• Asian Journal of Atmospheric Environment
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• v.2 no.2
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• pp.81-89
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• 2008

The numerical simulation of wind and ozone ($O_3$) transport in mountainous regions was performed with a computational fluid dynamics technique. A dry deposition model for $O_3$ was designed to estimate $O_3$ deposition in complex terrain, and the qualitative validity of the predicted $O_3$ concentration field was confirmed by comparison with observed data collected with passive samplers. The simulation revealed that wind velocity increases around ridge lines and peaks of mountains. The areas with strong wind corresponded well with the sites of tree decline at high altitudes, suggesting that it is an important factor in the localization of tree/forest decline. On the other hand, there is no direct relationship between forest decline and $O_3$ concentration. The $O_3$ concentration, however, tends to increase as wind velocity becomes higher, thus the $O_3$ concentration itself may be a potential secondary factor in the localized decline phenomena. While the diffusion flux of $O_3$ is not related to localized tree decline, the pattern of advection flux is related to those of high wind velocity and localized tree decline. These results suggest that strong wind with large advection flux of $O_3$ may play a key role in the promotion of tree/forest decline at high mountain ridges and peaks.

• The Korean Journal of Ecology
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• v.26 no.2
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• pp.87-89
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• 2003

Although a forest damage of large area due to air pollution has not yet been found in Korea, declines of Korean red pine (Pinus densiflora Sieb. et Zucc.), the most common coniferous species, have been locally reported. To evaluate the effect of air pollution and acid deposition on the forests, SO$_2$ concentration, acid load, soil pH and tree decline were monitored for 13 years from 1988 to 2001 in Namsan, Doowang and Gyebangsan with the gradient of air pollution. During the study period, annual mean SO$_2$ concentration in Namsan, Doowang and Gyebangsan were 14 ppb, 13 ppb and 6 ppb, respectively. Annual mean acid loads in Namsan and Doowang were three to four times more than that in Gyebangsan. As respected, forest surface soils in Namsan and Doowang were acidified to pH 4.1 and 4.3, whereas that in Gyebangsan showed normal value as pH 5.4. On the other hand, decline degrees of Korean red pines in Namsan and Doowang in both 1996 and 2001 were higher than those in Gyebangsan. It is reasonable that the severer tree declines in Namsan and Doowang could be closely related with the higher air pollution, acid load, and the effects (possibly Ca deficit and Al toxicity) of soil acidification.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.241-249
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• 2023

Background: This study analyzed the drought responses of five forest tree species grown in Korean peninsula, Korean fir Abies koreana (Ak), eastern white pine Pinus strobus (Ps), keyaki Zelkova serrata (Zs), tulip tree Liriodendron tulipifera (Lt), and Japanese elm Ulmus japonica (Uj). Physiological (chlorophyll, root collar diameter [RCD]) and biochemical responses (non-structural carbohydrates, proline, lipid peroxidase and abscisic acid [ABA]) of the plants grown under mild (MD) and severe drought (SD) were compared. Results: In this study, three soil moisture regimes: control (100% precipitation), MD (60% reduction in precipitation) and SD (20% reduction in precipitation) were applied. Soil moisture content showed high water content in control site compared to MD and SD. A decline in RCD was found for Korean fir, keyaki, and tulip plants, with eastern white pine and Japanese elm showing no significant decline to the prolonged drought exposure (both MD and SD). Total chlorophyll showed a significant decline in Korean fir and tulip, with the sugar levels indicating a significant increase in Korean fir and keyaki species under SD compared to control plants. Non-significant decline in sugar level was noted for eastern white pine and Japanese elm. High accumulation of ABA, malondealdehyde and proline was noted in Korean fir, tulip, and keyaki under SD compared to control. Signs of tree mortality was only observed in Korean fir under MD (38%) and SD (43%). Conclusions: The observed findings indicate the drought responses of five tree species. The majority of the morpho-physiological (especially mortality) and biochemical variables assessed in our study indicate superior long-term drought resistance of Ps and Uj compared to the highly sensitive Ak, and moderately sensitive Lt and Zs. The results provided will help species selection for afforestation programs and establishment of sustainable forests, especially of drought-tolerant species, under increased frequency and intensity of spring and summer droughts.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.2
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• pp.1-10
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• 2011

Six pine trees (Pinus densiflora S. et Z.) at the Euilimji Lake Park in Jecheon were collected to investigate tree ages, growth decline pattern and the years of death. Tree-ring measurement was carried out using the Lintab with a resolution of 0.01mm. Tree age were 80-176 years. Cross-dating between the tree-ring series of each tree and the local chronology from Worak Mountain resulted that four and two trees died in 1998 and 1999, respectively. Three dead trees had only formed earlywood in the outermost tree ring and the others had incomplete latewood. Therefore, it was proven that the former trees died between spring and early summer, whereas the later ones died during late summer and/or autumn. The simultaneous deaths of trees suggest the insect damage and/or drought may be the crucial reason of the death, but frequent reaction woods, which were formed by leaning stem, and scars formed by physical damage may also contribute to the death.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.287-297
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• 1994

To elucidate the cause of growth decline of pitch pine (Pinus rigida) in Seoul, tree density, tree age and physico-chemical properties of soils were investigated at 33 sites of pitch pine forests in metropolitan Seoul, its vicinity and rural areas. The physical properties of soils except for soil texture in Seoul did not differ from those in rural areas. pH values, base saturation, and Ca and Mg contents of soils in Seoul, however, were significantly lower than those in suburbs and rural areas. In contrast, soluble Al and $S0_4^{2-}-S$ contents in Seoul were higher than those in rural areas. Low pH of forest soils in Seoul and suburbs seems to be caused by acid deposition. According to multiple regression analysis, growth of pitch pine in Seoul was affected by several factors in the following order: soil bulk density < Al content of soils < tree density < Mg contents of soil < tree age. We concluded that the acidification of forest soil can be a predisposing factor for the growth decline of pitch pine in metropolitan areas.

