Hi, I'm an urban forester intern at the Missouri Department of Conservation. I'm currently working with the 2.0 version of the i-Tree Suite, more specifically STRATUM. First, after reading through the i-Tree glossary of terms, I found some broad definitions of what STRATUM considers a "street tree". I was wondering if you could give me any more specifics into what a private and public tree means within the context of street trees. The reason I ask is the fact that I must present my findings from STRATUM to a public that could very well ask what a true definition of a street tree is.
Second, I was curious as to how much data needs to be collected and what I really need to know to get an accurate data set for use in STRATUM. I have tried to find information on this in the manual and personally haven't been able to. I plan on conducting a small 100% inventory of street trees here in Kansas City.
Thanks for your time!
STRATUM definitions and data collection
Moderators: i-Tree Support, i-Tree Team
STRATUM definitions & data requirements
STRATUM allows the user to distinguish between public and private trees because there can be much variability between communities and project objectives. Ultimately, the project manager will define the parameters based on his or her own unique situation.
Some project managers are only interested in collecting data for street trees that are on public property and managed by municipal resources. Conversely, rural communities may not have sidewalks and clearly defined right-of-ways where many of the privately owned trees function as street trees. Municipal resources may not be utilized to care for these private trees but their proximity to the public right-of-way provides public benefits.
Also, please take a look at page 86 of the following document which defines public & private trees in a STRATUM collection http://www.fs.fed.us/psw/programs/cufr/ ... fr_128.pdf . I hope that this may help you.
I have also copied text from secteion 2.7.2 of the manual pertaining to your question on obtaining an accutate date set:
For STRATUM, sample inventories are generally a 3-6% sample of total street segments, depending on community size and variation from segment to segment, and will produce about a 10% standard error for the total number of trees citywide.
The following, general guidelines can be used as a starting point for determing sample sizes in communities based on human population sizes:
• For communities with less than 50,000 persons, sample size is 6% of total street miles
• For communities between 50,000 and 150,000 persons, sample size is 5%
• For communities between 150,000 to 250,000 persons, sample size is 4%
• For communities over 250,000 persons, sample size is 3%
It is important to note that all communities differ in their tree density, street miles and population characteristics. Therefore, no single sampling intensity will work uniformily
for all communities of a similar size. Ultimately, it is up to the user to determine sampling size and an acceptable level of error based on how the results will be used.
Regards,
Al
Some project managers are only interested in collecting data for street trees that are on public property and managed by municipal resources. Conversely, rural communities may not have sidewalks and clearly defined right-of-ways where many of the privately owned trees function as street trees. Municipal resources may not be utilized to care for these private trees but their proximity to the public right-of-way provides public benefits.
Also, please take a look at page 86 of the following document which defines public & private trees in a STRATUM collection http://www.fs.fed.us/psw/programs/cufr/ ... fr_128.pdf . I hope that this may help you.
I have also copied text from secteion 2.7.2 of the manual pertaining to your question on obtaining an accutate date set:
For STRATUM, sample inventories are generally a 3-6% sample of total street segments, depending on community size and variation from segment to segment, and will produce about a 10% standard error for the total number of trees citywide.
The following, general guidelines can be used as a starting point for determing sample sizes in communities based on human population sizes:
• For communities with less than 50,000 persons, sample size is 6% of total street miles
• For communities between 50,000 and 150,000 persons, sample size is 5%
• For communities between 150,000 to 250,000 persons, sample size is 4%
• For communities over 250,000 persons, sample size is 3%
It is important to note that all communities differ in their tree density, street miles and population characteristics. Therefore, no single sampling intensity will work uniformily
for all communities of a similar size. Ultimately, it is up to the user to determine sampling size and an acceptable level of error based on how the results will be used.
Regards,
Al
A member of the i-Tree Team
STRATUM definitions & data requirements
Al,
Thank you very much for your help. I've found everything you've posted to be very helpful!
Thank you for taking the time to help me,
Brice
Thank you very much for your help. I've found everything you've posted to be very helpful!
Thank you for taking the time to help me,
Brice