City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: https://read.dmtmag.com/i/510169
24 City Trees without laboratory testing. Behavioral clues, however, provide good indicators of the subspecies in question. The EHB, for example, tends to swarm one to two times annually. The swarms are larger and thus need a larger cavity, like those found in trees, to build a nest. The AHB, on the other hand, can swarm every six weeks and may swarm ten or more times a year. Because the AHB swarms are smaller in size, they can successfully nest in smaller cavities and have been found in water meter boxes, metal utility poles, old tires, and below-ground cavities. The smaller AHB nests often go undetected until disturbed. While all honeybees defend their nests, the AHB is considerably more aggressive than the EHB in doing so. Not only is the AHB colony more easily disturbed than the EHB, once disturbed, the AHB will respond by sending hundreds more guard bees to sting and will pursue for a greater distance and sting more than the EHB. After a disturbance, the EHB colony will usually become calm after one to two hours, while the AHB requires a longer time to settle down. As the AHB has spread throughout South and Central America and into the southwest United States and Florida, it has hybridized with the EHB in regions where both subspecies are present. This hybridized bee is commonly known as the Africanized honey bee. Twenty-five years ago, the AHB, continuing on its northward journey, crossed from Mexico into the United States and was found in Texas near the small border town of Hidalgo. Since then, according to Dr. Mike Merchant, Professor and Extension Urban Entomologist with the Texas A&M AgriLife Extension Service, it has spread across the state and hybridized with our wild (feral or escaped) EHB population, mak - ing it best to proceed with caution and assume that any wild bee colony seen in Texas parks or backyards is Africanized. As such, the way we urban foresters handle bees in Fort Worth, Texas, largely depends on these two factors: What conflict are they presenting, and who is the land manager responsible? For example, as part of the parks and community services department, the forestry section which I am a part of has jurisdiction over all trees on City property, but is only funded for tree risk abatement. When there is a bee swarm on the outside of a tree, we refer the concerned resident or City department to a beekeeper. We currently do not have bee suits for our pruning crews, so when bees are inside broken limbs to be removed, the pruning crew has blocked off any cavity entrances into the limb that would allow the bees to escape. In the time it takes the bees to find another exit, the crew has typically completed the broken limb removal and moved on to another job site. As much as possible, we will schedule the removal of low limbs, known to have bees, for winter months or cool - er mornings when the bees tend to be less active. For the most part, we have not found bees to be a big concern in day-to-day pruning work. Interestingly, another stinging insect that can cause allergic reac - tions in people, the fire ant, is frequently found by our pruning crews in both cedar elm and American elm trees. Tree removals are another story, since bees are more commonly found in trunk and branch cavities of dead and declining trees. Our number of tree removals with bees inside has increased proportionately the last three years as the number of tree removals has increased due to drought, but remains a small percentage of all removals. The forestry section contracts out our tree removals. Because our con - tractor is expected to handle any tree removal that has bees, several years ago we amended our pruning and removal bid specs to include this provision, "The Contractor shall be responsible for the removal of bees and/or any other insects, animals or wildlife that may be present and interfering with the required scope of work without additional compensation." Whenever we are aware that bees are present, we will note it on the work order for the contractor. Our contractor has worked with a local beekeeper to have bees removed before taking down a tree and also has full bee protection suits for their crews. An arborist wearing a bee suit while operating a chain saw looks like something resembling a scene in a sci-fi movie and should be enough to catch anyone's attention, but we have recently had one incident of a pedestrian walking into a clearly delineated work zone, only to take off running the opposite direction when the bees began to swarm around him! While the forestry section has jurisdiction over all City-owned trees, we are not the land managers of Fort Worth's more than 200 parks and public land spaces citywide. This responsibility lies with the five regional supervisors who manage the parks in their respective area. Because they have a responsibility for both park maintenance and public safety, they do work with a beekeeper to remove bee swarms that are in close proximity to higher traffic areas such as playgrounds, walking trails, and picnic tables. Like us, they will typically remove low limbs over park trails and other areas in winter months when bees are less active. On occasion, however, they have had to call a beekeeper to remove a hive in order for pruning work to continue, and will use pesticides on wasps on an as-needed basis. —Melanie Migura, Forester, City of Fort Worth, Texas