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In 2013, the epidemics of pine wilt disease caused by the pine wood nematodes (Bursaphelenchus xylophilus) resulted in damages to the forests of black pine (Pinus thunbergii Parl.) trees in Jeju Island, Korea. Among the affected trees, an old black pine tree at Cave Temple on Mt. Sanbangsan was included and died due to the prevalence of pine wilt disease. The tree was on Mt. Sanbangsan, which was designated as a National Scenic Place with the Number 77 and was believed to be more than 400 years old in age. By examining the disc of the tree stem obtained from the height of 2 m, we counted the tree rings from 4 different directions and cross-dated the readings by comparing the records of drought simulated from the BROOK Model. Our analysis indicates that the tree seems to have grown since late 1860s. Contrary to the belief of the general public, we can conclude that the age of the tree was estimated to be at maximum 150 years, which means that it was not the same old tree as was shown in the painting of the Tam-Ra-Sun-Ryeok-Do (an old painting book for the Inspection Tour of Jeju Island) published in 1702. Discussion was extended to the life history of the tree in growth and leaning and the measures to protect the tree species from the damages of the pine wilt disease caused by pine wood nematodes.

Since the initiation of national Long-Term Ecological Research (LTER) Network activities in the US and China from 1980 and 1988, respectively, and that of the International LTER (ILTER) Network activities from 1993, there are currently more than 40 national/territorial LTER networks developed globally. The developmental stage of each national/territorial LTER network can be evaluated as a fully active network, a consolidating network, or an inactive network. In order for the Korea LTER Network to be promoted from a consolidating network to a fully active network, the categories and criteria for evaluating the stage of the Networks were suggested by stage, current status was evaluated, and further directions were suggested for each category. In this review, the developmental histories of the fully active LTER networks of the US and China were reviewed, and best practices were introduced. In order for the Korea LTER Network to be promoted from a consolidating network to a fully active network, the criteria to be further promoted include: establishing bylaws and organizational entities specified in the bylaws; making strategic plans in science, monitoring, and research; and finding the core mechanism to serve societies in education and outreach. The highest priority is to develop a strategic plan to promote the Korea LTER Network.

I conducted extensive analyses of daily weather data of precipitation and temperature monitored from the Surface Synoptic Meteorological Station in Seoul from 1 October 1907 to 31 December 2009 to understand how the climate is changing and the ecological implications for Seoul, Korea. Statistical analyses of the data, including the lengths of seasons and growing degree-days (GDD), showed a clear warming trend in the Seoul area over the study period. The mean daily temperature in Seoul increased by 2.40°C over the period of one hundred years, which was about three times faster than the global trend and it was striking to notice that mean daily temperature in Seoul in recent 30 years was increasing with the rate of 5.50°C per hundred years, which is an extremely fast rate of increase in temperature. In the last 100 years, an increase in the number of summer days was apparent, coupled with a reduction in the average number of winter days for about 27 to 28 days based on the analysis of mean daily temperature. Although the lengths of spring and autumn have not changed significantly over the century, early initiations of spring and late onsets of autumn were quite apparent. Total annual precipitation significantly increased at the rate of 2.67 mm/year over the last 100 years, a trend not apparent if the analysis is confined to periods of 30 to 40 years. The information has the potential to be used not only for better understanding of ecological processes and hydrology in the area, but also for the sustainable management of ecosystems and environment in the region.

To understand day-to-day fluctuations in soil moisture content in Seoul, I simulated daily soil moisture content from 1908 to 2009 using long-term climatic precipitation and temperature data collected at the Surface Synoptic Meteorological Station in Seoul for the last 98 years with a hydrological simulation model, BROOK. The output data set from the BROOK model allowed me to examine day-to-day fluctuations and the severity and duration of droughts in the Seoul area. Although the soil moisture content is highly dependent on the occurrence of precipitation, the pattern of changes in daily soil moisture content was clearly quite different from that of precipitation. Generally, there were several phases in the dynamics of daily soil moisture content. The period from mid-May to late June can be categorized as the initial period of decreasing soil moisture content. With the initiation of the monsoon season in late June, soil moisture content sharply increases until mid-July. From the termination of the rainy season in mid-July, daily soil moisture content decreases again. Highly stochastic events of typhoons from late June to October bring large amount of rain to the Korean peninsula, culminating in late August, and increase the soil moisture content again from late August to early September. From early September until early October, another sharp decrease in soil moisture content was observed. The period from early October to mid-May of the next year can be categorized as a recharging period when soil moisture content shows an increasing trend. It is interesting to note that no statistically significant increase in mean annual soil moisture content in Seoul, Korea was observed over the last 98 years. By simulating daily soil moisture content, I was also able to reconstruct drought phenomena to understand the severity and duration of droughts in Seoul area. During the period from 1908 to 2009, droughts in the years 1913, 1979, 1939, and 2006 were categorized as ‘severe’ and those in 1988 and 1982 were categorized as ‘extreme’. This information provides ecologists with further potential to interpret natural phenomenon, including tree growth and the decline of tree species in Korea. Key words: BROOK model, daily soil moisture content, drought duration, drought severity, fluctuation of soil moisture content, hydrological simulation model, Seoul

After introducing various aspects of the National Ecological Observatory Network (NEON) being planned and established in the US, the author tries to suggest the future direction for the development of similar activities of the NEON to be carried out in the region of East Asia including Korea. A review was carried out in terms of the challenges, major questions, missions, developmental history, and some other specifics of the NEON design. It was further extended to the discussion of the issues for the regional construction of the Ecological Observatory Network (EON) in East Asia. The author hopes that this review could be used as a preliminary guide in ultimately promoting and advancing research, science and technology in conservation and preservation of ecosystems being degraded due to anthropogenic disturbances in the region of East Asia.

To date, restoration ecology has focused on local areas, particularly small-scale ecosystems. As such, restoration ecology has been applied to areas with clear boundaries, such as roads, abandoned mines, wetlands, and forest ecosystems. However, those involved in these restoration efforts, due to their tendency to implement comprehensive plans to change the landscape structure, and their mismanagement of the restoration process, have more often than not wound up weakening the ecological functions of surrounding ecosystems, and in further degrading the ecosystem which they were trying to restore. To resolve these problems and restore a comparatively large-scale region, methods to assess the impact of such restoration efforts on surrounding ecosystems must be developed. These include expanding the scale of restoration efforts; in other words, moving from the local to the landscape scale. As a conclusion, practice of ecological restoration is increasingly moving towards landscape scale in order to deal with these problems.