Forest resources play intrinsic role to maintain global ecosystem and biodiversity balancing ecological and environmental systems. Depletion of Global forest resources over the years due to natural disasters and human intervention grows up forest cover changes declining biodiversity comes threats and challenges for sustainability of forest ecosystem and environmental protection. Reviewed and assessment of forest cover change in global, regional and national scales together with implications on biodiversity this paper evaluated through monitoring results of global scale comprising as a case study of Nepal. Since 1990 global forest area changed in 31.6% accounting 3999 million ha in 2015 whereas in Nepal forest area was changed annually by 2.1% with annual changing rate of -1.1% in 2015. As tropics biodiversity covers 78% flora and fauna decline rate of forest area, deforestation and fragmentation of forest habitat, degradation and loss of ecosystems challenging by the manmade anthropogenic changes. Since earth's life existence, over-exploitation of the natural resource base changing biological diversity continuously due to human kind interventions or induced direct impacts in ecosystems with triggering loss of biodiversity and interrupt to recover the natural ecosystem. However, improving national policies, plan and programs, implementing legislative measures and instruments together with research and innovation as well as promoting renewable energy can be the useful for sustainable management of forest and biodiversity. Natural forests and woodlands play vital role to protect environment and balancing ecosystem together with havens for wildlife and protection of endangered species or critical flora and fauna, Nepal endowed immense biodiversity can be managed through replacing forest base dependency and by increasing green cover with sustainable development.