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Feature ArticleApril 27, 2001

Metro Urban & Community Forest Health Surveys

April and December, 2000

In 2000, two surveys of the Metro Region urban and community forest contacts were conducted. The first, in April, explored their resource needs. The second, asked for specific information on insect and disease occurrences in their area.


Of the 188 urban contacts, 49 responded to the April survey and 48 responded in December, a 26% response rate for both surveys. Respondents indicated their primary source of information was the DNR (33%), followed by the U of MN (15%). The majority (63%) of respondents felt their information needs were being met. With multiple answers possible, printed material was the most preferred format for shared information (43% of the responses), while email was the second most preferred (24%). Eight or 14% said they used all forms of information available.

Twenty-six (54%) of the communities responding in December, submitted insect and disease reports. Seventeen communities (65%) reported tree removals for Dutch elm disease control (see table 1). They removed a total of 1,682 elm trees, for an average of 99 trees per community. Fifteen communities (58%) removed a total of 530 oak wilt spore trees, an average of 37 trees per community. To control the spread of oak wilt via root grafts, communities reported plowing a total of 26,850 ft of plow line, for an average of 1,790 ft per community.

Table 1. Wilt diseases reports
Area Elm Oak
Treated Sites Trees Removed Feet Trenched Untreated Sites Treated Sites Trees Removed Feet Trenched Untreated Sites
East 0 16 0 2 2 15 100 10
North 10 457 0 10 87 390 26200 49
West 8 1209 0 0 14 125 550 1
Total 18 1682 0 12 103 530 26850 60

For each community, one report was given for each damage type observed. See Table 2. Wilt diseases were the most common damage agents reported (36 of 145 reports or 25%). Spring defoliators, leaf/needle spots and storm/wind were the most common non-wilt damage agents (15, 13 and 12 reports, respectively). Among damage types occurring on a community-wide basis, spring defoliators, leaf/needle spots and root injury/girdling were the most common (7, 6 and 5 reports). Looking at biotic versus abiotic damage agents, 35 reports or 24% were due to abiotic causes.

Table 2. Damage types by severity
  High Medium Low Blank Totals
bark beetles 2   3 1 6
discoloration   1     1
distorted growth 1       1
leaf/needle galls 1 5 2 2 10
leaf/needle spots 1 3 7 2 13
root injury/girdling 1 2 2 5 10
rots or declines 3 1   1 5
spring defoliators 1 5 4 5 15
stem galls or rusts 1 1     2
storm damage 4 2 3 3 12
sucking insects 1 1 1 1 4
summer/fall defoliators 1 1 1   3
tipblights 1 1   3 5
weather injury 3 3 3 2 11
wilt       36 36
wood borers 1 2   2 5
wounds/cankers   1 4 1 6
Totals 22 29 30 64 145

Excluding reports missing their severity data and the wilt diseases, 22 reports or 27% were of high severity (see table 3). Storm damage, weather injury and rots/declines were the most severe (4, 3 and 3 reports of high severity). Twenty-nine reports (36%) were of moderate severity and 30 reports (37%) were of low severity. Fifty-eight or 40% of the reports lacked severity information.

Five of six communities reporting bark beetle and borer damage, described it as community-wide. Seven of eleven communities reporting root rots, declines and cankers again described the distribution as community-wide. Defoliators, galls, sucking insects and weather related damage typically occur over a larger scale and thus allow some opportunity to examine regional patterns. However, of the 70 reports of these damage types, only 24 occurred over a large scale. Fifteen of 145 reports (10%) omitted the distribution information.

Table 3. Damage type by distribution
  Blank Community wide Individual Trees Pockets of Trees Totals
bark beetles 1 2   3 6
discoloration     1   1
distorted growth       1 1
leaf/needle galls 1 2 6 1 10
leaf/needle spots 2 6 1 4 13
root injury/girdling 1 5 4   10
rots or declines 1 1 3   5
spring defoliators 2 7 3 3 15
stem galls or rusts     1 1 2
storm damage 1 4 2 5 12
sucking insects 1 2   1 4
summer/fall defoliators     2 1 3
tipblights 2 2   1 5
weather injury 1 4 4 2 11
wilt       36 36
wood borers 1 3   1 5
wounds/cankers 1 2 3   6
Totals 15 40 30 60 145


A good number of communities returned their survey form which allowed us to update their records, something that was badly needed. However, most choose not to submit the other information requested. Many that submitted damage reports, left crucial data blank, such as host and damage severity. Based on the apparent confusion about how to interpret the classifications provided, the form used needed more explanation.