• Journal of Korean Society of Rural Planning
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• v.28 no.4
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• pp.1-9
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• 2022

Rural decline due to the decrease of the local population is an inevitable phenomenon, and a vicious cycle has been formed between a lack of basic living services and a population decrease in rural areas. Therefore, the study aims to derive the migration decision-making characteristics based on basic living service infrastructure data in rural areas. To do this, the population change over the past 20 years was categorized into six types, and the relationship between the classified population change types and the number of basic living service infrastructures was analyzed using decision tree analysis. Of the total 3,501 regions, 801 regions were the continuous decline type, of which 740 were rural areas. On the other hand, among 569 regions that were the continuous increase type, 401 regions were urban areas, confirming the population imbalance between rural and urban areas. As a result of the decision tree analysis on the relationship between population change types and the distribution of basic living service infrastructure, the number of daycare centers was derived as an important variable to classify the continuous increase type. Hospitals, parks, and public transportation were also found to be major basic living services affecting the classification of population change types.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.383-387
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• 2005

In order to clarify the causal of free decline, which observed around the industrial complex, we analyzed pH, electrical conductivity (EC), and cation in rainfall and throughfall cations concentration in the air in tree areas, suburban and rural area. pH of both rainfall and throughfall was lower in the industrial area than the suburban and rural areas. Among the abiotic and biotic factors analyzed in this study, relations between decline degree of Pinus thunbergii and ingredients of rainfall, pH and $Ca^{2+}$ showed negative and positive correlations, respectively.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.109-113
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• 2009

Tree-ring width analysis has been used to assess the effects of air pollution on tree growth around industrial complexes. Our study was conducted to elucidate the effect of air pollutants on annual ring growth in black pines (Pinus thunbergii) of age 41$\sim$48 years around Ulsan Metropolitan City. The growth data were analyzed by multiple regression and the results are as follows: 1. The annual ring increment of black pines increased with tree age until age 40 years and then decreased gradually after age 40 years. 2. The increment of annual ring width of black pines was affected more by precipitation and evapotranspiration than air temperature. An annual ring decline appeared in the years 1968$\sim$1983, when annual ring indices below zero were observed. Decreased annual ring growth during this period may have been due to air pollution. 3. The heavy metal with the strongest effect on annual ring growth of black pines in the experimental stand was lead (Pb). The concentration of lead in the stand was estimated as over 6 ppm. 4. The technique of tree-ring width analysis may be useful for estimation of the extent of pollution in forest areas near industrial complexes.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1134-1138
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• 2006

Forest tree leaves (12 different species) of semi hilly arid region of Punjab State were collected at 30-day interval throughout the year to assess the seasonal variations in tannin profile. Tannins were extracted and fractionated from fat free samples and data were analyzed statistically by $12{\times}12$ factorial design. The leaves of Anogeissus latifolia had the highest (p<0.05) concentration of total phenols (17.4%), net (15.9%) and hydrolysable (16.9%) tannins, followed by leaves of Acacia nilotica. Majority of the tree leaves selected had moderate levels (2-5%) of net tannins. Leaves of Carrisa had the highest (p<0.05) concentration of condensed tannins (CT), whereas the leaves of Anogeissus had the lowest (p<0.05) concentration of condensed tannins. The protein precipitable phenols (PPP) corresponded well with the net tannin content present in different tree leaves. Seasonal variation data revealed that in summer, net tannins and PPP decline in leaves of Bauhinia and Zizyphus whereas the net tannin content of Anogeissus and that of Carrisa increased during summer. The CT and PPP content in the leaves of Pheonix, Leucaena, Zizyphus and Ougenia increased in winter till spring season. Tree leaves generally had higher concentration of HT during summer months. It was concluded that leaves of leaves of A. nilotica, A. latifolia and L. leucocephala could serve as an excellent alternate feed stuffs for ruminants. However, leaves of Phoenix, Carrisa, Bauhinia and Dodonea should be avoided.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.2
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• pp.76-81
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• 2021

With continuous decline of Philippine forest cover, sustainable forest management and restoration are essential to restore destroyed forest ecosystems. Unfortunately, of ten most planted trees in reforestation projects in the Philippines, eight are exotic species, with large leaf mahogany (Swietenia macrophylla) being the most dominant. In this study, effect of Swietenia macrophylla in reforestation projects on native tree species was evaluated. Effects of S. macrophylla leaf litter, frequency, and canopy closure on the growth of the Philippine native species Pterocarpus indicus were investigated. Results showed that S. macrophylla leaf litter significantly inhibited the growth of P. indicus seedlings based on root collar-to-shoot height. The standardized growth rate of seedlings in plots without S. macrophylla leaf litter was significantly higher than the growth rate of seedlings in plots with leaf litter. Furthermore, there was no significant difference in the standardized growth rate of seedlings between plots without leaf litter and a control plot. On the contrary, S. macrophylla tree frequency and canopy closure showed no significant effect. These results attest to the negative effect of widely planted S. macrophylla to a valuable Philippine native tree P. indicus. With accumulating scientific evidence about negative effects of S. macrophylla on native trees, discontinued use in tree planting and reforestation efforts with active management of restoration sites previously planted with large leaf mahogany are needed.