中國天然橡膠進口貿易之引力模型分析

Abstract

天然橡膠是一種重要的戰略物資，中國雖是世界上最大的天然橡膠消費國，但國內自我供給能力嚴重不足因僅在中國西南地區部分省份種植，對外依存度則常年高居75%以上。本研究從分析國際和中國天然橡膠生產和進口現狀作爲切入點，描述其變化趨勢，並通過拓展的引力模型，對影響中國天然橡膠進口多元化的關鍵因素進行實證分析。本研究選擇 2013-2022年，與中國有 5 年及以上天然橡膠貿易往來的六個來源國的面板資料， 運用引力模型並導入雙向固定效應對中國天然橡膠進口影響因素進行分析。 實證結果顯示，來源國的天然橡膠種植面積和雙邊距離對促進中國天然橡膠進口有顯著正向影響，而中國國內生產總值、來源國國內生產總值、國內外天然橡膠相對價格和來源國國家風險則對進口貿易存在抑制作用。從引力模型的理論探討，距離應該是負向影響，因為相對距離的增加可能導致運輸成本的增加。但天然橡膠作為中國嚴重依賴進口的必需品且短時間內難以替代，特別在「一帶一路」政策支持下，遠在非洲的象牙海岸輸入量持續上升，應可提供事實支持。其次根據測算出的來源國貿易潛力和貿易差額進行優化佈局分析。泰國作為中國天然橡膠進口最主要的來源國之一，貿易潛力為0.827，説明未來仍有較大的提升空間。貿易差額為正說明2023年相對於2022年進口有下降趨勢。中國對泰國天然橡膠依賴指數高達 22.49，説明目前仍依賴於泰國進口，但將逐漸向多元進口方向轉型。 根據研究發現，依賴一國的供給不利於保障中國進口供應鏈的穩定，因此中國還應積極開拓新的來源管道，將其配額分散至其他天然橡膠來源國，降低中國天然橡膠外部供應的不確定性。

Natural rubber is a crucial strategic material. Although China is the world's largest consumer of natural rubber, its domestic self-sufficiency is significantly lacking, with cultivation limited to certain southwestern provinces. Consequently, China's reliance on imports exceeds 75% annually. This study analyzes the current status of international and Chinese natural rubber production and imports, examines trends, and uses an expanded gravity model to empirically investigate the key factors influencing the diversification of China's natural rubber imports. Panel data from six source countries with over five years of trade with China (2013-2022) were utilized. The gravity model, incorporating two-way fixed effects, highlights that the source country's natural rubber planting area and bilateral distance positively influence China's imports. Conversely, China's GDP, the source country's GDP, relative domestic and foreign rubber prices, and the source country's risks negatively impact import trade. While theoretically, greater distance should hinder trade due to higher transportation costs, the necessity of natural rubber for China, supported by the "Belt and Road" initiative, mitigates this effect. For instance, imports from Ivory Coast continue to rise. An analysis based on trade potential and balance indicates Thailand, a major source, has a trade potential of 0.827, suggesting significant room for future growth. A positive trade balance shows a declining trend in 2023 imports compared to 2022. China's dependence index on Thai rubber is 22.49, indicating heavy reliance but a gradual shift towards diversified imports. The study concludes that dependence on a single source is detrimental to the stability of China's import supply chain. Hence, China should explore new sources and diversify its import quotas to mitigate supply uncertainty.