Can we assume modern tines?
no Religion relevant?
noRelevant which state?
yes Head of a state = HAF? HAM?
this Head of the state = prime minister? King
thisish; no to rest/queen? Others? Pope? Relevant?
Perhaps if you wanted to guess who they were, but their specific title isn't relevantDid the gesture become memorable?
not particularly A symbol of something?
yope - it wasn't strictly symbolic War times relevant?
yes Was the tree planted for practical reasons?
no Political reasons?
yesish As a sign of piece (e.g. the house was a the borders)?
no Relevant which type of tree?
the type of tree was chosen carefully, but the specific tree is irrelevant to the solution Were in the yard was it put?
as above In the middle? In one of the corners? Others?
specifics here are irrelevant Did it happen in the desert?
yes (but irrelevant)Relevant who was the small and insignificant man?
no, hence his insignificance The head?
yes if you wanted to play this as a history quiz, otherwise no Relevant their relationship?
no Was the man alive/present when the tree was planted?
yes Did the tree represent a tomb?
no Had the tree a meaning for the nation?
no For the men?
yes, but a different meaning for both For someone?
yes (see above) Had the yard other trees?
yes, but irrelevant Had it been a huge tree, would the puzzle still have worked?
yes, although the scenario would be much less likely to arise Did the tree sustain something (e.g. the roof of the house)?
no(t relevantly) Hide something?
no Is it the first time a tree is planted in a yard for order of the head of the state?
noWas the teee planted for the first time?
this one was, yes Relevant the man's job?
no Christmas tree relevant?
no Was the tree a tree that could give fruit?
irrelevant Relevant? Is agriculture relevant?
no Type of ground in which it was planted?
no Oasis? Was it a metropolis and a certain amount of green must be present?
noCould the tree have been planted somewhere else equivalently?
not to the same effect Did the man exploit the tree somehow?
no(t relevantly) Shadow relevant?
no Does the presence of the tree indicate something relevant?
yope Was the tree a trace?
Please define 'trace' Was the tree planted in the yard of a citizen of the state of which the politician is the head?
yes If so, colonialism relevant?
no, but explore African countries/India/Australia?
no to these Depuration of a river?
no Did they want to see if the tree was able to grow?
noGalFiskWould any of the mentioned small and insignificant thing eventually become large? Significant?
no to both Was this the only tree planting he ordered?
in the grander scheme of things, no Relevant who performed it?
no Did he do it for a good reason? Bad reason? Evil? Stupid?
yope to all 
Was it a mistake?
arguably yes Based on a mistake?
no