The oxygen concentration data in a forest canopy in 2020 in Beijing Gongqing Forestry Farm

ChangShan Xing

doi:10.12688/f1000research.129399.1

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Data Note

The oxygen concentration data in a forest canopy in 2020 in Beijing Gongqing Forestry Farm

[version 1; peer review: 1 approved with reservations]

ChangShan Xing

PUBLISHED 20 Jul 2023

Author details Author details

Beijing Gongqing Forestry Farm, Beijing Municipal Forestry and Parks Bureau, Beijing, China

ChangShan Xing
Roles: Conceptualization, Data Curation, Formal Analysis, Investigation, Methodology, Writing – Original Draft Preparation

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Abstract

Background: With the outbreak of global climate problems in recent years, more and more countries have proposed carbon neutral plans. The measurement of forest carbon sinks is gradually becoming a research hotspot in the field of carbon sinks.
Methods: Based on observations of the amount of change in oxygen concentration in the forest canopy, we propose a simple and accurate method of forest carbon sinks measurement.
Conclusions: In this data note, we provide the data of oxygen concentration in the canopy of a 160-hectare forest in Beijing, and give a convenient equation for calculating the carbon sequestration and carbon sink according to the changes of 15 days oxygen concentration.

Keywords

Forest Carbon Sinks; Measurement; Average oxygen concentration; Carbon Sequestration

Corresponding author: ChangShan Xing

Competing interests: No competing interests were disclosed.

Grant information: The author(s) declared that no grants were involved in supporting this work.

Copyright: © 2023 Xing C. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

How to cite: Xing C. The oxygen concentration data in a forest canopy in 2020 in Beijing Gongqing Forestry Farm [version 1; peer review: 1 approved with reservations]. F1000Research 2023, 12:856 (https://doi.org/10.12688/f1000research.129399.1) First published: 20 Jul 2023, 12:856 (https://doi.org/10.12688/f1000research.129399.1) Latest published: 20 Jul 2023, 12:856 (https://doi.org/10.12688/f1000research.129399.1)

Introduction

Forest carbon sinks represent the ability of forest ecosystems to absorb and store carbon dioxide by quantifying the mass of carbon dioxide fixed by plants.¹^,² It is an important indicator for assessing the impact of global climate change, management measures, and human disturbance on forest ecological function, growth, and survival.³^,⁴ Therefore, accurate quantification of carbon sinks is essential for the effective assessment of forest function dynamics. However, the most common way to measure the changes in carbon sequestration right now is the stock-difference method, which calculates the forest gross primary productivity (GPP) rather than net ecosystem productivity.⁵ The gain-loss method⁶ is based on monitoring the changes of carbon dioxide in the air, which not only have large errors but also cannot be verified by test and measurement. Therefore, an accurate, accessible, low-cost, short-period observation method is useful for observing forest functional dynamics and convenient to promote in the forestry, agriculture, grass industry, and other related industries.

In this data note, we provide the data on oxygen concentration in the canopy of a 160-hectare forest in Beijing, and give a convenient equation for calculating the carbon sequestration and carbon sink according to the changes of 15 days’ oxygen concentration.

Methods

Overview of the research area

The research was conducted in Beijing Gongqing Forestry Farm, which is located in the northeast of Beijing. This area was selected as the ecological environment here is very representative of northern China. The details of the forest are as follows:

(1) The geographical coordinates are 166.40 E and 40.10 N;
(2) The altitude is 25 meters;
(3) The soil type is sandy soil;
(4) The forest type is planted forest;
(5) The main tree species are populus canadensis Moench. The average tree height of the poplars was 21 meters, the average canopy height was 12 meters, and the average tree age was 25 years;
(6) The region has a warm, temperate, semi-humid, continental monsoon climate with four distinct seasons; it is dry and windy in spring, hot and rainy in summer, cool and crisp in autumn and cold and dry in winter;
(7) The annual average temperature is 11.5 °C;
(8) The annual sunshine is about 2750 hours;
(9) The average annual rainfall is about 625 mm; the area is relatively arid.

Experimental setup

The forest carbon sink was observed by a 30 meter high measuring tower which was set in the center of the 160-hectare forest. An oxygen concentration detector (HeNan ChiCheng Electric Co. Ltd, QB2000N) was installed 15 meters above ground on the measuring tower to ensure the detector was located in the middle of the canopy. This setup was designed specifically for this research. The error value of the oxygen concentration detectors had been adjusted to less than ±0.5%.

The oxygen concentration detector measured the oxygen concentration (% Vol.) every 5 minutes per day.⁷ Furthermore, we calculated the daily average oxygen concentration of the forest (Figure 1; Table 1). Since trees only begin to grow and release oxygen at a temperature higher than their biological zero (and the biological zero of poplar is more than 10 degrees Celsius), and the average temperature of Gongqing Forestry Farm from March 10th to March 24th is 10.17 degrees Celsius, the starting point of data recording in spring was March 10. The endpoint of data recording in autumn should be set at the time point when the oxygen concentration was higher than the starting point in spring, so the endpoint in autumn is October 5th.

