Nice article. Can I point you to the group Street Trees for Living? They do exactly what you describe, in Lewisham mostly. The main barrier is that it is not just more costly than it should be, but more complicated to plant on urban streets. There is a lot of underground infrastructure, and even where the council are supportive, as Lewisham are, the cost to them of a tree going wrong and damaging property is very high. So they are quite conservative about what they allow, where.
The quick answer is that saplings are much more likely to survive, and will root better with less chance of disturbing pavements and walls. It's also way cheaper (like, ten times cheaper) and the concept of a quick return doesn't really match why people want to do it, unless they are literally about to sell their house.
Nice article. Can I point you to the group Street Trees for Living? They do exactly what you describe, in Lewisham mostly. The main barrier is that it is not just more costly than it should be, but more complicated to plant on urban streets. There is a lot of underground infrastructure, and even where the council are supportive, as Lewisham are, the cost to them of a tree going wrong and damaging property is very high. So they are quite conservative about what they allow, where.
Is there any reason you have to plant sapplings? It is much more expensive to move bigger trees but it probably has a quicker return.
The quick answer is that saplings are much more likely to survive, and will root better with less chance of disturbing pavements and walls. It's also way cheaper (like, ten times cheaper) and the concept of a quick return doesn't really match why people want to do it, unless they are literally about to sell their house.