The world's forests continue to shrink as populations increase and forest land is converted to agriculture and other uses, but over the past 25 years, the rate of net global deforestation has slowed down by more than 50%, the U.N. Food & Agriculture Organization (FAO) said in a report published Sept 7.

Some 129 million hectares of forest — an area almost equivalent in size to South Africa — have been lost since 1990, according to FAO's most comprehensive forest review to date, The Global Forest Resources Assessment 2015.

However, FAO noted that an increasing amount of forest areas have come under protection while more countries are improving forest management. This is often done through legislation and includes the measuring and monitoring of forest resources and a greater involvement of local communities in planning and in developing policies.

The FAO study covers 234 countries and territories and was presented at this week's World Forestry Congress in Durban, South Africa.

"Forests play a fundamental role in combating rural poverty, ensuring food security and providing people with livelihoods. And they deliver vital environmental services such as clean air and water, the conservation of biodiversity and combating climate change," FAO director-general Jose Graziano da Silva said in releasing the report.

He noted an "encouraging tendency towards a reduction in rates of deforestation and carbon emissions from forests," as well as improved information that can inform good policy, noting that presently national forest inventories cover 81% of global forest area, a substantial increase over the past 10 years.

"The direction of change is positive, but we need to do better," Silva cautioned. "We will not succeed in reducing the impact of climate change and promoting sustainable development if we do not preserve our forests and sustainably use the many resources they offer us," he added.

While in 1990 forests made up 31.6% of the word's land areas, or some 4 128 million hectares, this has changed to 30.6% in 2015, or some 3 999 million hectares, according to the assessment.

Meanwhile, the net annual rate of forest loss has slowed from 0.18% in the early 1990s to 0.08% during the period 2010-15.

Today, the bulk (93%) of the world's forest area is natural forest — a category that includes primary forest areas where human disturbances have been minimized, as well as secondary forest areas that have regenerated naturally, FAO explained. Planted forest, another subcategory, currently accounts for 7% of the world's overall forest area, having increased by more than 110 million hectares since 1990.