Finally, a tool to measure guilt.

Today is the day we are removing a large post oak from our garden, to make way for an extension on the house.

tree whose days are numbered

As you can see, the tree is massive and poses a threat to the house. A good summer hurricane could send a limb (or, heaven forbid, the trunk) crashing through the roof. Such a disaster happened to a family friend of ours years ago. She was fortunate to be in another part of the house at the time, but the tree cut her living room in half.

My daughter helpfully informed me that by cutting down the tree, I was contributing to global warming. I already possessed plentiful stores of guilt about removing the tree and I began to second-guess my decision. But ultimately, I thought, how much damage could be wrought by the removal of one tree? How guilty should I feel?

They have an app for that. As I dwelt on the miserable choice before me, I happened across i-Tree, a free, online peer-reviewed software program from the USDA Forestry Service that offers multiple applications for urban forestry, benefit and value assessment, planning, and advocacy. As I am not operating on a city- or region-wide planning scale, I won’t go into the program’s capabilities to that end. But a homeowner can use its Design mode to locate her property (it pulls in Google Earth satellite maps), pinpoint a specific tree in relation to her home, input specifics about its species, size, and general health, and find out a host of reasons why she should feel bad about cutting it down.

step 1 copy

After you enter your address, this page finds the map of your property. The yellow and green bands around the house’s perimeter (which I marked) indicate preferred planting zones. The green pin on the map indicates the tree in question. It’s actually much closer to the house than that, but it’s close enough for the calculations.

CY overall

Apparently, my tree provides huge stormwater benefits; the details appear outlined below. Good thing I put in that massive rain garden!

CY stormwater


Precisely how guilty should I feel about contributing to global warming? A bit over a quarter-ton per year. Or we could round up and say a half-ton. Half a ton of guilt.

FY5 energy

Here, you can see the future benefits (5 years, but you can assess anywhere from 1-99 years) I will not reap. I suppose you won’t reap them either; we’re all sharing the same atmosphere. I am sorry about that.

On the plus side, I should be able to do some modeling to show how many pawpaws and persimmons I will need to make up for the removal of the oak. I’ll tell you in another post.