• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.482-489
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• 2022

This study aimed to determine the optimal planting density of Fraxinus rhynchophylla assessed from the early growth performance at various planting densities over the 7-year period after planting. The study site was in Pyeongchang County, South Korea, and seedlings of 2-year-old (bare-root seedlings) F. rhynchophylla were planted at four densities (3,000, 5,000, 7,000, and 10,000 trees ha^-1) in March 2015. The survival rate, root-collar diameter (RCD), and height (H) were measured from 2015 to 2021, and the H/D (H/RCD) ratio and stem volume were calculated. The survival rate (84-97%) and H/D ratio (54.5-59.2%) were not affected by the planting density during the study period, but the RCD, H, and stem volume were significantly higher for 7,000 trees ha^-1 than for other planting densities. Especially, the stem volume (cm³ tree^-1) at 7 years after planting was highest for 7,000 trees ha^-1 (1,356.1), followed by 10,000 trees ha^-1 (958.6), 5,000 trees ha^-1 (773.0), and 3,000 trees ha^-1 (579.5). As the planting density increased, F. rhynchophylla seedlings showed initial rapid growth due to light competition, but relatively low growth at excessive planting densities. In the future, use of a suitable planting density considering planting costs should provide outstanding growth performance of F. rhynchophylla on plantations.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.219-226
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• 2014

Evaluation of tree responses to temperature elevation is critical for a development of forest management techniques coping with climate change. We conducted a study on the growth responses of Betula costata, Fraxinus rhynchophylla, and Quercus variabilis seedlings to open-field artificial warming. Artificial warming set-up using infra-red heater was built in 2012 and the temperature in warmed plots was regulated to be consistently $3^{\circ}C$ higher than that of control plots. The seeds of three species were sown, and the responses of growth, biomass allocation, and net photosynthetic rate of newly-germinated seedlings on the open-field artificial warming were determined. As a result, the growth responses of the seedlings differed with the species. B. costata showed decreases in the height to diameter ratio (H/D ratio), biomass, root weight to shoot weight ratio, and net photosynthetic rate. However, root collar diameter (RCD), height, biomass, and net photosynthetic rate of Q. variabilis were increased, while the response of F. rhynchophylla was rather obscure. There was no significant difference between warmed and control plots in seedling growth for 3 species in July, whereas, RCD, height, and H/D ratio of Q. variabilis were increased and H/D ratio of B. costata was decreased in November under warming. Species-specific growth responses to warming were similar to the species-specific responses of net photosynthetic rate and biomass allocation; therefore, net photosynthetic rate and biomass allocation might attribute to growth responses to warming. Besides, a relatively obvious response in autumn compared to summer might be affected by the phenological change following artificial warming. Species-specific responses of three deciduous species to warming in this study could be applied to the development of adaptive forest management policies to climate change.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.373-381
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• 2011

This study was carried out to investigate the growth and physiological responses to shading treatment of 1-year-old containerized seedling of Quercus myrsinaefolia. Experimental process was conducted in a facility that consisted of compartments under the lighting control with full sunlight and shading (35%, 55% and 75% of full sunlight). Height and root collar diameter growth were high in the seedlings under both 35% and 55% shading. Regardless of shading level, root collar diameter growth lasted for more than 4 weeks compared to height growth. Highest H/D ratio was observed in the seedlings under 35% shading as 4.31, and the lowest ratio was 3.63 under 75% shading. It was found that seedlings under 55% shading showed highest dry mass production, which was followed in seedlings under 35% shading. In case of leaf dry weight ratio (LWR) after shading treatment, the highest value was 0.53 under 55% shading, and followed in seedlings under 35% shading as 0.52. But root dry weight ratio (RWR) was highest as 0.36 under 75% shading (highest level of shading). In terms of shading treatment, it was found that the higher level of shading had a tendency toward the higher content of chlorophyll a and the higher total chlorophyll content in the leaves of Quercus myrsinaefolia, but there was no significant difference in the content of chlorophyll b depending on the level of shading. It was found that high photosynthesis and transpiration rate were more correlated with high level of shading than full sunlight, but the rates of seedlings had a tendency to be higher under 35% and 55% shading than under 75% shading. The results on growth and physiological responses to different shading levels of 1-year-old containerized seedlings of Quercus myrsinaefolia could be useful in setting up the optimum light intensity for growth, and in estimating the shade tolerance of the species.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.172-180
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• 2023

