• Journal of Ecology and Environment
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• v.32 no.3
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• pp.159-165
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• 2009

The purpose of this study was to investigate the effects of thinning on fine root biomass and vertical distribution. and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, Kangwon Province. Fine root (< 2 mm in diameter) biomass ($367\;g/m^2$) in the site 'OC_75', thinning once in 1975, was 68% of those in the site 'CON', no thinning after planting, and in the site 'TC_00', thinning twice in 1975 and 2000. There were no significant differences of dead roots among treatments. Diameter $0{\sim}1\;mm$ roots were vertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 ($5.2\;Mg\;ha^{-1}\;yr^{-1}$) and TC_00 ($4.7\;Mg\;ha^{-1}\;yr^{-1}$), but the composition of litterfall was different: The proportion of leaves and branches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensis density by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots production by neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowground as well as aboveground responses, including both over- and understory vegetation, should be considered to measure the responses of trees in thinned forest ecosystems.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.721-729
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• 2015

Wood properties depend on not only environmental factors such as soil, climate change, or forest stand characteristics, but also silviculture practices such as thinning, regeneration, or selection. This study report influences of the extent of thinning intensity from no thinning, moderate and heavy thinning to the wood property of Quercus acuta forest stands in Wan-do arboretum, Jeollanam-do Province. The results showed that there were close relationships between thinning intensity and anatomical, physical or mechanical properties of Quercus acuta wood. Especially, there are close relationships between thinning intensity and ring width or mechanical properties of wood. As a result, this study showed high correlations between Quercus acuta wood properties and thinning intensity of Quercus acuta forest stand. These findings are expected to be very useful as fundamental data for the implementation of silviculture practices of this specie to produce timber.

• Fire Science and Engineering
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• v.22 no.1
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• pp.45-53
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• 2008

The effect of thinned trees which are produced from forest thinning on forest fire was studied in this work. To investigate the effect of thinning slash, Yang-yang, In-je, and Ga-pyeong-gun were selected as thinning-areas and non-thinning areas. The research was carried out with the variations of tree's types, area's characteristics, thinning strength, thinning types, and pile types of thinned tree. The survey areas of 14 areas were selected at Yangyang-gun(5 areas), Gapyeong-gun(4 areas), and Inje-gun(5 areas), and on-the-spot investigations were carried out at the thinning areas of 9 and the non-thinning areas of 5, respectively. Non-thinning areas of 5, which are adjacent to thinning areas, were selected for the comparison with thinning areas and for the analysis of risk of forest fire. It is considered that forest fire have no chance to diffuse to a tree trunk because the height of thinned trees was lower than 1 m. However, it is considered that forest fire may affect directly to a tree trunk if it spread to piled thinned tree because there was no space between thinned trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.4
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• pp.157-164
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• 2011

Long-term annual water balances are analyzed for two forest catchments located in Gwangneung covered with forests of different types and ages. The water balance trends of the two catchments from 1982 to 2009 are compared to identify the effect of forest growth and thinning on the water balance in a planted coniferous forest catchment. According to the averaged annual precipitation and runoff for the four designated periods from 1982 to 2009, the water balance of the old natural broad-leaved forest catchment (GB) remained relatively unchanged. In contrast, the young planted coniferous forest catchment (GC) showed significant changes in the water balance due to the forest growing and thinning. The results showed that the catchment runoff decreases with increasing tree age whereas the forest thinning results in an increase in catchment runoff. The mean annual runoff from the catchment GC after thinning increased by 1.7 times, compared with the mean annual runoff before forest thinning. The mean annual runoff from the catchment GB was very stable throughout the period. However, such an effect of forest thinning appeared to last only for about 10 year-period, after which the water yield increment in the catchment GC disappeared. It indicates that the proper forest management should be reconsidered at the interval of 10 years to effectively reduce water loss and increase water yield in the planted coniferous forest.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.208-219
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• 2020

Forest thinning brought the large variation to forest ecosystem including environment and animal. Our study was result of long-term monitoring for ground-dwelling arthropod communities after thinning in forest ecosystem. In this study, we conducted field study on plantation forest in Chuncheon, Korea in 2018, and compared with previous study data (2006 and 2008). We found that the effect of thinning was still existent 10 years later from thinning with difference of habitat environment(depth of ground organic matter, coverage rate of ground vegetation and canopy). And ground-dwelling arthropod communities showed changes of abundance and taxa at the study area and thinning conditions. Ground-dwelling arthropod communities in 2018 were dominant in the order of Diptera, Hymenoptera, Coleoptera (Insecta), Araneae (Arachnida) and Collembola (Collembola). Among the conditions of thinning, Araneae (Arachnida), Coleoptera and Hymenoptera (Insecta) showed amount of abundance in heavy thinning. And Collembola (Collembola) and Diptera (Insecta) were most common in area of light thinning. In 2018 ground-dwelling arthropod communities, abundance of Diptera and Coleoptera (Insecta) and Isopoda (Crustacea) were decreased although Hemiptera and Orthoptera (Insecta) were increased than 2008 arthropod communities. Arthropod communities in 2018 were more similar with those in 2008 (after thinning) than with those in 2006 (before thinning).