Figure 1. Daily average oxygen concentration from March 10th to October 5th.

Table 1. Forest carbon sinks meter.

Date	Cell	Average oxygen concentration	Difference of average value of oxygen concentration every 15 days	Summation of average difference of oxygen concentration	Unites: oxygen concentration: % vol; Mass: kg; Oxygen Density: kg/m³; Height: m; Area: m²
Date	Cell	Average oxygen concentration		Summation of average difference of oxygen concentration	Canopy height	Area	The mass of sequestrated CO₂	The mass of released CO₂	Forest carbon sinks
3.10-3.24	1	20.56		0.43	12		M_CO₂ = 0.431.43121000044/32 = 101458.5 kg	M_CO₂ = -0.361.43121000044/32 = -84942 kg	M = 16516.5 kg
			0.08
3.25-4.08	2	20.64			12
			0.11
4.09-4.23	3	20.75			12
			0.07
4.24-5.08	4	20.82			12
			0.01
5.09-5.23	5	20.83			12
			0.08
5.24-6.07	6	20.91			12
			0.08
6.08-6.22	7	20.99			12
			-0.11	-0.36
6.23-7.07	8	20.88			12	10000 m²
			-0.02
7.08-7.22	9	20.86			12
			0
7.23-8.06	10	20.86			12
			-0.03
8.07-8.21	11	20.83			12
			-0.02
8.22-9.05	12	20.81			12
			-0.04
9.06-9.20	13	20.77			12
			-0.14
9.21-10.05	14	20.63			12

The measurement of forest carbon sinks

During photosynthesis, plants absorb carbon dioxide and release oxygen. Their amount of substance is equal to the mass divided by the molar mass. Therefore, the value of plant carbon sequestration can be calculated by the following formula:

M_{{co}_{2}} = (\sum v) ρ hs ({mr}_{{co}_{2}} / {mr}_{o_{2}})

M_co₂ is the mass of plant fixed carbon dioxide, and $\sum v$ is the accumulated value of oxygen concentration difference during a specific period (based on experience, 15 days is used as the most appropriate the measurement period), ρ is the oxygen density 1.43kg/m³, h is the average height of the photosynthetic part of the plant, s is the area of the plant, mr_co₂ is the molecular weight of CO₂ (44), and mr_o₂ is the molecular weight of O₂ (32).

Data availability

Underlying data

figshare: The oxygen concentration data in Forest Canopy of 2020 in Beijing Gongqing Forestry Farm, https://doi.org/10.6084/m9.figshare.22735811.v1.⁷

This project contains csv files of oxygen concentration data, labelled with the collection dates.

Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).

Acknowledgments

This article has previously been made available as a preprint (DOI: https://doi.org/10.21203/rs.3.rs-1141066/v1). Thanks to both authors JIANG LV and YUN SHI for their contributions to this article.

References

1. UNFCCC: Kyoto Protocol to the United Nations Framework Convention on Climate Change.1998. Acesso em: 25 out. 2019. Reference Source
2. Pan Y, Birdsey RA, Fang J, et al.: A Large and Persistent Carbon Sink in the World’s Forests. Science. 2011; 333: 988–993. PubMed Abstract | Publisher Full Text
3. Gampe D, Zscheischler J, Reichstein M, et al.: Increasing impact of warm droughts on northern ecosystem productivity over recent decades. Nat. Clim. Chang. 2021; 11(9): 772–779. Publisher Full Text
4. Sitch S, Friedlingstein P, Gruber N, et al.: Recent trends and drivers of regional sources and sinks of carbon dioxide. Biogeosciences. 2015; 12: 653–679. Publisher Full Text
5. Forestry Carbon Sequestration Editorial Board: Forestry Carbon Sequestration: practice in Beijing. China Forestry Publishing House; 2016. (In Chinese).
6. Li NY, Lv J: Carbon Inventory Methods. China Forestry Publishing House; 2009. (In Chinese).
7. Xing: The oxygen concentration data in Forest Canopy of 2020 in Beijing Gongqing Forestry Farm. [Dataset]. figshare. 2023. Publisher Full Text

Comments on this article Comments (0)

Version 1

VERSION 1 PUBLISHED 20 Jul 2023

Author details Author details

Beijing Gongqing Forestry Farm, Beijing Municipal Forestry and Parks Bureau, Beijing, China

ChangShan Xing
Roles: Conceptualization, Data Curation, Formal Analysis, Investigation, Methodology, Writing – Original Draft Preparation

Competing interests

No competing interests were disclosed.

Grant information

The author(s) declared that no grants were involved in supporting this work.

