• The Korean Journal of Mycology
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• v.42 no.2
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• pp.133-137
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• 2014

This study was conducted to investigate the effect of thinning on ectomycorrhizal fungal communities in a forest. Ectomycorrhizal root tips were collected from forest soils in thinning and non-thinning sites and identified using morphological characteristics and molecular analysis of ITS rDNA sequences. As a result, species richness of ectomycorrhizal fungi was significantly increased and ectomycorrhizal fungal community composition was changed by thinning. These results suggest that forest management such as thinning, could be an important factor affecting mutualistic relationships and belowground microorganisms in forest ecosystems.

• Journal of Forest and Environmental Science
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• v.39 no.2
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• pp.81-95
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• 2023

Due to the multiple ecosystem benefits that iconic large, old growth trees provide, forest managers are applying thinning treatments around these legacy trees to improve their vigor and reduce mortality, especially in the face of climate change and other forest health threats. One objectives of this study was to analyze sub-hourly stem fluctuations of legacy ponderosa (Pinus ponderosa Dougl. Ex P. & C. Laws) and sugar pines (Pinus lambertiana Dougl.) in the mixed-conifer forests of the Sierra Nevada in multiple different radius thinning treatments to assess the short-term effects of these treatments. Thinning treatments applied were: R30C0 (9.1 m radius), R30C2 (9.1 m radius leaving 2 competitors), and RD1.2 (radius equaling DBH multiplied by 1 ft/in multiplied by 1.25). The other objective was to assess climatic drivers of hourly stem fluctuations. Using the dendrometeR package, we gathered daily statistics (i.e. daily amplitude) of the stem fluctuations, as well as stem cycle statistics such as duration and magnitude of contraction, expansion, and stem radial increment. We then performed correlation analyses to assess the climatic drivers of stem fluctuations and to determine which radial thinning treatment was most effective at improving growth. We found an important role that mean solar radiation, air temperature, and relative humidity play in stem variations of both species. One of the main findings from a management perspective was that the RD1.2 treatment group allowed both species to contract less on warmer and higher solar radiation days. Furthermore, sugar pine put on more stem radial increment on higher solar radiation days. These findings suggest that the extended radius RD1.2 thinning treatment may be the most effective at releasing legacy sugar and ponderosa pine trees compared to the other forest management treatments applied.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.282-288
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• 2005

This study was carried out to estimate aboveground carbon contents associated with four years of thinning treatment of Quercus acuta stands in Wando Arboretum, Jeonnam. Stand thinning was conducted over four years using stand table projection for each thinning treatment. Ten sample trees were cut in the surveyed area. Estimation of aboveground biomass was made using the equation model $W=aD+bD^2$ where W is oven dry weight and D is DBH in cm. The total aboveground biomass for each intensity treatment area was : control (148.4 ton/ha), light (105.6 ton/ha), moderate (68.7 ton/ha) and heavy (39.1 ton/ha). Aboveground carbon storage for Quercus acuta stands was found by multiplying dry weigh t (ton/ha) by 0.5. Carbon storage and increment after four years was: control (74.2 tonC/ha), light (52.8 tonC/ha), moderate (34.3 tonC/ha) and heavy thinning intensity area (38.2tonC/ha).

• Journal of Forest and Environmental Science
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• v.35 no.3
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• pp.197-204
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• 2019

A tree-length harvesting system using the HAM300, which is mounted on a farm tractor prototype machine, have been recently introduced in South Korea for thinning old (>30 years) forests. However, no research has previously been conducted on the characteristics of residual stand damage associated with cable yarding systems on thinning treatment stands in South Korea. Therefore, there were assessed on the degree and quantity of residual stand damage caused by felling and yarding process to broaden the knowledge of residual stand damage on semi-mechanized skyline thinning operations. This study investigated scar size, direction, area, shape type and their distribution on the residual stand damage caused by felling and yarding operations. Damage to residual trees was generated for 7.4% and 6.9% of residual trees in felling and yarding operations, respectively. Damaged direction of scars was located in front-side (38.9%) and up-side (34.7%) for felling operations while the highest scar damage was found on down-side (44.6%) for yarding operations. Scar heights of felling damage were higher than those of yarding damage. In yarding operation, the most of the scars was located within l0m from the center of the skyline corridor. These results should be useful information for forest managers and landowners to reduce residual stand damages and retain valuable timber volume from thinning treatments.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.352-358
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• 2011

Field Cage plots ($1m{\times}1m{\times}1m$) were established (7 units) to find the lowest limit time about the tending of red pine forest (Pinus densiflora) which can no longer be used as a habitat by Monochamus alternatus, vector insect of pine wilt disease at the experimental forest of the southern forest research center of the Korea forest research institute in February in 2010. Thinning slashes (length, 1 m; diameter, 5~10 cm) tended at the different times were put in cages, and 4~6 couples of adult M. alternatus were put into each the cage in June. Presence or absence the larval entrance holes and larval were determined in November in 2010. Incase of the combination 24, 18, 12 and 6-month-old thinning slashes from thinning times to the time of adult emergence inside a single cage, larval entrance holes were found in the 6-month-old and 12-month-old thinning slashes but larvae were found only in the 6-month-old thinning slashes (treatment 1). In case of the combination 24, 18, 15 and 12-month-old thinning slashes inside a single cage, larval entrance holes were found in the 15-month-old and 12-month-old thinning slashes but larvae were found only in the 12-month-old (treatment 2). When 24, 18, 15, 12 and 6-month-old thinning slashes with treated dry and humid condition were put separately inside each cage, larval entrance holes were found in the 18, 15, 12, 6-month-old thinning slashes without the relation of the dry and humid conditions. But larvae were found in the 15, 12, 6-month-old thinning slashes in the dry conditions and only in the 6-month-old thinning slashes in the humid conditions. Results indicated the lowest limit time which can no longer be used as a habitat by M. alternatus is before 24 month from the time of adult emergence.

• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.268-273
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• 2016

This study was conducted to clarify the differences in habitat structure and amphibian and reptile (herpetofauna) populations between before and after thinning in the coniferous and deciduous forests from June to September 2014 and 2015 at the Mt. Maewha of Hongcheon, Gangwon province, Korea. Forest structure was dramatically changed after thinning. Coverage of understory and mid-story were decreased while volume and number of downed trees were increased after thinning. We used line transect sampling method on a total of 4 transect lines, 2 lines in each forest type. 119 individuals of 5 amphibian species and 5 individuals of 3 reptile species were recorded. Mean number of amphibian species were decreased after thiining in the coniferous forest. There was no observed reptiles after thinning in the coniferous and deciduous forests. Detailed monitoring with different area, frequency and intensity might be needed to clarify more precise differences characterisitics of herpetofauna by thinning.

• Journal of Ecology and Environment
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• v.34 no.4
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• pp.347-355
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• 2011

Effects of forest thinning on community level properties have not been understood yet in Korea. We investigated regeneration patterns and trajectories after a disturbance by applying a chronosequence approach. Light availability, litter and woody debris cover, and species composition were determined for twenty 50 m line-transect samples representing a disturbance duration gradient (within 11 years). Environmental factors such as light availability and coverage of woody debris and litter changed abruptly after thinning and then returned to the pre-disturbance state. Although species richness was gained at shrub and ground layer in a limited way in both forests, cover of various functional types revealed diversity in their responses. Notably, Alnus firma stands exhibited a larger increment of cover in woody plants. Ordination analysis revealed different regeneration trajectories between natural and planted stands. Based on ordination analysis, rehabilitated stands showed movement to alternative states compared with natural ones, reflecting lower resilience to perturbation (i.e., lower stability). Our results suggest that community resilience to artificial thinning depends on properties of the dominant species. But to get more explanatory ecological information, longer-term static observations are required.

• Journal of Korean Society of Forest Science
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• v.97 no.5
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• pp.516-524
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• 2008

We investigated on the distribution of nutrient contents (N. P and K) in current and one-year old needles of Korean pine, Pinus koraiensis, to understand the physiological effects of alternate bearing. One experimental set was designed with three types of cone number (one, three and five) under natural state and cone number of another one was controlled by thinning. Test samples were separated to collect into three fractions; current needles on the shoot and one-year old needles above and under the cone. On the branch without cone, N, P and K concentrations in needles on the shoot were higher than those in needles of one-year old branch. At natural state, needle P concentration was the lowest in needles on the five-cone branch in August. Macronutrient concentrations were the lowest in needles above the cone, which was remarkably observed in needle K concentration. Under cone thinning, N. P and K concentrations were the highest in needles on one-cone branch and the lowest in needles on five-cone branch. Needle nutrient concentrations were the lowest in needles above the cone, which was remarkably observed in the needle on five-cone branch. In conclusion, the current needles of the shoot and cones are a strong sink of nutrient like N. P and K, and the increase of cone number influences nutrient removal from needles.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.397-403
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• 2010

This study was conducted to investigate the changes in soil temperature, soil moisture content, light availability (photosynthetically active radiation, PAR) and diameter growth in 46-year-old Korean pine (Pinus koraiensis Siebold et Zuccarini) plantation located in Gwangneung experimental forest after 4 years from thinning. Three different thinning intensities [control, 45%(T45), and 60%(T60) basal area reduction] were applied in 2004. Mean soil temperature and soil water content were $8.9^{\circ}C$ and 14.3% for control, $10^{\circ}C$ and 16.1% for T45 and $10.2^{\circ}C$ and 16.1% for T60, respectively. Mean soil temperature and moisture content were significantly different among the treatment plots (p<0.05). Mean PAR in control, T45 and T60 was 44, 143 and178 ${\mu}mol/m^2$/sec, respectively and the differences were also statistically significant among the treatment plots (p<0.05). Mean annual diameter growth in control, T45 and T60 was 0.4, 1.5 and 1.2 mm, respectively. Diameter growth of Pinus koraiensis was steadily increased after thinning in comparison to control. Consequently, the results suggested that soil temperature, soil moisture content and light availability were likely to last beyond the 4 years after thinning in this Korean pine plantation.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.73-81
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• 2016

The objectives of this study were to determine the effects of thinning intensity on the changes of vegetation structure in Japanese Evergreen Oak(Quercus acuta Thunb.) stands in Wando-arboretum. The flora were composed of 24 families, 33 genera, and 36species in thinned sites. The dominant layer of control site showed higher number of plant species than that of treatment sites. On the while, the sub-dominant layer, shrub layer, and herbaceous layer treatment sites showed higher number of plant species than control site. According to the analysis of importance value, Q. acuta in the dominant layer, Q. acuta and Camellia japonica in sub-dominant layer, and Camellia japonica in shrub layer showed the highest importance values, respectively. The importance value of Trachelospermum asiaticum was the highest in the herbaceous layer. According to the results, species diversity was higher in descending order of heavy thinning, light thinning, and control. This result could be explained by increased light transmissions from higher thinning intensity than in other treatments. In this context, the results of this study may be useful for selecting appropriate tending methods in terms of forest management and biodiversity conservation.