The meaning of the word kienapfel seems to be pine cone, or possibly acorn. In my www searches I came across this traslation of a document where this is mentioned.

The Excerpt from the whole document:

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"The road now went upon Fehrbellin; and Forster," Forester, "Brand, as woodkeeper for the King in these parts, rode along with us. When we came upon the patch of Sand-knolls which lie near Fehrbellin, his Majesty cried:--

"'Forester, why aren't these sand-knolls sown?'

FORESTER. "'Your Majesty, they don't belong to the Royal Forest; they belong to the farm-ground. In part the people do sow them with all manner of crops. Here, on the right hand, they have sown fir-cones (KIENAPFEL)'.

KING. "'Who sowed them?'

FORESTER. "'The Oberamtmann [Fromme] here.'

THE KING (TO ME). "'Na! Tell my Geheimer-Rath Michaelis that the sand-patches must be sown.'--[TO THE FORESTER] 'But do you know how fir-cones (KIENAPFEL) should be sown?'

FORESTER. "'O ja, your Majesty.'

KING. "'Na! [a frequent interjection of Friedrich's and his Father's], how are they sown, then? From east to west, or from north to south?' ["VAN MORGEN GEGEN ABEND, ODER VAN ABEND GEGEN MORGEN?" so in ORIG. (p. 22);--but, surely, except as above, it has no sense? From north to south, there is but one fir-seed sown against the wind; from east to west, there is a whole row.]

FORESTER. "'From east to west.'

KING. "'That is right. But why?'

FORESTER. "'Because the most wind comes from the west.'

KING. "'That's right.'

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