Dummy quesion about environment

Hi,
I'm trying to understand environment object in R.
I used the example:
  f <- function(x) {
         y <- 10
         g <- function(x) x + y
         return(g)
     }
     h <- f()
     h(3)
then i saw that f return an environment

h

function(x) x + y
<environment: 01B28570>
but I coudn't access to x and y object in that environment:
I tried 
get("x",env=h)
I tried
h$y
can I access y and x?
how can I see an environment tree? oes search does it?
Thanks,
Ron