Article Versions (1)

version 1

Published: 20 Jul 2023, 12:856

https://doi.org/10.12688/f1000research.129399.1

© 2023 Xing C. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Xing C. The oxygen concentration data in a forest canopy in 2020 in Beijing Gongqing Forestry Farm [version 1; peer review: 1 approved with reservations]. F1000Research 2023, 12:856 (https://doi.org/10.12688/f1000research.129399.1)

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Open Peer Review

Version 1

VERSION 1

PUBLISHED 20 Jul 2023

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Reviewer Report 26 Oct 2023

Zheng-Hong Tan, Professor of Ecology, Yunnan University, Kunming, Yunnan, China

Approved with Reservations

https://doi.org/10.5256/f1000research.142084.r194292

I can not follow the logic or principle of calculating carbon sequestration by oxygen concentration data as provided by author. As shown in closed chamber method, we will calculate the flux by a linear fitting on concentration data. In this case, there less a confidential control volume below the sensor height where lateral flow might occur. More importantly, it is not reasonable to calculate flux with a too coarse interval (15 days).

By the way, authors did not provide enough information on measurement. i.e. calibrations, maintenance, sampling interval etc.

The major content should match to the title. Since authors want to show some oxygen concentration data, no need jumps into the carbon sequestration issues. If they want to, please provide more methodological information and apply appropriate and theoretically sounding method.

Is the rationale for creating the dataset(s) clearly described?

Partly
Are the protocols appropriate and is the work technically sound?

No
Are sufficient details of methods and materials provided to allow replication by others?

No
Are the datasets clearly presented in a useable and accessible format?

Partly

Competing Interests: No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

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Author Response 29 Nov 2023

ChangShan Xing, Beijing Gongqing Forestry Farm, Beijing Municipal Forestry and Parks Bureau, Beijing, China

29 Nov 2023

Author Response

First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, ... Continue reading First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, which have been addressed in the preprint paper available at https://doi.org/10.21203/rs.3.rs-1141066/v1. In response to the need for validation of the method in a closed space, I will provide the experimental data from experiments conducted in a closed greenhouse later, which fully demonstrates that the regularity of observation results in open and closed spaces is completely consistent. Whether in a closed or open space, the experimental verification of this method has demonstrated its practicality, operability, and accuracy:

The reason for considering a 15-day period as the calculation unit for oxygen concentration is that the rate of photosynthesis is directly related to temperature. By conducting a one-way analysis of variance, we can determine that the temperature differences between 15-day intervals are significant. The following is the additional experimental data provided:

An oxygen concentration detector was installed at the center position of a 11x6 square meter sunlit greenhouse. The detector was placed at a height of 25 centimeters above the ground. The greenhouse contained naturally growing wild plants. Depending on the drought conditions, intermittent irrigation was applied to water the wild plants. The oxygen concentration inside the greenhouse was continuously measured at a frequency of once every 5 minutes. The average daily oxygen concentration value for the wild plants was then calculated. The measurements were taken from February 24, 2020, to November 19, 2020.
The oxygen concentration data for wild plants in an enclosed space：

data | 2.24-3.9 | 3.10-3.24 | 3.25-4.8 | 4.9-4.23 | 4.24-5.8 | 5.9-5.23 | 5.24-6.7 | 6.8-6.22 | 6.23-7.7 | 7.8-7.22 | 7.23-8.6 | 8.7-8.21 | 8.22-9.5 | 9.6-9.20 | 9.21-10.5 | 10.6-10.20 | 10.21-11.4 | 11.4-11.19|

The
average
oxygen | 20.676 | 21.022 | 21.068 | 21.112 | 21.172 | 21.173 | 21.178 | 21.19 | 21.189 | 21.172 | 21.147 | 21.171 | 21.201 | 21.164 | 21.083 | 20.946 | 20.84 | 20.746 |
concentration

difference | +0.364 | +0.046 | +0.044 | +0.06 | +0.001 | +0.005 | +0.072 | -0.001 | -0.017 | -0.025 | +0.024 | +0.03 | -0.037 | -0.081 | -0.137 | -0.106 | -0.064 |

grass | 0.3 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 |
height

The carbon sequestration of wild grass in an enclosed space：

The variation of wild grass in an enclosed space over a continuous period of 15 days shows a noticeable increase and decrease at both ends with a relatively stable fluctuation in the middle. From February 24th to March 24th, the oxygen concentration gradually increased. From March 25th to October 5th, it showed a gradual and mild fluctuation. The peak occurred from August 22nd to September 5th during the summer, reaching 21.201 L/mol. Taking the average oxygen concentration from February 24th to March 9th, which is 20.676, as the starting point, we subtract the average oxygen concentration in the later period from the average in the earlier period. Then, using the highest oxygen concentration value as the threshold, we add up all the differences to obtain the total oxygen concentration. Using the formula $M_{co2}=(\sum v)\rho hs(mr_{co2}/mr_{o2})$ , $M_{co2}$ represents the mass of carbon dioxide fixed by plants, $\sum v$ is the sum of the oxygen concentration, $\rho$ is the density of oxygen（1.43kg/m³），the average height h of the plant undergoing photosynthesis, and s is the area of the plant，mrCO2 is the molecular weight of CO2, which is 44, and mrO2 is the molecular weight of O2, which is 32.Calculate the total carbon sequestration mass of wild grass in a closed space during the growth period：

