기후변화에 따른 산림병해충 영향과 대응과제

Abstract

전 세계적으로 기후변화가 큰 관심사다. 기후변화는 본래 긴 시간 동안 천천히 발생하나 산업혁명 이후 가속화된 상황이다. 급격한 기후변화는 인간뿐만 아니라 지구 전체에 큰 피해를 줄 수 있다. 이러한 기후변화에 대응하기 위해 세계 각국은 교토의정서, 파리협약 등의 대응을 펼쳤으며, 이외에도 국가적으로 다양한 기후변화 대응 정책을 펼치고 있다.

산림 분야에서도 기후변화는 큰 관심사다. 기후변화에 따라 산림이 인간에게 주는 혜택에 변화가 나타날 수 있으며, 오히려 인간에게 피해가 발생할 수도 있기 때문이다. 특히, 기후변화에 따라 발생할 수 있는 피해로 산림병해충이 지목된다. 이에 기후변화와 산림병해충의 발병 관계에 대한 연구가 단계적으로 수행되고 있다. 하지만 기후변화에 따른 산림병해충의 경제적 영향에 대한 연구는 아직 미비한 실정이다.

본 연구는 기후변화에 따른 산림병해충 피해의 영향을 계측하는 방법을 제시하였다. 구체적으로 병해충 피해에 영향을 미치는 직·간접적 요인을 고려한 피해함수를 수립하고, 향후 기후변화에 따른 미래 피해율을 예측하였다. 예측된 피해율을 이용해 병해충으로 인한 미래 산림 경영소득 변화, 벌기령 변화, 방제의 효과 등 병해충이 산주의 소득과 산림관리 의사결정에 미치는 영향을 분석하였다. 마지막으로 정책실험을 수행하여 효과적 산림 병해충 관리를 위한 과제를 제시하였다.

Research Background The effects of climate change, such as drought and abnormal temperatures, are progressively becoming more of a reality. The change that climate change brought on the forest environments and emersion of pests call for a more delicate management measure. Therefore, it is necessary to reevaluate the current control method and establish a direction of a new preventive strategy considering the trend of climate change. For this effort, basic research should be conducted to objectively assess the damage and the potential economic threat of forest pests. In particular, it is very important to establish the damage rate (damage function) that reflects direct and indirect factors of forest pests. The damage rate must be determined in order to measure the actual loss caused by the damage such as its effect on economics. The pest prediction model currently in use in Korea predicts the occurrence risk; however, it is limited as to measuring a definite damage rate and the economic ripple effect that it causes. Analyzing the damage and the economic impact of forest pests is crucial as it provides the basic information necessary to solve upcoming ecosystem disturbances and maintain healthy and productive forests. It can also serve as an objective foundation for policy-making to prevent other pest disasters caused by climate change and to help adapt to future climates.

Research Method The target subjects of this study are the most common forest pests and the main damaged tree species in Korea. With the advice of experts in the field, the pine wilt disease and the oak wilt disease have been selected as the target pests - reflecting the increasing trend of deciduous forests. To measure the damages inflicted by pests, the structural damage function used in studies such as Cobourn et al. (2011) and Kim Yongjun et al. (2015) was implemented, and also the nonlinear panel probit model and the GEE estimation method were introduced. In addition, the mean per panel value was added to the model according to the method proposed by Mundlak (1978) and Chamberlain (1980) to reflect the fixed effect that has not been observed. The estimated damage function and RCP8.5 data were used to predict the future damage rate of pests caused by climate change. The damage rate of future pine tree wilt and oak wilt was predicted for the next 80 years from 2018 to 2100, and GIS was used to show the future damage rate by city/county areas. In the assessment of the economic impact by the forests, the concept of environmental payout was introduced to take into account the economics of wood and non-wood materials. For the economic analysis, three scenarios were set up: no pest outbreak (baseline), pest infestation (no pest control), and pest infestation (prevention and control). And the earnings and the forest management revenues that included the wood and non-wood materials for each scenario were compared. Based on the results of the analysis, simulation was conducted to investigate the changes in forest management revenues such as changes in wood market prices, environmental payouts, climate change, and usage of infected trees.

Research Results and Implications After the estimation of the damage function and prediction of the future damage rate, it was confirmed that the future damage owing to forest pests and the extent of the damage areas would increase due to climate change. In addition, the analysis of economic impacts showed that the increase of pest damage caused by climate change would worsen forest management revenues and increase uncertainty. As pest damage brought on by climate change is expected to increase uncertainties and economic losses, there is a marked need to review the policies that have been focusing only on post-response tasks. In addition to proper post-incident management, it is necessary to stably control pests through the reinforcement of pre-incident management. As a precautionary strengthening measure, identification of key management subjects, improvement of tree health, improvement of pest resistance through the development and replacement of species, and elimination of externalities through environmental payment were suggested. Until now, low forest management revenues have led to a lack of incentives for forest owners to focus on pest control, thus depending on the country to carry out pest control. However, if the pest increases due to climate change in the future, the current government-based management system may face a shortage of budget and workforce. Therefore, there is a need to encourage individual forest owners to actively manage pests through better profit caused by healthy forests. In order to supplement the post-treatment measures, it is possible to immediately treat dead trees due to oak wilt disease; strengthen the prevention of artificial spreading of pine wilt disease; and expand the use of infected trees to enhance forest management profits. The contributions of this study are that it establishes pest damage functions that consider various factors and evaluates the economic impact of pest insect considering management factors using dynamic analysis. Previous studies mostly used the static method such as partial equilibrium when they evaluate economic effects of the forest pests, and did not consider various management factors such as pest control which can possibly affect the real damage. However, in this study, the demographic variables used to assess anthropogenic activities have limitations in that they do not reveal a specific correlation between detailed history of activities and the damage rates. It is necessary to identify substitutional variables that can represent the details of future artificial activities and reflect them in the model. The relationship between the details for pest control, the efficiency of the pest control and the profitability of the forest management can be suggested as a future research topic.

Researchers: An Hyunjin, Lee Sangmin, Choi Junyeong Research period: 2018. 1 . ~ 2018. 10. E-mail address: hjan713@krei.re.kr