Carbon and Nitrogen Responses in Litterfall and Litter Decomposition in Red Pine (Pinus densiflora S. et Z.) Stands Disturbed by Pine Wilt Disease

Abstract

Research Highlight: Forest disturbance by insects or disease can have a significant influence on nutrient return by litterfall and decomposition, but information regarding disturbance gradients is scarce. This study demonstrated that the disturbance intensity caused by pine wilt disease greatly altered the quality and quantity of carbon (C) and nitrogen (N) in litterfall components and decomposition processes. Background and Objectives: This study was conducted to evaluate the C and N status of litterfall and litter decomposition processes in a natural red pine (Pinus densiflora S. et Z.) stand disturbed by pine wilt disease in southern Korea. Nine red pine plots with varying degrees of disturbance caused by pine wilt disease were established based on differences in the stand basal area. Litterfall and the decomposition of needle litter and branches under different degrees of disturbance were measured for three years. Results: There was a significant correlation (p < 0.05) between disturbance intensity and the C and N concentration of litterfall components depending on the time of sampling. The annual C and N inputs through litterfall components decreased linearly with decreasing disturbance intensities. The decomposition rates of branches were higher in slightly disturbed plots compared with severely disturbed plots for the late stage of branch decomposition, whereas the decomposition rates of needle litter were not affected by the disturbance intensity of pine wilt disease. Carbon and N concentrations from needle litter and branches were not linearly related to the intensities of disturbance, except for the initial stage (one year) of needle litter decomposition. Conclusions: The results indicated that the incidence of pine wilt disease was a major cause of C and N loss through litterfall and decomposition processes in pine wilt disease disturbed stands, but the magnitude of loss depended on the severity of the disease disturbance.

Comparisons of carbon and nitrogen dynamics of litterfall components in adjacent Pinus densiflora and Quercus variabilis stands

“…The C concentrations of the litterfall components were similar to other study results, in which the leaf litter was approximately 50% in P. densiflora stands in South Korea (Kim et al 2019) and 47.5% in Q. variabilis stands in China (Du et al 2017), but lower than those of P. brutia stands (51.24 %) in Turkey (Erkan et al 2020). The mean N concentrations of the leaf, branch, reproductive, and miscellaneous litter in this study are comparable to other studies in Q. variabilis in China (Du et al 2017) and in P. brutia stands in Turkey (Erkan et al 2020).…”

“…C and N concentrations of litterfall components. The variations in the C and N concentrations of the litterfall components are mainly determined by the species and sampling months (Thomas, Martin 2012;Kim et al 2019;See et al 2019;Erkan et al 2020). Many studies have reported that the C concentration of the litterfall is negatively correlated with the N and positively correlated with the lignin concentration (Macinnis-Ng, Schwendenmann 2015; Kim et al 2017;See et al 2019).…”

“…Thereby, the importance of a quantitative evaluation of the C and N inputs by litterfall is increasing. However, the C and N concentrations and litterfall input are determined by environmental factors, ecological factors, and forest management activities (An et al 2017;Kim et al 2019;Erkan et al 2020;Jasińska et al 2020). In particular, differences in the litterfall inputs among stands may have crucial consequences for the C and N cycling of a stand due to the differences in the leaf or non-leaf litter inputs (Bray, Gorham 1964;Erkan et al 2020).…”

Effect of Litter Quality on Needle Decomposition for Four Pine Species in Korea

“…Although a few studies on litter decomposition have been conducted in pine forests, there is limited information on the effects of physicochemical litter quality on decomposition of different pine litter species, because these studies contain only a simple description of changes in nutrient elements in decaying litter [38][39][40][41]. Moreover, it is difficult to directly compare the results of these studies, because each pine species was independently studied at different times, with varying areas, litter type, and forest floor characteristics [38][39][40][41][42][43][44][45][46]. Also, it is not clear if the differences in decomposition rate of each type of pine litter is attributable to the kinds of environmental conditions present or the chemical properties of the litter.…”

Different Molecular Characterization of Soil Particulate Fractions under N Deposition in a Subtropical Forest

“…Compared with other analytical techniques, pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) is more efficient and can provide a larger view of SOM chemical structural information [19,22]. In addition, py-GC/MS also facilitates a better understanding of the extent of the decomposition/preservation in SOM pools and a detailed comparison of the SOM produced under different managements [23][24][25]. Furthermore, advantages of this pyrolysis analysis over others include good repeatability and a relatively small amount of soil samples required [26][27][28].…”