MCO=1.429×0.364×0.4×66×(44/32)=18.88kg
MCO=1.429×0.168×0.6×66×(44/32)=13.08kg
MCO=18.88+13.08=31.96kg

During the stage when the oxygen concentration gradually decreases after the inflection point, calculate the mass of oxygen consumed and the mass of carbon dioxide released during the growth process of wild grass.：

MCO=1.429×0.037×0.55×66×(44/32)=2.64kg
MCO=1.429×0.388×0.4×66×(44/32)=20.13kg
MCO=2.64+20.13=22.77kg

The carbon sink is the difference between the absorption of carbon dioxide before the inflection point and the release after the inflection point: MCO=31.96-22.77=9.19kg.

During the growth period, the total carbon sequestration mass of wild grass is 31.96 kilograms. Harvesting 66 square meters of wild grass yields 41 kilograms of dry matter, and after measuring the organic carbon content, the total carbon sequestration mass is determined to be 20.067 kilograms. The measured carbon sequestration mass of the wild grass accounts for 62.8% of the calculated carbon sequestration mass, primarily due to the fact that the carbon sequestration mass of the roots and other plants in the soil was not measured, resulting in a lower measured value than the calculated carbon sequestration mass.

From June 23rd to August 6th, the oxygen released by photosynthesis of the wild grass was less than the oxygen consumed by respiration, mainly due to the high temperature suppressing the photosynthesis of the wild grass.
First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, which have been addressed in the preprint paper available at https://doi.org/10.21203/rs.3.rs-1141066/v1. In response to the need for validation of the method in a closed space, I will provide the experimental data from experiments conducted in a closed greenhouse later, which fully demonstrates that the regularity of observation results in open and closed spaces is completely consistent. Whether in a closed or open space, the experimental verification of this method has demonstrated its practicality, operability, and accuracy:

The reason for considering a 15-day period as the calculation unit for oxygen concentration is that the rate of photosynthesis is directly related to temperature. By conducting a one-way analysis of variance, we can determine that the temperature differences between 15-day intervals are significant. The following is the additional experimental data provided:

An oxygen concentration detector was installed at the center position of a 11x6 square meter sunlit greenhouse. The detector was placed at a height of 25 centimeters above the ground. The greenhouse contained naturally growing wild plants. Depending on the drought conditions, intermittent irrigation was applied to water the wild plants. The oxygen concentration inside the greenhouse was continuously measured at a frequency of once every 5 minutes. The average daily oxygen concentration value for the wild plants was then calculated. The measurements were taken from February 24, 2020, to November 19, 2020.
The oxygen concentration data for wild plants in an enclosed space：

data | 2.24-3.9 | 3.10-3.24 | 3.25-4.8 | 4.9-4.23 | 4.24-5.8 | 5.9-5.23 | 5.24-6.7 | 6.8-6.22 | 6.23-7.7 | 7.8-7.22 | 7.23-8.6 | 8.7-8.21 | 8.22-9.5 | 9.6-9.20 | 9.21-10.5 | 10.6-10.20 | 10.21-11.4 | 11.4-11.19|

The
average
oxygen | 20.676 | 21.022 | 21.068 | 21.112 | 21.172 | 21.173 | 21.178 | 21.19 | 21.189 | 21.172 | 21.147 | 21.171 | 21.201 | 21.164 | 21.083 | 20.946 | 20.84 | 20.746 |
concentration

difference | +0.364 | +0.046 | +0.044 | +0.06 | +0.001 | +0.005 | +0.072 | -0.001 | -0.017 | -0.025 | +0.024 | +0.03 | -0.037 | -0.081 | -0.137 | -0.106 | -0.064 |

grass | 0.3 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 |
height

The carbon sequestration of wild grass in an enclosed space：

The variation of wild grass in an enclosed space over a continuous period of 15 days shows a noticeable increase and decrease at both ends with a relatively stable fluctuation in the middle. From February 24th to March 24th, the oxygen concentration gradually increased. From March 25th to October 5th, it showed a gradual and mild fluctuation. The peak occurred from August 22nd to September 5th during the summer, reaching 21.201 L/mol. Taking the average oxygen concentration from February 24th to March 9th, which is 20.676, as the starting point, we subtract the average oxygen concentration in the later period from the average in the earlier period. Then, using the highest oxygen concentration value as the threshold, we add up all the differences to obtain the total oxygen concentration. Using the formula $M_{co2}=(\sum v)\rho hs(mr_{co2}/mr_{o2})$ , $M_{co2}$ represents the mass of carbon dioxide fixed by plants, $\sum v$ is the sum of the oxygen concentration, $\rho$ is the density of oxygen（1.43kg/m³），the average height h of the plant undergoing photosynthesis, and s is the area of the plant，mrCO2 is the molecular weight of CO2, which is 44, and mrO2 is the molecular weight of O2, which is 32.Calculate the total carbon sequestration mass of wild grass in a closed space during the growth period：

