• Proceedings of the PSK Conference
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• 2003.04a
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• pp.263.2-263.2
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• 2003

There is now increasing evidence that free radicals and active oxygen species are involved in a variety of pathological events. Free radical-mediated cell damage and free radical attack on polyunsaturated fatty acids result in the formation of lipid radicals. These lipid radicals react readily with molecular oxygen to produce peroxy radicals responsible for initiating lipid peroxidation. The peroxidation of cellular membrane lipid can lead to cell necrosis and considered to ve implicated in a number of pathophysiological conditions including liver disease. (omitted)

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.378-388
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• 2012

This study was carried out to investigate the optimum condition for sap exudation of Juglans mandshurica in comparison with Acer mono Max. trees in a site of Inje-Gun, Gangwon-Do, Korea. Amount of sap exudation, air temperature, relative air humidity and tree diameter at breast height (DBH) were monitored for the period of February 1 through March 31, 2008, and correlation analysis of several factors affecting on sap exudation was carried out. Sap exudation from J. mandshurica initiated on Feb. 28 as the same time in case of A. mono and continued for a month, and enhanced in early March compared to around the middle of March for A. mono. The amount of sap of A. mono was linearly proportional to the diameter at breast height (DBH) but there was no apparent relationship for J. mandshurica. As the amount of sap exudation per tree increased then sap exudation per unit DBH was also linearly proportional in both J. mandshurica and A. mono. The amount of sap exudation per unit DBH of J. manshurica were $0.3{\pm}0.1{\ell}/cm$ on average, which was one third times of $0.9{\pm}0.1{\ell}/cm$ for A. mono. During the days of enhanced sap exudation, the atmospheric conditions such as air temperature and relative humidity around J. manshurica trees were very similar with those of A. mono. The minimum temperature was a significant factor affecting the amount of sap of J. mandshurica whereas the range of temperature was the principal factor for A. mono. In conclusion, the sap of J. mandshurica exudated in atmospheric conditions similar to A. mono, but the amount of sap was affected by different atmospheric factors compared to A. mono.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.325-332
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• 2020

This study was conducted on cultivation farms in the Gimcheon area, which is the main production area of walnuts, in order to compare and analyze the yield and fruit quality of walnut trees (Juglans sinensis Dode) derived from seedlings. The official trees were classified into nine classes from 10 to 60 years old, and a total of 135 trees were selected, with 15 trees selected for each grade. The growth and fruit characteristics for each age group were then examined. The average tree height was 10.3 m, and the average crown area was 63.7 ㎡. The average number of fruit settings per tree was 573.1, with the largest number of walnuts per tree at 35 years (974.0 walnuts), and the lowest walnuts per tree at 10 years (124.7 walnuts). In addition, the number of fruit settings per bearing mother branch in 35 year old trees was the highest at 3.1. The average weight for each fruit type was found to be 58.7 ± 4.0 g of walnuts in green peel, 10.5 ± 0.5 g of dried shell walnuts, and 4.9 ± 0.2 g of walnuts, respectively. The average yield by fruit type was 32.5 ± 13.8 kg of walnuts in green peel, 5.9 ± 2.5 kg of dried shell walnut, and 2.8 ± 1.2 kg of walnuts. The yield was positively correlated with the crown area, the number of fruits setting per bearing mother branch, and the number of fruits setting per 1 ㎥. The formula used to estimate the yield per tree by age was calculated as y = 8993.9 ln (tree age-9) 8230.3, R² = 0.8531 (walnut in green peel) and y = 1647.1 ln (tree age-9) 1442.1, R² = 0.8527 (dried shell walnut).

• Journal of Korean Society of Forest Science
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• v.7 no.1
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• pp.3-7
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• 1968

