Ash tree

Asked June 9, 2016, 2:21 PM EDT

We have a 20-25 year old Ash tree 18' from our deck. The branches overhang the deck by one or two feet. We would like to add 4' to our deck which would require digging 3 footings for deck support. The three footings would be 12" in diameter and be about 42" deep. They would be 14' away from the tree trunk but inside the canopy or drip line by about 6'. I am sure the holes would damage some roots. We do not want to do this if we are putting the tree at risk in any way. Can you tell us if we can put in the three footings without damaging the tree? Thank you in advance for your prompt response. Jerry

Carver County Minnesota construction ash trees

1 Response

Hi Jerry,

You are right that some roots will be injured but a healthy tree should be able to withstand this work. Make sure that you don't pile the excavated soil on top of the root zone. You may want to ensure a little extra water for this tree for the next year or two, once the deck is in place. Here is some information about construction projects and trees:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/protecting-trees-from-construction-dama...

Ash trees are particularly vulnerable these days with the invasive Emerald Ash Borer. Some experts are claiming that we are going to lose most of our ash trees in Minnesota. Some homeowners are choosing to prophylactic treat their trees but this is rather expensive, and never-ending. Here is some information about this recent pest:http://www.extension.umn.edu/garden/insects/find/emerald-ash-borer/