In the current study, four groups; control, 500, 1000, and 2000 mg/L, were treated to investigate the effects of physiological and growth characteristics on Machilus thunbergii under various fertilization levels. As a result of the physiological response to the fertilization treatment, the fertilized group demonstrated relatively higher levels of A, ITE, WUEi, V_camx, PI_abs, and SFI_abs in comparison to the control. The best photosynthetic mechanism was most clearly seen at 1000 mg/L, which involved gas exchange through active stomatal opening and closing. For a productive photosynthetic mechanism. As seen in the growth response of M. thunbergii to fertilization treatment, the fertilized group has significantly higher height, DRC, leaf dry weight, stem dry weight, total dry weight, LWR, and SWR than the control group. A healthy seedling quality index was particularly evident at 1000 mg/L, and other growth indicators were also at a decent level. 500 mg /L also demonstrated growth characteristics that were comparable to those at 1000 mg/L. As a result, M. thunbergii featured the best physiological and growth characteristics in response to the fertilization treatment at 1000 mg/L, and 500 mg/L also showed a similar trend, which is considered to be a good option from an economical perspective.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.281-290
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• 2020

The purpose of this study was to determine the optimal planting density for Zelokva serrata plantations. The study sites were located in Gyeongsan (GS) and Sunchang (SC), Korea. One-year-old, bare-root seedlings were planted at densities of 3,000; 5,000; 7,000; and 10,000 trees ha^-1 at the end of March 2015. We measured the root collar diameter and height each September from 2015 to 2019, and then calculated the H/D ratio and stem volume. The root collar diameter and height increased with increased planting density, and the stem volume was significantly higher at 10,000 trees ha^-1 than those at the other planting densities. Planting density did not affect the survival rate or H/D ratio. The root collar diameter, height, and stem volume were higher in GS than those in SC five years after planting. This study highlights that early growth performance was improved at increased planting densities at both sites. This study suggests that the initial planting density of 10,000 trees ha^-1 is suitable to improve the early growth performance of Z. serrata plantations, and that the improved growth performance at higher planting densities may be a silvicultural characteristic of Z. serrata.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.536-542
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• 2015

This study was examined for the growth response of tree diameter and volume to thinning treatments from different thinning intensities using three long-term thinning trials for Japanese Evergreen Oak (Quercus acuta Thunb.) stands in Wando island, Korea. After thinning in 1999, annual tree growth of diameter and volume was highest in heavy thinned stands for individual tree and this growth pattern of thinning response showed similar tendency to the individual tree growth response in light thinned stands. By increasing diameter growth, the value of H/D ratio (HDR) as an indicator of stem form was properly decreased and improved up to 80%. Although there is significant growth response of basal area in both heavily and lightly thinned stands, the growth potential both of heavily and lightly thinned stands in total stand volume is not likely to reach at the level of unthinned stands because of basal area growth loss associated with both light and heavy thinnings.

• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.465-472
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• 2017

In this study, containerized seedlings of Pinus densiflora (2-0) were planted in Iso-ri, Hwadong-myeon, Sangju-si, Gyeongbuk on April, 2015. It was planted by lightweight planting auger that Kyungpook University has developed and mattock which is the general planting method of containerized seedlings. With the square planting method ($1.8{\times}1.8m$), 225 trees were planted respectively and about 2 years of initial growth, survival rate and seedling quality index (SQI) were analyzed and investigated. According to the analysis result, the average root collar diameter (mm) of planted containerized seedlings that used lightweight planting auger and mattock reached 3.77 and 3.94 in 2015, 18.73 and 15.32 in 2016, and 27.8 and 23.9 in 2017 respectively. In addition, the average height of containerized seedlings rated 33.4 and 33.4 in 2015, 89.8 and 74.7 in 2016 and 120.7 and 97.9 in 2017. It turns out that the height of initial growth of containerized seedlings that are planted by lightweight planting auger were much higher than mattock. The survival rate of the containerized seedlings that used lightweight planting auger was also higher by 10% than that used mattock. Also, H/D rate (healthiness) and T/R rate were almost the same, however, for the SQI, 0.60 was for lightweight planting auger and 0.24 for mattock. It seems like the lightweight planting auger is more advantageous than mattock in initial growth.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.414-422
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• 2010

