Shrinking Forests of Kilimanjaro— The Impact of Fire and Climate Change

Rainfall reduction combined with increased temperature has caused major changes in Kilimanjaro ecosystems. Long-term rainfall data from three stations located on the southern slopes of Kilimanjaro show a decrease in annual rainfall of 34, 27, and 39 percent for the periods 1902–2004, 1911–2004, and 1922–2004, respectively. In addition, temperature data between 1976 and 2002 from Amboseli on the northern side of Kilimanjaro reveals a drastic increase of mean daily maximum temperature at a rate of more than 2 K per decade.

Both these climatic changes caused not only the melting of the ice cap but have had a tremendous impact on the forest by increasing its vulnerability to fire. Between 1976 and 2000, fires have destroyed approximately 15,500 hectares of Erica forest, representing 83 percent of that forest type. As the Erica forest forms the upper tree line, the fires have actually lowered the altitude of the upper forest boundary by up to 800 meters in some areas. The Erica forest used to play a significant role in the water balance of the mountain. Located above 2,700 meters where clouds lay almost every day, the forest collects a large amount of cloud moisture, which contributes significantly to the water needs of more than one million Chagga people who live on the slopes of the mountain, by far exceeding the hydrological consequences of the loss of the glaciers.

REFERENCES

Altmann et al. (2002). Dramatic change in local climate patterns in the Amboseli basin, Kenya. African Journal of Ecology, 40, 248–251

Hemp, A. (2005). Climate change-driven forest fires marginalize the impact of ice cap wasting on Kilimanjaro. Global Change Biology, 11 (in press)