How gullible is this neighbour? How about offering to wrap or dip the base in a magic concrete neutraliser* that makes the post safe for his precious trees.
*tap water
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local