“The parties to this agreement… recognizing the need for an effective and progressive response to the urgent threat of climate change based on the best available scientific knowledge… acknowledging that climate change is a common concern of humankind… recognizing the importance of the conservation and enhancement, as appropriate, of sinks and reservoirs of the greenhouse gases referred to in the convention… Have agreed as follows.”
- Excerpted from The Paris Agreement.

  In December 2015, in The Paris Agreement, the international society signed an agreement with the goal of ‘Limiting the increase in global average temperature to 2℃ below pre-industrial level by 2100’ to alleviate global warming and to achieve this goal, they collected their opinions about the need for more upward policies than the existing ones. In this context, the international society has declared ‘Carbon Neutrality’ as a comprehensive policy direction to cope with climate change, and each country is actively pursuing its policy. In October 2020, though ‘2050 Declaration of Carbon Neutrality’, Korea also became aware of the response to the climate crisis with the international community. Recently, forests are being discussed in the carbon neutral policy, and CBT reporter would like to investigate scientific facts related to forests with Professor Kim Jung-sung of the Dept. of Forest Science at CBNU.

Q1) What is ‘Forest’?

  Historically, early forests provided humans with the required resources for food, clothing, and shelter. Humans also got this through passive retrieval and hunting. In modern times, humans started agriculture and artificial selection, selecting and proliferating crops are convenient and beneficial for human use among wild-state biological resources in the existing forest to develop new biological resources that maximize the desired characteristics. Through these, it can be seen that these have evolved in the direction of obtaining efficient and excellent forest resources based on human standards, rather than obtaining basic resources through early forests. Here, forest resources are composed of edible plants, fruits, wood, water, wild animals, landscapes, and recreational resources. In this way, forests support human survival in various forms and provide habitats for animals and plants in addition to humans by their existence. However, forests are now devastated due to by-products caused by human activities, and this situation has led to the climate crisis.

Q2) Why are forests attracting attention in carbon-neutral policy?

  The problem in the climate crisis is not the carbon source itself, but the proportion of it. This is because the climate crisis was not caused by the emergence of carbon sources that did not exist in nature, because carbon sources that originally existed in certain proportions are accumulated as large amounts of emissions and increases due to by-products of human activities, whereas forests that absorb carbon sources continue to decrease. In short, supply is constantly increasing and accumulating, while consumption is decreasing, and the supply cannot be handled at the current consumption. As a result, the existing balance was broken and the mechanism that enables atmospheric circulation collapsed, and this is the greenhouse effect. The key to solve is to bring the broken balance back to its original state and re-establish it. Humans can think two ways: limiting the supply of carbon sources and removing carbon sources that have already been released. The latter means that humans artificially capture and remove carbon sources, but physical removal has technical and economic limitations. The former is the way humans reduce their carbon emissions and increase forests that absorb carbon.

Q3) Which tree functions and characteristics should be considered in a carbon-neutral policy?

  Plants use the light energy captured through their leaves to perform photosynthesis, converting carbon dioxide(CO₂) and water into glucose and oxygen(O₂). In this process, CO₂ is converted into O₂ and released into the atmosphere. Photosynthesis is complexly affected by external environmental factors such as temperature, carbon concentration, and amount of light. When comparing the carbon concentration under the same conditions, the higher the carbon concentration, the higher the efficiency of photosynthesis, but after a certain degree, the efficiency is maintained. Also, it is affected by tree species and age. In the case of young trees, it can be said that photosynthetic efficiency is the highest in the life of the tree as the stage of vigorous growth, but this is not high efficiency. Comparing the efficiency of young and old trees is like comparing the intake of babies versus the intake of adults with each one’s weight. If you compare the absolute value of carbon uptake of a young tree that has just started growing and the absolute value of carbon uptake of a tree that has finished growing, the tree after growth can be relatively large. However, when comparing the amount of carbon uptake compared to the area occupied by trees, young trees may be larger than trees that have finished growing. In this context, it is desirable to take care of existing aged trees and plant young trees to grow the entire forest area. When implementing afforestation to expand the forest area, it is necessary to consider the location, environment, and ecosystem of the afforestation area from a long-term perspective to select species with a high carbon absorption rate.

By Park Su-min l psm0129@cbnu.ac.kr