Development processes and growth pattern of Pinus densiflora stands in central eastern Korea.

Stand growth and developmental processes were investigated in Pinus densiflora Siebold et Zucc. stands of different ages in the central eastern region of Korea. Stands were inventoried and five trees per stand were sampled for stem analysis, age estimation, and growth analysis. More than 80% of sampled trees in a stand were established within 3-5 years, and most stands had a single cohort structure. The initial growth of pine seedlings was slow, but the height growth accelerated beyond 2-3 m height, 5-10 years after establishment. Linear growth was maintained until 10-12 m height, at which suppressed trees fell behind and might die out. The young stand was composed of pure pines, while few pine seedlings and saplings were found in the understory of older stands. The peak of diameter growth rate occurred around 5-15 years after tree establishment, implying that competition begins during that period. The pine stand development follows four stages: (1) the young stage when the growth rate increases and peaks; (2) the height competition stage when trees focus on height growth for light while maintaining a narrow DBH and height distribution; (3) the differentiation stage when suppressed trees die out, and the DBH distribution becomes wider; and (4) the mature stage when stands have a multi-canopy structure with a wide DBH and height distribution, while the understory is dominated by other tree species. The changes in growth rates and stand structure through forest development would be implemented to predict alterations of above-ground carbon sequestration rates.

Changes in Thoracic Kyphosis and Thoracolumbar Kyphosis in Asymptomatic Korean Male Subjects Aged >50 Years: Do They Progress Above T5, T10, T12, or L2?

STUDY DESIGN: Retrospective analysis of prospectively collected data. PURPOSE: To evaluate the natural progression of segmental kyphosis in thoracic and thoracolumbar spine with advancing age. OVERVIEW OF LITERATURE: To our knowledge, the evolution of segmental thoracic kyphosis (TK) in individuals aged >50 years has not been reported. METHODS: Total 179 normal, asymptomatic Korean men were divided in to three groups (6th, 7th, and 8th decade) according to their age. Standard sagittal spinopelvic parameters, including TK and thoracolumbar kyphosis, were measured and subdivided into the following four segments: A (C7 upper end plate [UEP]-T5 UEP), B (T5 UEP-T10 UEP), C (T10 UEP-T12 lower end plate [LEP]), and D (T12 LEP-L2 LEP). These segments of the three study groups were analyzed. RESULTS: In segment B, the segmental kyphosis of group 3 (20.2°±8.0°) showed a statistically larger value than that of group 1 (15.6°±6.8°) and group 2 (16.7°±8.8°) (p=0.017). In segment C, the segmental kyphosis of group 2 (12.9°±6.5°) and group 3 (12.2°±7.1°) showed statistically larger values than that of group 1 (9.5°±6.2°) (p=0.016). The A and D segments of the three groups were not significantly different. CONCLUSIONS: Increased TK was observed in the middle (segment B) and lower (segment C) thoracic segments in normal asymptomatic male subjects with age. The results from the natural progression of segmental kyphosis with age would provide baseline reference data to help surgeons choose the optimal point of the upper instrumented vertebra level for preventing proximal junctional kyphosis.

The Characteristics of the Growth and the Active Compounds of Angelica gigas Nakai in Cultivation Sites.

The active compounds of medicinal plants vary in composition and content depending on environmental factors, such as light, temperature, and soil. According to the Korean Pharmacopoeia standards for herbal medicine, the sum of nodakenin, decursin, and decursinolangelate, which are the marker components of Korean Angelica, should be at least 6.0 g/100 g. However, the content of the components in Korean Angelica cultivated in South Korea often fall below 6.0 g/100 g, due to weather conditions and cultivation site characteristics. This study aimed to gather information about environmental factors that affect the root growth and the content of active compounds. In total, 18 cultivation sites in Pyeongchang, Jecheon, and Bonghwa regions in Korea were investigated for this study. Environmental factors, such as the monthly mean temperature, mean relative humidity, duration of sunshine, total precipitation, soil acidity, and the characteristics of soil nutrient, were investigated over the growing season from April to October 2017. As for the growth characteristics, the dry weight of roots of Korean Angelica was measured. The sum of the contents of the three active compounds was 5.3-7.0 g/100 g and the nodakenin content was 0.3-1.3 g/100 g in the cultivation sites. This study concludes that the root yields in the cultivation sites would be improved if weather conditions are maintained with similar levels as those in their natural habitats. Additionally, the environment that improves root growth did not increase the content of active compounds; however, when there was a lot of gravel or high temperatures during the growth period, the content of active compounds was relatively high.

Insecticidal and acetylcholine esterase inhibition activity of Asteraceae plant essential oils and their constituents against adults of the German cockroach (Blattella germanica).

The fumigant and contact toxicities of 16 Asteraceae plant essential oils and their constituents against adult male and female Blattella germanica were examined. In a fumigant toxicity test, tarragon oil exhibited 100% and 90% fumigant toxicity against adult male German cockroaches at 5 and 2.5 mg/filter paper, respectively. Fumigant toxicities of Artemisia arborescens and santolina oils against adult male German cockroaches were 100% at 20 mg/filter paper, but were reduced to 60% and 22.5% at 10 mg/filter paper, respectively. In contact toxicity tests, tarragon and santolina oils showed potent insecticidal activity against adult male German cockroaches. Components of active oils were analyzed using gas chromatography, gas chromatography-mass spectrometry, or nuclear magnetic resonance spectrometer. Among the identified compounds from active essential oils, estragole demonstrated potent fumigant and contact toxicity against adult German cockroaches. ß-Phellandrene exhibited inhibition of male and female German cockroach acetylcholinesterase activity with IC50 values of 0.30 and 0.28 mg/mL, respectively.

Carbon and nitrogen storage in an age-sequence of Pinus densiflora stands in Korea.

The carbon (C) and nitrogen (N) storage capabilities of Pinus densiflora in six different stand ages (10, 27, 30, 32, 44, and 71 years old) were investigated in Korea. Thirty sample trees were destructively harvested and 12 were excavated. Samples from the above and belowground tree components, coarse woody debris (CWD), forest floor, and mineral soil (0-30 cm) were collected. Tree biomass was highest in the 71-year-old stand (202.8 t ha(-1)) and lowest in the 10-year-old stand (18.4 t ha(-1)). C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands, mainly due to higher soil C and N concentrations. Consequently, the total ecosystem C and N storage (tree+forest floor+CWD+soil) was positively correlated with stand age: increasing from a minimum in the 10 year old stand (18.8 t C ha(-1) and 1.3 t N ha(-1)) to a maximum in the 71-year-old stand (201.4 t C ha(-1) and 8.5 t N ha(-1)). The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence, while N storage in the CWD, forest floor and mineral soil showed no significant temporal trends. Our results provide important insights that will increase our understanding of C and N storage in P. densiflora stands and our ability to predict changes according to stand age in the region.