The Three-year Effect of Thinning Intensity on Biomass in Larix kaempferi and Pinus koraiensis Plantation

Vireak Chhorn,Yeongwan Seo,Daesung Lee,Jungkee Choi 강원대학교 산림과학연구소 2020 Journal of Forest Science Vol. No.

This study aimed to figure out and compare the increment of biomass by thinning intensity focused on the plantation of the two major coniferous species (Larix kaempferi and Pinus koraiensis) of South Korea. The inventory interval was three years under the effects of three types of thinning treatments; control (no thinning), light (20% thinning) and heavy (40% thinning). The results showed standing biomass increment of both species decreased as thinning intensity increased (heavy<light<control). Biomass increment of each tree compartment (roots, stem, branches and foliage) also followed the increment pattern of the total biomass. In contrast, the rate of biomass growth increased as increasing thinning intensity (heavy>light>control). Meanwhile, the lowest of on-site biomass changes occurred in the control plot, and the greatest was in the heavy thinning plot because thinning was involved with leaving the felling residual biomass (leaves, branches and roots) on the site. According to the results from this short-term study, unthinned stands is preferable for maximizing standing biomass as well as carbon sequestration. However long-term investigation should be considered in order to see more clear results.

The Three-year Effect of Thinning Intensity on Biomass in Larix kaempferi and Pinus koraiensis Plantation

Vireak Chhorn,서영완,이대성,최정기 강원대학교 산림과학연구소 2020 Journal of Forest Science Vol.36 No.1

This study aimed to figure out and compare the increment of biomass by thinning intensity focused on the plantation of the two major coniferous species (Larix kaempferi and Pinus koraiensis) of South Korea. The inventory interval was three years under the effects of three types of thinning treatments; control (no thinning), light (20% thinning) and heavy (40% thinning). The results showed standing biomass increment of both species decreased as thinning intensity increased (heavy<light<control). Biomass increment of each tree compartment (roots, stem, branches and foliage) also followed the increment pattern of the total biomass. In contrast, the rate of biomass growth increased as increasing thinning intensity (heavy>light>control). Meanwhile, the lowest of on-site biomass changes occurred in the control plot, and the greatest was in the heavy thinning plot because thinning was involved with leaving the felling residual biomass (leaves, branches and roots) on the site. According to the results from this short-term study, unthinned stands is preferable for maximizing standing biomass as well as carbon sequestration. However long-term investigation should be considered in order to see more clear results.

Comparison of Growth and Allometric Change of Stand and Dominant Trees in Pinus koraiensis Plantation over 34 Years

서영완,이대성,Vireak Chhorn,최정기 강원대학교 산림과학연구소 2018 Journal of Forest Science Vol.34 No.3

This study was conducted to find out the growth pattern of Pinus koraiensis plantation over 34 years, focusing on DBH, height, basal area and allometric change. Total increment (TI), mean annual increment (MAI) and correlation coefficient were calculated and compared with stand and dominants. Total increment and mean annual increment of both DBH and height of dominants were bigger than those of stand. The difference was apparently shown bigger in DBH than height. Unlike DBH and height the total increment and mean annual increment of basal area per hectare of dominants were distinctively smaller than those of stand. Furthermore MAI of dominant was increasing until age 42, while MAI of stand increased at early ages and then gradually decreased after culmination like MAIs of DBH and height. MAIs of basal area of dead trees at each measurement tended to increase until early age (18 years in this study), while it reached a peak and gradually decrease after that (21 years in this study). Correlation coefficient between DBH and height tended to decrease as both dominant and stand age and the difference between dominant and stand was not clearly shown over the measurement period. Correlation coefficients between DBH and crown width tended to decrease as the trees age and correlation coefficients of dominant were clearly shown smaller than that of stand. Correlation coefficients of height and crown width also was found to be similar to correlation coefficients between DBH and crown. Meanwhile correlation coefficient of height and crown width dropped more radically than coefficient of DBH and crown width as the trees age.

Comparison of Growth and Allometric Change of Stand and Dominant Trees in Pinus koraiensis Plantation over 34 Years

Seo, Yeongwan,Lee, Daesung,Chhorn, Vireak,Choi, Jungkee Institute of Forest Science 2018 Journal of Forest Science Vol.34 No.3

This study was conducted to find out the growth pattern of Pinus koraiensis plantation over 34 years, focusing on DBH, height, basal area and allometric change. Total increment (TI), mean annual increment (MAI) and correlation coefficient were calculated and compared with stand and dominants. Total increment and mean annual increment of both DBH and height of dominants were bigger than those of stand. The difference was apparently shown bigger in DBH than height. Unlike DBH and height the total increment and mean annual increment of basal area per hectare of dominants were distinctively smaller than those of stand. Furthermore MAI of dominant was increasing until age 42, while MAI of stand increased at early ages and then gradually decreased after culmination like MAIs of DBH and height. MAIs of basal area of dead trees at each measurement tended to increase until early age (18 years in this study), while it reached a peak and gradually decrease after that (21 years in this study). Correlation coefficient between DBH and height tended to decrease as both dominant and stand age and the difference between dominant and stand was not clearly shown over the measurement period. Correlation coefficients between DBH and crown width tended to decrease as the trees age and correlation coefficients of dominant were clearly shown smaller than that of stand. Correlation coefficients of height and crown width also was found to be similar to correlation coefficients between DBH and crown. Meanwhile correlation coefficient of height and crown width dropped more radically than coefficient of DBH and crown width as the trees age.

DBH growth for three years after thinning on even-aged Pinus koraiensis and Larix kaempferi plantations in South Korea

서영완,Somsanouk Pathammavongsa,Vireak Chhorn,이대성,최정기,차두송 한국산림과학회 2019 Forest Science And Technology Vol.15 No.1

This study was conducted to determine the effects of different thinning intensities on the DBH growth of Pinus koraiensis and Larix kaempferi trees. Permanent monitoring plots were installed in 26 P. koraiensis plantations and 36 L. kaempferi plantations in 2012 and 2014, respectively. To evaluate the effect of thinning intensity, each plot consisted of three square or rectangular plots; control or non-thinned, light thinning, in which 20% of the total basal area was removed, and heavy thinning, in which 40% of the total basal area was removed. The mean DBH increments for 3 years were computed and compared across thinning intensities. Other factors, such as slope, altitude, or stand density, were compared across thinning treatments to understand why DBH increment did not follow thinning intensity. Overall mean DBH increment for 3 years after thinning was affected by different thinning intensities: heavy thinning>light thinning>control. ANOVA showed that there was a significant difference in DBH increment among thinning intensities in both species. Also, Duncan’s multiple range test showed that all thinning treatments were significantly different from each other. Other factors that affect DBH besides thinning intensity were identified, such as residual basal area, slope gradient, and aspect.