couldn't find any guide about tree's q, so decided to test it:
1) "model": t.pot(67)+soil(63)+water(55)+h.table(156)+seed(86) = 88
2) "soil": t.pot(67)+soil(10)+water(55)+h.table(156)+seed(86) = 79
3) "water": t.pot(67)+soil(63)+water(10)+h.table(156)+seed(86) = 84
4)"seed": t.pot(67)+soil(63)+water(55)+h.table(156)+seed(108) = 100
5) "h.table": t.pot(67)+soil(63)+water(55)+h.table(309)+seed(86) = 104
calculating:
soil (63-10)/(88-79)=5.8
water (55-10)/(88-84)=11.25
h.table (309-156)/(104-88)=9.5
seed (108-86)/(100-88)=1.8
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PS: test of tree's quality in different stages of growing:
st.2 - q16(38%) / st.3 - q25(59.5%) / st.4-q33(78.5%) / st.5-q42(100%)