Hey there, The decision to get storm windows or replace your old windows depends on a few factors... If you have decided to replace your storm windows, be sure to check up on the factors we outlined here: http://blog.custombuiltri.com/steps-to-replacing-your-residential-storm-windows

Not likely a wood chip. Possible that it picked up a pebble and flung it when they were grinding it up. That picture is terrible and if they are facing inside, it appears the damage was done from the interior to be honest. With regards to your other questions: Totally depends on the window in question. Usually glass is measured and prepared before coming to the jobsite to deglaze and repair. Find some of the operable units and look for warranty/serial number on the glass, in the head jamb, on the sashes, etc. If they have acknowledged that it was then that damaged the glass, they will probably bill you and do some sort of warranty holdback credit on the open bill for a modest amount. Without seeing the window, I couldn't even hazard a guess as to the repair/replacement cost so that holdback would be dependent on that.

IGUs (Insulated glass units) are replaced as a unit and can't be field repaired on one side. Can the window sash be easily removed from the window? If so take it to a glass shop and get an estimate on the repair. If the frame comes off easily then one can take just the IGU to a shop and have it replaced, then reinstall in the frame. I can see three options: 1) have the tree guy coordinate the reapir with your tenant, 2) Call a local glass company, have them go to the property amd do the repair and deduct it from the tree guy's invoice. 3) Ask your tenant to handle the repair and compensate him/her accordingly. You don't say the size of the window and you're picture doesn't hint at the level of effort to remove and replace the IGU on this particular window, so it's difficult to guestimate the level of effort to fix it.

@WoW Washington Unfortunately I'm missing one storm window. The storms are fine. just needs to be painted. I might be missing 1 set of screens that got damage. Two windows sashes have damage panes, but I have replacements in the garage. theoretically this looks easy to switch. one of the balance tubes might need to be adjusted or replace to get it to close properly. the weather stripping all around looks shot. the plastic thing is so brittle . but replacement weather stripping will take about 2 min per window to change. and its dirt cheap from marvin. (5 dollars a window) ZERO wood rot. just needs a sand + paint job on the outside. The biggest issue is that they were just caulked into place and fiber glass + caulking was put in to weather seal them. There is no sill flashing. I know this because I had to rip out the frame on oen window that was hit by a tree. (i wanted to see the rough opening before ordering) Its in the back of the house with a good over hang, so I don't see it being an issue. But foam + full flashing all around would have been my preferred method. I still have room to foam them on the sides, but still wont be 100%, but good enough. The other thing is I could just go a head and get tilt pac replacements from marvin. Cuz what i realized I would have to buy new brick mould to match the previous look and pay extra to have that installed. I attached a set of pictures, looks like a dimond in the rough? Part of me still looking at high end vinyl as a replacement for all the windows. I'm about to pull the trigger on a elevate replacement for the window that blew out. but i also just came back from Windsor dealer And im thoroughly impressed. sorry for the long post again :)