The objective of this study was to find optimal water condition of containerized seedling production of two tropical species for high seedling quality. This study was conducted to investigate photosynthesis, water use efficiency(WUE), Stomatal conductance(gs) and growth performances of containerized seedlings of Eucalyptus pellita and Acacia mangium growing under three different irrigation periods (1 time/1 day, 1 time/2 days and 1 time/3 days). E. pellita showed outstanding photosynthetic capacities at 1time/1day irrigation and A. mangium showed good photosynthetic capacity at all treatments. As irrigation period were shortened, gs of two species increased, while WUE of two species decreased. Root collar diameter and height of two species were the highest at 1 time/1 day irrigation, while the lowest at 1 time/3 days irrigation. As irrigation period were shortened, H/D ratio, biomass and seedling quality index (DQI) of two species increased but T/R ratio of two species showed the opposite tendency. These results showed that 1 time/1 day irrigation is optimal water condition of containerized seedling production of two tropical species and irrigation controlling is very important for growth and seedling quality of containerized seedling.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.28-38
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• 2012

This study was conducted to investigate growth performance, photosynthesis, water use efficiency (WUE), and stomatal conductance ($g_s$) of container seedlings of Liriodendron tulipifera and Zelkova serrata growing under three different irrigation periods (1 time/1 day, 1 time/2 days and 1 time/3 days) for high seedling quality. The root collar diameter and height of L. tulipifera and Z. serrata seedlings were highest with 1 time/1 day irrigation, whereas they were lowest with 1 time/3 days irrigation. The two species showed low drought tolerance. As irrigation period was shortened, biomass and seedling quality index (SQI) of the two species increased. The ratio of height to root collar diameter (H/D) and the ratio of below to aboveground biomass (T/R) of the two species were lower with 1 time/3 days than at other irrigation periods. L. tulipifera and Z. serrata seedlings showed significantly higher photosynthetic capacity with 1 time/1 day irrigation. As irrigation period was shortened, $g_s$ of two species increased, while their WUE decreased significantly (P<0.05) These results show that 1 time/1 day irrigation provides the most optimal water condition for container seedling production of two species and irrigation controlling is very important for growth and quality of container seedlings.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.455-462
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• 2013

The objectives of this study were to compare soil physical and chemical properties and early growth of Pinus densiflora and Larix kaempferi seedlings in harvested Larix kaempferi and Pinus rigida stands. Study stands were located in harvested L. kaempferi (Yeongju) and Pinus rigida (Wonju) plantations. Seedlings of L. kaempferi (1-1) and P. densiflora (1-0) were planted in April, 2008, Yeongju. Also, seedlings of L. kaempferi (1- 1) and P. densiflora (1-1) were planted with the density of 3,000 seedlings/ha in April, 2010, Wonju. We analyzed soil physical and chemical properties and the relative growth rate of seedlings using diameter at root collar and seedling height. Soil organic matter, total nitrogen and available phosphorus concentrations in harvested P. rigida stand were significantly higher than those in harvested L. kaempferi stand. The relative growth rate of P. densiflora seedlings with former stands were not significantly different. The relative growth rate of diameter at root collar of L. kaempferi seedling in harvested P. rigida stands were significantly higher than that in harvested L. kaempferi stand. Higher concentrations of organic matter, total nitrogen and available phosphorus in harvested P. rigida stand was probably positively affect to the early growth of seedlings.