Effects of Thinning Intensity on Litterfall Production, Soil Chemical Properties, and Fine Root Distribution in Pinus koraiensis Plantation in Republic of Korea.

It is crucial to evaluate the effects of thinning on litterfall production, soil chemical properties, and fine root dynamics when implementing thinning as a silvilcultural technique to enhance tree growth and timber yield in Pinus koraiensis plantations. Thus, we determined the 10-year effects (2007-2017) of different thinning intensities on litterfall production, soil chemical properties, and fine root biomass and necromass within a P. koraiensis plantation in South Korea. The soil chemical parameters and fine root biomass and necromass were also compared across three soil depths (0-10, 10-20, and 20-30 cm). Three thinning treatments were employed: no thinning (CON), light thinning (32% removed, LT), and heavy thinning (64% removed, HT). Results revealed that litterfall was consistent across all thinning treatments, but broadleaf species had considerably higher litterfall production at HT stands than at CON/LT stands. Soil chemical properties, except exchangeable K+, were generally lower at LT stands, particularly at a depth of 20-30 cm soil. After ten years, there was a decrease in fine root biomass and necromass with increasing soil depth. Over 80% of fine roots were found in the upper layer (0-20 cm), while very fine roots (0-1 mm) consisted mainly of 47% pine and 53% other species and were concentrated in the 0-10 cm soil depth in HT. In conclusion, different thinning intensities had diverse effects on the parameters measured within the plantation. Future studies can explore how the effects of thinning intensities on litterfall production, soil chemistry, and fine root dynamics affect species diversity, carbon storage, and understory vegetation in P. koraiensis plantations.

A Comparison of Effect between Wet Gauze with Cold Normal Saline and Wet Gauze with Cold Water on Postoperative Thirst, Oral Cavity Condition, and Saliva pH / 기본간호학회지

PURPOSE: This study was aimed to compare the effect between wet gauze with cold normal saline and wet gauze with cold water on thirst, oral cavity condition, and saliva pH among postoperative patients. METHODS: This study was a quasi-experimental study with 56 participants. The experimental group received wet gauze with cold normal saline, and control group received wet gauze with cold water for three times at 15 minute intervals. Data were collected using visual analog scale for thirst, oral assessment guide for oral cavity condition and acidity tape for saliva pH. Measurement were made before applying the gauze and at 15min, 30min, and 45min after applying gauze. Data were analyzed using repeated measured ANOVA. RESULTS: Thirst, oral cavity condition, and saliva pH improved in both groups with increasing number of gauze application. Thirst for the experimental group improved more than for the control group (F=4.29, p=.009), oral cavity condition except saliva, and saliva pH were not significantly different between the groups. CONCLUSION: This study results indicated that nurses can apply wet gauze with cold normal saline to reduce thirst and saliva acidity, and to improve the oral cavity condition for postoperative patients.

Negative density dependence regulates two tree species at later life stage in a temperate forest.

Numerous studies have demonstrated that tree survival is influenced by negative density dependence (NDD) and differences among species in shade tolerance could enhance coexistence via resource partitioning, but it is still unclear how NDD affects tree species with different shade-tolerance guilds at later life stages. In this study, we analyzed the spatial patterns for trees with dbh (diameter at breast height) ≥2 cm using the pair-correlation g(r) function to test for NDD in a temperate forest in South Korea after removing the effects of habitat heterogeneity. The analyses were implemented for the most abundant shade-tolerant (Chamaecyparis obtusa) and shade-intolerant (Quercus serrata) species. We found NDD existed for both species at later life stages. We also found Quercus serrata experienced greater NDD compared with Chamaecyparis obtusa. This study indicates that NDD regulates the two abundant tree species at later life stages and it is important to consider variation in species' shade tolerance in NDD study.