed forest and replacing it with a plantation, 4.5 years of continuous eddy covariance measurements of CO2 fluxes and soil respiration measurements were conducted in a conifer‐broadleaf mixed forest in Hokkaido, Japan. The mixed forest was a weak carbon sink (net ecosystem exchange, −44 g C m−2 yr−1), and it became a large carbon source (569 g C m−2 yr−1) after clearcutting. However, the large emission in the harvest year rapidly decreased in the following 2 years (495 and 153 g C m−2 yr−1, respectively) as the gross primary production (GPP) increased, while the total ecosystem respiration (RE) remained relatively stable. The rapid increase in GPP was attributed to an increase in biomass and photosynthetic activity of Sasa dwarf bamboo, an understory species. Soil respiration increased in the 3 years following clearcutting, in the first year mainly owing to the change in the gap ratio of the forest, and in the following years because of increased root respiration by the bamboo. The ratio of soil respiration to RE increased from 44% in the forest to nearly 100% after clearcutting, and aboveground parts of the vegetation contributed little to the RE although the respiration chamber measurements showed heterogeneous soil condition after clearcutting.

Section: Discussionmentioning

confidence: 55%

Change in CO₂ balance under a series of forestry activities in a cool‐temperate mixed forest with dense undergrowth

Fukuzawa

Liang

et al. 2009

Global Change Biology

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“…Annual precipitation in 2002 was 1,170 mm, of which snow accounted for 30% of the total (Fig. 1b;Takagi et al 2005). Temperature and precipitation in 2002 were in the range of average data from long-term climatic observation .…”

Section: Study Sitementioning

confidence: 79%

“…The annual mean air temperature in 2002 was 5.6°C, with monthly mean temperatures of 16.1°C and À7.5°C in August and December, respectively ( Fig. 1a; Takagi et al 2005). Annual precipitation in 2002 was 1,170 mm, of which snow accounted for 30% of the total (Fig.…”

Section: Study Sitementioning

confidence: 98%

Vertical distribution and seasonal pattern of fine‐root dynamics in a cool–temperate forest in northern Japan: implication of the understory vegetation, Sasa dwarf bamboo

Fukuzawa

Shibata

et al. 2006

Ecological Research

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We measured the vertical distribution and seasonal patterns of fine-root production and mortality using minirhizotrons in a cool-temperate forest in northern Japan mainly dominated by Mongolian oak (Quercus crispula) and covered with a dense understory of dwarf bamboo (Sasa senanensis). We also investigated the vertical distribution of the fine-root biomass using soil coring. We also measured environmental factors such as air and soil temperature, soil moisture and leaf area indices (LAI) of trees and the understory Sasa canopy for comparison with the fine-root dynamics. Fine-root biomass to a depth of 60 cm in September 2003 totaled 774 g m À2 , of which 71% was accounted for by Sasa and 60% was concentrated in the surface soil layer (0-15 cm), indicating that understory Sasa was an important component of the fine-root biomass in this ecosystem. Fine-root production increased in late summer (August) when soil temperatures were high, suggesting that temperature partially controls the seasonality of fine-root production. In addition, monthly fine-root production was significantly related to Sasa LAI (P<0.001), suggesting that fine-root production was also affected by the specific phenology of Sasa. Fine-root mortality was relatively constant throughout the year. Fine-root production, mortality, and turnover rates were highest in the surface soil (0-15 cm) and decreased with increasing soil depth. Turnover rates of production and mortality in the surface soil were 1.7 year À1 and 1.1 year À1 , respectively.

Ammonia Emission from a Young Larch Ecosystem Afforested after Clear-Cutting of a Pristine Forest in Northernmost Japan

Hayashi

Noguchi

et al. 2008

Water Air Soil Pollut

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The present study aimed to elucidate the atmosphere-forest exchange of ammoniacal nitrogen (NH X -N) at a young larch ecosystem. NH X -N exchanges were measured at a remote site in northernmost Japan where 4-year-old larches were growing after a pristine forest had been clear-cut and subsequent dense dwarf bamboo (Sasa) had been strip-cut. The site was a clean area for atmospheric ammonia with mean concentrations of 0.38 and 0.11 μg N m