The Capacity of wood to absorb water is very important as the basis data for wood industry, particularly in preservatives impregnation, manufacturing of improved wood, selection of packing boards, etc. In this study differences in Water absorbing Capacity of wood by structual section, water soaking time were investigated. (1) The species used in this investigation were Larix olgensis Henry Var. Koreana Nakai and Juglans mandshurica Max., and dimension of these testing wood block was $30{\times}30{\times}100cm$; and these were soaked in fresh water of $25{\pm}1^{\circ}C$ for 8.5day and 0.5 day, before measurement. (2) The result showed that the water absorption by cross sections was greater than by either radial or tangential section and there were no differences between radial and tangential section. (3) The water absorption of Juglans mandshurica Max. which has the relatively low specific gravity was greater than Larix olgensis Henry Var. Koreana Nakai which has generally high specific gravity. (4) The result showed an increase in the absorbed water with increase in the length of soaking time. However the water absorption rate during the early period of soaking was very high and thereafter the rate decreased with passage of time. More than a half of the total water absorption was achieved during the first 2 days approximately. (5) The relationships between the length of the soaking-time and water absorption were found to be as follows : Larix olgensis Henry Var. Koreana Nakai Cross section : $y=111.1{\times}^{0.6516}$ radial section : $y=32.2{\times}^{0.5146}$ tangential section : $y=36.5{\times}^{0.5112}$ Juglans mandshurica Max. Cross section : $y=216.1{\times}^{0.5914}$ radial section : $y=27.9{\times}^{0.5832}$ tangential section : $y=50.9{\times}^{0.4769}$ Where : y is amount of water absorption ($mg/cm^2$) x is water-soaking time (days).

• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.548-557
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• 2001

This study was carried out to classify forest vegetation of Mt. Myeonsan with phytosociological analysis of ZM School and to explain community types with CCA ordination. The research sites were located in the northern part of Kyungsangpook-Do area and in the southern part of Kangwon-Do. The 73 plots were investigated in the study areas which were including 291 plant species. The forest vegetation was classified into Quercus mongolica community group, Juglans mandshurica community group, and Larix leptolepis plantation. Q. mongolica community group was divided into 9 communities such as Rhododendron schlippenbachii community, Symplocos paniculata community, Pinus densiflora community, Betula schmidtii community, Fraxinus rhynchophylla community, Populus davidiana community, Tilia amurensis community, Betula costata community and Betula davurica community. J. mandshurica community group was divided into 5 communities and 4 groups such as Acer mono community (subdivided into Quercus serrata group and typical group), Fraxinus mandshurica community, Ulmus laciniata community (subdivided into typical group and Ribes mandshuricum group), Malus baccata community and Carpinus laxiflora community. And it was entirely classified into 17 vegetation units. According to CCA, Q. mongolica community group showed high positive correlation to topography, altitude and slope degree, and J. mandshurica community group showed high positive correlation to bare rock. However, L. leptolepis community group was not significantly ordinated with the gradient of environmental factors. And in correlation of axes, important environmental variables were topography and altitude.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.64-85
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• 1997

This study was to establish the floristic composition and vegetation of resources vascular plants of Mt. Mandukbong(1,035.3 m; $128^{\circ}$54'24'E, $37^{\circ}$36'53'N). This work were investigated during the period of 1996. Resources vascular plants were composed of 97 families, 298 genera, 406 species, 70 varieties and 8 formae, Totaling 484 taxa. Among the investigated resources plants. 15 taxa(2.6%) were Korean endemic species. The forest were comparatively well conservated by Pteridophyta calculation(Pte-Q), 1.1 Useful of resources plants were Edible source(46.7%), Pasture source(37.2%), Medicinal source(35.5%), Ornamental source(12.1%)and Timber source(5.9%) respectively. The forest vegetion was classified into 1 order, 1 alliances, 1 suballiances and 4 communities; Rhododendro - Quercetalia mongolicae Kim 1990 Lindero - Quercion mongolicae Kim 1990 A. Typical community B. Quercus variablilis - Quercus mongolica Community Callicarpo - Quercenion serratae Kim 1990 C. Carex humilis v. nana - Pinus densiflora Community D. Juglans mandshurica - Urtica angustifloia community

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.243-247
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• 2020

This study investigates bench grafting (BG) and field grafting (FG) in walnut by comparing the graft take rate, grade ratio, and simple earning rate using a conventional method. The mean grafting-take rate of the BG was 30.3% while that of FG was 77.1%. The quality of grafted seedlings is classified as good, fair, and poor. The quality grade ratio of FG seedlings is 3:4:3 (good:fair:poor) while the grade ratio of BG seedlings is 2:3:5. Field grafting resulted in 20% more good and fair seedlings than the BG method. As a result of calculating the earning rate with the sales income versus the input cost, FG has 1.5 times higher earning rate than BG. In summary, FG could be an alternative to conventional epicotyl grafting because it produced high-quality seedlings and increased productivity due to its high graft-take rate and earning rate.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.399-410
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• 2015

