As a tree surgeon/forester, I've been using these saws for years......
https://www.qualitygardentools.com/product/silky-zubat-330mm-saw/
I've worn out 3 of the above model, and would recommend them above all others.
I would strap the scabbard to my leg, with the saw attached on a long leash, this model will cut through 6" green Oak, with ease. I used my small Stihl saw, far less in favour of the silky for high pruning.
But, and it is a big but........they are fearsomely sharp......so much so that you can have a severe cut......and not know it until you see the red stuff.....they take no prisoners......Mea culpa......ouch... :doh