There is a widespread custom of planting trees or entire forests in honor of individuals. The Lubavitcher Rebbe wrote a very sharp letter regarding this custom, saying that there are many halachos (laws) and minhagim (customs) addressing all aspects of Jewish life, but that he was unable to find any source for this custom. Planting a tree to mark a babys birth is acceptable, but not in someones honor. Creating a new concept, even if facilitates fundraising and settling the land, could approach the issur, prohibition, of bal tosif, adding a new concept to Torah which has no Torah source. People should rather use methods that are Torah-true to celebrate events and pay homage to special individuals.