Replacing a fruit tree with another

[ChingfordHarry]

Hi

I've been doing some work on the community orchard on my allotment site, and noticed that some of the fruit trees don't look too healthy and might need to be replaced in the near future.

I know that it's not normally a good idea to replace one tree with another of the same species in the same place, to avoid any specific diseases that are in the soil, and also because species specific nutrients will be depleted, but I was wondering how closely related the replacement could "safely" be. So, for example, what about replacing an apple with a pear? Or a plum with a cherry?

Thoughts?

[ameno]

Plum with a cherry is a definite no. They are the same genus, after all, even if not the same species.
Pear and apple are more distantly related, so you might get away with it, but personally I still wouldn't want to risk it. They are both still fairly closely related.

You say there are several that need replacing, so is it not possible to "swap" the trees? So if, say, a plum and an apple look like they need replacing, could you not plant a new plum where the apple was, and a new apple where the plum was?
Failing that, you could always dig out the old soil from the plant hole and swap it with some soil from elsewhere. A hole about 75cm x 75cm, and 40cm deep ought to be enough. The tree only needs untainted soil for it's first two to three years, and after that should be fine growing out into soil that previously had another closely related tree in it.

[ChingfordHarry]

Many thanks, I'll remember this as I work my way through the orchard (which will take quite some time as I'm the only person on site who has shown any interest in it and I now have to leave clearing the undergrowth for the nesting season...).