Ralph Zentz, city forester in Fort Collins, calls this distinct attraction to Scotch pine a fatal one for the beetles. These pines produce copious amounts of resin and are usually successful in “pitching out” (and drowning) the beetles. In most cases (in Fort Collins, about 90%), pines that have been hit by beetles actually survive the attack. In the forest, these pines would be considered “goners”.
Trees in urban settings are usually watered more thoroughly or more often than their counterparts in nature. Trees use the water as a component of the resin, so more water equals more resin and more resin equals more successful pitch-outs. There is less competition for resources in the urban setting than in the forest, producing a healthier tree (they aren’t spaced so closely). Many pines are also treated for a variety of pests. Some of these applied chemicals may help protect them from MPB.
At this time, there is a low-level epidemic in ponderosas along the Front Range. They are found most-
ly in lower elevations, but closer to town than the lodgepole pines of higher elevations. More com-
munities are reporting MPB presence than in past years. Foresters believe that the newer infestations
are coming from the infested native stands, wood stockpiles or other, unidentified infested trees in our
communities. It’s a good bet that a lot of beetles are inadvertently brought in on firewood.
As Master Gardeners, here are the messages we need to communicate to our urban citizens: