Spatial distribution of carbon dynamics and nutrient enrichment capacity in different layers and tree tissues of Castanopsis eyeri natural forest ecosystem.

Taimoor Hassan Farooq,Wende Yan,Muhammad Farrakh Nawaz,Xen Xincheng,Sher Muhammad Shahzad,Muhammad Haroon U Rashid,Uttam Kumar,Awais Shakoor,Muhammad Farhan Bashir

doi:10.1007/s11356-021-16400-1

Abstract

Forest ecosystem carbon (C) storage primarily includes vegetation layers C storage, litter C storage, and soil C storage. The precise assessment of forest ecosystem C storage is a major concern that has drawn widespread attention in global climate change worldwide. This study explored the C storage of different layers of the forest ecosystem and the nutrient enrichment capacity of the vegetation layer to the soil in the Castanopsis eyeri natural forest ecosystem (CEF) present in the northeastern Hunan province, central China. The direct field measurements were used for the estimations. Results illustrate that trunk biomass distribution was 48.42% and 62.32% in younger and over-mature trees, respectively. The combined biomass of the understory shrub, herb, and litter layers was 10.46 t·hm-2, accounting for only 2.72% of the total forest biomass. On average, C content increased with the tree age increment. The C content of tree, shrub, and herb layers was 45.68%, 43.08%, and 35.76%, respectively. Litter C content was higher in the undecomposed litter (44.07 %). Soil C content continually decreased as the soil depth increased, and almost half of soil C was stored in the upper soil layer. Total C stored in CEF was 329.70 t·hm-2 and it follows the order: tree layer > soil layer > litter layer > shrub layer > herb layer, with C storage distribution of 51.07%, 47.80%, 0.78%, 0.25%, and 0.10%, respectively. Macronutrient enrichment capacity from vegetation layers to soil was highest in the herb layer and lowest in the tree layer, whereas no consistent patterns were observed for trace elements. This study will help understand the production mechanism and ecological process of the C. eyeri natural forest ecosystem and provide the basics for future research on climate mitigation, nutrient cycling, and energy exchange in developing and utilizing sub-tropical vegetation.

Highlights

As a dominant part of the terrestrial ecosystems, forests are essential for the earth’s biosphere
This study aimed to explore the (i) C content and contributions of C storage of different vegetative layers, litter layer, and soil layer at different depth profiles and (ii) nutrient enrichment capacity of vegetative layers to the soil in C. eyeri natural forest ecosystem (CEF) in the sub-tropical zone of central China
No significant difference was observed between residues litter and semi-decomposed litter (P= 0.084); Fig. 2 Comparing different diameter classes and age groups of Castanopsis eyeri in biomass distribution percentage among different tree organ. (DC1, 8-cm diameter at breast height (DBH), 10–15 years old; DC2, 16cm DBH, 15–25years old; DC3, 24-cm DBH, 25–35 years old; DC4, 32-cm DBH, 34–45 years old; DC5, 48-cm DBH, 45–60 years old)

Summary

Introduction

As a dominant part of the terrestrial ecosystems, forests are essential for the earth’s biosphere. They play a unique role in soil and water conservation, maintaining the regional and local environment, mitigating the greenhouse effect, and regulating carbon (C) balance (Farooq et al 2021a). They are the basis for the survival and development of various living materials on earth (Farooq et al 2019a). The research on forest ecosystem C storage and its C sink function has become a hot spot in international research

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