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Single year drought impacts on trees and forests. Steve D’Eon, R.P.F. Program Forester. Drought: From a tree perspective? Impact on trees. Impact on forests. What you should know about it. Drought: 1 st How bad was it? Rain Gauge Data Forest fires. 2012 -------. 2011 -------.
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Single year drought impacts on trees and forests Steve D’Eon, R.P.F. Program Forester
Drought: From a tree perspective?Impact on trees.Impact on forests.What you should know about it.
2012 ------- 2011 ------- Month < 50 mm Month < 25 mm Source: http://www.agricorp.com/en-ca/Programs/ProductionInsurance/ForageRainfall/Pages/RainfallData.aspx
Why I don’t like monthly rain gauge data. Daily data from Cormac Data courtesy Frank Ahern, Cormac, Ontario
30 days prior to July 16th Red = 60 mm less than normal precip. Source: http://www4.agr.gc.ca/DW-GS/historical-historiques.jspx?lang=eng&jsEnabled=true
1939 1960’s 2012 Env. Canada, Ottawa airport data
Spring Freshette = soil moisture source www.wateroffice.ec.gc.ca Normal year 2012 2012: spring melt was early and not replaced by rain.
Figure courtesy Glen McLeod, Trees Ontario Season when drought strikes is important
Worst time to have a drought: Shoot and leaf/needle elongation
Newly planted seedlings Drought when they were elongating shoots….
For a tree, Stress is Cumulative 2012 acorn crop 2010 spring frost Recent harvest
When drought pushes trees beyond their Tipping Point: Aug. 20th looking sick but not dead.
3. Drought Impacts on trees • Stress into the future • Growth loss, stem form • Crown dieback • Root dieback • Death (especially newly planted)
Stress into the future Parts of a tree die.
Stress into the future Trees try to recover by epicormic buds. Left is early Sept. Above is Aug. 20th. Photo: Linda Touzin OMNR
Stress into the future Excessive flowering or what is called a stress cone or seed crop.
Drought impact: Growth loss Diameter, Height 2013? 2012 2011
Drought impact: Stem Form 2011 2010 2009
Crown/Root Dieback Root dieback lies unseen but weakens the tree’s anchor, uptake.
Crown/Root Dieback Early leaf fall, Dead and dying parts in the crown. August 28th
Drought caused Mortality Germanicus Road, Eganville
4. Drought Impacts on forests • Forests are resilient. • Forests are more than just trees. • The resource is the site, trees are the crop.
Drought Impacts on forests Stress continues into the future. (don’t add more stress!) Off-site species, thin soils, restricted rooting, sandy gravelly soils, poorly managed stands will all see greater impact from drought stress.
Drought Impacts on forests Photo curtsey of OMNR Pembroke fire
Drought Impacts on forests Taylor Scarr, OMNR
South facing slopes Micksburg
Zion Line, Cobden South facing slope Goshen Road, Renfrew
Thin soiled knolls Behind Renfrew Toyota
Thin soiled knolls Zion line
Recently planted 2009 (age 3) 2012 (age 6) Lake Clear Road
Recently planted Kutschke Road
Random patches Goshen Road, Renfrew
5. What you should know • Monitor, don’t jump to conclusions. • Seek qualified advice for things you don’t know. • Best advice is to keep forests healthy and properly managed. • Take a long-term perspective.
What you should know Dead Alive Near Barry’s Bay Confirm dead, Refill plant, Supplement nature. Watering maple, Zion Line, Cobden
Sanitize or let nature heal? Wood from browned out trees is marginally marketable up until dries out this spring. Hennen Road, Pembroke
Monitor, advice Ips pini CFB Petawawa Monitor for secondary pests, Sanitize, Let nature heal. White spotted pine sawyer beetle
What you should know: • Don’t add more stress!!! • Green (live branches) pruning, • any activity that: compacts the soil, removes organic matter, removes nutrition, allows wind to blow through and dry out your stand…..
What Should You Know? • Don’t add more stress!!!
Drought: From the perspective of a tree.Impact on trees.Impact on forests.What you should know.
Thank You Steve D’Eon, R.P.F. 613 732-5595 sdeon@sympatico.ca steve.deon@ontario.ca