Hi Maxic and welcome to GoY. No it is not normal for a Monkey Puzzle tree to suddenly g brown, could you take a photo of the whole tree and a close up of the problem. When did you plant, is it in the ground or a container, have you had a summer of little water and a lot of sunshine? All this will help us advise you, though Bamboo who lives in the south of England may already have a good idea!

In the meantime don't feed at this time of year.

As Stera recommends, don't feed it. I am of the opinion that as it originates from South America with its extremes of climate it should thrive in most parts of our country. I do have to say that I believe that once it starts for go brown it seldom regenerates.

Usually the lower branches might start to turn brown, not always all of them, but when that starts, those branches are on the way out.If its all the branches, possibly a result of earlier drought, especially if its in a pot. Photo would be good, but if not, more info. Is it in a pot or in the ground, how long have you had it, how much of it is going brown...

i have grown a couple of them in pots and learned the hard way that they like to be kept moist in a good well drained soil. also really like humidity.

If it's in a pot I would imagine there lies your problem?