Did English Walnut kill my apple tree?

A 15 year Juglans regia 3 metres from a similar age and much smaller apple tree. Both behind a hazel same age. The hazel has blocked the light from the apple, the walnut has been drawn up over the hazel. The apple cropped well last 5 years. This year it looked weak no fruit then died. My first thought was lack of light, then I read more about black walnut effect on apples and wondered maybe it's the walnut. I have the same apple tree and another variety another 3 metres away and I really dont want to lose these 2. I plan to coppice the hazels right down as the nuts all get eaten unripe by squirrels and the stems are uneven and wonky. This will let light in, but what if it's the walnut ? I havent had a crop off the walnut, its a nice straight butt. And My squirrel population is very high.

The walnut will compete with the apples, but these species can easily coexist. I doubt that there is a direct link between the loss and the nearby walnut. Squirrels will sometimes chew bark and girdle trees. Was there any bark missing?

Sounds to me like a very fast demise from either low light levels or juglone. Presumably the hazel and walnut were also there in the prior years?
Any signs of insect damage or fungal infection on the apple?

we have a front yard full of black walnut trees but no retardant effect at all , and the sunchokes ,ragweed and wild rose keeps needing to be beaten back . we have a peach tree close to the walnuts that is dyeing but for us it is because the chickens unearthed the roots with all their dusting and then we had 6 weeks of drought

I would look at what other stresses the tree had

Black Walnut is not the same as european walnut . When I took over here at La Ravardiére I found at least three dead and nearly dead apple trees caused I am sure by invasive walnuts .

David

I didnt see any barking, so I will take the chance and leave the walnut in place, while increasing light levels by coppicing the hazel

David Livingston wrote:Black Walnut is not the same as european walnut . When I took over here at La Ravardiére I found at least three dead and nearly dead apple trees caused I am sure by invasive walnuts .

David

I did a little research looking for any sort of reporting on the impact of walnuts. It came up that apples in particular are vulnerable. But I have not yet found any sort of information as to how juglone works upon apple trees. You say you are sure your apple trees were killed by walnut - do you have any indication as to how long it took to kill these trees? What characteristics brought you to the certainty that the walnut(s) killed the apples?

I am fairly certain that mere shade would not kill a previously healthy apple tree in one growing season. At the least it would take a profound blockage of light.

I am intuitively dubious that a tree that has been healthy and productive for many years would die off in one season from the further encroachment of a neighboring walnut - one that has been present in the vicinity for all of these years.

Not trying to argue or challenge you, but asking - how does one recognize the impact of juglone poisoning in a plant? Will it really kill a tree in just one season?
If it can, makes it a pretty darn good argument for using them in the right combinations with plants and trees that can grow in their company, because the walnut will minimize your work in keeping that guild "weed free"

Hey Tim, Toby Hemenway actually talks about apple trees being pretty susceptible to the juglone secreted by walnuts. His recommendation is to plant trees like mulberry or black locust, which are resistant to juglone, in between walnuts and apples as a barrier.

the shade was almost total, 10 ft apple, 20 ft hazel and other fruit trees shading apple with 30ft field maple to the east, so total shade really

apple did get a little barked 2 winters ago by my sheep, and recovered and cropped 2x years

it's an english walnut so tho im aware of toby and black jugalone etc im not convinced enough to fell the walnut this winter, i will instead fell maples and coppice hazel to let light in and plant a mulberry there

Black walnut and Americans are most deadly but if you plant European Asian together Appel and other suseeptble European has juglions