Garden trees, ok to get topped ?

[herby1]

Hi all, we've got 3 trees in our garden about 30 meters from our house, our house is surrounded by flat fields in Lincolnshire so very exposed to high winds from all directions.

The trees are 1 birch, 2 poplar ( I think from trying to identify ) all about 40 feet high.

Would it be ok to have the trees topped & trimmed to reduce the amount of wind hitting them, what time of year, & roughly how much to take off the top/sides ?

I will be employing a tree surgeon to do the job (Done some tree trimming in the past but 40 feet is way, way too high for me  )  but would be good to get some info first, most are good, but some cowboys out there.

Any help appreciated 

[Mick Dempsey]

We need pictures.