If you know the name of the trees, you can google about their pruning. They will certainly be straighten up if you can prune them properly.
Here's from RHS and deciduous trees, which I believe they are!
When to prune trees
Deciduous trees
Deciduous trees (ones that lose their leaves in winter) are usually pruned in autumn and winter. In some cases, for example with magnolias and walnuts, pruning is best done in late summer, as healing is quicker.
Trees such as
Prunus sp, which are prone to
silver leaf disease are best pruned from April to July when the disease spores are not on the wind, and the tree sap is rising rather than falling (which pushes out infection rather than drawing it in).
Some trees can
bleed sap if pruned in late winter and early spring. Although seldom fatal, this is unsightly and can weaken the tree. Birches and walnuts often bleed if pruned at the wrong time. Summer pruning can be useful to check over-vigorous growth, for example in suckering species of
Populus, or restricted forms of fruit such as espalier apples. This pruning is generally light, and is carried out late enough not to promote new growth. Similarly, healthy trees will generally tolerate minor pruning in the summer months, for example, corrective pruning to raise hanging branches, or removing weak growth, which can be easier to assess in full leaf.
Best is to find out their names and google from reputable sources!
