Trees/Gardening

I don't know much about the forests of Italy, but most mature forests include a number of species of trees. The trees wouldn't kill each other, but differing trees can prefer different growing conditions (soil, wetness, sun, temperature, altitude, etc.).

Pretty sure none of those would kill the others - except, small saplings of any of the varieties could die if they're under a large tree of any of the kinds - lack of sunlight.

The oaks are most notorious for causing problems for other trees because of the tannic acid in all their parts. Puma

Although some grasses/weeds will release chemicals to kill competition, never heard trees doing the same. As a woods man I have spent several hundred hours walking the forest in several states and found every species of trees I know in proximity. Only exception is when some disease or insect specific to one type invaded the area.

If I remember right, Japanese Black Pines kill off their competition. Puma

Most trees don't kill each other off, with notable exceptions being trees like the yew, which produces poison in the bark, fruit, sap etc and kills off everything in a radius around it.

I know my mum's orchard in Spain has figs, olives, almonds, apples and I believe a lemon tree all growing on the same plot.

Whistle_White said:

Hey all!

Strange question here. Does anyone know if certain types of trees can grow together?

To be exact, my story is set in middle-northern Italy, and thought I've been there I know nothing of the trees I saw. I've done research, and learned that you can find chestnuts, poplars, elder trees, and birch - but can these be found all together or would any of those kill the others?

Thank you in advance!

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The chestnuts would try to out-compete the others, but that could just mean you'd have more of them. If you are including forest edges, you could certainly have all of those, as far as I can tell.

The elders (like elderberries? They're technically shrubs, not trees ) could grow in more shade, so I'd think they'd fill in up near the chestnuts better than your other choices. I don't think they are heavy feeders.

So, imho, you'd have a bunch of chestnuts and elderberries, and fewer poplars and birch, which like the sunnier spots in the forest. They could be there, but they'd be clumpier, if that makes any sense

eta: I haven't checked out any blights, etc, common to that area in these species. Google should be able to tell you if there are any local problems with disease and your choices, which matters a ton!

In some areas you'd have different stages of succession. I know where I live the beech tree is the big ole tree you see in the 'climax stage.'

I found a picture for New Zealand: http://www.teara.govt.nz/en/forest-succession-and-regeneration/1/1

I don't know if Italy would have the same. (Its own stages, but different vegetation.)

But despite all the succession stuff, you often do find trees all mixed up together (where if the area were left alone and never developed by pepole you might not). And even in the climax beech-maple forest of New England you'll often find birch, some oak, a few evergreens, etc.

I can't speak for Italy or Italian horticulture, but there are a few trees that have allelopathic attributes, such as the black walnut. In the scheme of things, what will inhibit plants from growing together is not what their neighbors are, but whether they are in the right zone, right soil and moisture conditions, etc. Right plant for the right place. Many plants can be successfully grown together. Some can do so by treating them as annuals/tropicals (accepting that they will die after a growing season, or otherwise bringing them indoors for the winter).

That said, even Black Walnuts, with their allelopathies, where I work still are surrounded by lawn, pachysandra, hemorocallis, white pine, holly, rhododendrons, and the annuals I plant nearby. Norway Maples are also supposed to exude allelopathies (whatever the heck the right terminology is, science ain't my strong suit, even if plants are. I should be fired.)

If they were planted in a grove, given adequate space (say 3-5m) between each tree, then there would be no reason for there to be a problem with the trees.

In a forest (dense plantings) the faster growing species would take the light and nutrients from the other slower growing species, resulting in the slower trees being smaller/stunted.

Also it would depend on the soil conditions - plant the trees in rich alluvial soils and they will grow tall (with enough water). Plant them on a rocky hill and their roots will be restricted by the amount of soil and nutrients available, so the trees would be smaller for their age than the ones on the alluvial soil.