Tree Management Aided By Computer

Inventory

Reducing pertinent data to a minimal amount is advisable. This is particularly true when dealing with a large diverse tree population. Avoid details but don’t lose the essential managerial information. For example, it is enough to know a tree is large (46 to 60 foot range) compared to a medium-sized tree (21 to 45 foot range), rather than to precisely measure a tree to determine whether it is 52 feet or 53 feet tall. Rarely is it necessary in maintenance work to have exact measurements. However, sufficient information should be collected to avoid re-surveying. Occasionally a special survey may have to be conducted, but this would not have to be extensive because the basic survey is established. Even by simplifying pertinent data, one will usually end up with a broad data base because of the large number of trees and the possible combinations of data.

The data collected in Sacramento’s tree inventory include:

1. an individualized tree location for special retrieval if desired,

2. identification of the tree species (open-end listing for additional species),

3. tree height by five categories (range of height),

4. tree diameter at breast height by nine categories (ranging in 6-inch increments up to 48 inches),

5. general health conditions by four categories,

6. mistletoe infestations by three categories,

7. if roots are damaging sidewalk,

8. if tree needs pruning,

9. space is open for soil-related problems,

10. if irrigation is required.

Personnel for Survey

Inventory data are good only if reliable. Because of this, it is important that qualified persons conduct the surveys. Careful training is essential. Technical instructions as well as field experience should be emphasized, particularly in tree identification, tree location designations, and tree health evaluations. Other categories are relatively easy to define.

The experience of conducting a tree inventory of a large tree population is educational, particularly if a person has already had some background about trees. He or she is continually exposed to the inter-relationships of the host trees with the natural environment, man-made conditions, and pests and diseases. Promising employees within the Tree Department or college students studying environmental horticulture or pest management are good possibilities for doing surveys and handling maintenance update records.

INVENTORY ITEM CODES

Completion of Inventory

The tree inventory should be completed as quickly as feasible. The obvious advantage is to analyze and get a better perspective of the overall problems and to record work on the maintenance update file. Doing the inventory over a longer period of time is possible and in some cases, desirable in terms of available manpower to survey. If an inventory file is developed over a period of time without omitting records for maintenance update, work sheet records must be kept for future submittal to the computer after the inventory is completed.

Maintenance Update

The objective of maintenance update is to monitor operations and keep them efficient. It is used to identify problems, to check if reasonable progress is being made, or if jobs are being completed. No attempt should be made to threaten workers on their performance through this system. The system is intended to improve operations. It is important for employees to understand the value of recordkeeping and not to allow mistrust between the employee and the supervisor.

It is reasonable to require an employee to keep records of his daily work. Records are kept daily and turned in weekly. At any time during the week, the foreman or supervisor may request to review a worker’s time sheet. The time sheet should be designed to facilitate the employee completing the record in the minimum time and the least amount of writing. Below is an example of a work sheet form. Only pertinent data are entered into the computer. Other information is used by the supervisor or foreman for operation adjustments. The worker needs to fill out his name, crew, tree location(s), date worked, and hours on the job. The operation he performed and the major reason for the work is simply entered as codes. These are listed on the back of the work sheet. In our example, 26 basic operations have been identified, although most employees are involved in only a few of them. Pests and diseases and their controls are filled in by the foreman.

What is expected of an employee in performing any operation should be clear to the employee. This is accomplished by having training sessions and developing “workers manuals.” A basic operation is quite constant but within a basic operation, procedures and techniques may readily change. These need to be conveyed to the employee to keep accepted practices current.

Normally five to ten minutes are spent by workers to fill out daily work records. At the end of the week, these records are transcribed to the maintenance update computer sheets. The computer sheets are turned in once a month to Data Processing for a monthly report.

Application of the Inventory and Maintenance Systems

An example of the application of the inventory and maintenance update systems is found in managing a mistletoe epidemic. Upon investigating the mistletoe problem in Sacramento, the scope and severity of the problem was determined. The economic and visual impact was quite serious, in some ways being comparable to the Dutch elm disease in other communities. Below is a diagram outlining steps in solving the mistletoe problem and where the computer data were utilized to help provide information for analysis and decision-making.

Other examples of tree problems amenable to computer analysis include tree roots lifting and damaging sidewalks, prevention and control of Dutch elm disease, controlling “honeydew” secretion, and detecting and assessing smog damage to trees.

Integrated Pest Management (IPM)

The inventory and maintenance update systems are amenable to integrated pest management. A technical coordinator, such as an arborist, horticulturist, forester, or other pest management specialists is capable of utilizing data to best control pests and diseases. Their role would include:

1. analyze data to identify problems and their severity,

2. recognize or identify specialized pest and disease problems in the field by monitoring the population and by strategic sampling,

3. verify by laboratory testing in cooperation with State and University agencies the identity of special pests and disease, coordinate a control program,

4. determine species adaptation and tolerances,

5. balance population by phasing out problem species and re-planting with more desirable ones,

6. determine allowable percentage categories based on desirability and determine which species in each category,

7. make tree selections and introductions,

8. coordinate findings and make recommendations to the administrative staff,

9. coordinate recommendations with field operations,

10. conduct research on specialized pest and disease problems.

Summary

A computer is effective and efficient in processing data useful for street tree management. It provides information on adaptation of trees planted in the past, identifies and reveals the scope of present tree problems, and provides information that will minimize problems in the future. It is a nonbiased means of determining priority tree services needed in the community and gives the public a truer picture of problems that confront manage-merit. By using this tool wisely, the City can be assured of making the best use of funds for tree maintenance.