Question
We have a small front yard on our townhouse that gets full, unabated sun from 8:00am-2:00pm.  We have dense zoysigrass (not my favorite but at least it grows).  When we first bought the house, there was a small dead pine tree in the front.  We removed it, thinking the previous owners had brown thumbs.  But because our HOA insists upon every house having a tree in its front yard, we planted a dogwood.  After a noble start, its leaves browned and fell off.  It attempted to rally the second year, but the same occured.  It is now officially dead, with its lower bark peeling off - like rot.  

Two questions:  First, any idea for the cause?  Does the zoysia have a part in this?   Secondly, any suggestions for a 30' tree that would grow there?  

Thanks!

Answer
Several issues here, and I can only offer an educated guess that perhaps you might be able to confirm and update.

First, we don't know what went on at that Axis of Evil in the middle of your yard before you bought the house.  Possible the Pine was planted to replace a previous Tree.  Any way you can find out?

Next, and this is why you may have a problem, if you did not remove the ENTIRE PINE, but left stump and root parts or possible the entire sub-ground Tree, thinking you could just plant over it, you're in for some trouble.

Double trouble, actually:

(A) Trees are Wood.  Wood is Lignin.  It takes YEARS for Lignin to decompose.  Underground, it takes MORE YEARS.  The Joint Genome Institute points out that White-Rot Fungi -- so named because they turn tough Brown Lignin into soft White Cellulose -- 'are the only microbes capable of efficient depolymerization and mineralization of Lignin':

genome.jgi-psf.org/whiterot1/whiterot1.home.html

The only way to solve this problem is to remove every last piece of ground and un-ground stump from the Soil OR grow something else there.  Any Grass you plant will struggle and eventually fail the way all Grass fails when planted over old Trees that are no longer there.

(B) Pines produce chemicals to defend themselves form Fungus and insect attacks as well as competition from other plants and Trees.  This is a phenomenon called 'allelopathic'; in your case, it throws off the Nitrogen cycle.

There's more.

Ever hear of 慣erpenes?

We get the word 慣urpentine?from this word.  Botanists pay attention to Terpenes because they interfere with the germination and growth of new plants.

What are they?

Wikipedia can answer that:

'Terpenes are a large and varied class of hydrocarbons, produced primarily by a wide variety of plants, particularly conifers...'  Coincidentally, Wiki illustrates this point with a Pinetree (the caption: 'Many Terpenes are derived from conifer resins, here a Pine.')  Terpenes are what you smell when you put up a Christmas Tree.  They are flammable and intensify fires in Pine Forests.  Terpenes, Monoterpenes and Terpenoids are natural chemical inhibitors.  One internet-posted Bio 101 text:

www.biosbcc.net/b100plant/

explains how these chemicals work:

慣hese volatile or water-soluble chemicals are ...carried by the heat of the day or by water to the Soil.  The allelopathic agents may also leach out of the leaves or leaf litter to accumulate in the soil beneath.  These compounds effectively stunt the growth of plants and reduce or eliminate seed germination.'

They explain Allelopathy, as well.  'It ensures the limited moisture and nutrients available in the Soil are only capable of being used by the plant producing the allelopathic chemicals...?br>
Is there something else about your Soil that adds to this?  Remember, trouble always comes in 3's and we only have A and B up there.  Find out.  Get your Soil tested.  This is a basic maintenance procedure you should get out of the way once and for all, especially since you are having all kinds of trouble with this plot.  Find out what is in your Soil.  Then you'll know what ISN'T in it -- as far as Salt, Minerals and Cation Exchange Capacity.

Your gbest shot is going to be contacting either the previous owner(s) OR speaking with a neighbor who might have known what was going on in front of that house before you moved in.  And stop blaming the Zoysia.  It makes no Juglones, no Allelopathic chemicals, no Terpenes that would impede the establishment of a great big beautiful Tree.  If your HOA required a Tree way back when that was removed by the previous owners, its ghost may still be lurking underground, destroying all plant life several feet above.  Sorry, but you'll have to dig it up or encase it in cement, or nothing will ever make it there.  Not as long as the creature from the black lagoon is still decomposing.  And that could be decades from now.