I need help understanding deforestation and a reliable reference.

Two of the references below would be good sources to cite in an undergraduate paper on deforestation.
Deforestation is not just a modern issue, but has had a major effect on human ecosystems since the development of slash and burn agriculture, in which forests are cleared and then burned to create farmland. Unfortunately, this type of agriculture is extremely inefficient, as the soils left behind by this process are rarely suitable for sustainable agriculture once deprived of their forest canopies. In areas of the western United States such as Utah, pinyon-juniper forests are also destroyed to create grazing land, leading to rapid desertification. Logging is perhaps the major cause of deforestation, with urbanization and development also being major issues.
The first global negative effect of deforestation is that it reduces wildlife habitat and biodiversity, leading to species endangerment or extinction. An even more globally important issue is the way it disrupts climate cycles and contributes to global climate change. The main solutions are development of sustainable logging practices, tree planting initiatives, and creating global reserves of virgin forests. 
https://www.nationalgeographic.com/environment/global-warming/deforestation/

https://www.worldwildlife.org/threats/deforestation-and-forest-degradation