At the September 6th, 2012 General Issues Committee meeting, Forestry and Horticulture staff presented the Emerald Ash Borer (EAB) Management Plan. Council approved a ten year funding strategy to remove one tenth of the Ash Tree inventory annually based on the projection that 98% of the Ash trees will be killed by this insect over a ten year time frame. This update serves to inform the members of Council on the action plan to address the larger than projected increase in mortality observed this spring and the strategy to increase the rate of removals for 2015.
The Emerald Ash Borer update presented at the May 5th Public Works committee indicated that the next 3 weeks would allow trees to leaf out adequately for staff to monitor the full impact of the beetle infestation and the subsequent Ash tree decline.
In 2012, the projected rate of mortality indicated that a spike in dead Ash trees would occur starting in 2016 / 2017. Staff observations over the last 3 weeks show large numbers of dead trees that correspond with the projected 2016-17 peak.
Trees that were in healthy or marginally healthy condition in 2014 were over stressed due to extreme February cold and have subsequently advanced to a dead or dying state which warrants removal. Discussions with industry experts indicate that in areas of high infestation, mortality can increase rapidly (exponentially) impacting healthy trees nearby. From sample data collected during May, the mortality rate has significantly exceeded the projected rate of decline, doubling the number of removals required this year.
The current capital funding strategy of $1.6M annually to address proactive Ash tree removal at a rate of 2,300 each year was based on favourable tender results which also aligned to keep pace with projected mortality for 2013, 2014 and 2015. The capital budget for 2015 has been exhausted and 2,300 Ash trees have already been removed with many more requiring removal.
To address the dead or dying tree removals required for the remainder of 2015, a portion of the additional capital funds needed will be re-appropriated to the EAB program from Capital WIPS in Environmental Services, Forestry & Horticulture. The additional funds required will be obtained from other Operating and/or Capital projects or positive variances within Public Works.
As part of the Council approved EAB funding strategy, the budget for 2016 moving forward is $2.6M annually which is anticipated to be sufficient for removals in subsequent years.