A simplified method for assessing forest health, with application to Chinese fir plantations in Dagang Mountain, Jiangxi, China

Assessment of forest ecosystem health is the first step for making forest sustainable development. An improved Costanza model was developed to assess the health of 30-year-old Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) forest in Dagang mountain in Jiangxi province. The forest has suffered a severe disturbance in the great 2008 Chinese ice storm. Three indicators including vigor, organization, and resilience were designed and calculated respectively on an ecosystem scale. Then, three indicators were transformed or ‘scored’ to unitless 0 to 1 value by using standard scoring function. Finally, forest ecosystem health index of 9 plots were calculated using a modified Costanza formula. Forest health evaluated results showed that two plots were in the unhealthy status with scores ranged from 0.316 to 0.419, three plots were moderate with scores ranged from 0.558 to 0.569, and the other four were healthier, their evaluated value over 0.621. In the forest soils, high soil nutrients (soil organic carbon, total nitrogen, available phosphorus and available potassium) increased forest ecosystem health index. Generally, it can be concluded that the unhealthy and moderate plots should be in primary consideration for ecological protection and rehabilitation. Increasing soil nutrients is an effective way to improve forest health. This study provided a possible quantitative model for ecological planning and demonstrated the potential impact reasons for forest ecosystem health.