MCO=1.429×0.364×0.4×66×(44/32)=18.88kg
MCO=1.429×0.168×0.6×66×(44/32)=13.08kg
MCO=18.88+13.08=31.96kg

During the stage when the oxygen concentration gradually decreases after the inflection point, calculate the mass of oxygen consumed and the mass of carbon dioxide released during the growth process of wild grass.：

MCO=1.429×0.037×0.55×66×(44/32)=2.64kg
MCO=1.429×0.388×0.4×66×(44/32)=20.13kg
MCO=2.64+20.13=22.77kg

The carbon sink is the difference between the absorption of carbon dioxide before the inflection point and the release after the inflection point: MCO=31.96-22.77=9.19kg.

During the growth period, the total carbon sequestration mass of wild grass is 31.96 kilograms. Harvesting 66 square meters of wild grass yields 41 kilograms of dry matter, and after measuring the organic carbon content, the total carbon sequestration mass is determined to be 20.067 kilograms. The measured carbon sequestration mass of the wild grass accounts for 62.8% of the calculated carbon sequestration mass, primarily due to the fact that the carbon sequestration mass of the roots and other plants in the soil was not measured, resulting in a lower measured value than the calculated carbon sequestration mass.

From June 23rd to August 6th, the oxygen released by photosynthesis of the wild grass was less than the oxygen consumed by respiration, mainly due to the high temperature suppressing the photosynthesis of the wild grass.
Competing Interests: No competing interests were disclosed. Close
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Author Response 29 Nov 2023

ChangShan Xing, Beijing Gongqing Forestry Farm, Beijing Municipal Forestry and Parks Bureau, Beijing, China

29 Nov 2023

Author Response

First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, ... Continue reading First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, which have been addressed in the preprint paper available at https://doi.org/10.21203/rs.3.rs-1141066/v1. In response to the need for validation of the method in a closed space, I will provide the experimental data from experiments conducted in a closed greenhouse later, which fully demonstrates that the regularity of observation results in open and closed spaces is completely consistent. Whether in a closed or open space, the experimental verification of this method has demonstrated its practicality, operability, and accuracy:

The reason for considering a 15-day period as the calculation unit for oxygen concentration is that the rate of photosynthesis is directly related to temperature. By conducting a one-way analysis of variance, we can determine that the temperature differences between 15-day intervals are significant. The following is the additional experimental data provided:

An oxygen concentration detector was installed at the center position of a 11x6 square meter sunlit greenhouse. The detector was placed at a height of 25 centimeters above the ground. The greenhouse contained naturally growing wild plants. Depending on the drought conditions, intermittent irrigation was applied to water the wild plants. The oxygen concentration inside the greenhouse was continuously measured at a frequency of once every 5 minutes. The average daily oxygen concentration value for the wild plants was then calculated. The measurements were taken from February 24, 2020, to November 19, 2020.
The oxygen concentration data for wild plants in an enclosed space：

data | 2.24-3.9 | 3.10-3.24 | 3.25-4.8 | 4.9-4.23 | 4.24-5.8 | 5.9-5.23 | 5.24-6.7 | 6.8-6.22 | 6.23-7.7 | 7.8-7.22 | 7.23-8.6 | 8.7-8.21 | 8.22-9.5 | 9.6-9.20 | 9.21-10.5 | 10.6-10.20 | 10.21-11.4 | 11.4-11.19|

The
average
oxygen | 20.676 | 21.022 | 21.068 | 21.112 | 21.172 | 21.173 | 21.178 | 21.19 | 21.189 | 21.172 | 21.147 | 21.171 | 21.201 | 21.164 | 21.083 | 20.946 | 20.84 | 20.746 |
concentration

difference | +0.364 | +0.046 | +0.044 | +0.06 | +0.001 | +0.005 | +0.072 | -0.001 | -0.017 | -0.025 | +0.024 | +0.03 | -0.037 | -0.081 | -0.137 | -0.106 | -0.064 |

grass | 0.3 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 |
height

The carbon sequestration of wild grass in an enclosed space：

The variation of wild grass in an enclosed space over a continuous period of 15 days shows a noticeable increase and decrease at both ends with a relatively stable fluctuation in the middle. From February 24th to March 24th, the oxygen concentration gradually increased. From March 25th to October 5th, it showed a gradual and mild fluctuation. The peak occurred from August 22nd to September 5th during the summer, reaching 21.201 L/mol. Taking the average oxygen concentration from February 24th to March 9th, which is 20.676, as the starting point, we subtract the average oxygen concentration in the later period from the average in the earlier period. Then, using the highest oxygen concentration value as the threshold, we add up all the differences to obtain the total oxygen concentration. Using the formula $M_{co2}=(\sum v)\rho hs(mr_{co2}/mr_{o2})$ , $M_{co2}$ represents the mass of carbon dioxide fixed by plants, $\sum v$ is the sum of the oxygen concentration, $\rho$ is the density of oxygen（1.43kg/m³），the average height h of the plant undergoing photosynthesis, and s is the area of the plant，mrCO2 is the molecular weight of CO2, which is 44, and mrO2 is the molecular weight of O2, which is 32.Calculate the total carbon sequestration mass of wild grass in a closed space during the growth period：

