Data from: Woody cover in wet and dry African savannas after six decades of experimental fires

1. Fire is an integral process in savannas because it plays a crucial role in altering woody cover of this globally important biome. 2. In this study we examine the long term effects of varying fire frequencies over a 60 year time period in South Africa. We analyse the effects of fire exclusion and of experimental burns every 1, 2 and 3 years on woody cover, tree abundance and stem structure on a wet and dry savanna. 3. Increased fire frequency did not display a consistent effect on woody cover. The presence of fire, irrespective of frequency, was much more influential in lowering tree abundance in the wet savanna than the dry savanna. In the dry savanna, fire was more effective in greatly increasing coppicing in trees, when compared to the wet savannas. 4. Synthesis: The effects of fire on three measures of savanna woody vegetation differed between wet and dry experimental sites. We suggest that vegetation responses to fire are dependent on local conditions, which are likely influenced by rainfall. Therefore we suggest that management strategies should take account of whether a savanna is a wet or dry system when implementing fire management regimes.

1. 火灾是稀树草原（savanna）生态系统中不可或缺的过程，其在改变这一全球重要生物群落的木本植被覆盖度方面发挥着关键作用。
2. 本研究针对南非一处持续60年的长期样地，探究不同火灾频率所产生的长期效应。我们分析了禁火措施，以及每1年、2年、3年进行一次的实验性火烧，对干湿两类稀树草原的木本覆盖度、树木丰度以及茎干结构的影响。
3. 火灾频率的提升并未对木本覆盖度呈现出一致的影响。无论火灾频率高低，相较于干旱稀树草原，火灾对湿润稀树草原的树木丰度降低作用更为显著。而与湿润稀树草原相比，干旱稀树草原中的火灾在大幅促进树木萌蘖（coppicing）方面效果更强。
4. 综合分析结果表明：火灾对稀树草原木本植被三项指标的影响在干湿实验样地中存在显著差异。我们认为，植被对火灾的响应取决于当地环境条件，而此类条件大概率受降雨因素调控。因此，在推行火管理方案时，我们建议管理策略应充分考虑目标稀树草原属于湿润还是干旱类型。