Publications by authors named "Nam-Jin Noh"

Invasive alien plants (IAPs) pose significant threats to native ecosystems and biodiversity worldwide. However, the understanding of their precise impact on soil carbon (C) dynamics in invaded ecosystems remains a crucial area of research. This review comprehensively explores the mechanisms through which IAPs influence soil C pools, fluxes, and C budgets, shedding light on their effects and broader consequences.

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The frequency and intensity of summer extreme climate events are increasing over time, and have a substantial negative effect on plants, which may be evident in their impact on photosynthesis. Here, we examined the photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings to extreme heat (+ 3 °C and + 6 °C), drought, and heavy rainfall by conducting an open-field multifactor experiment. Leaf gas exchange in L.

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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 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 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).

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Carbon (C) sequestration capacity in forest ecosystems is generally constrained by soil nitrogen (N) availability. Consequently, N fertilization is seen as a promising tool for enhancing ecosystem-level C sequestration in N-limited forests. We examined the responses of ecosystem C (vegetation and soil) and soil N dynamics to 3 years of annual nitrogen-phosphorus-potassium (NPK = 11.

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Significantly more carbon (C) is stored in deep soil than in shallow horizons, yet how the decomposition of deep soil organic C (SOC) will respond to rising temperature remains unexplored on large scales, leading to considerable uncertainties to predictions of the magnitude and direction of C-cycle feedbacks to climate change. Herein, short-term temperature sensitivity of SOC decomposition (expressed as ) from six depths within the top 1 m soil from 90 upland forest sites (540 soil samples) across China is reported. Results show that significantly increases with soil depth, suggesting that deep SOC is more vulnerable to loss with rising temperature in comparison to shallow SOC.

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Plant respiration can acclimate to changing environmental conditions and vary between species as well as biome types, although belowground respiration responses to ongoing climate warming are not well understood. Understanding the thermal acclimation capacity of root respiration (Rroot) in relation to increasing temperatures is therefore critical in elucidating a key uncertainty in plant function in response to warming. However, the degree of temperature acclimation of Rroot in rainforest trees and how root chemical and morphological traits are related to acclimation is unknown.

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Atmospheric carbon dioxide enrichment (eCO) can enhance plant carbon uptake and growth, thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO concentration. Although evidence gathered from young aggrading forests has generally indicated a strong CO fertilization effect on biomass growth, it is unclear whether mature forests respond to eCO in a similar way. In mature trees and forest stands, photosynthetic uptake has been found to increase under eCO without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO unclear.

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Determining soil carbon (C) responses to rising temperature is critical for projections of the feedbacks between terrestrial ecosystems, C cycle, and climate change. However, the direction and magnitude of this feedback remain highly uncertain due largely to our limited understanding of the spatial heterogeneity of soil C decomposition and its temperature sensitivity. Here we quantified C decomposition and its response to temperature change with an incubation study of soils from 203 sites across tropical to boreal forests in China spanning a wide range of latitudes (18°16' to 51°37'N) and longitudes (81°01' to 129°28'E).

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To quantify stem respiration (R ) under elevated CO (eCO ), stem CO efflux (E ) and CO flux through the xylem (F ) should be accounted for, because part of respired CO is transported upwards with the sap solution. However, previous studies have used E as a proxy of R , which could lead to equivocal conclusions. Here, to test the effect of eCO on R , both E and F were measured in a free-air CO enrichment experiment located in a mature Eucalyptus native forest.

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Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO. In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future (around 2085) changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model.

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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.

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We investigated the influence of stand density [938 tree ha(-1) for high stand density (HD), 600 tree ha(-1) for medium stand density (MD), and 375 tree ha(-1) for low stand density (LD)] on soil CO(2) efflux (R (S)) in a 70-year-old natural Pinus densiflora S. et Z. forest in central Korea.

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To investigate annual variation in soil respiration (R (S)) and its components [autotrophic (R (A)) and heterotrophic (R (H))] in relation to seasonal changes in soil temperature (ST) and soil water content (SWC) in an Abies holophylla stand (stand A) and a Quercus-dominated stand (stand Q), we set up trenched plots and measured R (S), ST and SWC for 2 years. The mean annual rate of R (S) was 436 mg CO(2) m(-2) h(-1), ranging from 76 to 1,170 mg CO(2) m(-2) h(-1), in stand A and 376 mg CO(2) m(-2) h(-1), ranging from 82 to 1,133 mg CO(2) m(-2) h(-1), in stand Q. A significant relationship between R (S) and its components and ST was observed over the 2 years in both stands, whereas a significant correlation between R (A) and SWC was detected only in stand Q.

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