MCO=1.429×0.364×0.4×66×(44/32)=18.88kg
MCO=1.429×0.168×0.6×66×(44/32)=13.08kg
MCO=18.88+13.08=31.96kg

During the stage when the oxygen concentration gradually decreases after the inflection point, calculate the mass of oxygen consumed and the mass of carbon dioxide released during the growth process of wild grass.：

MCO=1.429×0.037×0.55×66×(44/32)=2.64kg
MCO=1.429×0.388×0.4×66×(44/32)=20.13kg
MCO=2.64+20.13=22.77kg

The carbon sink is the difference between the absorption of carbon dioxide before the inflection point and the release after the inflection point: MCO=31.96-22.77=9.19kg.

During the growth period, the total carbon sequestration mass of wild grass is 31.96 kilograms. Harvesting 66 square meters of wild grass yields 41 kilograms of dry matter, and after measuring the organic carbon content, the total carbon sequestration mass is determined to be 20.067 kilograms. The measured carbon sequestration mass of the wild grass accounts for 62.8% of the calculated carbon sequestration mass, primarily due to the fact that the carbon sequestration mass of the roots and other plants in the soil was not measured, resulting in a lower measured value than the calculated carbon sequestration mass.

From June 23rd to August 6th, the oxygen released by photosynthesis of the wild grass was less than the oxygen consumed by respiration, mainly due to the high temperature suppressing the photosynthesis of the wild grass.
First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, which have been addressed in the preprint paper available at https://doi.org/10.21203/rs.3.rs-1141066/v1. In response to the need for validation of the method in a closed space, I will provide the experimental data from experiments conducted in a closed greenhouse later, which fully demonstrates that the regularity of observation results in open and closed spaces is completely consistent. Whether in a closed or open space, the experimental verification of this method has demonstrated its practicality, operability, and accuracy:

The reason for considering a 15-day period as the calculation unit for oxygen concentration is that the rate of photosynthesis is directly related to temperature. By conducting a one-way analysis of variance, we can determine that the temperature differences between 15-day intervals are significant. The following is the additional experimental data provided:

An oxygen concentration detector was installed at the center position of a 11x6 square meter sunlit greenhouse. The detector was placed at a height of 25 centimeters above the ground. The greenhouse contained naturally growing wild plants. Depending on the drought conditions, intermittent irrigation was applied to water the wild plants. The oxygen concentration inside the greenhouse was continuously measured at a frequency of once every 5 minutes. The average daily oxygen concentration value for the wild plants was then calculated. The measurements were taken from February 24, 2020, to November 19, 2020.
The oxygen concentration data for wild plants in an enclosed space：

data | 2.24-3.9 | 3.10-3.24 | 3.25-4.8 | 4.9-4.23 | 4.24-5.8 | 5.9-5.23 | 5.24-6.7 | 6.8-6.22 | 6.23-7.7 | 7.8-7.22 | 7.23-8.6 | 8.7-8.21 | 8.22-9.5 | 9.6-9.20 | 9.21-10.5 | 10.6-10.20 | 10.21-11.4 | 11.4-11.19|

The
average
oxygen | 20.676 | 21.022 | 21.068 | 21.112 | 21.172 | 21.173 | 21.178 | 21.19 | 21.189 | 21.172 | 21.147 | 21.171 | 21.201 | 21.164 | 21.083 | 20.946 | 20.84 | 20.746 |
concentration

difference | +0.364 | +0.046 | +0.044 | +0.06 | +0.001 | +0.005 | +0.072 | -0.001 | -0.017 | -0.025 | +0.024 | +0.03 | -0.037 | -0.081 | -0.137 | -0.106 | -0.064 |

grass | 0.3 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 |
height

The carbon sequestration of wild grass in an enclosed space：

The variation of wild grass in an enclosed space over a continuous period of 15 days shows a noticeable increase and decrease at both ends with a relatively stable fluctuation in the middle. From February 24th to March 24th, the oxygen concentration gradually increased. From March 25th to October 5th, it showed a gradual and mild fluctuation. The peak occurred from August 22nd to September 5th during the summer, reaching 21.201 L/mol. Taking the average oxygen concentration from February 24th to March 9th, which is 20.676, as the starting point, we subtract the average oxygen concentration in the later period from the average in the earlier period. Then, using the highest oxygen concentration value as the threshold, we add up all the differences to obtain the total oxygen concentration. Using the formula $M_{co2}=(\sum v)\rho hs(mr_{co2}/mr_{o2})$ , $M_{co2}$ represents the mass of carbon dioxide fixed by plants, $\sum v$ is the sum of the oxygen concentration, $\rho$ is the density of oxygen（1.43kg/m³），the average height h of the plant undergoing photosynthesis, and s is the area of the plant，mrCO2 is the molecular weight of CO2, which is 44, and mrO2 is the molecular weight of O2, which is 32.Calculate the total carbon sequestration mass of wild grass in a closed space during the growth period：

