Weakened

[Magpie]

Hi, I like this, very relatable and strong images. Some notes:

Weakened

When the workmen descended I like descended here, an attack.
upon the spruce and pine
to protect the electric
pylons they cut a gateway
dissecting the forest,
a slice that severed ancient
limbs leaving a corridor
of sanitised destruction.
These blights to the human eye seem to become a favored path for wildlife dealing with loss of habitat. Don't know if this thought is of any use to you.

When the storm descended Descended seemed odd here, especially because storms don't have the intention of workmen. I'm unsure if that helps or hurts the poem. -- noted - I was trying to mirror the first stanza but I see your point
to the loch and through the glen
it shook the doors centuries old Still trying to figure out why you don't say "centuries old doors". I know the break on old is good but it reads awkwardly. Doors might not be a bad break either because you're putting humans back in the forest even in this more natural strophe. -- yeah i was trying to clever I suppose as in 'sentries' I was thinking about 'cent'ries' but it looks odd 
and rattled the roots of noble I like this line, it's what scares me during storms.
firs and toppled sycamores,
a swathe that ripped ancient
limbs leaving a corridor "ancient limbs" come off as a bit cliche here, it didn't bother me above. -- I was going for symmetry again but it doesn't seemed to have helped my cause
of natural destruction.
I'm a fan of the five different trees, a mixed forest is a much different image than one or two. 
Now I clamber fallen 
oak where we once laughed.
This would read smoother as "a fallen" or "oaks", I prefer "a fallen" because it givens me room to imagine a comma after clamber if I want to. Love clamber. -- trying to be clever with enjambment here as in it's the narrator who is 'fallen'. Is oak also the plural of oak, not sure, my intention was that there were more than one.

I better stop and post this, too much already?  Thanks for posting this, I hope something in there helps.  -- don't worry about writing too much I will never mind. 

Thanks Ella for reading and commenting on, it's the first poem I've written in a long time so just getting back into it.
The idea that I had was one part of the forest being weakened by work and then that enabling the destruction of another part of the forest.

I wanted to compare it with some form of surgery, perhaps for cancer where an operation which may seem to be for the best ultimately creates a weakness. That was what the last two lines were supposed to reveal. I realise now looking at it that those two lines are ambiguous. I was going to say, 'laughed and loved' to indicate a relationship with someone that has since gone.

I'll think on how to improve.

Thanks again