[Commentary] Tree-Species Conversion in Areas Affected by Pine Wilt Disease Requires Caution Under the “Right Tree in the Right Place” Principle

Recently, as pine wilt disease has spread amid the climate crisis, tree-species conversion (species renewal)—cutting down Korean red pines in affected areas and planting other trees in their place—is being actively carried out nationwide. New trees are being introduced because they are considered economically valuable or resistant to pests and diseases. However, from the perspective of a scholar who spent more than 40 years in public forestry service, served as head of KFS, and now researches forest climate and the environment while training the next generation at a university, it is difficult not to be deeply concerned that the recent trend toward tree-species conversion could become a hasty measure that overlooks the essence of forest ecosystems.
 Accounting for about one-quarter of South Korea’s forests, Korean red pines form woodlands of 1.6 billion trees and are a native species that has shared the joys and sorrows of the Korean people. Their historical and cultural value is also profound; since the Joseon era, the government has enforced policies that strictly prohibited logging them. There is one very important ecological fact we must not overlook. Of the Korean red pine forests currently growing in South Korea, only about 7% consist of artificially planted trees. Most of the rest are native stands that have perfectly adapted to the Korean Peninsula’s natural environment and flourished on their own over many centuries.
 Korean red pine is a highly light-demanding species that thrives in sunlight and puts down strong roots even in barren land with nutrient-poor, dry soil. In other words, forests where Korean red pine grows naturally in clusters are likely to have originally been harsh and arid environments in which other species would have struggled to survive. Therefore, when converting areas affected by pine wilt disease to other tree species, the first priority must be a precise ecological analysis of why Korean red pine, rather than other trees, grew there for so many years.
 Recent media reports have clearly shown the painful consequences of changing tree species while ignoring these ecological characteristics and site conditions and pursuing only users’ demands or short-term economic returns. After pest-control measures, a substantial portion of the areas cleared for tree-species conversion was planted with Japanese cypress because of its high added value. However, more than half of the trees died in mass after failing to withstand the severe drought. Planting Japanese cypress, which requires high atmospheric humidity and fertile soil, in the dry, barren native range of Korean red pine was a foreseeable failure that disregarded ecological principles.
 A forest is not a factory. Factories can replace machinery and facilities and change their products at any time in response to market demand and consumer preferences, but natural ecosystems, which are complex living organisms, do not work that way. From collecting healthy seeds and raising sturdy saplings in nurseries to planting them in barren mountain terrain and securing adequate establishment rates, the preliminary preparations alone require many years. Moreover, it takes decades, or even centuries, for the trees to mature and perform the full functions of a forest. This is a clear reason not to renew tree species hastily, swayed by administrative convenience or temporary trends.
 Ultimately, tree-species conversion in areas affected by pine wilt disease must be based firmly on the principle of the “right tree in the right place”—planting the suitable tree in the suitable location. The government’s “customized forest map” should be actively used to scientifically analyze local conditions, including soil characteristics, moisture levels, terrain, and microclimate, and select the optimal species. In addition, a process must first be carried out to incorporate detailed on-site assessments by forest ecology experts and the opinions of forest owners who will directly manage the forests.
 Nature has immutable principles that humans cannot recklessly defy. We must remember the vitality of Korean red pines, which quietly covered barren rock crevices and dry land in green, and conform to nature rather than pursuing excessive and artificial replacement. With the grave responsibility of safeguarding the forests’ future for the next century, this is the time to exercise greater caution than ever when converting to other tree species.