Find the largest tree - clips

Question

I'm getting too many results. What's the matter? Clipping the result as in the prolog does not exist?
(deffacts mytree
(below birch poplar)
(above linden maple)
(below pine fir)
(below linden birch)
(above pine poplar))
(defrule high-low-tree
(below ?tree1 ?tree2)
(not (above ?tree1 ?tree2))
(or (above ?tree2 ?tree1)
(not (above ?tree2 ?tree1)))
=>
(printout t "The tallest tree " ?tree2 crlf)
(printout t "The lowest tree " ?tree1 crlf))

Answer 1

Finding the tallest and lowest:
CLIPS>
(deffacts mytree
(tree birch)
(tree poplar)
(tree linden)
(tree maple)
(tree pine)
(tree fir)
(below birch poplar)
(above linden maple)
(below pine fir)
(below linden birch)
(above pine poplar))
CLIPS>
(defrule high-low-tree
(tree ?tallest)
(tree ?lowest)
(not (below ?tallest ?))
(not (above ? ?tallest))
(not (below ? ?lowest))
(not (above ?lowest ?))
=>
(printout t "The tallest tree " ?tallest crlf)
(printout t "The lowest tree " ?lowest crlf))
CLIPS> (reset)
CLIPS> (run)
The tallest tree fir
The lowest tree maple
CLIPS>
Ranking them all:
CLIPS> (clear)
CLIPS>
(deffacts mytree
(tree birch)
(tree poplar)
(tree linden)
(tree maple)
(tree pine)
(tree fir)
(below birch poplar)
(above linden maple)
(below pine fir)
(below linden birch)
(above pine poplar)
(tree-list))
CLIPS>
(defrule order-trees
(tree ?tallest)
?t <- (tree-list $?list)
(test (not (member$ ?tallest ?list)))
(not (above ?above&:(not (member$ ?above ?list)) ?tallest))
(not (below ?tallest ?below&:(not (member$ ?below ?list))))
=>
(retract ?t)
(assert (tree-list ?list ?tallest)))
CLIPS>
(defrule print-list
(declare (salience -10))
(tree-list $?list)
=>
(printout t "Trees (tallest to lowest): " (implode$ ?list) crlf))
CLIPS> (reset)
CLIPS> (run)
Trees (tallest to lowest): fir pine poplar birch linden maple
CLIPS>