Vast areas of forest in Canada and Russia were lost to fire in 2013, according to new satellite data. But there were encouraging signs from Indonesia, where the loss of forest cover fell to the lowest level in a decade.

Scientists from Global Forest Watch collated 400,000 images of the Earth’s surface to map the world’s forests down to a resolution of 30 metres. Their findings showed that overall the world lost 18m hectares of forest in 2013.

Between 2011 and 2013 fires in the boreal forests of Canada and Russia accounted for almost a quarter of global forest losses. Some of this will return, but northern forests are particularly slow to recover after fire.

Boreal forests are one of the world’s great carbon sinks. But scientists predict that climate change will cause them to burn more often and with greater intensity, unlocking the carbon stored in the wood and soil. Already they are burning more than at any point in the past 10,000 years.

As many as 90-95% of fires in Russia are ignited by human interventions ... This is very different to North America.

Dr Nigel Sizer, study co-author and director of the forests programme for the World Resources Institute (WRI), said the increase of fires in northern forests had worrying implications for the climate. “If global warming is leading to more fires in boreal forests, which in turn leads to more emissions from those forests, which in turn leads to more climate change. This is one of those positive feedback loops that should be of great concern to policy makers.”

Dimitry Aksenov, the director of Russian NGO Transparent World said: “In Russia, according to official statistics and to experts, the dominant amount of fires are caused by humans.” As many as 90-95% of fires in Russia are ignited by human interventions, he said. “This is very different to North America.”

Forestry and oil and gas exploration have driven roads through previously inaccessible forests, increasing the risk of fires.

Olga Gershenzon, founder of Russian commercial satellite imagery company ScanEx who contributed to the data, said forest management and fire prevention in Russia and Canada was in need of improvement.

“This should be a clear call to action to look closely at forest management in Russia and Canada in the face of climate change. The massive tree cover loss shows there is much to be improved in terms of monitoring and understanding the causes and types of forest fires.”

Around 70% of the Russian and Canadian losses could be attributed to fire. The researchers said logging and pests could also account for the increased loss of northern forests.

Indonesian forest losses bucked their recent trend by falling​ in 2013​ to their lowest level in a decade

Brazil, the US and Indonesia rounded out the five largest contributors to tree-cover loss between 2011 and 2013. But in a sign that recent efforts to tackle deforestation may be working, Indonesian forest losses bucked their recent trend by falling to their lowest level in a decade in 2013.

WRI scientists said it was too early to know whether the destruction of the country’s rainforest was coming under control. Recent forest preservation efforts have been bolstered by mercurial market effects, such as a drop in palm oil prices, which have almost halved since 2012. Additionally, many of Indonesia’s accessible forest have already been cleared.

Forest cover loss in Indonesia 2001-2013. Photograph: WRI

Because of the massive loss of its forests and peatlands, Indonesia has become the world’s third largest emitter of carbon dioxide. The new government of Joko Widodo has made stemming deforestation a major commitment.

Indonesia’s minister of environment and forests Siti Nurbaya said the news was positive but didn’t amount to a turnaround. “It is too early to say this is a definitive trend, and the ministry is now examining how our numbers compare with this finding. If it holds true, this could be a powerful indicator that Indonesia’s significant investments in forest protection are paying off. We intend to take additional steps to ensure these positive trends continue.”

Agustin Teras Narang, the governor of Central Kalimantan province in Borneo said his region had seen its forests protected through cooperation between local communities, regional and national government and the UN’s REDD+ programme, which offers financial incentives for forest protection.