I've never been one to concern myself with "parameters" I'm old school. I subscribe to the K.I.S.S. method. listen, here's the thing... If a tree were to fall in the water, dead or alive what typically happens? The fish flock to it for cover... Could you see them saying to each other...
"Hey Bob, this water tastes like crap"
"Yeah Jim, let's get outa here"
My point is... well, I really don't have one except for I'm not worried LOL The tree was cut down in the middle of summer about 8-9 months ago. I'm sure eventually tannins will leech into the water but nothing that will hurt the fish... How's that go... God made dirt, dirt don't hurt... Also, live or dead wood will leech things into the water
And if any bugs like a grub or something eventually finds it's way out... I'm pretty sure something will take care of it
No worries mate
Although... it did have some yellow snow on it when I put it in the water LOL