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.263-268
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• 2008

Estimates of genetic gain (in volume growth) and diversity (expressed as status number, $N_s$) were determined in a clonal seed orchard of Pinus koraiensis. The genetic thinning was based on clonal breeding values (represented by general combining ability) obtained from progeny tests, clonal fertility estimated by strobilus production, and clonal size variation determined by the ramet numbers per clone. Parental GCA values for volume growth were calculated, based on height and diameter at breast height measured from field trials. Clonal fertility was estimated from the assessments of strobilus production over twelve years from 1991 to 2003, and used for the calculation of status number. There are 179 clones and 5,268 ramets in 12ha area of P. koraiensis clonal seed orchard. Genetic gain and diversity estimates were determined under assumptions of 30% pollen contamination and inferior genetic value of contaminating pollen. Genetic gain increased as thinning rates were set from 10% to 60%. However, for the higher thinning intensities, the increase of genetic gain was not remarkable. Genetic thinning by means of truncation selection resulted in a greater genetic gain but a large decrease in status number. Status number was represented around 40 clones for 10% through 60% thinning intensities, but for the higher thinning intensities, it was a bit fluctuated. Based on the present results, it could be concluded that thinning rate should not be stronger than 60% to optimize genetic gain while conserving genetic diversity. Consequently 50% or 60% thinning rate might be appropriate for genetic thinning in the clonal seed orchard of P. koraiensis. The effect of pollen contamination on the genetic gain and the consequence of genetic thinning for seed production in the clonal seed orchard, and seed orchard management scheme were also discussed.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.151-159
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• 2007

This study was conducted to investigate the effects of thinning on changes in stand characteristics and understory vegetation in a silvopasture practiced Japanese larch plantation in the Research Forest of Kangwon National University, Korea. Three different thinning intensities (64%, 35%, and control) were applied. Before and after thinning, the understory plant species increased its number from 48 (7 tree species, 7 shrubs species, 28 herbaceous species, and 6 woody climbers) to 100 (11 tree species, 15 shrub species, 67 herbaceous species, and 7 woody climbers). Thinning made plants invade easily on the forest floor, and plot A (325 stems/ha) had much higher number of undersory species than those Of plot B (575 stems/ha) and control plot (1,150 stems/ha). In three years after thinning, understory aboveground biomass (kg/ha) of herbs were 523 for control, 1,230 for plot B, and 1,288 for plot A. The canopy coverage had remarkable influence on the understory biomass production, resulting in relatively small amount of herbage production on control plot. The differences were statistically significant between thinned plots and unthinned plot, but there were no significant differences among the thinned plots (p<0.05).

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.208-213
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• 2007

This study is designed to provide forest managers and landowners with tools to estimate the effect of forest management on carbon storage, investigating living tree biomass, detritus, and harvested wood products as variables. Thinning, selection cutting, and uncutting were applied to the three different forest types in New York, USA. Carbon storage of the original stands was 90, 56, and $101Mg\;ha^{-1}$ at the Allegheny hardwood forest, Northern hardwood forest, and Oak - black cherry forest, respectively. Among treatments, uncutting generally stored the greatest amount carbon. However, the rate of carbon storage was the smallest at the uncut treatment in all the sites. The 50% thinning, 50% selection, and 50% thinning treatments were the highest rate of carbon storage at the Allegheny hardwood forest, Northern hardwood forest, and Oak - cherry forest, respectively. In this study, only short term was applied to simulate carbon sequestration after silvicultural treatment. So, more research is needed to determine whether any silvicultural treatment can store significantly more carbon than no treatment over the long term.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.225-230
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• 2009

Using dynamic programming, which is one of operations research techniques, the best pathway was chosen to maximize the total harvest volume for a Korean white pine (Pinus koraiensis) stand. This study was carried out in an age class III at Chuncheon National Forest, Gangwon province. That stand was assumed to apply 3 different thinning intensities of none, 30% and 50% thinnings. These thinning pathways are planned to implement two times, of thinning at 35 age and 55 age. The final cutting (rotation age) is assumed to carry out in 70 years. A growth function for Korean white pine stand was developed with forest inventory data, the volume was calculated with this growth function. As a result, the best thinning pathway for this Korean white pine stand using dynamic programming is to implement 30% at the first thinning and 50%at the second thinning.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.132-138
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• 2016

The objectives of this study were to infer the parameters of forest stand growth functions of STEMS for Cryptomeria japonica stands of Jeju Hannam Experimental Forest, Korea Forest Research Institute, and to investigate the effects of thinning regimes on the patterns of stand growth and carbon absorption. The forest stand growth functions for the potential diameter growth, modifier, crown ratio and mortality are the major ones composing the independent-tree/distance-free forest stand growth simulator, STEMS. The parameters were inferred using the sets of growth data obtained from stem analyses of 39 trees, chosen from 13 sample plots of the forest stands. The effects of thinning regimes on the patterns of stand growth and carbon absorption were investigated by simulating the stand growth patterns of the case study stand with 3 different thinning regimes: no-thinning, early thinning with low intensity and late thinning with high intensity using the simulator. According to the results of the analyses, the different thinning regimes cause significant effects on the growth patterns of average DBH, average height, diameter distribution and stand volume as well as the amount of carbon absorptions.