11. Adequate documentation and assistance. The 

 DBMS, for ease of use, must be well documented and 

 provide assistance for common user problems. 



12. Analysis! reporting capabilities. Linkage to 

 analysis and reporting software enhances the useful- 

 ness of the data. The ability to calculate commonly 

 used stand and plot-level attributes, such as basal 

 area or trees per acre, from the tree data is another 

 important capability. Reports that show incremental 

 changes through time are especially useful. 



SURVEY OF EXISTING SYSTEMS 



First Questionnaire 



A survey of existing systems for managing remeas- 

 ured plot data was conducted using two separate ques- 

 tionnaires. The first questionnaire was sent to as large 

 an audience of forestry people as possible with the pur- 

 pose of identifying existing systems and their features. 



The first questionnaire (appendix A) was designed 

 to take only a short time to complete. It consisted 

 mainly of questions needing only a yes/no response 

 along with a few short written answers. A cover let- 

 ter describing the purpose of the survey was sent with 

 each questionnaire. A stamped, self-addressed enve- 

 lope was enclosed to encourage a response. 



The first questionnaire asked if a DBMS was used 

 for remeasured plot data. If the answer was no, the 

 questionnaire was to be returned without proceeding. 

 Otherwise, several questions were asked about the 

 computer hardware and software in use. The next 

 few questions inquired about the amount of data (in 

 terms of plots and trees) presently stored in the system. 

 The next section asked if the system could perform 

 the major tasks previously described. And finally, the 

 respondent was asked to write down other capabilities 

 a DBMS for remeasured plots should include. 



Several sources were used in developing the mailing 

 list for the first questionnaire. First, all member or- 

 ganizations of the INGY Cooperative were included. 

 Second, all Regions of the Forest Service were in- 

 cluded, as were working units of Forest Service Re- 

 search Stations that dealt with growth and yield or 

 silviculture. And finally, members from the Forest 

 Resources Systems Institute (FORS), an international 

 nonprofit association that supports and promotes the 

 use of computers in forestry, were contacted. In addi- 

 tion, other members of the forestry profession known 

 to have at least some interest in this field were in- 

 cluded on the mailing list. In total, more than 270 

 organizations were contacted from both the United 

 States and Canada. Questionnaires were sent out in 

 December of 1987, with requests for return by early 

 February 1988. A total of 133 responses were re- 

 ceived from this initial mailing. 



Second Questionnaire 



A second questionnaire (appendix B) was developed 

 for those respondents of the first questionnaire who 

 indicated the existence of a system for managing per- 

 manent plot data. This second questionnaire was far 

 more detailed and addressed more specifically the de- 

 sirable system features that were only touched upon 

 in the first questionnaire. Of the 47 individuals who 

 were mailed this second questionnaire, 36 returned 

 completed questionnaires. The responses received 

 from the second questionnaire were then summarized 

 in tabular form. A rating procedure was developed to 

 evaluate each system's capabilities in regard to the 12 

 desired DBMS features. 



EVALUATION OF DATA BASE 

 MANAGEMENT SYSTEMS 



Criteria were developed for evaluating the strengths 

 and weaknesses of each of the 36 systems (those with 

 responses from both the first and second question- 

 naires). The evaluation was based strictly on answers 

 provided by the organizations responding to the ques- 

 tionnaires. No specific tests have been done to validate 

 actual system components and their adequacy. Never- 

 theless, we believe that this evaluation provides the 

 necessary information to determine any general trends 

 among the systems as to attributes that are adequately 

 (or inadequately) addressed. Our intention in doing 

 this evaluation was not to pass judgment, either posi- 

 tive or negative, on any of the systems for we realize 

 that organizations have limits on the resources they 

 can expend to implement all of these desired features. 



System for Rating DBMS Criteria 



For each of the desirable DBMS features described 

 previously, a simple rating of +, 0, 0+, 0—, or - was 

 determined for each system, based on how many of the 

 criteria for that feature were met. Each of the DBMS 

 features had one to three criteria. If there was one 

 criterion, a rating of + was given if the criterion was 

 met or — if the criterion was not met. If there were 

 two criteria, a rating of + was given if both criteria 

 were met, if only one of the criteria were met, or - 

 if neither of the criteria were met. For those features 

 with three criteria, a rating of + was given if all three 

 criteria were met, 0+ if two of the three criteria were 

 met, 0- if one of the three criteria were met, or - if 

 none of criteria were met. Table 1 presents a tabular 

 summary of the rating system. 



Criteria for Rating DBMS Features 



The criteria used in determining the rating for 

 each DBMS feature and the questions used from 



2 



