Before we get to the letterspacing, do reconsider the font choice: Helvetica is a staple of large nasty corporations, and everybody knows it (or at least feels it); are you sure you want it for a tree company? Actually even if it's a large nasty corporation, since you wouldn't want to let that on! Unless you're being a sneaky conscientious designer. :-)

And that "a"... yuk. Gag me with a pinecone.

hhp

Less space between the r and the e and a hair more between the double e. Maybe try slightly less traditional colors to offset the use of the traditional font. Green and brown for the tree biz is kind of cliché. If you're going helvetica and geometric, look at some of the classic swiss design. The very obvious T + A = a tree combo needs to be countered with something a little less expected.

Thanks for the comments, I can see how the whole geometric/helvetica look is a bit too cold and corporate for a small tree nursey. Any suggestions for a warmer more personabile font? I think I may have to change the style completely

If your tree doesn't have to be an exact triangle, look to the work of Evert Bloemsma.
https://www.fontfont.com/designers/evert-bloemsma

hhp

I like the concept a lot.

This is close but a little more friendly https://www.fontfont.com/fonts/schulbuch

(FontFont FTW!)

It kind of depends on what type of tree company it is. Do they raise trees for industrial lumber or sell Christmas trees? Focus on the audience and the image they need to project. The concept is nice, but I get an institutional vibe, like a forest ranger asking to see my permit.