inventory help

[OTG BOSTON]

We recently completed a tree inventory that includes all of the street trees in Boston. The problem we are facing right now is how to integrate it with our current tracking system.
The field work was done by volunteers and the entire project was administered by a non-profit organization.
My question is how much of their work should I review before accepting their version of the inventory?
Any help is greatly appreciated.

 

[NYCHA FORESTER]

Most databases accept excel spreadsheets rather easily...... one way or another..... talk to your software people to see what you have to to to import it in.....

My concern regarding inventory data from volunteers is....well... everything. That data usually is not the best or even accurate however at least you know a tree exists (or available growing site) so it give you a starting point. I would import all of their data but flag it as just that "volunteer data" so whom ever looks at it will realize that it "might" not be correct.

You can also go out and review a sample of that data to determine how good each persons data is.

If it is completely useless then it may be time to purge it from the data.

 

[OTG BOSTON]

Most databases accept excel spreadsheets rather easily...... one way or another..... talk to your software people to see what you have to to to import it in.....

My concern regarding inventory data from volunteers is....well... everything. That data usually is not the best or even accurate however at least you know a tree exists (or available growing site) so it give you a starting point. I would import all of their data but flag it as just that "volunteer data" so whom ever looks at it will realize that it "might" not be correct.

You can also go out and review a sample of that data to determine how good each persons data is.

If it is completely useless then it may be time to purge it from the data.

It is already in the hands of our IT guy, so I'm not concerned with that piece. The volunteers did have a certain criteria which was approved by me so I'm somewhat confident in the results.

I guess my question is how many sites should I sample? Or what is an acceptable percentage? Thanks NYCHA, this is all greek to me!

 

[NYCHA FORESTER]

How many trees were inventoried?

I have heard that a minimum sample of 3% is commonly used....... but I don't know if I would want to hang my hat on that figure. On the other hand if each person only did 1,000 trees (not including growing sites) then I would probably do 10 or 20%. That number will vary widely depending on how accurate the first 100 trees are. Some data maybe completely useless while others.... will be great.

I lost my sampling guideline book during 9/11 so thats all I can offer off the top of my head but 3% sticks in my head for some reason.

I'm sure a Google search on Population Sampling would be a good start.

 

[OTG BOSTON]

Thanks

I did a search, seems 10% is about right. I'm gonna start with 3% and do ten if I still have concerns. There are 35,000 sites that were looked at:help:

Thanks again.

 

[John Paul Sanborn]

I did a search, seems 10% is about right. I'm gonna start with 3% and do ten if I still have concerns. There are 35,000 sites that were looked at:help:

Thanks again.

I would do a small sample of each vollenteer/group first to determine which are most reliable. (if possible) Then look deeper into the ones with a higher problem rate.

 

[treeseer]

I would do a small sample of each vollenteer/group first to determine which are most reliable. (if possible) Then look deeper into the ones with a higher problem rate.

Good tip; this should also be done with professional inventories imo. I got called in to give a second opinion on 268 Large Trees that were called removals by a national company. This would have busted the town's budget--and much of their urban forest, needlessly. Only 23 had to go.

 

[John Paul Sanborn]

Good tip; this should also be done with professional inventories imo. I got called in to give a second opinion on 268 Large Trees that were called removals by a national company. This would have busted the town's budget--and much of their urban forest, needlessly. Only 23 had to go.

And I assume that comapny would be bidding on the removals too.

It's probably that they had a very low risk tolerance. I saw a seminar once where the speaker was giving almost every defect a very high risk rating for muni use.

A few years ago Wauwatosa had decided to remove all the mature N. maple an a street in the (I think) Ravenswood area. The citizens on the strees were up in arms.

The reason for the plan was that the trees were very mature, with some starting to decline. Doing it all at once would have saved a ton of money.

It would have changed the whole look of the neighborhood too. I was asked by a friend of a client to look at it, and many of the trees were still in good shape.

Of course they thought I would do the consulting as some sort of civic duty...

I did call that cities forestry dept and spoke my opinion, but the plan was toned down at the council level.