# How Will Rwandan Land Use/Land Cover Change under High Population Pressure and Changing Climate?
## 4 Discussion  
### Analysis of Historical Land Use/Land Cover Change  
Forest land, grassland and cropland are the main LULC types in the study area, and the total amount between 1990 and 2015 remained essentially constant. However, analysis of the conversion between different LULC types indicated that the conversion between the three LULC types was quite pronounced (Table 2). Between 1990 and 2000, the LULC change consisted mainly of the conversion of grassland and a large amount of forest land to cropland. Of the newly transferred cropland, 72% was converted from forest land and 28% from grassland. This was caused by the surge in population during that period. Wars and turbulence during the early 1990s in Rwanda caused the loss of a significant amount of population by death and displacement. After the wars, the displaced population gradually moved back, and the population began to recover. However, the economic impacts of the war meant that the survival of the returning population could not be effectively guaranteed [39]. Therefore, large portions of forest were cut down for firewood and charcoal to cope with the energy shortage caused by the insufficient production capacity [40]. At present, the vast majority of the rural population (93%) uses firewood for cooking. In cities, charcoal is used by 51% of households, followed by firewood (45%) [41]. The precipitation and temperature conditions unique to Africa cause the rapid deterioration of the surface humus in woodland areas after logging [42], producing fertile soil, which is then converted to cropland. Even in barren, underdeveloped shrublands or woodlands, fire is used to clear the ground in order to produce farmland with high organic matter content [41]. Between 2000 and 2010, there were mutual conversions between forest and cropland, and between grassland and cropland. However, the circulation among the three land types achieved an overall balance, and the total amount of change was not significant. The population of Rwanda continued to increase between 2000 and 2010, but there was no significant reduction in forest area. This was considerably influenced by afforestation during the early part of the 21 st century. A large reforestation effort increased the overall forest cover by an average of 8% annually between 2000 and 2005, although virtually none of the resulting forest is classified as primary forest. The demographic structure during this period also contributed to this phenomenon. Although the population growth rate began to increase gradually (from 1.2% to 2.6%) after the post-war population migration [3], the migrating population primarily consisted of women and children; compare with young adult men, such populations do not have a high production capacity [43]. Therefore, there was no major change in the amount of forest land during this period. After 2010, there was a massive conversion of forest to cropland and grassland; this was accompanied by a conversion of cropland to grassland. Of the forest area that was transferred, 83% became cropland and 17% became grassland. This was attributed to the dual effects of a rapidly growing population and a rapidly developing economy. Owing to the high population pressure, Rwanda is facing an energy crisis, food security problems, and other similar social challenges. The development undertaken to overcome these challenges causes deforestation. The abundant surface vegetation can be used directly as energy material. The newly transformed cropland (from forest) exhibits high nutrient content, good soil structure, and high yield. Moreover, as part of the 'Vision 2020' of Rwanda, its national economy has also witnessed rapid growth. Between 2004 and 2014, the gross agricultural product accounted for 34% of the total annual GDP [44]. This means that the crops produced on the limited arable land not only need to meet the survival needs of the large population, but also need to support the GDP growth as part of the rapid development vision.