However, without further context, it's impossible to know the exact English equivalent. It could be referring to:
* A tree that is one year old.
* A tree that grows for one year.
* A tree that produces fruit/wood in one year.
* A tree that is one year old in a specific context, like a tree planted this year.
To provide a more accurate translation, I need more context. Please provide the full sentence or the situation where "maram oru varam" is used.