MCO=1.429×0.364×0.4×66×(44/32)=18.88kg
MCO=1.429×0.168×0.6×66×(44/32)=13.08kg
MCO=18.88+13.08=31.96kg

During the stage when the oxygen concentration gradually decreases after the inflection point, calculate the mass of oxygen consumed and the mass of carbon dioxide released during the growth process of wild grass.：

MCO=1.429×0.037×0.55×66×(44/32)=2.64kg
MCO=1.429×0.388×0.4×66×(44/32)=20.13kg
MCO=2.64+20.13=22.77kg

The carbon sink is the difference between the absorption of carbon dioxide before the inflection point and the release after the inflection point: MCO=31.96-22.77=9.19kg.

During the growth period, the total carbon sequestration mass of wild grass is 31.96 kilograms. Harvesting 66 square meters of wild grass yields 41 kilograms of dry matter, and after measuring the organic carbon content, the total carbon sequestration mass is determined to be 20.067 kilograms. The measured carbon sequestration mass of the wild grass accounts for 62.8% of the calculated carbon sequestration mass, primarily due to the fact that the carbon sequestration mass of the roots and other plants in the soil was not measured, resulting in a lower measured value than the calculated carbon sequestration mass.

From June 23rd to August 6th, the oxygen released by photosynthesis of the wild grass was less than the oxygen consumed by respiration, mainly due to the high temperature suppressing the photosynthesis of the wild grass.
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Zheng-Hong Tan, Yunnan University, Kunming, China

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26 Oct 2023 | for Version 1

Zheng-Hong Tan, Professor of Ecology, Yunnan University, Kunming, Yunnan, China

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Approved With Reservations

Is the rationale for creating the dataset(s) clearly described?

Partly
Are the protocols appropriate and is the work technically sound?

No
Are sufficient details of methods and materials provided to allow replication by others?

No
Are the datasets clearly presented in a useable and accessible format?

Partly

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No competing interests were disclosed.

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Author Response

29 Nov 2023

ChangShan Xing, Beijing Gongqing Forestry Farm, Beijing Municipal Forestry and Parks Bureau, Beijing, China

First of all, thank you very much to the reviewers for their hard work on reviewing this paper.

The reviewer has raised questions about the principle of this method, which have been addressed in the preprint paper available at https://doi.org/10.21203/rs.3.rs-1141066/v1. In response to the need for validation of the method in a closed space, I will provide the experimental data from experiments conducted in a closed greenhouse later, which fully demonstrates that the regularity of observation results in open and closed spaces is completely consistent. Whether in a closed or open space, the experimental verification of this method has demonstrated its practicality, operability, and accuracy:

The reason for considering a 15-day period as the calculation unit for oxygen concentration is that the rate of photosynthesis is directly related to temperature. By conducting a one-way analysis of variance, we can determine that the temperature differences between 15-day intervals are significant. The following is the additional experimental data provided:

An oxygen concentration detector was installed at the center position of a 11x6 square meter sunlit greenhouse. The detector was placed at a height of 25 centimeters above the ground. The greenhouse contained naturally growing wild plants. Depending on the drought conditions, intermittent irrigation was applied to water the wild plants. The oxygen concentration inside the greenhouse was continuously measured at a frequency of once every 5 minutes. The average daily oxygen concentration value for the wild plants was then calculated. The measurements were taken from February 24, 2020, to November 19, 2020.
The oxygen concentration data for wild plants in an enclosed space：

data | 2.24-3.9 | 3.10-3.24 | 3.25-4.8 | 4.9-4.23 | 4.24-5.8 | 5.9-5.23 | 5.24-6.7 | 6.8-6.22 | 6.23-7.7 | 7.8-7.22 | 7.23-8.6 | 8.7-8.21 | 8.22-9.5 | 9.6-9.20 | 9.21-10.5 | 10.6-10.20 | 10.21-11.4 | 11.4-11.19|

