Fire and Water, a story of climate on our trees...
or Drought, the Gift That Keeps on Giving
Mother Nature's Moment
by Lesley Bruce Smith ISA Certified Arborist
Two Hundred Year Old Sugar Maple; Lesley Bruce SmithThis week our entire staff attended the annual Illinois Arborist Association convention for two days. It is just one of the ways we stay abreast of the ever changing science and art of arboriculture. We were reminded of the many ways that the drought of 2012 continues to wreak havoc on our friends, the trees.
Two Hundred Year Old White Oak; Lesley Bruce SmithIn 2012 we experienced the worse drought Chicago has had since the great Chicago Fire of 1871. Although our ability to fight fires has greatly improved, our trees’ ability to withstand the effects of drought has not changed, and maybe even lessened due to the many more stresses placed on them from pollution and the impact of living around so many more people. Have you ever thought about the fact that many of the old Oaks we care for were around when the last horrible drought hit our metropolis?
Drought destroys little tree roots and those are the ones that take up all the critical water and nutrients that the trees need to produce their food. When a drought like the one we experienced last year happens, ALL the trees lose roots. Some of the ones that receive supplemental watering lose fewer roots but every tree struggled last year. Then this year we had the wettest April and May in recorded history. When the soil gets super saturated it drives oxygen out of the soil and kills tree roots. To the trees, too much water feels just like not enough. Maybe a better term for “global warming” would be “global climate extremes”. Trees struggle in the extremes. Extreme cold, extreme hot, extreme dry and extreme wet are all things that make it tough for all of us and especially our trees.
Pine Tree killed outright from the drought; Lesley Bruce SmithWhen little roots die on a mature tree we often don’t see the tree change much on the outside, but there are BIG changes that happen on the inside and at the molecular level. The best way to explain it is that when we run down our immune system by not getting enough sleep or good food or healthy exercise we may be able to keep going for a long time, especially if we started out vibrant and healthy. But eventually we can’t keep going like that without consequences.
We will feel the effects and sometimes they can be catastrophic, especially if we were in a compromised state when we started the abuse.
Needle Cast on Blue Spruce; Lesley Bruce SmithWhen our trees lose roots to drought or excessive water (flooding) it takes a long time for them to overcome that difficulty and when we have several years in succession of extreme weather our trees have a hard time fighting off the attacks of insects and diseases. One example of this is the increase of boring insects we are seeing. Borers, can “smell” a stressed tree from far away and will pick it out from the non-stressed ones. When the female bores into the cambium layer just beneath the bark she is looking for a place to lay her eggs and she knows that a healthy tree literally will crush her babies with the tree sap or shove her larvae back out the hole she came in, leaving them vulnerable for an ant or bird to gobble up.
So...if you feel that we are suggesting ever increasing methods of treatment for your trees, you are probably right. They are struggling and need extra help and will for 5 to 6 years to come, and that is if we have terrific weather conditions over that period.
Tree Riddled with borers; Lesley Bruce SmithTrimming to get rid of dead helps to keep those borers out of healthy wood because they go for the dead stuff first.
Certain non-toxic or low toxicity applications to control new diseases that we have never before encountered.
Mulching to help conserve water and nutrients.
Watering properly, watering and mulching are the two most important and least expensive things we can do for our trees before, during and after drought!
It seems strange to think that droughts that are long over can still be effecting our trees, but it’s true. Remember to water in the spring in April and May especially if it is dry and watch for our revised Watering Abstract this winter to get detailed instructions on how to do this. Heavily for (12-24 hours) and infrequently, like once a month.
We had the opportunity to travel to Door County last weekend and enjoy the beautiful fall color display. This photo is looking out over Green Bay at Peninsula State Park.
This weekend is the peak of fall color - don’t miss out! Try visiting one of these local forest preserves to see the optimum fall color display:
Fort Sheridan Forest Preserve in Lake Forest - To access the Fort Sheridan Forest Preserve, take Old Elm Road east of Sheridan Road, turn left on Leonard Wood Circle North and left again on Gilgare Road.