Question 974810
Length =L
width= G, which is a square, so 4G is the girth.
L+ G=130
Tree is 70 inches long.  
I am going to assume nobody is using the diagonal of the package.

L=130-4G
I am also assuming that the question has a mistake, and one wants the minimum width and height for the package, since the maximum has no bound.

The easy answer is that 4G, the girth, is 60 inches.

If I use the hypotenuse packing, then the floor of the  package is a right triangle with hypotenuse z^2, and the sides L^2 and G^2

Then z^2=L^2 + G^2
 But the hypotenuse across the box, from lower to upper, is another right triangle, with one of the legs the original hypotenuse and the other leg G.

That is [z^2+ G^2]=4900;   (L^2+G^2)+G^2=4900 ;;; L^2 + 2G^2=4900

We know that L=130-4G; L^2=16900-1040G +16G^2

Substituting, 16900-1040G +16G^2+2G^2=4900

18G^2-1040G+12000=0
9G^2-520G+6000=0

x=(1/18) [520 +/- sqrt (270400-216000)     ;;; discriminant is 233.2
x=(1/18) * 753.2  ;;   (1/18) (286.8)= 15.933
x=41.844, which won't work

Minimum box girth is G=63.73; all 4 sides are 15.933 inches.

Length is 66.268

{{{graph(300,300,-5,70,-500,2000,9x^2-520x+6000)}}}