I would like to thank Upreshpal Singh of Friends of the Orang Utans for responding to my article . I am, however, surprised by his lack of constructive debate when it comes to Malaysia’s forests.

The Food and Agriculture Organisation of the United Nations (FAO) data has been available for more than five months, but he has chosen not to speak on it until now. At the time of the release, even Greenpeace appeared to concede that the global picture on forests is improving; Greenpeace also cited Global Forest Watch data on tree cover and forest cover as a form of confirmation - just as I did.

The Union of Concerned Scientists’ Dr Doug Boucher also reported the data positively and constructively, pointing out its strengths and weaknesses, also drawing on positive data from the Intergovernmental Panel on Climate Change.

The key to all of this is a constructive discussion based on the facts and the research. Unfortunately, Upreshpal appears to have chosen instead to focus on personal insults. Why?

My article focused on the positive news for Malaysian forests from the United Nations report but because I work in partnership with the Malaysian palm oil industry - as I do with many sectors around the world - he has used this as an excuse to criticise me personally.

This is an old tactic. In football it is referred to as ‘playing the man, not the ball’. In public debate, if a fact is unfavourable to your argument, you simply discredit whoever is saying it as ‘biased’. That is what Upreshpal finds himself doing. But Upreshpal’s actual disagreement appears to be with the UN FAO, its review processes, its use of the term ‘forest area’, as well as the credibility of Malaysian officials.

The FAO has a process for reviewing and standardising its data; a process that takes place over a number of years with a range of reviewers as well as an advisory board. His outright dismissal of the term ‘forest area’ as ‘dubious’ is somewhat extraordinary. The UN FAO’s definition of forest has been agreed upon by all nations through a consensus process. His is an objection to the idea that a planted forest or a plantation has any value at all.

Assessing forest area, forest cover and/or tree cover is significant, but methodologies and data vary significantly. The UNFAO definition of forests can be be found here (oil palm plantations have never been considered as forest in the FAO definition).

The data that Upreshpal cites from the University of Singapore, for example, is from 2011. But it should be noted that the same lead author of that study contributed to a 2014 paper with significantly different assessments of forest cover in the region; the difference between the forest cover estimates for Indonesia, for example, was 18 million hectares.

Similarly, a comparison of three different satellite methodologies gives greatly varying estimates for forest area in Malaysia. A number are significantly higher than the figures for Malaysia under the FAO.

The FAO data is, as Upreshpal correctly points out, collated by Malaysian officials . The data is from no less than six departments and overseen by 14 officials, all of whom have considerably more experience in Malaysian forestry than myself or Upreshpal. It is not perfect; even FAO officials concede that point and have their own criticisms of the data.

It is therefore impossible for me to concede that I am somehow ‘spreading misinformation’. The FAO data is a consensus-based approach where, clearly, there are a range of different estimates of forest area and forest cover. But ultimately, it is produced and published by experts: and as I wrote in my article, I respect that, and it is good news for Malaysia that these experts clearly accept that Malaysia’s forest cover is robust.

It is important that the debate around forests, oil palm, and biodiversity, is conducted constructively. It is sad that Upreshpal prefers negativity instead of engaging in constructive discussion.

PERRE BOIS D’ENGHIEN is a renowned agronomist and environmental expert, who has worked with many of Europe’s leading players in plantations and agricultural development. He has a Master’s degree in Environmental Management, and currently works with Socfin, SIAT, and Feronia as well as other agricultural leaders. He also serves as an auditor to the Roundtable on Sustainable Palm Oil (RSPO). Bois d’Enghien is a well-publicised author and commentator in Europe on environmental matters, including for major newspapers. He travels widely in his role as an agronomist and consultant, including Africa and South-East Asia.