Re: tall or long       Possibly tall, but also high..    Long referring to distance (as opposed to time) is always horizontal - eg The garden is 120 metres long and 30 metres wide.    Tall is used to describe height for people  - John is 5ft tall - and can be used for certain objects - eg tall buildings and also tall trees :    A picturesque lake surrounded by tall trees.   
But high is also used :    A woodland road, flanked by high trees in the foreground,   
So you could use either in the sentence you quote.         |