Just to confirm, growing or cutting down Natura Redwood trees does not have any kind of negative impact on the server, any disconnects experienced by players nearby are simply due to the connection between their server and client or the client computer getting overloaded by the number of block changes.
I have done some testing and found that with a reasonable internet connection (seemingly 10Mbps+ is fine) and a fairly decent computer growing them shouldn't be an issue for players.
As for cutting them down the drops combined with the block changes is a lot more client intensive and for some reason this is a lot worse when Treecapitator is involved, overloading players a considerable distance away.
I have therefore disabled Treecapitator for this tree type, however the Tinkers Lumber Axe can still be used. This essentially eliminates the chance of disconnecting nearby players, although again this does depend somewhat on internet connection speed and the players computer.
If you do experience disconnect issues when cutting down a Natura Redwood, just use a less powerful Lumber Axe to reduce the number of block changes and drops, it will take a bit longer to cut it down but at least you wont have to keep reconnecting!