A single tree?? Probably not. That quoted statement really only applies to eucs grown in plantations. All eucs do have a strong tendency towards allelopathy so that may be where the supposed lack of biodiversity comes into the picture.

I planted 6 Eucalyptus degluptas in my back yard, in a linear fashion, which is more like a meadow than like a forest. The field has a mixture of pines, palms, fruit trees, figs, avocados, jacaranda etc. It's like I am developing a mini botanical garden in a field size of more than an acre with rather low quality "soil" that consists of mostly crushed lava stone and some low quality soil that were dumped there by many dozens of large truck loads on top of rather solid lava rock layer. The E. deglupta foliage does not have any typically eucalyptian smell, so I was wondering whether E. deglupta are so different from other eucalyptus species that they may have different "behaviour" and habits. While some already have their trunks as wide as 4" to 5" the typical E. deglupta trunk colours are still not there, with mostly light brown and light green bark present.