Abstract:

Aims During mid-January and mid-February 2008, an unexpected severe ice storm occurred over southern China that caused heavy damage to forests. Our objectives were to examine the effect of this storm on subtropical planted forests and to quantify biomass and carbon losses.

Methods We evaluated damage to the forest ecosystem at Qianyanzhou Ecological Station in subtropical China. Twenty-one plots of 10 m × 10 m dimensions were investigated in the affected slash pine (Pinus elliottii) plantation. The relationship between damaged area and terrain factors was analyzed using Digital Elevation Model data.

Important findings Of the five major plantations at the ecological station, damages occurred mainly in the slash pine plantation. The area of severely damaged forest with most fallen trees was 7.72 hm², accounting for 6.12% of the total forest area. The aboveground carbon loss in the severely damaged area ranged from 655 to 5 230 g·m^-2, with a mean value of 1 462 g·m^-2. Continuous low-temperature and strong rainfall, particularly when accompanied by strong winds on February 1, 2008, were the direct causes of the damage. Analysis shows that elevation is a good indicator for ice storm damage in the hilly area even though the elevation range was small (60-140 m), because elevation is tightly linked to local terrain factors and weather conditions. Forest growing on the top of a hill was vulnerable to the ice storm due to the barren soil and strong wind. We found that trees planted on the sunny slopes tended to form unbalanced crowns; this might be the reason that severe damage occurred mainly on sunny slopes. The vulnerability of slash pine to the ice storm is believed related to crown types, timber quality, root distribution, leaf characteristics and resin tapping.

Key words: freezing rain, natural disturbance, plantation, plant-carbon loss