关键词: 净初级生产力, SEBAL模型, 高程, 坡度, 光能利用率模型

Abstract: Forest fire is the free spread fire in woodland ecosystems. There are two types of forest fire, i.e., prescribed (controlled) fire and wildfire. The effects and the duration of fires depend upon the fire severity. Fires can affect soil structure through the combustion of soil organic matter and the alteration of soil clay minerals, leading to the increase of soil bulk density and the decrease of soil water holding capacity. Over a long period of time,  fires can reduce soil organic matter. After burning, the increase of soil temperature and pH can promote soil respiration, while the decrease of microbial biomass, death of roots, and decrease of decomposable materials can reduce soil respiration. Forest fires consume the forest litter layer by oxidation, volatilization, leaching, and convection of ash particles, which results in soil nutrient loss. Forest fires also have important effects on soil organisms. The high temperature of burning can directly kill soil microbes, and indirectly affect soil microbe survival and microbial community structure through changing the soil physical and chemical properties and the woodland microenvironment. The effects of fires on soil animals are less obvious than on microbes because the soil animals have higher mobility to escape fires. Low and moderate severity fires indirectly affect soil enzymes by altering soil environment, whereas high severity fires could directly denature soil enzymes because of the extreme high temperature. In the future, the studies on forest fires should be focused on the longterm study with interdisciplinary cooperation, especially for the interrelationships among soil animals, microbes, and ecosystem responses after burning, and the effects of prescribed and wildfires on soil organic carbon, stability of soil nutrient pool, soil water repellency, soil and water loss, and biodiversity.

Key words: net primary productivity, SEBAL model, elevation, slope., light utility efficiency model