Comparison of Carbon Dynamics among Three Cool-Temperate Forests (&amp;lt;i&amp;gt;Quercus serrata, Larix kaempferi&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Pinus densiflora&amp;lt;/i&amp;gt;) under the Same Climate Conditions in Japan

Mitsutoshi Tomotsune,Yuki Kato,Yuta Koyama,Rina Masuda,Yoshiaki Sakamaki,Yohei Suzuki,Nobuhiko Suminokura,Hiroshi Koizumi

doi:10.4236/jep.2019.107055

Abstract

To understand the role of forest ecosystems in the global carbon cycle, it is important to clarify the factors affecting the carbon balance of forest ecosystems. However, little is known about the direct effect of forest types, especially dominant species, on their different carbon dynamics. To clarify the effect of difference in forest types, an experiment was conducted in three forests, which were located in the same place and exposed to the same climate conditions. These forests were middle-aged (40 - 45 years) and dominated by Quercus serrata (Q forest), Larix kaempferi (L forest) and Pinus densiflora (P forest). Net primary production (NPP), heterotrophic respiration (HR) and net ecosystem production (NEP) were estimated in each forest, using a biometric method over one year. For NPP estimated from the annual growth of tree biomass (ΔB) and amount of litter (LF), P forest NPP (5.3 MgC·ha-1·yr-1) was higher than Q and L forest NPP (4.6 and 3.2 MgC·ha-1·yr-1). The difference was affected by a significant difference in ΔB (p = 0.032) and LF (p -1·yr-1) was higher than L and P forest (2.3 and 2.1 MgC·ha-1·yr-1). This difference could result from the amount of litter (respiration substrate) and chemical properties of litter (lability of decomposition). The NEP, which was calculated from the difference between NPP and HR, varied widely among the forest types (0.5, 0.9 and 3.2 MgC·ha-1·yr-1 in Q, L and P forests, respectively). The range of values among the forest types was comparable to those among age sequences and climate zones in previous studies. These results suggest that the difference in forest types (especially dominant species) can potentially lead to a large variation in carbon dynamics, in ecosystems located in the same place.

Highlights

Many studies have found that forest ecosystems have a major role in the global carbon cycle as a carbon sink between the ecosystem and atmosphere [1] [2]
The net ecosystem production (NEP), which was calculated from the difference between Net primary production (NPP) and heterotrophic respiration (HR), varied widely among the forest types (0.5, 0.9 and 3.2 MgC·ha−1·yr−1 in Q, L and P forests, respectively)
The carbon balance of forest ecosystems has been generally evaluated as net ecosystem exchange (NEE) and net ecosystem production (NEP) by eddy covariance and biometric methods

Summary

Introduction

Many studies have found that forest ecosystems have a major role in the global carbon cycle as a carbon sink between the ecosystem and atmosphere [1] [2]. The carbon balance of forest ecosystems has been generally evaluated as net ecosystem exchange (NEE) and net ecosystem production (NEP) by eddy covariance and biometric methods The former method can directly measure the carbon balance between the ecosystems and the atmosphere, and has been used to determine the carbon balance on a regional scale [3] [4] [5]. The sum of the flow rate is regarded as the total carbon balance of the ecosystem to atmosphere (NEP) and can clarify which components affect variations in the total carbon balance [6] [7] [8] This method is suitable for a comparison of carbon dynamics between different ecosystems or inter-annual variations within an ecosystem

Methods

Discussion

Conclusion