It does actually have something to do with the falcons ... Merlins and American Kestrels rely on the bugs and birds and small mammals that live in the city. Many of those rely on Winnipeg's 100+ year old urban forest to survive. Bird species all have specific habitat needs. No songbirds means no nests, no nests means fewer meals for crows, fewer big trees mean fewer crows, fewer crows means fewer Merlins as they nest exclusively in crows' nests. Fewer trees means fewer bugs and small mammals, means fewer nesting cavitities for Kestrels and less prey for they to eat.
Fewer trees also means fewer other plans such as shrubs (need the protection and many need the shade/partial shade) house prices go down (a mature deciduous tree increases house prices by about $10K), hydro costs goes up (air conditioning in summer, heating in winter as protection is lost), water usage goes up (less shade means more water needed for plants), ear plug sales go up (trees help to reduce sound from air and land vehicle traffic), air quality is reduced (trees are purifiers and carbon sinks) and leaf rake sales drop dramatically.
Yes there are lots of different tree species in Winnipeg, but the oldest and in most cases largest are the American Elms that are being so hard hit by DED. Banding your trees (all of your deciduous trees) helps to reduce the cankerworm population (part of their lifecycle requires that they crawl from the ground up the tree) which in turn reduces the stress on the trees. It is not unusual for cankerworms to strip a tree of all of its foliage which forces the tree to use additional stored resources to grow new ones in order to convert solar radiation into energy for survival. Add that the stresses of living in an urban environment - road salt & sand, pollution, construction, etc - and a changing climate that, for Winnipeg has meant warmer and wetters winters. Warmer may mean that the trees do not enter a sort of hibernation state until later, again using more of their stored resources because their leaves have fallen. Wetter can mean real problems for root systems and moist conditions are never good for funguses, of which DED is one - the fungus is carried by the Elm Bark Beetle from sick tree to healthy tree, the beetle itself just lives in the elms.
So by banding the trees in the fall and then cleaning off the band and reapplying tanglefoot in the spring, you reduce the number of cankerworms and can catch the fall elm bark bettles and help to keep your trees, elms and otherwise healthier which in turn will enable them to withstand other environmental and not-so-environmental pressures. Sort of like Vitamin C (see-the-band?) for trees. (like that one, going to save it and use it again I think)
Bands should go on by September 15th (or the first frost, whichever comes earlier) and off around May 15th to catch both seasons of crawlies.
For more information:
Coalition to Save the Elms Hug a falcon by banding your trees!