The
average
oxygen | 20.676 | 21.022 | 21.068 | 21.112 | 21.172 | 21.173 | 21.178 | 21.19 | 21.189 | 21.172 | 21.147 | 21.171 | 21.201 | 21.164 | 21.083 | 20.946 | 20.84 | 20.746 |
concentration

difference | +0.364 | +0.046 | +0.044 | +0.06 | +0.001 | +0.005 | +0.072 | -0.001 | -0.017 | -0.025 | +0.024 | +0.03 | -0.037 | -0.081 | -0.137 | -0.106 | -0.064 |

grass | 0.3 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 |
height

The carbon sequestration of wild grass in an enclosed space：

The variation of wild grass in an enclosed space over a continuous period of 15 days shows a noticeable increase and decrease at both ends with a relatively stable fluctuation in the middle. From February 24th to March 24th, the oxygen concentration gradually increased. From March 25th to October 5th, it showed a gradual and mild fluctuation. The peak occurred from August 22nd to September 5th during the summer, reaching 21.201 L/mol. Taking the average oxygen concentration from February 24th to March 9th, which is 20.676, as the starting point, we subtract the average oxygen concentration in the later period from the average in the earlier period. Then, using the highest oxygen concentration value as the threshold, we add up all the differences to obtain the total oxygen concentration. Using the formula $M_{co2}=(\sum v)\rho hs(mr_{co2}/mr_{o2})$ , $M_{co2}$ represents the mass of carbon dioxide fixed by plants, $\sum v$ is the sum of the oxygen concentration, $\rho$ is the density of oxygen（1.43kg/m³），the average height h of the plant undergoing photosynthesis, and s is the area of the plant，mrCO2 is the molecular weight of CO2, which is 44, and mrO2 is the molecular weight of O2, which is 32.Calculate the total carbon sequestration mass of wild grass in a closed space during the growth period：

MCO=1.429×0.364×0.4×66×(44/32)=18.88kg
MCO=1.429×0.168×0.6×66×(44/32)=13.08kg
MCO=18.88+13.08=31.96kg

During the stage when the oxygen concentration gradually decreases after the inflection point, calculate the mass of oxygen consumed and the mass of carbon dioxide released during the growth process of wild grass.：

MCO=1.429×0.037×0.55×66×(44/32)=2.64kg
MCO=1.429×0.388×0.4×66×(44/32)=20.13kg
MCO=2.64+20.13=22.77kg

The carbon sink is the difference between the absorption of carbon dioxide before the inflection point and the release after the inflection point: MCO=31.96-22.77=9.19kg.

During the growth period, the total carbon sequestration mass of wild grass is 31.96 kilograms. Harvesting 66 square meters of wild grass yields 41 kilograms of dry matter, and after measuring the organic carbon content, the total carbon sequestration mass is determined to be 20.067 kilograms. The measured carbon sequestration mass of the wild grass accounts for 62.8% of the calculated carbon sequestration mass, primarily due to the fact that the carbon sequestration mass of the roots and other plants in the soil was not measured, resulting in a lower measured value than the calculated carbon sequestration mass.

From June 23rd to August 6th, the oxygen released by photosynthesis of the wild grass was less than the oxygen consumed by respiration, mainly due to the high temperature suppressing the photosynthesis of the wild grass.

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Competing Interests

No competing interests were disclosed.

Alongside their report, reviewers assign a status to the article:

Approved - the paper is scientifically sound in its current form and only minor, if any, improvements are suggested

Approved with reservations - A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit.

Not approved - fundamental flaws in the paper seriously undermine the findings and conclusions

[1] 1. UNFCCC: Kyoto Protocol to the United Nations Framework Convention on Climate Change.1998. Acesso em: 25 out. 2019. Reference Source

[2] 2. Pan Y, Birdsey RA, Fang J, et al.: A Large and Persistent Carbon Sink in the World’s Forests. Science. 2011; 333: 988–993. PubMed Abstract | Publisher Full Text

[3] 3. Gampe D, Zscheischler J, Reichstein M, et al.: Increasing impact of warm droughts on northern ecosystem productivity over recent decades. Nat. Clim. Chang. 2021; 11(9): 772–779. Publisher Full Text

[4] 4. Sitch S, Friedlingstein P, Gruber N, et al.: Recent trends and drivers of regional sources and sinks of carbon dioxide. Biogeosciences. 2015; 12: 653–679. Publisher Full Text

[5] 5. Forestry Carbon Sequestration Editorial Board: Forestry Carbon Sequestration: practice in Beijing. China Forestry Publishing House; 2016. (In Chinese).

[6] 6. Li NY, Lv J: Carbon Inventory Methods. China Forestry Publishing House; 2009. (In Chinese).

[7] 7. Xing: The oxygen concentration data in Forest Canopy of 2020 in Beijing Gongqing Forestry Farm. [Dataset]. figshare. 2023. Publisher Full Text

The oxygen concentration data in a forest canopy in 2020 in Beijing Gongqing Forestry Farm

Abstract

Keywords

Introduction

Methods

Overview of the research area

Experimental setup

Figure 1. Daily average oxygen concentration from March 10th to October 5th.

Table 1. Forest carbon sinks meter.

The measurement of forest carbon sinks

Data availability

Underlying data

Acknowledgments

References

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