Distribution patterns were not as expected for the various types of damage, and biotic damage agents were more commonly reported than abiotic agents, even though abiotic agents typically cause more damage. This suggests a bias in what is being seen and what is deemed "worthy" of being reported. The data gaps and inconsistencies have masked large scale patterns in the damage observed. So while damage agents generally ignore community boundaries, occurring in pockets as a function of site condition, damage occurrence appears to be random. So the survey did not adequately address the need to monitor and assess urban forest health across the region.

However, the survey did accomplish a couple of things. There were several communities who volunteered their services in tracking pest occurrences on an annual basis, if we can provide a realistic format for doing so (and a method of verifying or ranking data accuracy). Monitoring damage occurrence across the diverse and fragmented urban forest is difficult. It is nearly impossible where aerial detection is limited, so our current methods could stand to be enhanced. The willingness of these folks to assist in the effort is encouraging.

The surveys also provided some valuable information on resource needs. Apparently, the DNR is doing a good job of reaching people in the metro area. Most feel their needs are being met. That is good to know. So far, we have met that need through our monthly newsletter and cooperative trainings (primarily the Shade Tree Short Course). More than a third of those responding expressed interest in receiving electronic information as well as the newsletter and asked to be but on a list server. Doing so would allow a two-way exchange of information that could serve both DNR managers and our clients. It could open other opportunities as well to announce grant opportunities, enlist help to monitor pest outbreaks, gather and share data on important problems and report exotic species. Although we do not apparently have the staffing to manage such a system, it is something that ought to be explored in the future.

Finally, the surveys served to highlight those issues that have (or in some cases have not) gained the attention of community leaders. Many of the communities reported that they do not have a tree inspector, city forester or any other type of natural resource manager on board. This is understandable for the smaller communities, but many of the larger communities have a substantial natural resource that they are largely ignoring. This highlights the need for us to work with the Metropolitan Council to incorporate natural resource conservation into community comprehensive planning, and to explore other means of outreach and education which promote natural resource conservation.

Of those communities with professional staff, most have focused on the serious threat to their forest resources that the wilt diseases pose. However, many communities do not have an active DED or oak wilt program. Given the increase in both DED and OW seen over the last few years, the importance of wilt disease management needs to be better communicated. Improved methods of locating disease pockets, alerting city managers and supporting management efforts need to be explored. Finally, the number of reports of questionable accuracy highlights the need for general education, even among professionals. While DNR's outreach efforts are to be commended, we must do all we can to keep the current budget crisis from becoming an excuse to back off.

Top Notch Survey

tree removal graph

Top Notch Tree Care conducted a similar survey of the perceptions held by community foresters on various forest health issues. While a discussion of their results does not constitute an endorsement, they are worth noting. The issues addressed included wilt disease impacts, and buckthorn management among several other urban forestry issues. Although the responses varied among communities, overall the number of trees removed by the survey participants jumped dramatically in 2000. The wounding effect of the 1997 and 1998 storms was the most common reason given for the increase, next to mild winters and staffing shortages that have hindered sanitation efforts. Other factors named by the respondents as contributing agents include an increase in the number of elms - largely volunteer elms in unmanaged areas, wounding associated with increased development, an increase in bark beetle populations, and a more aggressive strain of the fungus (the last two unconfirmed).

Almost all communities responding to the survey practice some form of buckthorn management (no numbers available). Most are small scale operations on public property. However, there are a number of communities that actively encourage neighborhood organizations to get involved in the effort. The management techniques and the chemicals used, as well as the success rates reported vary widely among communities. Public awareness of the issue is fairly high in the opinion of those responding. Both individuals and neighborhood groups are working to control the invasion. The biggest issue is the difficulty of follow through in what must be a long term project. For more information on the Top Notch Survey, contact Jeff Borst at 612-922-3239.

This newsletter is developed as a service to forest land managers and shade tree owners. The Forest Health Unit would appreciate comments concerning the newsletter and its contents. These can be directed to Jana Albers, Editor, 1201 E. Highway # 2, Grand Rapids, MN 55744. To add, change or delete your name from our mailing list, please contact the editor. Thanks.