Overhanging Tree in Common Area

I  live in WA part of a set of Townhouses

There is a large Gum Tree in the Common Area that is close to the fence that boarders our property.  The tree has quite a bit of over hang over our home.

I am getting quotes to have our other trees trimmed and want to included this to get done.  I am 100% happy to pay for the cost.  I can not see in the WA Strata By-Laws that would dis-allow me doing this.  I do not want it completely chopped down, just trimmed. 

I have emailed and called our manager without luck for over a month.  I want to get this done, but I do not want to break any laws in the process.  Getting it down through the Strata and costs and the possibility of raising a special levy will take months.

Thanks