Big Leaf Maple Decline
I'm looking for an expert in big leaf maples to advise me, I am getting conflicting advice, including from certified arborists. I have a big leaf maple, about 60+ years old, about 10' diameter, and 80+ feet tall. It has experienced some decline as compared to other local trees, the crown has a section which died back. The tree is on an undeveloped area, there appears to be a bot of root trauma many years ago in that one large woody surface root has some bark scars, but nothing has happened on that land in at least 10-12 years other than nearby mowing. It is not irrigated, no flooding, no development, no root zone man made compaction (there are deep clay layers in the soil); yes, summer droughts, I did begin supportive deep watering last summer, no herbicide use.
Cutting that dead wood out has been offered, but the bald eagles love to perch there so I'd like to keep it if that will not harm the tree. The crown is much thinner and lacier in look than other big leaf maples nearby. One arborist suggested cutting back the crown by 1/3- good or bad idea?
The other options I've been offered are to do deep watering during droughts (on it!) and to use injectable fertilizer (24.). In researching online, I see reports mentioning the risks of drilling all those holes and that is a logical concern. Other arborists seem to be against the injectables. I could do fertilizer stakes? Or broadcast surface fertilizer (2-2-2?) having dug holes on a 1x1 grid of the crown.
All the ideas sound 'good' when the person explaining them is the person who believes in them, but I can find flaws in each point. I want to save this tree if possible and would love to find some sort of expertise to help me do that.
Whatcom County Washington
P.S. As a best management practice, you should keep grass away from the tree--at least outside the dripline and maybe a little further. A good mulch should be applied instead. Also make sure that no herbicides of any kind are applied anywhere near the tree.
Thank you for your well-considered response! I agree with most of what you've said, not that I want to scour the internet to find the people who agree with me, but it makes sense to me that the injections ($300-$400!) are risky and might not help. I can see your point about trees in nature holding their own, but I am willing to help this tree as he is the only tree within 40-80' and is gorgeous, so I would make an exception; however, I don't want to try a bunch of things which result in worsening of the overall condition. Regarding cutting back the crown, I can see the person's point, as the trees along our street which were pollarded in the 60s & 70s do have lush thick healthy canopies, but they are also very unnatural in shape! Thus I am torn as to whether to allow it to be done!
We recently purchased the vacant lot where the tree is, with no plans to develop it. It's been covered with Himalyan Blackberries, buttercup, thistle, and assorted grasses. If I clear those, then a light cover of mulch Like 1-2-3 inches, not 6+?