The objective of our study was to predict future cultivation areas for walnut trees (Juglans sinensis), using the cultivation suitability map provided from Korea Forest Service and MaxEnt modelling under future climate conditions. The climate conditions in 2050s and 2070s were computed using the Regional Climate Prediction (RCP) 4.5 and 8.5 scenarios with the HadGEM2-AO model. As a result, compared to the present area, the cultivation area of the western Korea including Chungcheongnamdo, Jeollabuk-do, Jeollanam-do decreased on a national scale under RCP 4.5, and those of Gyeongsangbukdo and part of Gyeongsangnam-do decreased under RCP 8.5. However, Gangwon-do which is located in higher altitude over 600 meters than other regions showed increases in cultivation areas of 18.3% under RCP 4.5 and of 56.6% under RCP 8.5 by 2070s. The predicted map showed large regional variations in the cultivation areas with climate change. From the analysis of current top ranking areas, the cultivation areas in Gimcheon-si and Yeongdong-gun dramatically decreased by 2070s under RCP 4.5 and 8.5; that of Gongju-si decreased more under RCP 4.5; and those of Muju-gun and Cheonan-si sustained the areas by 2070s under both scenarios. The results from this study can be helpful for providing a guide for minimizing the loss of walnut production and proactively improving productivity and quality of walnuts with regard to unavoidable climate change in South Korea.

• Journal of Nutrition and Health
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• v.47 no.4
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• pp.236-246
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• 2014

Purpose: Walnut is known to have unique favorable fatty acids, phytochemicals, and other nutrient profiles. As a result, there has been growing interest in evaluation of its health benefit related to cardiovascular disease (CVD). Although inverse associations of nut consumption and risk factors of cardiovascular disease have been reported in many epidemiological studies and qualitative reviews, few meta-analysis studies have been reported. This meta-analysis was conducted in order to evaluate the effect of a walnut-enhanced diet on CVD risk factors. Methods: We searched Pubmed, Cochrane, Science Direct, and KISS (Korean studies Information Service System) through July 2014. A random-effects meta-analysis was conducted on 17 trials reporting total cholesterol (TC), 14 trials reporting LDL cholesterol (LDL-C), 15 trials reporting HDL cholesterol (HDL-C), 17 trials reporting triglyceride (TG), and four trials reporting flow-mediated dilation (FMD). Results: In meta-analysis, intake of a walnut-enhanced diet resulted in significantly lowered TC, LDL-C, and TG by -0.124 mmol/l (95% CI, -0.209, -0.039; p = 0.004), -0.085 mmol/lL (95% CI, -0.167, -0.004; p = l0.039), and -0.080 mmol/l (95% CI, -0.155, -0.004; p = 0.039), respectively. The overall pooled estimate of the effect on FMD was +1.313% (95% CI, 0.744, 1.882, p = 0.000). HDL-C was not affected by walnut intake. No statistical heterogeneity was observed for any analysis. Results of funnel plots and Egger's regression suggested a low likelihood of publication bias in all biomarkers (p > 0.05). Conclusion: Findings of this meta-analysis provide consistent evidence that walnut-enhanced diet intake reduces the CVD risk factors.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.298-303
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• 2010

To explore on the defense strategies against hervivory of Juglans regia and J. mandshurica, morphological characteristics of the leaf, leaf domatia structure and the number, herbivores insects and mites on the leaves, collected from the trees growing in Mt. Chiak, Mt. Cheongtae, Mt. Jungwang, Namyangju-si and Wonju-si, were investigated from May to October, 2009. Domatia of J. mandshurica revealed tuft type, these of J. regia revealed pocket+tuft type. Domatia number per leaflet proved the higher figures, 28.3/leaflet for J. mandshurica, and the lower, 19.6/leaflet for J. regia. Leaf surface trichomes of J. regia revealed stellates only on the domatia structures, and that of J. mandshurica does dense stellates and glandular hairs on the leaf-blade and vein. Predatory mites' number per leaflet proved highly significant differences among tree species, and mean of predatory mites was higher values (4.8/leaflet) in J. mandshurica and lower values (3.5/leaflet) in J. regia. Small amount of nectar are found distal veinparts on the leaf margin of J. mandshurica. Dense glandular hairs on the lower leaf surfaces of J. mandshurica estimates useful strategy against herbivory. It may be possible to breed J. regia for better expression of leaf traits such as dense glandular hairs that increase predator populations and efficacy.