agentes a montante da fileira

15:22 Mar 2, 2015 

This was all very helpful!

20:53 Feb 12, 2015 

Your text states that they created a monitoring structure of wood markets to prevent and combat abuses by the wood industry suppliers (because they have a very strong negotiating power).

20:39 Feb 12, 2015 

2. ("wood industry value chain"): https://www.google.pt/search?q="wood industry value chain"&e...

I believe that the word "fileira" comes from the French word "filière".
3. ("Filière": En économie, la notions de filière désigne le regroupement cohérent ... des opérateurs et des activités"): http://fr.wikipedia.org/wiki/Filière
4. ("filière de bois" »» "wood chain"): http://iate.europa.eu/SearchByQuery.do?method=searchDetail&l...

20:39 Feb 12, 2015 

The economic concept of "fileira" (or "fileira industrial)" is the concept of "market/sector", more or less addressed in the perspective of the "value chain" concept of Michael Porter.(vd links)
Thus, the closest expression in EN may be "industry value chain". But in many contexts the most frequent general reference is just "the market / sector".
In your case, "os agentes a montante" refers to the economic agents upstream the chain. Eg. In the case of link2 image, the upstream agents are the owners of forests, which are producers / suppliers of wood, and sawmills. They are the agents upstream of wood processing.
vd links:
1. ("industry value chain"): http://en.wikipedia.org/wiki/Value_chain