Do you know why Ted Hughes compares the laburnum tree to a machine?
It is a clear example of the profound influence of industrial revolution where villages/countries are slowly giving way to cities and the natural bounty, agriculture etc. are replaced by concrete buildings, machines, industries etc. The poet too gets the picture of a machine in his mind since he lives in a world of machines. You can't expect a poet to compare the tree to a computer in Shakespearean age as there were no computers.