would you expect each aspen tree to look exactly like the next in terms of phenotype?

Answer 1

Absolutley, unless it had a disease or was different genotype(species).

Aspen trees in groves are actually a single organism. One seedling produces a grove of trees which share a common root system....so they should be exactly the same in terms of phenotype if they are from the same genotype.

http://en.wikipedia.org/wiki/Aspen

Answer 2

Within a clonal grove, the phenotypes would be the same, but there would be some slight variation in the way they look. Some genes, or combinations of genes, control the range of expression for a phenotype (such as tall or short), but environmental factors such as nutrition will affect exactly where an individual falls within that range. In trees, for example, general branching patterns are genetic, but an individual might be lopsided because one side was shaded out by a nearby tree.

Answer 3

No. No two trees (like no two people) are exactly alike. Small genetic variations (single nucleotide polymorphisms) create variations in phenotype.

Additionally, no two trees have the exact same environment. Even trees a few feet apart will experience different levels of nutrients in the soil and different amounts of water. Environment also affects phenotype.